DirectX5.0 Latest Game Programming Guide

xiaoxiao2021-03-06 49

Review

For numerous game makers, the launch of Microsoft's DirectX 5 is not an excellent news. It contains the preparation of next-generation computer games and multimedia applications

The latest technologies and tools provide a wide range of application interface APIs to make programmers to design high-performance real-time applications. DirectX makes running in Microsoft

The game under the Windows operating system is better interactive than the game running under the MS-DOS operating system, even more than the dedicated gaming machine.

The primary purpose of Microsoft Development DirectX is to improve the easiness of game development in the Windows environment. Prior to this, most of the games on your computer are based on MS-DOS.

The game developers must prepare different programs for different hardware interface cards, although the code is similar, but it is inevitably there are many repetitive labor. Use DirectX, game development

Personnel can get the advantages of DirectX hardware independence, while also accessing hardware directly. The most important goal of DirectX is to provide direct hardware access directly in MS-DOS.

Sex, simultaneously remove the hardware identification issues brought by adding new hardware in your computer.

Because the hardware upgrade is inevitable, DirectX actually provides another method for plugging. Therefore, using DirectX can develop high performance real-time

Using the program, you can directly access hardware in the computer and the hardware devices in the future system. DirectX provides a consistent interface between hardware and applications to reduce installation and configuration

Complexity and the utilization of hardware reaches optimal. With interface provided by DirectX, programmers can take advantage of hardware features without considering their specific details. An excellent basis

Windows's high-performance games should be able to use the system as follows:

Accelerated acceleration card for improved performance

Plug and play PNP (PLUG AND PLAY)

Communication service embedded in Windows, including Directplay

DirectX 5 includes seven parts, which are described below with a brief description.

(1) .directDraw By supporting the hardware and hardware acceleration technology of the memory in the middle of the memory, it is quickly accessed, and the bit block transmission and buffer flip function of the hardware is quickly directly accessed by supporting the access screen.

(2) .directSound provides a hardware and software sound mixing and recording and reproducing.

(3) .directPlay makes the game more simple and convenient to the connection between the modem and the network.

(4) .direct3D provides a high-level retention mode interface and aimediate-mode interface. The former allows the program to be easily completed

The full 3D graphics system, the latter makes the program fully controlled the colored pipe.

.DirectInput provides an API and driver based on Windows game-based input, not only supports current keyboard, mouse, and joystick, but also supports future Windows-based

input device.

.DirectSetup provides a disposable installation process for DirectX.

(7) .autoplay It is the feature of Windows 95, when you put the disc in the optical drive, it automatically runs the installer or game. In fact, AutoPlay is also Microsoft Win32

Part of the API, not only in DirectX SDK. .

By querying various DirectX object interfaces, you can detect which version of DirectX is installed in the system, in the DirectX SDK in GetDxversion.cpp

The getDxversion function can complete this task. This function creates some key DirectX objects - a DirectDraw object, a DirectDrawSurface object and one

DirectInput object - to detect the version of DirectX installed in the system. If the old version of DirectX SDK is installed in the system, you must make sure not to include its Include and Lib path, using the DirectX 5 header compiled code with the DirectX 3 library link will appear unpredictable errors.

Because C languages are more directly accessible to computer hardware, DirectX uses C languages as the development of the main language. And DirectX is also specifically for Visual C

Designed, write DirectX programs can be made under Visual C . Of course, Borland C 5.0 is no problem, just configuring some differences, the following will mention this question.

question. In order to reduce the difficulty of programming, some companies also develop controls running in different programming environments for DirectX, such as Arakelian Soft's ActiveX control Directstudio98

For Visual Basic 5.0, Tegosoft's Tegosoft ActiveX for Visual Basic, and John Pullen, PAUL Bearne and Jeff Kurtz development running under Delphi

Delphi Games Creator et al. Considering compatibility issues, it is best to use Visual C .

First, DirectX and Parts Object Model COM

1.1, component object model COM (Component Object Model)

Most of the APIs in DirectX consists of COM-based objects and interfaces. COM is the foundation based on object-based system, which is the core model of COM programming.

It is also an interface specification. At the operating system level, it is another object model.

Many DirectX APIs are created as an instance of a COM object. You can see an object as a black box, the object communicate with the object through the interface, send it to the pair through the COM interface.

A command received from an object is called a method. For example, the iDirectdraw2 :: getDisplayMode method is to get the current display from the DirectDraw object via the iDirectDraw2 interface.

formula. Objects can be bundled with other objects at runtime and can use the interfaces of these objects. If you already know an object is a COM object, and you know the object support

The interface, your application or other objects can determine the service that the first object can perform. One way to inherit all COM objects is the query interface method, which makes you indeed

Set an interface supported by an object and create a pointer to these interfaces.

1.2, iUnknown interface

All COM interfaces are derived from a interface called IUNKNOWN, which provides DirectX's control and operational multi-interface capabilities for object survival. Iunknown

Contains three methods:

.AddRef When an interface or another application is bundled up to an object, use the AddRef method to add the index value of the object to 1.

.QueryInterface is queried by the characteristics supported by pointer to a specific interface.

.Release reduces the index value of the object, which is released from memory when the index value is 0.

The addRef and the release method are responsible for maintaining the index value of the object. For example, if you create a DirectDrawSurface object, the index value of the object is set to 1, each

When there is a function returns a pointer to the object, the function must be added to the index value of the object by returning a pin. Every addRef is called

A Release call corresponds to it. When the index value of the object reaches 0, the object is revoked, and all interfaces of the object are not reused.

QueryInterface method Determines whether an object supports the specified interface, if support, QueryInterface returns a pointer to the interface. Then you can use the method to communicate with the object. If QueryInterface successfully returns a pointer to the interface, it automatically invokes the AddRef method to increase the index value of the object. Before the interpuls of the interface pointer

Call the Release to reduce the index value of the object.

1.3, DirectX COM interface

The interface in DirectX is created with considerable basic COM programming. Each interface characterized by the object of the device is derived from the IUNKNOWN COM interface, such as IDirectDraw2,

IdirectSound and IDirectPlay are like this. The creation of the basic object is handled by the special function in the dynamic link library DLL.

Typically, the DirectX object model provides a primary object for each device. Other support services are derived from the primary object. For example, DirectDraw objects

The display adapter is displayed. You can use DirectDraw to create DirectDrawSurface objects that represent memory and behave the DirectDrawPalette object that characterizes the hardware palette. same

The truth, the DirectSound object characterizes the audio card and uses it creates the DirectSoundBuffer object that represents the sound source.

In addition to enabling sub-objects, the main object of the device can also determine the performance of the device it characterizes, such as the size of the screen and the number of colors, whether the sound card supports wave form synthesis.

1.4, C and COM interface

For C programmers, the COM interface is like an abstract base class. In the base class of C , all methods are defined as pure, which means no code is the same.

Related together. The purely virtual C function and the COM interface use a device called a virtual table (VTABLE). A virtual table contains a declaration for all functions applied to the interface. in case

You want programs or objects to use these functions, you can check the interface where the object exists with the queryinterface method, get the pointer of the interface, call QueryInterface, apply or

The pointer to the virtual table is actually received from the object, and all interface methods applied to the object can be invoked by the pointer.

Another similarity of COM objects and C is the first parameter of the method is the name of the interface or class, and C is called this parameter. Because COM objects and C objects are complete

Binary compatibility, the compiler is equipped with the COM interface as the C abstraction class, and has the same syntax, which makes the code simple.

1.5, get a new interface

The component object model is not a function of updating the object by changing a new interface containing new features by changing the existing interface. Situation in the existing interface status

Next, the COM object is free to expand the service and maintains the same old application compatibility. DirectX components follow this principle, for example, DirectDraw parts support iDirectdrawsurface interface

Three versions: iDirectdrawsurface, IDirectdrawsurface2 and iDirectdrawsurface3. To use the features provided by the new interface, you must call the object

IUNKNOWN :: QueryInterface method, specify the global unified identity of the interface to get to get the GUID (Global Unique Identifier). The GUID of the interface is declared in the relevant header file.

