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#ifndef PLANE_CLIPPING_INCLUDED
#define PLANE_CLIPPING_INCLUDED
//Plane clipping definitions. Uses three planes for clipping, but this can be increased if necessary.
#if CLIP_ONE || CLIP_TWO || CLIP_THREE || CLIP_FOUR
//If we have 1, 2 or 3 clipping planes, PLANE_CLIPPING_ENABLED will be defined.
//This makes it easier to check if this feature is available or not.
#define PLANE_CLIPPING_ENABLED 1
//http://mathworld.wolfram.com/Point-PlaneDistance.html
float distanceToPlane(float3 planePosition, float3 planeNormal, float3 pointInWorld)
{
//w = vector from plane to point
float3 w = - ( planePosition - pointInWorld );
float res = ( planeNormal.x * w.x +
planeNormal.y * w.y +
planeNormal.z * w.z )
/ sqrt( planeNormal.x * planeNormal.x +
planeNormal.y * planeNormal.y +
planeNormal.z * planeNormal.z );
return res;
}
//we will have at least one plane.
float4 _planePos;
float4 _planeNorm;
//at least two planes.
#if (CLIP_TWO || CLIP_THREE)
float4 _planePos2;
float4 _planeNorm2;
#endif
//at least three planes.
#if (CLIP_THREE)
float4 _planePos3;
float4 _planeNorm3;
#endif
#if (CLIP_FOUR)
float4 _planePos4;
float4 _planeNorm4;
#endif
//discard drawing of a point in the world if it is behind any one of the planes.
void PlaneClip(float3 posWorld) {
// quita esto
#if CLIP_FOUR
clip(float4(
distanceToPlane(_planePos.xyz, _planeNorm.xyz, posWorld),
distanceToPlane(_planePos2.xyz, _planeNorm2.xyz, posWorld),
distanceToPlane(_planePos3.xyz, _planeNorm3.xyz, posWorld),
distanceToPlane(_planePos4.xyz, _planeNorm4.xyz, posWorld)
));
#else //CLIP_FOUR
#if CLIP_THREE
clip(float3(
distanceToPlane(_planePos.xyz, _planeNorm.xyz, posWorld),
distanceToPlane(_planePos2.xyz, _planeNorm2.xyz, posWorld),
distanceToPlane(_planePos3.xyz, _planeNorm3.xyz, posWorld)
));
#else //CLIP_THREE
#if CLIP_TWO
clip(float2(
distanceToPlane(_planePos.xyz, _planeNorm.xyz, posWorld),
distanceToPlane(_planePos2.xyz, _planeNorm2.xyz, posWorld)
));
#else //CLIP_TWO
clip(distanceToPlane(_planePos.xyz, _planeNorm.xyz, posWorld));
#endif //CLIP_TWO
#endif //CLIP_THREE
#endif //CLIP_FOUR
}
//preprocessor macro that will produce an empty block if no clipping planes are used.
#define PLANE_CLIP(posWorld) PlaneClip(posWorld);
#else
//empty definition
#define PLANE_CLIP(s)
#endif
#endif // PLANE_CLIPPING_INCLUDED
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