source: GTP/trunk/App/Games/Jungle_Rumble/src/physic/physics/include/NxIntersectionPointTriangle.h @ 1378

#ifndef NX_INTERSECTION_POINT_TRIANGLE
#define NX_INTERSECTION_POINT_TRIANGLE
/** \addtogroup physics
  @{
*/

#include "Nxp.h"

//namespace NxCollision {

        /**
        \brief Point-in-triangle test.
        
        We use the edges as parameters in case the user has access to edges directly
        This is actually a "point-in-prism" test since it returns true as long as the point is bound by the edge planes.

        \warning #NxCreatePhysicsSDK() must be called before using this function.

        \param[in] p Point to test. <b>Range:</b> position vector
        \param[in] p0 Triangle vertex. <b>Range:</b> position vector
        \param[in] edge10 Triangle edge. <b>Range:</b> direction vector
        \param[in] edge20 Second triangle edge. <b>Range:</b> direction vector
        
        \return True on intersection

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : Yes
        \li PS3  : Yes
        \li XB360: Yes

        @see NxPointTriangleIntersect2D
        */
        NX_INLINE NX_BOOL NxPointTriangleIntersect(const NxVec3& p, const NxVec3& p0, const NxVec3& edge10, const NxVec3& edge20)
                { 
                NxReal a = edge10|edge10;
                NxReal b = edge10|edge20;
                NxReal c = edge20|edge20;
                NxReal ac_bb = (a*c)-(b*b);

                NxVec3 vp = p - p0;

                NxReal d = vp|edge10;
                NxReal e = vp|edge20;

                NxReal x = (d*c) - (e*b);
                NxReal y = (e*a) - (d*b);
                NxReal z = x + y - ac_bb;

                // Same as: if(x>0.0f && y>0.0f && z<0.0f)      return TRUE;
                //                      else                                                    return FALSE;
                return (( NX_IR(z) & ~(NX_IR(x)|NX_IR(y)) ) & NX_SIGN_BITMASK);
                }

        /**
        \brief Dedicated 2D version of previous test

        \warning #NxCreatePhysicsSDK() must be called before using this function.

        \param[in] px Point to test, X
        \param[in] pz Point to test, Z
        \param[in] p0x Vertex of triangle to test, X
        \param[in] p0z Vertex of triangle to test, Z
        \param[in] e10x Edge of triangle to test, X
        \param[in] e10z Edge of triangle to test, Y
        \param[in] e20x Second edge of triangle to test, X
        \param[in] e20z Second edge of triangle to test, Y

        \return True on intersection

        <b>Platform:</b>
        \li PC SW: Yes
        \li PPU  : Yes
        \li PS3  : Yes
        \li XB360: Yes

        @see NxPointTriangleIntersect
        */
        NX_INLINE NX_BOOL NxPointTriangleIntersect2D(
                NxReal px, NxReal pz,
                NxReal p0x, NxReal p0z,
                NxReal e10x, NxReal e10z,
                NxReal e20x, NxReal e20z)
                { 
                NxReal a = e10x*e10x + e10z*e10z;
                NxReal b = e10x*e20x + e10z*e20z;
                NxReal c = e20x*e20x + e20z*e20z;
                NxReal ac_bb = (a*c)-(b*b);

                NxReal vpx = px - p0x;
                NxReal vpz = pz - p0z;

                NxReal d = vpx*e10x + vpz*e10z;
                NxReal e = vpx*e20x + vpz*e20z;

                NxReal x = (d*c) - (e*b);
                NxReal y = (e*a) - (d*b);
                NxReal z = x + y - ac_bb;

                // Same as: if(x>0.0f && y>0.0f && z<0.0f)      return TRUE;
                //                      else                                                    return FALSE;
                return (( NX_IR(z) & ~(NX_IR(x)|NX_IR(y)) ) & NX_SIGN_BITMASK);
                }

//}

/** @} */
#endif


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