The following example shows how to query a new interface:

LPDIRECTDRAW LPDD1;

LPDIRECTDRAW2 LPDD2;

DDRVAL = DirectDrawCreate (NULL, & LPDD1, NULL);

IF (Failed (DDRVAL)) Goto Errorout;

// query for the iDirectdraw2 interface

DDRVAL = LPDD1-> query interface (IID_IDIRECTDRAW2, (Void **) & lpdd2);

IF (Failed (DDRVAL))

Goto errorout;

// now That We Have An IDirectDraw2, Release The Original Interface

LPDD1-> Release ();

The new interface does not support the method provided by the previous version of the interface, and the IDirect3ddevice2 interface is just such an interface. If your application requires an earlier version

The features provided by the interface you can use the GUID of the old interface, use the above-described routine to query the interface.

1.6, access COM object with C

Any COM interface method can also be called using the C language. Calling an interface method with C language requires main two things:

The first parameter of the method is always the object (ie this) that has been created.

Each method in the interface is referenced by a pointer to the object.

The following example uses the C language to create a surface that is associated with the same DirectDraw object using CreateSurFace method:

RET = LPDD-> LPVTBL-> CreateSurface (LPDD, & DDSD, & LPDDS,

NULL);

Where the LPDD parameter is the DirectDraw object associated with the new surface, and the method fills a structure & DDSD that describes the surface (SURFACE), returning to the new interface & lpdds

Pointer. Call the IDirectDraw2 :: createSurFace method, first point to the virtual table of the DirectDRAW object, then get the method in the virtual table. The first parameter provided in the method

It is an index of the DirectDraw object that has been created. The following code illustrates the differences between C and C to COM object method calls:

Ret = LPDD-> CreateSurface (& DDSD, & LPDDS, NULL)

Second, the new content in DirectX 5

Everyone knows that DirectX 5 is the latest version of DirectX. Before this, Microsoft has released DirectX, DirectX2, DirectX3 (without DirectX4). Obviously, DirectX

5 provides more features and services than DirectX3, but the programs written by DirectX3 API can be successfully compiled and running without modification. Below is DirectX5 and DirectX3

The main difference:

2.1, DirectDraw

DirectDraw extends new video port capabilities, allowing applications to control data streams from the hardware video port to the DirectDRAW surface in memory. In addition, DirectDraw

Hardware Simulation Layer Hel (Hardware Emulation Layer) can use the acceleration performance provided by the Pentium MMX processor. DirectDraw detects when you first create a surface

The processor is the MMX processor, on the non-Pepsc processor's computer, the test will cause the debugger to report an event, which does not affect the performance and stability of the program.

DirectDraw supports a wide-screen surface (OFF-Screen Surface) than the primary surface, as long as the hardware allows, you can create a sufficiently wide surface.

DirectDRAW supports the Advanced Graphics Port feature. In an AGP device system, you can create a surface in a non-local display memory. DDSCAPS Structure Support Standard (Local) Display Memory and AGP (Non-Local) Display Memory Different Signs. DirectDRAW can transmit DDCAPS structures to non-local display block blocks

Member information.

2.2, DirectPlay

DirectPlay contains a new interface IDirectPlay3, other than iDirectPlay2 except for new methods. Similarly, IDirectPlayLobby2 is also

The upgrade version of IDirectPlayLobby. Directplay's new features include the ability to hide the service provider (Service Provider) by creating connection shortcuts,

Hold the list of updates available sessions, apply the setSessionDesc method to better support password protection sessions, support confidential service connections and use CoCreateInstance to create multiple

DirectPlay object.

2.3, DirectSound

DirectSound contains a new interface IKSPROPERTYSET that supports extended services provided by the sound card and related drivers. COM-based function DirectSOUNDCAPTURE

Also new, it can access the driver directly.

2.4, Direct3D

Direct3D instant mode (IMMEDIATE MODE) now supports Drawing Primitive without having to work directly in the buffer. Direct3D Reserved Mode (Retained Mode)

Support interpolation allows you to adjust colors, smoothly moving objects, deformed grids, and perform many other transformations. The retention mode also supports progressive grid, that is, allow you to start starting with a thickness.

Rough grid and then refine it.

5, DirectInput

DirectInput provides a COM interface of the joystick, and also provides a COM interface of a keyboard and a mouse equivalent feedback device.

6, DirectSetup

DirectSetup now contains more user interface customization capabilities, which is provided by a callback function. This backup function passes the current installation status to the installer, you can

Use this information by customized user interface to display the installation status. In addition, DirectSetup provides a number of players' games, in the game, players can use

DirectPlayLobby removes registration information from the registry.

6. AutoPlay AutoPlay is the same as DirectX3, not changed.

DirectX5.0 Latest Game Programming Guide

DirectDraw articles

DirectDraw is one of the main parts of the DirectX SDK, which allows you to display memory operations directly, support hardware bit block transfer, hardware coverage, surface flipping, and maintain a look

The front Windows-based application and driver are compatible.

DirectDraw is a software interface that keeps also compatible with Windows Graphics Device Interface in addition to the display device access.

For graphics, it is not an advanced application interface. DirectDRAW provides a method-free approilt that makes Windows-based applications and games (for example

3D graphics software package and digital video games) can directly obtain the characteristics of the display device.

DirectDraw can work in a wide variety of display devices, from simple SVGA displays to advanced display devices that provide shear, stretching, and non-RGB formats. DirectDraw

The interface allows your application to simulate the performance of basic hardware and use hardware acceleration features; hardware does not provide features will be simulated by DirectX. DirectDraw provides access to devices that display memory that makes you easily manage display memory. Your application only needs to identify some basic device properties, they are all standard hardware applications, such as RGB

And the color of the YUV format. You don't need to call special procedures to use bit blocks to transfer or manipulate palette registers. With DirectDraw, you can easily display memory, charge

Dividing the bit block transmission and color decompression function of different types of display devices without the need to rely on specific hardware. DirectDraw can run in Windows95 / NT4.0 and later versions

in.

DirectDraw's hardware abstraction layer HAL (Hardware Abstract Layer) provides a unified interface, through which program can be directly displayed memory or video memory

Work, get the best performance of hardware.

DirectDraw estimates the performance of video hardware, as long as you may use the specific performance provided by the hardware. For example, if the video card supports bit block transmission, DirectDraw will put

The bit block transmission is delegated to the video card, the CPU does not participate in the processing of bit block transmission, which greatly improves the performance of the program. In addition, DirectDraw provides hardware simulation layer HEL (Hardware

Emulation Layer allows software simulation to support the characteristics that should be provided by these hardware when some hardware does not exist.

DirectDraw runs on Windows 95, which can utilize 32-bit memory superiority and "flat" memory models provided by the operating system. DirectDraw will system memory and video

It is used as a large block storage rather than a small segment. In addition, DirectDraw also brought a lot of power for Windows graphics:

.DirectDraw makes the page turnover of multiple background buffers in full screen mode easy

Support window mode and cutting function in full screen mode

. Support 3D Z buffer

Hardware auxiliary coverage in support Z direction

. Access to hardware for image stretching

Access standard and enhanced display device memory area

Dynamic palette, exclusive hardware access, resolution switch, etc.

Combine these features together, you can easily prepare a game that exceeds GDI-based standard Windows games or even MS-DOS.

First, DirectDraw's basic image concept

DirectDraw offers a set of graphical terms that are different from GDI, so it is necessary to use DirectDraw, first you should understand the concepts. Here are the medium of DirectDraw

An introduction to the concept.

1.1 Device independent bitmap DIB (device-independent bitmap)

DirectX uses device-independent bitmap Dib as the primary graphic file format. A DIB file mainly protects the following information: the dimension of the image, the number of colors used, described

Color value and data describing each pixel. The DIB file also protects less use parameters, like information about file compression, and physical dimension of the image. DIB file extension is general

Yes ".bmp", sometimes it may be ".dib".

Because DIB is extremely widely used in Windows programming, DirectX SDK already contains many related functions. For example, DDUTIL.CPP files provided by DirectX SDK

There is a function that combines the Win32 and DirectX functions, the concept is to load a DIB file into the DirectX surface, the code is as follows:

Extern "C" iDirectdrawsurface * DDLoadBitmap (iDirectdraw * PDD,

LPCSTR SZBITMAP, INT DX, INT DY

{

Hbitmap HBM;

Bitmap BM; DDSURFACEDESC DDSD;

IDirectdrawsurface * pdds;

// this is the win32 part.

// Try to load the bitmap as a resource, if That Fails, TRY IT as a file.

HBM = (hbitmap) loading (getModuleHandle (NULL), SZBITMAP, Image_bitmap, DX, DY, LR_CREATEDIBSECTION;

IF (hbm == null)

HBM = (Hbitmap) loadImage (NULL, SZBITMAP, Image_bitmap, DX, DY, LR_LOADFROMFILE | LR_CREATEDIBSECTION);

IF (hbm == null)

Return NULL;

// Get the size of the bitmap.

