D3DXVEC4CATMullROM function
CATMULL-ROM interpolation is performed between 4-D vectors.
definition:
D3DXVECTOR4 * WINAPI D3DXVEC4CATMULLROM (D3DXVector4 * Pout,
Const d3dxvector4 * pv0,
Const d3dxvector4 * pv1,
Const d3dxvector4 * pv2,
Const d3dxvector4 * pv3,
Float S
);
Parameters
pout
[in, out] points to the operation result of the D3DXVECTOR4 structure.
PV0
[in] Points to the location vector of the D3DXVector4 structure.
PV1
[in] Points to the location vector of the D3DXVector4 structure.
PV2
[in] Points to the location vector of the D3DXVector4 structure.
PV3
[in] Points to the location vector of the D3DXVector4 structure.
s
Weight Coefficient. Review.
return value:
Point the CATMULL-ROM interpolation result of the D3DXVector4 structure.
Description:
For example, give four points (P1, P2, P3, P4), find a function q (s) to satisfy the following conditions:
Q (s) is a three-time function.
Q (s) is interpolated between P2 and P3 when the S ranges from 0 to 1.
Q (s) is when S is 0, it is parallel to the P1 to P3 cable.
Q (s) is when S is 1, it parallel P2 to P4.
V1 = P2
V2 = P3
T1 = (p3 - p1) / 2
T2 = (p4 - p2) / 2
Q (s) = (2S3 - 3S2 1) V1 (-2S3 3S2) V2 (S3 - 2S2 S) T1 (S3 - S2) T2
Q (s) = (2S3 - 3S2 1) P2 (-2S3 3S2) P3 (S3 - 2S2 S) (P3 - P1) / 2 (S3 - S2) (P4 - P2) / 2
The finishing is as follows:
Q (s) = [(-S3 2S2 - S) P1 (3S3 - 5S2 2) P2 (-3S3 4S2 S) P3 (S3 - S2) P4] / 2
Function information:
HEADER
D3DX9Math.h
Import Library
D3DX9.LIB
Minimum operation systems
Windows 98
Function related:
D3DXVEC2CATMULLROM, D3DXVEC3CATMULLROM
