ID3DXPRTEngine::ClosestRayIntersects method
Uses efficient ray-tracing in precomputed radiance transfer (PRT) simulations to determine whether a ray intersects a mesh. If an intersection is found, the method returns the index of the closest mesh face hit by the ray and the barycentric coordinates of the intersection point.
Syntax
BOOL ClosestRayIntersects(
[in] const D3DXVECTOR3 *pRayPos,
[in] const D3DXVECTOR3 *pRayDir,
[in] DWORD *pFaceIndex,
[out] FLOAT *pU,
[out] FLOAT *pV,
[out] FLOAT *pDist
);
Parameters
-
pRayPos [in]
-
Type: const D3DXVECTOR3*
Pointer to a D3DXVECTOR3 structure, specifying the point where the ray begins.
-
pRayDir [in]
-
Type: const D3DXVECTOR3*
Pointer to a D3DXVECTOR3 structure, specifying the normalized direction of the ray.
-
pFaceIndex [in]
-
Type: DWORD*
Pointer to the index of the current mesh face that is first hit by the given ray, based upon stacking all blocker mesh faces in front of the current mesh.
-
pU [out]
-
Type: FLOAT*
Pointer to a barycentric hit coordinate, U, for vertex 0 of the triangle.
-
pV [out]
-
Type: FLOAT*
Pointer to a barycentric hit coordinate, V, for vertex 1 of the triangle.
-
pDist [out]
-
Type: FLOAT*
Pointer to the distance of the intersection point along the ray.
Return value
Type: BOOL
Returns TRUE if the ray intersects the current mesh; otherwise, returns FALSE.
Remarks
Use ID3DXPRTEngine::SetMinMaxIntersection to set minimum and maximum distances of intersection with the ray.
The barycentric coordinate of the third vertex (vertex 2) of the triangle is 1 - ( U + V ).
This method executes slower than ID3DXPRTEngine::ShadowRayIntersects. Use ID3DXPRTEngine::ShadowRayIntersects if the location of the intersection point is not needed.
Barycentric coordinates define a point inside a triangle in terms of the triangle's vertices. For a more in-depth description of barycentric coordinates, see Mathworld's Barycentric Coordinates Description.
Requirements
| Requirement | Value |
|---|---|
| Header |
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| Library |
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See also