GetObject (HBM, SIZEOF (BM), & BM);

// Now, return to DirectX Function Calls.

// Create a DirectDrawSurface for this bitmap.

ZeromeMory (& DDSD, SIZEOF (DDSD));

Ddsd.dwsize = sizeof (ddsd);

DDSD.DWFLAGS = DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH;

DDSD.DDSCAPS.DWCAPS = DDSCAPS_OFFSCREENPLAIN

Ddsd.dwwidth = bm.bmwidth;

DDSD.DWHEIGHT = BM.BMHEIGHT;

IF (PDD-> CreateSurface (& DDSD, & PDDS, NULL)! = DD_OK)

Return NULL;

DDCopyBitmap (PDDS, HBM, 0, 0, 0, 0);

DeleteObject (HBM);

Return PDDS;

}

1.2, drawing surface (Drawing Surface)

The drawing surface accepts video data and displays it as an image. In most Windows applications, you can use the Win32 function such as getDC to access the drawing table.

surface. GETDC Getting the Device Context DC (Device Context), after obtaining the device, you can redraw the surface. However, the image function of Win32 is provided by GDI.

GDI is part of the system that provides an abstract layer that allows the standard Windows program to draw surfaces.

The disadvantage of GDI is that it is not designed for high-performance multimedia software, which is mainly used for commercial software such as word processing and spreadsheet software. GDI provides videos in system memory

Access to the buffer, but do not provide access to video memory. Although GDI is very suitable for most commercial software, it is too slow to multimedia applications and game software.

On the other hand, DirectDraw provides a drawing surface that characterizes real video memory, which means that when you use DirectDraw, you can write data directly to the video, so that

The display speed of the image is fast enough. These surfaces are characterized as a continuous memory block that makes it easier to address addresses.

1.3, bit block transmission blit

Blit is a story of "Bit Block Transfer", indicating bit block transmission. It is a way to transmit a data of one address in memory to another address. Block transmission is often used

In the elf animation. You can use the iDirectdrawsurface3 :: BLT method and the iDirectdrawsurface3 :: Bltfast method to perform bit block transmission. 1.4, Page Flipping and Back Buffering

Page flips is the key to multimedia, animation, game software. The software page flip is an simulation of cartoon painters to motion image motion. For example, the painter draws a character on a piece of paper.

Then placed it in the working state of the next frame, and only the character image is changed for each frame. When you quickly flip the sheet of paper, the continuous character image seems to have an animation.

The page flips in the software is similar to the above process. First, you have established a series of DirectDraw surfaces, which are ready to "flip" to the screen. The first surface is seen

It is the primary surface, which is called a background buffer after all surfaces behind the main surface. The application writes data to the background buffer, then flip the main surface, so the background is slow

The punch is displayed on the side. When the system is displaying an image, the program can write data to the background buffer, which has continued until the end of the animation, which makes you fast and efficiently

Change the discrete image into an animation. DirectDRAW can utilize relatively simple double buffers (a main surface and a background buffer), you can also use more complex technologies.

Other background buffers. Make you can easily create a program that flipped.

1.5, rectangle

One of the most important concepts that run through DirectDraw and Windows is the object on the surface - a bounded rectangle. A bounded rectangle is determined by two points, namely the upper left corner and the right

angle. When writing data in a block transmission, most applications use the RECT structure to transmit information about the boundary rectangle. The RECT structure is defined as follows:

Typedef struct tagRect {

LONG LEFT; // this is the top-left corner's x-coordinate.

Long Top; // The top-left corner's y-coordinate.

Long Right; // The Bottom-Right Corner's X-Coordinate.

Long bottom; // the bottom-right corner's y-coordinate.

} Rect, * Prect, Near * nPRECT, FAR * LPRECT

Where the LEFT and TOP member variables are the value of the X, Y coordinate of the upper left corner of the rectangle, and Right and Bottom are the coordinate values of X, Y in the lower right corner.

1.6, Elf (Sprite)

Many video games use the elves. In the most basic sense, a wizy is an image that moves on the screen. The elves draw on a surface and covered on an existing background.

The synthetic image is sent to the screen.

1.6.1, Transparent Blitting and Color Key

The difficulty in the elf animation is the treatment of the elves of non-standard rectangles. Because the bit block transport function is working in a rectangular mode, your elf must be placed in a rectangle, not

Tube it is rectangular on the screen.

The elf image itself is not a rectangular, but it is included in the rectangular area. When the image is transferred to the destination when using the bit block to the destination, the pixels that do not belong to the elves are "transparent".

deal with. The programmer selects any color to create a wizard, which is used as a transparency "color key". It is an uncommon color, and the programmer is only used to indicate

Brightness or specific color range.

With the idirectdrawsurface3 :: setColorKey method, you can set the Color Key for a surface. After setting the Color Key, call the idirectdrawsurface3 :: bltfast method to use the set of Color Key, regardless of whether the pixel matches the color key. This type of Color Key is the source Color Key. Source Color Key prohibits "transparent"

The pixel is written to the destination, so that the original background pixel is retained, making the elf look up and the wizard can also move on the background.

In addition, you can also use a Color Key to influence the surface of the target (the purpose of the purpose of the purpose). Destination Color Key is also a color on the surface, which is used to indicate whether pixels are

Can be covered by the elves.

1.6.2, Sprite and Patch Rectangle (SPRITE AND PATCHLE)

In order to produce the effect of the elf movement, you must erase the elf image from the old position from the background before drawing the elf to the new location. Of course, you can also re-transfer the entire background

Heavy attention to the elves, but this will greatly reduce the quality of animation. In fact, you can keep the last trajectory of the elongated rectangle, and then redraw only the location. This method is called "patching".

In order to fix the outstanding position, you can use the original background image (already transferred to a screen outside the surface) to redraw this location. Block transmission is used in this process

Methods, in the cycle of the entire surface, it is necessary to consume very small processing time. Below is a simple step of this process:

(1). Setting the repair rectangle of the first position of the elf

(2). Use the bit block to transfer the primary copy of the background image in the outer surface of the screen to this position

(3). Update wizard is a rectangle of destination, which reflects the new position of the elf

(4). Transfer the wizard block to the latest updated rectangular position on the background

(5). Repeat

Combine the powerful image features provided by DirectDraw with a linear C / C program, using the above steps, you can create a simple elf animation.

1.6.3, boundary check and collision detection (Bounds Checking and Hit Detection)

In the elf animation, boundary inspection and collision detection is two very workshop and a very important task. The boundary is the scope of the restrictions, and the boundary check is through the RECT structure.

To check the location of the elves, determine if the wizel exceeds a defined range.

Collision detection is to check if multiple elves take up the same location. Most collision detection is to check if there is a coverage between the rectangles of each elf.

Second, the system of DirectDraw

Multimedia software requires high performance image. Through DirectDraw, Microsoft makes programs that are sensitive to image sensitivity are greatly improved in GDI,

At the same time, it maintains the device-independent, and the tools provided by DirectDraw can complete the following key tasks:

. Operation multiple display surfaces

Direct access to video memory

Page flip

Background buffer

Palette management

Shear

In addition, DirectDraw allows you to query the performance of the display of the hardware and then provide the optimal performance that the display device can support.

DirectDraw provides a COM-based service interface, using the most used iDirectdraw2, idirectdrawsurface3, idirectdrawpalette, idirectddrawclipper, and

IdirectDrawvideOport. In addition to these interfaces, DirectDraw continues to support previous versions of interfaces.

The DirectDRAW object is characterized to display the adapter, reveal its method through the iDirectdraw and the iDirectDraw2 interface. In most cases, you can use DirectDrawCreate

Function to create a DirectDraw object or use COM functions CocreateInstance.

Once you have created a DirectDraw object, you can call the IDirectDraw2 :: createSurface method to create a surface for that object. The surface characterizes the memory of the display hardware, which can be a video

Memory can also be system memory. DirectDraw expands support for palette, shear, and video ports through other interfaces.

1, DirectDraw object type

DirectDraw objects can be either a separate object or a combination of several objects. The latest version of DirectDRAW has the following types of objects:

1.1, DirectDRAW object

The DirectDraw object is the core of the DirectDraw application, which is the first object you created. Once you have created a DirectDraw object, you can create other sites on it.

