GuTriangle.h

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#ifndef GU_TRIANGLE_H
#define GU_TRIANGLE_H
 
#include "foundation/PxVec3.h"
#include "foundation/PxUtilities.h"
#include "foundation/PxUserAllocated.h"
 
namespace physx
{
namespace Gu
{
    // PT: I'm taking back control of these files and re-introducing the "ICE" naming conventions:
    // - "Triangle" is for actual triangles (like the PxTriangle class)
    // - If it contains vertex indices, it's "IndexedTriangle".
    // - "v" is too ambiguous (it could be either an actual vertex or a vertex reference) so use "ref" instead.
    //   Plus we sometimes reference edges, not vertices, so "v" is too restrictive.
 
    template <class T>
    struct IndexedTriangleT : public PxUserAllocated
    {
        PX_INLINE   IndexedTriangleT ()                                     {}
        PX_INLINE   IndexedTriangleT (T a, T b, T c)                        { mRef[0] = a; mRef[1] = b; mRef[2] = c; }
        template <class TX>
        PX_INLINE   IndexedTriangleT (const IndexedTriangleT <TX>& other)   { mRef[0] = other[0]; mRef[1] = other[1]; mRef[2] = other[2]; }
 
        PX_INLINE   T&              operator[](T i)             { return mRef[i]; }
        PX_INLINE   const T&        operator[](T i)     const   { return mRef[i]; }
 
        template<class TX>//any type of IndexedTriangleT <>, possibly with different T
        PX_INLINE   IndexedTriangleT <T>&   operator=(const IndexedTriangleT <TX>& i)   { mRef[0]=i[0]; mRef[1]=i[1]; mRef[2]=i[2]; return *this; }
 
        void    flip()
        {
            PxSwap(mRef[1], mRef[2]);
        }
 
        PX_INLINE bool contains(T id) const
        {
            return mRef[0] == id || mRef[1] == id || mRef[2] == id;
        }
 
        PX_INLINE void center(const PxVec3* verts, PxVec3& center)  const
        {
            const PxVec3& p0 = verts[mRef[0]];
            const PxVec3& p1 = verts[mRef[1]];
            const PxVec3& p2 = verts[mRef[2]];
            center = (p0+p1+p2)*0.33333333333333333333f;
        }
 
        float area(const PxVec3* verts) const
        {
            const PxVec3& p0 = verts[mRef[0]];
            const PxVec3& p1 = verts[mRef[1]];
            const PxVec3& p2 = verts[mRef[2]];
            return ((p0-p1).cross(p0-p2)).magnitude() * 0.5f;
        }
 
        PxU8    findEdge(T vref0, T vref1)  const
        {
                    if(mRef[0]==vref0 && mRef[1]==vref1)    return 0;
            else    if(mRef[0]==vref1 && mRef[1]==vref0)    return 0;
            else    if(mRef[0]==vref0 && mRef[2]==vref1)    return 1;
            else    if(mRef[0]==vref1 && mRef[2]==vref0)    return 1;
            else    if(mRef[1]==vref0 && mRef[2]==vref1)    return 2;
            else    if(mRef[1]==vref1 && mRef[2]==vref0)    return 2;
            return 0xff;
        }
 
        // counter clock wise order
        PxU8    findEdgeCCW(T vref0, T vref1)   const
        {
                    if(mRef[0]==vref0 && mRef[1]==vref1)    return 0;
            else    if(mRef[0]==vref1 && mRef[1]==vref0)    return 0;
            else    if(mRef[0]==vref0 && mRef[2]==vref1)    return 2;
            else    if(mRef[0]==vref1 && mRef[2]==vref0)    return 2;
            else    if(mRef[1]==vref0 && mRef[2]==vref1)    return 1;
            else    if(mRef[1]==vref1 && mRef[2]==vref0)    return 1;
            return 0xff;
        }
 
        bool    replaceVertex(T oldref, T newref)
        {
                    if(mRef[0]==oldref) { mRef[0] = newref; return true; }
            else    if(mRef[1]==oldref) { mRef[1] = newref; return true; }
            else    if(mRef[2]==oldref) { mRef[2] = newref; return true; }
            return false;
        }
 
        bool isDegenerate() const
        {
            if(mRef[0]==mRef[1])    return true;
            if(mRef[1]==mRef[2])    return true;
            if(mRef[2]==mRef[0])    return true;
            return false;
        }
 
        PX_INLINE void denormalizedNormal(const PxVec3* verts, PxVec3& normal)  const
        {
            const PxVec3& p0 = verts[mRef[0]];
            const PxVec3& p1 = verts[mRef[1]];
            const PxVec3& p2 = verts[mRef[2]];
            normal = ((p2 - p1).cross(p0 - p1));
        }
 
        T   mRef[3];    //vertex indices
    };
 
    typedef IndexedTriangleT<PxU32> IndexedTriangle32;
    typedef IndexedTriangleT<PxU16> IndexedTriangle16;
 
    PX_COMPILE_TIME_ASSERT(sizeof(IndexedTriangle32)==12);
    PX_COMPILE_TIME_ASSERT(sizeof(IndexedTriangle16)==6);
}
}
 
#endif