|Microsoft DirectX 9.0|
Determines if a ray intersects with a mesh.
LPD3DXBASEMESH pMesh, CONST D3DXVECTOR3 *pRayPos, CONST D3DXVECTOR3 *pRayDir, BOOL *pHit, DWORD *pFaceIndex, FLOAT *pU, FLOAT *pV, FLOAT *pDist, LPD3DXBUFFER *ppAllHits, DWORD *pCountOfHits );
- [in] Pointer to an ID3DXBaseMesh interface, representing the mesh to be tested.
- [in] Pointer to a D3DXVECTOR3 structure, specifying the origin coordinate of the ray.
- [in] Pointer to a D3DXVECTOR3 structure, specifying the direction of the ray.
- [out] Pointer to a BOOL. If the ray intersects a triangular face on the mesh, this value will be set to TRUE. Otherwise, this value is set to FALSE.
- [out] Pointer to an index value of the face closest to the ray origin, if pHit is TRUE.
- [out] Pointer to a barycentric hit coordinate, U.
- [out] Pointer to a barycentric hit coordinate, V.
- [out] Pointer to a ray intersection parameter distance.
- [out] Pointer to an ID3DXBuffer object, containing an array of D3DXINTERSECTINFO structures.
- [out] Pointer to a DWORD that contains the number of entries in the ppAllHits array.
If the function succeeds, the return value is D3D_OK.
If the function fails, the return value can be E_OUTOFMEMORY.
The D3DXIntersect function provides a way to understand points in and around a triangle, independent of where the triangle is actually located. This function returns the resulting point by using the following equation: V1 + U(V2-V1) + V(V3-V1).
Any point in the plane V1V2V3 can be represented by the barycentric coordinate (U,V). The parameter U controls how much V2 gets weighted into the result and the parameter V controls how much V3 gets weighted into the result. Lastly, 1-U-V controls how much V1 gets weighted into the result.
Barycentric coordinates are a form of general coordinates. In this context, using barycentric coordinates represents a change in coordinate systems. What holds true for Cartesian coordinates holds true for barycentric coordinates.
Header d3dx9mesh.h Import library d3dx9.lib Minimum operating systems Windows 98