Have related objects. Creating a DirectDraw object is DirectDrawCreate.

1.2, DirectDrawSurface object

The DirectDrawSurface object characterizes a memory area where data is displayed as an image on the screen or moves to other surfaces. Create DirectDrawSurface

The object's approach is iDirectdraw2 :: createSurface, other related methods can pass interface IDirectdrawsurface, IDirectdrawsurface2 and iDirectdrawsurface3

1.3, DirectDrawPalette object

DirectDrawPalette object (sometimes "Palette") characterizes a 16-color or 256 colored index palette that is surface, which contains a series of descriptions of the same surface.

Off RGB color index value. The method for creating a DirectDrawPalette object is iDirectdraw2 :: CreatePalette. Other methods can be obtained from the interface IDirectDrawPalette.

1.4, DirectDrawClipper object

DirectDrawClipper objects (sometimes "clipper") helps you write data to a location or exceeding the surface, create DirectDrawClipper

The method is iDirectdraw2 :: CreateClipper, and other related methods can be obtained from Interface IdirectDrawClipper.

1.5, DirectDrawVideoPort object

The DirectDrawVideoPort object characterizes some of the video port hardware with only one system, which allows you to access the frame buffer without accessing the CPU or using the PCI bus.

You can first specify the IDDVIDEOPORTCONTAINER flag, then call the QueryInterface method to create a DirectDrawVideoPort object. Other related methods can be from interface

IddvideoPortContainer is available in IdirectDrawVideoPort.

2, hardware abstraction layer HAL (Hardware Abstract Layer)

DirectDraw provides devices independence through hardware abstraction layer HAL. HAL is a special equipment interface and is provided by equipment manufacturers. DirectDraw uses HAL direct

Work on the display device. Applications and different HAL interactions. Equipment manufacturer provides HAL in the form of 16 or 32-bit code under Windows95, under WindowsNT,

HAL is 32-bit code. HAL can be part of the display driver, or a dynamic link DLL that displays the driver communication with the private interface defined by the manufacturer.

DirectDraw HAL is provided by a chip, a board or OEM (Original Equipment Manufacture). HAL only provides device-related code, not simulated when executed. If one is

The function is not supported by hardware, and HAL will not treat this function as part of hardware performance. In addition, HAL does not confirm the parameters, and DirectDRAW will work in the call to complete the parameters prior to calling HAL.

3. Software emulation

When hardware HAL does not support a feature, DirectDraw is trying to simulate this feature with software. The simulation function is Hardware-Emulation Layer by hardware simulation layer.

which provided. Obviously, software simulation is not equivalent to the characteristics of hardware itself. You can use the iDirectdraw2 :: getCaps method to query the features supported by the hardware.

Sometimes, the inherent characteristics of hardware and the combination of both software simulation are slower than the software simulation alone. For example, if the display device driver supports DirectDraw but not

Write the way to write the block, when stretched from the video memory surface or the bit block transmission, it will produce a loss of performance. Because video memory is usually slower than the speed of the system memory, in the access video memory

The CPU must wait. Therefore, if your application uses hardware unable to provide features, it is best to create a surface in system memory to avoid CPU access video memory.

Performance loss.

4, system composition (System Integration)

The following figure shows the relationship between DirectDraw, graphics device interface GDI, hardware abstraction layer HAL, hardware simulation layer HEL, and hardware.

As shown in the figure, a DirectDRAW object is a parallel relationship with GDI, both through the device-related abstract layer access hardware. Different from GDI, DirectDraw as long as it is possible

It will make full use of the unique features provided by hardware. If the hardware does not support a feature, DirectDraw will try to simulate it with HEL. DirectDraw can also use the device context (Device

The Context is available in the form of surface memory, which you can use the GDI function to process surface objects.

Third, DirectDraw elements

The most basic elements in DirectDraw include collaboration level, display mode, DirectDraw object, surface, palette, cutting board, etc., the following is introduced one by one.

1, collaborative level (Cooperative Level)

Collaboration Level describes how DirectDRAW is interactive and the events that may affect the display. You can use the iDirectdraw2 :: setCoopeRarativeElevel method

Set collaboration level. In most cases, you can use the collaboration level to determine if the application runs in exclusive full screen mode or window mode. DirectDraw collaboration also has

The following role:

Make DirectDRAW to use X mode (Mode X) resolution.

If the user presses Ctrl Alt Del, the DirectDraw is prohibited from release the exclusive control and restart of the display (only in exclusive mode).

Make DirectDRAW to maximize and minimize events to respond to activated events.

The standard collaboration level indicates that the DirectDRAW program is a window application. In this case, you cannot change the palette and execution page of the main surface. In addition, you are still not

You can call those methods that have high degree of impact on display or video memory, such as IDirectDraw2 :: Compact.

Under the full-screen exclusive collaboration, you can use all of the hardware, set the usual palette and dynamic palette, change the display resolution, compact memory, and page flip. Full screen

The model does not prohibit other application allocation surfaces, nor does it prohibit them from using DirectDraw and GDI, but prohibiting other development applications changing display resolution and palette.

Because the application can use DirectDraw at multi-window, when the application requires work in DDSCL_NORMAL mode, the iDirectDraw2 :: setCoopeRATIVELEVELEVELEVELEVELEVELEVELE Way does not require a specified window handle. Pass NULL to the window handle, all of which work simultaneously in standard window mode.

2, display mode (Display Modes)

The display mode is a description of the size and bit-depth of the image that the display hardware is transmitted from the main surface to the display. The display mode can be combined to: width, high and bit depth. example

For example, most display adapters can display a wide range of 640 pixels, 480 pixels, and a data image of 8 bits per pixel, which is 640x480x256.

To get a larger resolution or bit depth, you need more display memory.

There are two types of display mode: color mode and non-torch mode. For toning display modes, each pixel is a pointing value pointing to the correlation palette. Display mode depth

The number of colors that can have in the palette is determined. For example, for an 8-bit color display mode, each pixel is a value from 0 to 255. In this display mode, the palette

Can contain 256 colors. The non-toning display mode does not use a palette, the bit depth in this mode indicates the total number of bits used to describe a pixel.

Any surfaces in the main surface and the main flush chain should be matched with the size, bit depth of the display mode, the bit depth, and pixel format.

2.1, detect the supported display mode

Because the display hardware is displayed, not all devices support all display modes. To detect the display mode supported by the system, you need to call

IDirectdraw2 :: EnumdisplayModes method. By setting the appropriate value and flag, the IDirectdraw2 :: EnumDisplayModes method can list all supported display mode,

Can also determine if a specified display mode is supported.

The first parameter DWFLAGS control method of the method controls the other options, usually set DWFLAGS to 0 to ignore other options; the second parameter LPDDSurfaceDesc is used

To describe the address of the structure DDSurfaceDesc to which the display mode is given, all modes can be set to NULL. The third parameter lpContext is a pointer.

DirectDRAW needs to pass the pointer to the callback function, if there is no additional data in the callback function, it can be set to NULL. The last parameter is

LpenumModesCallback, it is the address of the callback function called for each supported display mode call.

The callback function provided when calling the IDirectDraw2 :: EnumDisplayModes method must match the prototype of the EnumModesCallback function. For each of the hardware

The display mode, DirectDRAW calls your callback function to pass two parameters, the first is the address of the DDSurfaceDesc structure, which describes a supported display mode;

The second parameter is the address of the application defined when calling idirectdraw2 :: enumdisplayModes.

By checking the value of the DDSurfaceDesc structure to get the display mode it described, where the key members are dwwidth, dwheight, and DDPFPixElFormat. DWWIDTH

And dwheight describes the size of the display mode; DDPFPixElFormat is a DDPixElFormat structure that contains information about the depth of bit.

The DDPixelformat structure includes information describing the display mode bit depth and indicates whether the display mode uses a palette. If the dwflags member contains

DDPF_PALETTEINDEXED1, DDPF_PALETTEINDEXED2, DDPF_PALETTEINDEXED4 or DDPF_PALETTEINDEXED4 or DDPF_PALETTEINDEXED8 logo, the bit depth of the display mode is 1, 2, 4 or 8, and each pixel is an index of a phased palette. If dwflags contains a DDPF_RGB flag, the display mode is non-toner.

Display mode, and its bit depth is provided by DwrGbbitCount members in the DDPixelformat structure.

2.2, set display mode

You can call the iDirectdraw2 :: setDisplayMode method to set the display mode. This method accepts four parameters to set the size, bit depth and refresh of the resolution of the display mode.

rate. It uses the fifth parameters to specify a special option for a given mode, which is currently only used in 13 mode and X mode 320x200x8.

You can specify the bit depth of the desired display mode, but you cannot specify a pixel format that displays the hardware for the depth of the bit. To detect the RGB bit for display hardware for the current position depth

Shield, you can call the IDirectDraw2 :: getDisplayMode method after setting the display mode. If the current display mode is non-toning mode, you can check DWRbitmask,

DwGbitmask and the value in dwbbitmask get the positive red, green, and blue color position.

You can also change the display mode through multiple applications, as long as they share the same display card. You can also change the depth of the position, as long as the application can discuss DirectDraw exclusive

Objects, all DirectDrawSurface objects release surface memory after the display mode changes, so after changing the display mode, you must use iDirectdrawsurface3 :: Restore

The method is re-assigned to the object.

2.3, recovery display mode

If the display mode is done by calling the IDirectDraw2 :: SetDisplayMode method (not the iDirectdraw :: setDisplayMode method), you can call

IDirectdraw2 :: RestoredISplayMode method to restore to its original display mode. If the application is a single collaborative level, when you set the application's collaboration level

When the display mode is automatically restored to the original mode. If you use the DirectDraw interface, you must explicitly recover the display mode.

2.4, x mode and 13 mode

DirectDraw supports x mode and 13 mode two types of display modes. 13 mode is 320x200, each pixel is 8-bit color mode, and its 16-encycloped BIOS mode number is 13. mode

X is a mixed mode derived from a standard VGA 13 mode that allows the use of 256 KB display memory (13 mode only allows the use of the display memory).

Under Windows95, DirectDraw provides two X modes for all display cards (320x200x8 and 320x240x8). Some display cards also support linear low resolution mode,

Linear low resolution is silently up and down, the main surface can be locked or directly accessed, which is not allowed in x mode.

Just use DDSCL_AllowModex, DDSCL_FULLSCREEN, and DDSCL_FULLSCREEN and

DDSCL_EXCLUSIVE flags, X mode is available. If you do not specify a DDSCL_AllowModex flag, iDirectdraw2 :: EnumdisplayModes method is not

List the X mode, when requesting the x mode, the call to the idirectdraw2 :: setDisplayMode method will fail.

When the application does not use the idirectdrawsurface3 :: locksurface3 :: locksurface3 :: lock or idirectdrawsurface3 :: bLT method, write data to the main surface block, or you cannot use the idirectdrawsurface3 :: getDC method in the main surface or screen DC. X mode is specified by the DDSCAPS_MODEX flag in the DDSCAPS scapula, DDSCAPS

The structure is part of the DDSurfaceDesc structure returned by idirectdrawsurface3 :: getCaps and iDirectdraw2 :: EnumdisplayModes method.

2.5, high resolution and true color

DirectDraw supports all screen resolutions and bit depths supported by the display device driver. DirectDraw allows applications to change display mode to any computer display

The driver supported display mode, including 24-bit and 32-bit (true color) mode.

DirectDraw also supports the HEL block transmission of true color surfaces. If the display device driver supports bit block transmission at these resolutions, the memory - display memory bit block

Transfer will use hardware blocks, otherwise heel will use HEL to increase the performance of bit block transmission.

Windows95 and NT allow you to specify the type of display that is being used. DirectDraw checks a list of known display modes, if DirectDRAW detects the required mode

This monitor is not compatible, and the call to the idirectdraw2 :: setDisplayMode method will fail. When you call Method Idirectdraw2 :: EnumdisplayModes, only the display

The supported mode will be listed.

3, DirectDRAW object

The DirectDraw object is the core of all DirectDraw applications, as well as an organic component of the Direct3D application. DirectDraw object is the first one you created

Objects, create other related objects by this object. Generally create a DirectDraw object by calling the DirectDrawCreate function, the function returns an IDirectDraw connection

mouth.

DirectDraw objects characterize the display device. If the display device supports hardware acceleration, the DirectDRAW object can also utilize hardware acceleration. Every DirectDraw

Objects can process display devices and create surface objects, palette objects, palette objects, and clipboard objects that depend on the DirectDRAW object. For example, create a surface that needs to be called

IDirectDraw2 :: CreateSurface method, to attach a palette object on the surface, you need to call the IDirectDraw2 :: CreatePalette method. In addition, iDirectDraw2 is connected

The mouth also contains a similar method for creating a shear board object.

You can create multiple instances of a DirectDRAW object at the same time. The easiest example is the use of dual displays in a Windows95 system. Although Windows95 does not support more

The display is possible to write a DirectDraw hardware abstraction layer for each display device. Windows95 and GDI can identify display devices in creating default DirectDraw objects

The instance will be used. The display devices that Windows95 and GDI cannot be identified can be characterized by another independent DirectDRAW object. The object must use the second display device.

The Unified Identifier is created, and this GUID can be obtained by the function DirectDrawenumeRate.

DirectDRAW objects manages all other objects it created. It controls the default palette, Color Key, and hardware display mode, which also has allocated resources and retained resources

Make a marker.

The new version of DirectDraw adds new content in previous versions. The IDIRECTDRAW2 interface is increasing the IDIRECTDRAW2 :: GetAvailableVidmem method

The iDirectDRAW interface is expanded. This method allows you to query the display device's total available video memory and how much memory is used for one specified surface. IdirectDraw2 :: SetCoopeLevel method The interaction between IDirectdraw2 :: SetDisplayMode is different from these methods in the iDirectDRAW interface. If you should

Use the program

The iDirectDRAW interface sets the collaboration level of full-screen exclusive way and changing the display mode. When the standard collaboration level is returned, the display mode will not be automatically recovered, you must call

The iDirectdraw :: RestoredISplayMode method is explicitly recovered. If you use the IDirectDraw2 interface, the call to RestoreMode is not required. however

The iDirectdraw2 :: RestoredISplayMode method does not support explicitly recover the original display mode.

COM-based COM specifies that an object can provide new features by adding new interfaces without affecting its backward compatibility. So IdirectDraw2 interface can

Instead of the IDirectDRAW interface. The new interface can be obtained by iDirectdraw :: queryInterface method, as shown in the C code below:

// CREATE An IDirectDraw2 interface.

LPDIRECTDRAW LPDD;

LPDIRECTDRAW2 LPDD2;

DDRVAL = DirectDrawCreate (NULL, & LPDD, NULL);

IF (DDRVAL! = DD_OK)

Return;

DDRVAL = LPDD-> SetCooperativeElevel (hwnd,

DDSCL_NORMAL);

IF (DDRVAL! = DD_OK)

Return;

DDRVAL = LPDD-> QueryInterface (IID_IDIRECTDRAW2,

(Lpvoid *) & lpdd2);

IF (DDRVAL! = DD_OK)

Return;

A DirectDraw object is created in the example, then call the iUnknown :: queryinterface method for the iDirectDraw interface to create an IDirectDraw2 interface.

After getting an IDirectDraw2 interface, you can call its method to utilize the advantages of its new features. Because some methods may vary in the new version of the interface, so

Mixing using different versions of interfaces (such as IDirectDraw and iDirectDraw2) may result in unpredictable errors.

3.1, multiple DirectDRAW objects in each process

DirectDraw allows multiple DirectDrawCreate functions to be called multiple times in a process. Returns a unique independent independence every unique independent DirectDraw object after each call

Interface. Each DirectDRAW object can be used for the required relationship between the objects. Each object is like being created in the process alone.

DirectDrawSurface objects created by each DirectDraw object, DirectDrawPaletTe objects cannot be used by other DirectDraw pairs

Like use, because these objects are automatically undo when their parent target DirectDRAW objects are canceled.

The DirectDrawClipper object created using the DirectDrawCreateClipper function is an exception, and the DirectDrawClipper object in this case is independent of other arbitrary

DirectDRAW objects and can be used for one or more DirectDraw objects.

3.2, create a DirectDraw object with CoCreateInstance

You can also create a DirectDraw object using the CocreateInstance function and the iDirectDraw2 :: initialize method without using the DirectDrawCreate function. Below is the step of creating a DirectDraw object with a CoCreateInstance function:

i. Call Coinitialize initialization COM:

Failed (Coinitialize (NULL)))

Return False;

II. Create a DirectDraw object using the CocreateInstance function and iDirectdraw2 :: initialize method:

DDRVAL = CoCreateInstance (& clsid_directdraw,

NULL, CLSCTX_ALL, & IID_IDIRECTDRAW2, & LPDD);

IF (! failed (ddrval))

DDRVAL = iDirectdraw2_initialize (lpdd, null);

In the call to COCREATEINSTANCE, the first parameter CLSID_DIRECTDRAW is the class flag of the DirectDraw driver object class, and the IID_IDIRECTDRAW2 parameter is indicated.

The DirectDraw interface to create, the LPDD parameter points to the acquired DirectDraw object. If the call is successful, the function will return the DirectDRAW object that has been initially initialized.

Before using the DirectDraw object, you must also call the iDirectdraw2 :: initialize method, which does not use the GUID parameter (DirectDrawCreate function requires only as long as it is).

After the DirectDraw object is initialized, you can use it or release the object, just that the object is created by the DirectDrawCreate function. If you are calling

The approach to the IDirectdraw2 :: Initialize method will cause a DderR_notinitialized error.

Before closing the application, you should use the CounInitialize function to close the COM, the form is as follows:

Counitialize ();

4, surface (SURFACE)

A surface or DirectDrawSurface object characterizes a linear memory area. The surface usually resides in the display memory, and of course, it can also exist in system memory. Unless clear

Specify, DirectDraw places the DirectDrawSurface object where you can get the best performance when you create a DirectDrawSurface object. DirectDrawSurface object

It is also possible to use the special processor on the display card, which can not only speed up the execution speed of the task, but also to handle some tasks with the system CPU parallel.

With the iDirectdraw2 :: CreateSurface method, you can create a single surface object, a complex surface flip strand and a three-dimensional surface. Create your you want to use the CreateSurface method

Survey surface or flip chain and get a pointer to the IDirectdrawSurface interface of the main surface.

The IDirectDrawSurface3 interface allows you to access memory directly with bit block transmission methods, such as IDirectDrawSurface3 :: BLTFAST methods, etc. Surface object can improve a device

Here, it allows you to use the GDI function. In addition, you can access the display memory between the iDirectDrawSurface3 method. For example, you can use iDirectdrawsurface3 :: LOCK

Method locks the display memory and obtains the address of the relevant surface. The address of the display memory may point to the visible buffer memory (main surface) or invisible buffer (exterior surface or overlay surface).

Inasoless buffers typically reside in the display memory, but can be created in system memory, if the hardware allows or DirectDRAW uses software simulation functions. In addition, the IDirectdrawSurface3 interface extends some ways. With these methods, you can place or get the palette to work in the specified type surface.

4.1, surface interface (Surface Interface)

The DirectDrawSurface object expresses its function via IDirectdrawSurface, IDirectDrawSurface2, and iDirectDrawSurface3 interface. Each new version of the connection

The mouth has improved the same functionality as previous versions, and the features that have not been have emerged in the old version through new methods.

The oldest version in this class interface on the IDirectdrawSurface interface, when you use the idirectdraw2 :: createSurface method to create a surface, the default is this interface.

To use the new features provided by another version, you must also query the new version of the interface with the queryinterface method. The following code shows how to complete this:

LPDIRECTDRAWSURFACE LPSURF;

LPDIRECTDRAWSURFACE2 LPSURF2;

// CREATE SURFCES.

MEMSET (& DDSD, 0, SIZEOF (DDSD));

Ddsd.dwsize = sizeof (ddsd);

DDSD.DWFLAGS = DDSD_CAPS | DDSD_WIDTH | DDSD_HEIGHT;

DDSD.DDSCAPS.DWCAPS = DDSCAPS_OFFSCREENPLAIN |

DDSCAPS_SYSTEMMORY;

DDSD.dwwidth = 10;

DDSD.DWHEIGHT = 10;

DDRVAL = LPDD2-> CreateSurface (& DDSD, & lPSURF, NULL);

IF (DDRVAL! = DD_OK)

Return;

DDRVAL = LPSURF-> QueryInterface

IID_IDirectDrawSurface2, (lpvoid *) & lpsurf2);

IF (DDRVAL! = DD_OK)

Return;

DDRVAL = LPSURF2-> PageLock (0);

IF (DDRVAL! = DD_OK)

Return;

DDRVAL = LPSURF2-> PageUnlock (0);

IF (DDRVAL! = DD_OK)

Return;

The above example got the IDirectDrawSurface2 interface of the DirectDrawSurface object by specifying the IID_IDIRECTDRAW2 flag when calling the queryinterface method. want

Want to get the IDirectdrawSurface3 interface, use the IID_IDIRECTDRAWSURFACE3 flag instead of IID_IDirectDraw2.

4.2, Color Key

DirectDraw supports bit block transmission and overriding Source Color Key and destination Color Key. Set the table by calling the IDirectdrawSurface3 :: SetColorKey method

Color Key of the face. When using the bit block transmission, the source color key indicates the color or color range that is not copied, and the destination Color Key indicates the replaced color or color range.

Some hardware only support the color range of YUV pixel format. YUV data is usually video data, and the transparent background may not be a single color due to the quantization error in the conversion.

Color Key is specified with the pixel format of the surface. If the surface is a color format, the Color Key is specified as the range of indexes or indexes. If the surface of the pixel format is described by describing YUV

Fourcc code specified in the format, YUV Color Key is two members in three DDColorKey DWColorspacelowValue and DWColorspacehighValue

The three bytes are specified, and the three bytes are V, U, Y data, respectively. The dwflags parameter in the IDirectdrawSurface3 :: setColorKey method indicates whether the Color Key is overwritten or

The bit block transfer operation is whether it is a source color key or a destination color key. The following code is some examples of valid Color Key:

// 8-digit tone mode

// The palette entity 26 is a Color Key.

DWCOLORSPA PartLOWVALUE = 26;

DWCOLORSPACEHIGHVALUE = 26;

// 24 true color mode

// Color 255, 128, 128 is Color Key.

DWCOLORSPACLOWVALUE = RGBQUAD (255, 128, 128);

DWCOLORSPACEHIGHVALUE = RGBQUAD (255, 128, 128);

// Fourcc YUV mode

// any yuv color where y is between 100 and 110

// and u or v is Between 50 and 55 is transparent.

DWCOLORSPA PartLOWVALUE = YUVQUAD (100, 50, 50);

DWCOLORSPACEHIGHVALUE = YUVQUAD (110, 55, 55);

4.3, Pixel Format

The pixel format points out any explanation of each pixel data in surface memory. DirectDRAW describes various pixel information using the DDPixElFormat structure.

Members of the DDPixelformat structure describe the following characteristics of the pixel format:

Pinjet or non-torched pixel format

If it is a non-toner format, the pixel format is RGB or YUV format

Position depth

Position shielding of pixel format components

You can call the iDirectdrawsurface3 :: getpixelformat method to get the pixel format of the existing surface.

4.4, create a surface

The DirectDrawSurface object characterizes a surface that resides in the display memory. If the memory is displayed or explicitly created, the surface can also exist in system memory.

You can create one or more surfaces using the iDirectdraw2 :: CreateSurface method. When you call createSurface, you must specify the size of the surface, the surface type (is a single surface

It is a complex surface), pixel format (if the surface does not use the indexed palette). All of these features are included in the DDSurFacesc structure, which needs to be used when calling

The address is transmitted. If the hardware does not support request, the call will fail if those resources have been assigned to another DirectDrawSurface object.

Creating a single surface or multi-surface requires only a few lines of simple code. There are four main steps to create a surface. Every step needs more preparations than the previous step, but

Not too difficult, they are:

(1). Creating the main surface

(2) Create a screen outside the surface

(3). Create complex surfaces and flip chains

(4). Create a wide surface

In the default, DirectDraw creates a surface in the local video memory. If enough local video memory saves the surface, DirectDraw tries to use non-local videos.

Memory (only in some AGP device systems). You can explicitly specify the surface in which type memory is explicitly indicated to the DDSCAPS structure with the appropriate flag when calling createSurface.

4.4.1, create a main surface

The main surface is the surface currently visible on the monitor and indicated by the DDSCAPS_PRIMARYSURFACE flag, and each DirectDRAW object can only have a main surface. When you create a home surface, its size should match the current display mode. Therefore, in this case you don't need to indicate the size of the surface. In fact, if you indicate the surface

Size, even with the current display mode, it will also result in failure of the creation process.

The following example shows how relevant members of the DDSurfaceDesc structure are set to create the main surface:

DDSURFACEDESC DDSD;

Ddsd.dwsize = sizeof (ddsd);

// Tell DirectDraw Which Members Are Valid.

DDSD.DWFLAGS = DDSD_CAPS;

// Request a primary surface.

DDSD.DDSCAPS.DWCAPS = DDSCAPS_PRIMARYSURFACE;

4.4.2, create a screen outer surface

The exterior surface of the screen is usually used for the cache of bitmaps, which will be transferred by bit blocks into the main surface or background buffer. You must set the containing DDSC_WIDTH and DDSD_HEIGHT standard

Logging and setting dwwidth and dwheight members as the appropriate value to illustrate the size of the screen outside. In addition, DDSCAPS_OFFSCREENPLAIN must also be included in the DDSCAPS structure.

Sign.

DirectDraw uses system memory to create a surface when there is not enough display memory usage. You can include DWCAPS members in the DDSCAPS structure

DDSCAPS_SYSTEMEMORY or DDSCAPS_VIDEMEMORY flags explicitly indicate whether to create a surface in display memory or in system memory. The following example shows

Prepare the preparation before creating an exterior surface:

DDSURFACEDESC DDSD;

Ddsd.dwsize = sizeof (ddsd);

// Tell DirectDraw Which Members Are Valid.

DDSD.DWFLAGS = DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH;

// Request a Simple Off-Screen Surface, Sized

// 100 by 100 pixels.

DDSD.DDSCAPS.DWCAPS = DDSCAPS_OFFSCREENPLAIN

Dwheight = 100;

DWWIDTH = 100;

In the previous version of DirectX, the maximum width of the exterior surface cannot exceed the width of the main surface. In DirectX 5, you can create an exterior surface of any width, as long as the display is displayed

Prepare it. It should be noted that when the width of the exterior surface is declared, if the width of the surface of the requested surface is displayed, the surface will be created in the system memory. If

The use of video memory, while the video memory is not enough, the job created will fail.

4.4.3, create complex surfaces (Complex Surface) and flipping chain (FLIPPING CHAIN)

A complex surface is a combination of a set of single surfaces created with the iDirectdraw2 :: CreateSurface method. Set it when CreateSurface is called

DDSCAPS_COMPLEX flags, in addition to explicitly specified surfaces, DirectDRAW will also implicate one or more surfaces. You can manage complex tables as manageing a single surface

surface. Call iDirectDraw :: Release method Releases all surfaces, call IDirectdrawSurface3 :: Restore to recover these surfaces.

The most commonly used complex surface is a flip chain. Typically, a flip chain consists of a major surface and one or more background buffers. The DDSCAPS_FLIP flag shows that a surface is part of a flip chain. Creating a flip chain with this way also requires the DDSCAPS_COMPLEX flag. The following example creates a preparation required for a main surface flip chain:

DDSURFACEDESC DDSD;

Ddsd.dwsize = sizeof (ddsd);

// Tell DirectDraw Which Members Are Valid.

DDSD.DWFLAGS = DDSD_CAPS | DDSD_BACKBUFFERCOUNT;

// Request a primary Surface with a single

// Back Buffer

DDSD.DDSCAPS.DWCAPS = DDSCAPS_COMPLEX | DDSCAPS_FLIP |

DDSCAPS_PRIMARYSURFACE;

DDSD.DWBACKBUFFERCOUNT = 1;

This example constructs a double buffer overwhelming environment. Call the IDirectdrawSurface3 :: Flip method to swap the surface memory of the main surface and the background buffer. If DDSURFACEDESC

The member DwBackBufferCount in the structure is 2, and two back buffers will be created. The surface is turned around each time the FLIP will be looped and the three buffer overwhelming environments are provided.

4.4.4, create a wide surface (Wide Surface)

DirectDraw allows you to create an exterior surface that is wide than the main surface, of course, this needs to display hardware support. To determine if the display device supports the wide surface, you need to call

IDirectDraw2 :: getCaps method, see if DWCAPS2 members in the first DDCAPS structure include DDCaps2_WIDesurface flags. If the logo exists,

It is indicated that the outer surface of the exterior surface that is wider than the main surface can be created in the video memory. If the flag does not exist, create a wide surface in the video memory will fail, and return one

DDERR_INVALIDPARAMS error.

The system memory surface, the video port surface, and the buffer are supported by the wide surface.

4.4.5, flipping surface (Flipping Surface)

Any surfaces in DirectDraw can be constructed as a flip surface. A flip surface is capable of visiting the Front Buffer and Back Buffer

Arbitrary memory between mutual exchange. Typically, the front buffer is the main surface, but this is not required.

When using the IDirectDrawSurface3 :: FLIP method to perform surface flip operation, pointing to the surface memory of the main surface and a pointer to the surface memory of the background buffer interchange. Therefore, the surface

Flip is a display device to point to the pointer to the memory, not a copy of the surface memory. The only exception is that when DirectDraw is flipped with software simulation, it is simply copy table.

surface. DirectDraw uses software simulation to flip operations with software simulation when a background buffer cannot be loaded into memory or hardware does not support DirectDraw. When a flip chain contains one

When the main surface and multiple background buffers, the transition of the pointer uses the cycle of the way, as shown below:

Other additional surfaces of the DirectDraw object are not part of the flip chain, not affected by the FLIP method. Remember, the DirectDraw flip surface is swaping DirectDrawSurface

The object surface memory pointer is implemented instead of exchanging these objects. This means that when the bit block is transmitted to the background buffer, you must always use the same DirectDrawSurface object.

The buffer is a background buffer you create a flip chain. The pointing operation is always done by calling the FLIP method of the front desk buffer.

4.4.6 Losing Surface When the DirectDrawSurface object characterizing the surface memory is unnecessary, the surface memory associated with the surface is released. This is to lose the surface. DirectDrawSurface

Object When you have its surface memory, many methods do not perform other operations and return DDERR_SURFACELOST.

Since the display mode or another application has released all surface memory that is currently allocated, the surface may be lost.

The iDirectdrawsurface3 :: RESTORE method Recreate these lost surfaces and re-connects with the DirectDrawSurface object. The recovery surface does not place the position before the surface is lost.

Fig. Therefore, if the lost surface must be completely reloaded into the previously loaded graphics.

4.4.7, release surface (Releaseing Surface)

Like all COM interfaces, you must call the Release method to release the surface when you don't need a surface. Each individually created surface must be explicitly released. If it is a tuning

Explicitly created multiple surfaces (such as flip chains, etc.) explicitly created with IDirectdraw2 :: CreateSurface or iDirectdraw :: CreateSurface, you only need to release the front buffer. in

In this case, any pointer pointing to the surface of the background buffer will be explicitly released, and it is not available.

4.4.8, update surface characteristics (Updating Surface Characteristics)

You can use the iDirectdrawsurface3 :: setsurfaceDesc method to update features of the surface. Use this method to change the pixel format, or change DirectDrawSurface

There is a location in the system memory in the surface of the object, which is explicitly assigned by the application. It allows a surface directly using data in the previously assigned buffer without having to copy,

This new surface memory is allocated by the customer application and is also released by the customer.

When calling the idirectdrawsurface3 :: setsurfaceDesc method, the LPDDSD parameter must be the address of the structure of the new surface memory, which is point to

The memory address pointer. In the DDSurfaceDesc structure, only DWFLAGS members can be set to reflect the location, size, and pixel format of the surface memory. So dwflags can only

Contains a combination of DDSD_WIDTH, DDSD_HEIGHT, DDSD_PITCH, DDSD_LPSURFACE, and DDSD_PIXELFORMAT, etc., use these combinations to set

Effective structural members.

Before setting the value of the structure, you must allocate the memory to load the surface. The size of the assigned memory is very important. Not only do you need to assign enough memory to accommodate the width and high surface, you still need

To leave a sufficient memory space for the surface spacing (PITCH), the surface spacing is a Qword (8 bytes), the spacing is height rather than the pixel metric.

When setting the value of the surface in the structure, the LPSURFACE member is a pointer you assigned, DwHeight and DWWIDTH members describe the size of the surface in pixel units. If specified

The size of the surface also needs to populate the IPITCH member to reflect the surface spacing. DDPFPixelformat members describe the pixel format of the surface. In addition to the LPSurface members, if you don't make these

Corresponding value, IDirectDrawSurface3 :: setSurfaceDesc method uses the default value from the current surface.

Pay attention to some problems when calling the IDirectDrawsurface3 :: setSurfaceDesc method. For example, LPSurface must be a valid pointer for system memory (this method is not currently supported

Video memory pointer); DWPIDTH and DWHEIGHT must be a non-zero value; the main surface or other surface cannot be reassigned in the primary conversion chain. You can assign the same memory for multiple DirectDrawSurface objects, but you must notice that the memory is allocated to the memory when the memory is assigned to any surface object. Correct

The incorrect use of the setSurfaceDesc method can result in unpredictable reactions. Therefore, when you no longer need surface memory, you must remember to release it. However, when calling this method, DirectDraw

The surface memory explicitly assigned when the release is created.

4.4.9, directly access the frame buffer (Accessing the frame-buffer directly)

You can use the iDirectdrawsurface3 :: Lock method to directly access the surface memory in the frame buffer or system memory. When this method is called, the LPDESTRECT parameter is a RECT.

Structure pointer. This structure describes a rectangle on the surface to be directly accessed. To lock the entire surface, you can set the LPDESTRECT to NULL. You can also specify a surface that only contains the surface.

Part of RECT. If there is no two rectangles overlap, two processes can lock multiple rectangles in a surface.

The LOCK method fills the DDSurfaceDesc structure with all the information that needs to properly access the surface memory. This structure contains information about surface spacing and pixel format (in the same master

The pixel format of the surface is not at the same time). After completing access to the surface, call the iDirectdrawsurface3 :: UNLOCK method to unlock it.

4.4.10, use non-local video memory surface (use non-local video memory ")

DirectDraw supports advanced graphics port AGP (Advanced Graphics Port) features that can create surfaces in non-local video memory. In the AGP system, if the local view

Frequency memory has been used or the application explicitly requires non-local memory, and DirectDRAW will create a surface using a non-local video memory.

Currently, there are two AGP systems. One is "Execute Model), one is Direct Memory Access Model. In the execution model,

The display device supports non-local video memory and local video memory the same feature. Therefore, when you use the IDirectDraw2 :: getCaps method to obtain the performance of the hardware, the same bit block transmission is related

The logo DWNLVBCAPS, DWNLVBCAPS2, DWNLVBCKEYCAPS, DWNLVBFXCAPS, and DWNLVBROPS will indicate that the local video memory is used. In execution mode,

If the local video memory is run, DirectDRAW will automatically use non-local video memory.

In the DMA model, support for texture map transmitted from non-local video memory is limited. When the display device uses the DMA model, you want to get the performance of the hardware.

DWCAPS members will be set to the DDCaps2_nonlocalvidMemcaps flag. The same bit block transmission related logo is included in DWNLVBCAPS, DWNLVBCAPS2,

DwnLvbcKeyCaps, DwnLvbFXCaps, and DwnLvbrops. DirectDraw will not use non-local video memory to create surfaces unless explicitly indicated. DMA

The implementation of the model is different in support for non-local video memory surfaces. If the driver supports texture map from a non-local video memory surface, use iDirect3ddevice2 :: getcaps

Method When obtaining a performance of a 3D device, the D3DDEVCAPS_TEXTURENONONLOCALVIDMEM flag will be set.

4.4.11 Conversion Color and Format Non-RGB Surface Format is represented by the four characters of the code (FOURCC CODES). If the application calls the idirectdrawsurface3 :: getpixelformat method to request

The pixel format, and the surface is a non-RGB surface, the DDPF_FOURCC flag will be set, and the members dwfourcc in the DDPixElFormat structure will become effective. Such as

Fruit Fourcc code indicates a YUV format, DDPF_YUV flag will be set, dwyuvbitcount, dwybits, dwubits, dwvbits and dwyuvalphabits

Members will be a valid mask to be used to extract information from pixels.

If the current RGB format is current, the DDPF_RGB flag will be set, DWRGBITCOUNT, DWRBITS, DWGBITS, DWBBITS and DWRGBALPHABITS members will be able

Enough to a valid mask of advance information from the pixels.

During the colors and formats, there are two groups of FOURCC code for the application. A set of capabilities identified the power of hardware block transmission, and the other group identified hardware coverage.

4.4.12, cover surface (overlay surfaces)

The cover surface is a surface with special hardware support capabilities, which is usually used to display active video, record video, or still bitmap without requiring bit blocks to transfer to the main surface or change the main surface.

Rong. This is entirely provided by the word coverage surface, and DirectDraw supports the features supported by the display device driver, and DirectDRAW does not simulate the surface. Can cover the surface

As a plastic paper, we can draw this plastic and placed it in front of the display. When plastic paper is covered in front of the display, you can see the overlay and main surface, remove the plastic

After the paper, the main surface has not changed. The working principle of covering the surface is similar to the principle of transparent plastic paper. What is the display of the device driver when displaying a cover surface

How to make the cover surface visible. When the display device scan line is swatched to the display, it checks each pixel on the main surface to see if it is overwritten. If so, the display device is from

The data replacement of related pixels is extracted in the cover surface.

Using this method, display the adapter card generates the main surface and the synthetic surface of the cover surface, generating transparent and stretching effects without changing the content of each surface. synthesis

The surface is sent to the video data stream directly to the display. Because this processing and pixel replacement is the hardware level operation, there is no significant performance loss. In addition, this method also makes it possible

Synthesize the main surface and cover the surface in different pixel formats.

Creating a coverage surface You need to specify the DDSCAPS_OVERLAY flag in the DDSCAPS structure, then call the idirectdraw2 :: createSurFace method to overwrite the surface can only be inward

Create in the deposit, so you must also include the DDSCAPS_VIDEMEMORY flag. Like other types of surfaces, by including the appropriate logo, you can create a single coverage surface.

You can also create a flip chain consisting of multiple overrides.

You can call the iDirectdraw2 :: getCaps method to get information about supported overlay features. This method fills a DDCAPS structure with the description of all feature information. in

When reporting the hardware feature, the device driver sets the flag of the DWCAPS member to indicate when to enforce some type of constraint provided by the hardware. After the ability to get the driver, pass

Check the flag of the DWCAPS member to know the information provided. The DDCAPS structure contains nine members, which describes the constraints of coverage of the surface. The subscript is listed

Overwrites related members of their logo.

member

Sign

DWMaxVisibleOverlays

The member is always effective

DWCurrvisibleOverlays

The member is always effective

DwalignboundarySRCDCAPS_ALIGNBOUNDARYSRC

Dwalignsizesrc

DDCAPS_ALIGNSIZESRC

DwalignboundaryDest

DDCAPS_ALIGNBOUNDARYDES

DwalignsizeDest

DDCAPS_ALIGNSIZEDEST

DWMINOVERLAYSTRETCH

DDCAPS_OVERLAYSTRETCH

DWMAXOVERLAYSTRETCH

DDCAPS_OVERLAYSTRETCH

DwMaxvisibleOverlays and dwcurrvisibleoverlays members indicate the maximum number of overrides that the hardware can be displayed, as well as how many visible.

DwalignBoundarySRC, DwalignSizesrc, DwalignBoundaryDest, Dwalignsizedest, and DwalignstrideAlign members are the rectangular position and size of the hardware report

Constraint. The values of these members refer to how to determine the size and position of the source rectangle and the destination rectangle when the cover is displayed.

DWMINOVERLAYSTRETCH and DWMAXOverLaystretch are information about tensile factors.

A, source rectangular and destination rectangle (Source and Destination Rectangles)

To display an overlay surface, you need to call the idirectdrawsurface3 :: updateoverLay method, specify the DDOVER_SHOW flag in the dwflags parameter. This method requires you

A source rectangle and destination rectangle are specified in the LPSRCRECT and LPDESTRECT parameters. If the entire surface is used, the LPSRCRECT parameter is set to NULL. The destination rectangle is on the main surface

Generate a location where the surface is covered.

Source, the destination rectangle does not have to be the same. Generally, the destination rectangle must be large or small, and the hardware is automatically compressed or stretched when the hardware is displayed. To show a successful display

The cover surface may need to adjust the sources, the size of the destination rectangle, whether this process is necessary to depend on the limitations of the device driver.

B, boundary and size adjustment (Boundary and size alignment)

Due to different hardware restrictions, some device drivers are constrained on the size and position of the source rectangles and the destination rectangle of the cover surface. To find out the constraints of the device application,

Call the IDirectdraw2 :: getCaps method, then check the flag of the DDCaps structure that covered the relevant DWCAPS. The subscript lists members of the specified boundary and size adjustment constraints

And logo.

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