GuMeshAnalysis.h

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#ifndef GU_MESH_ANALYSIS_H
#define GU_MESH_ANALYSIS_H
 
#include "foundation/Px.h"
#include "common/PxPhysXCommonConfig.h"
#include "GuTriangle.h"
#include "foundation/PxHashMap.h"
#include "foundation/PxSort.h"
 
namespace physx
{
namespace Gu
{
    using Triangle = Gu::IndexedTriangleT<PxI32>;
 
    
    class MeshAnalyzer
    {
        struct Range
        {
            PxI32 start;
            PxI32 end; //Exclusive     
 
            Range(PxI32 start_, PxI32 end_)
            {
                start = start_;
                end = end_;
            }
 
            PxI32 Length() const { return end - start; }
        };
 
        template<typename T, typename S>
        static void splitRanges(PxArray<Range>& mergeRanges, const PxArray<PxI32>& indexer, const PxArray<T>& points, PxI32 dimIndex, S tol)
        {
            PxArray<Range> newMergeRanges;
 
            for (PxU32 i = 0; i < mergeRanges.size(); ++i)
            {
                const Range& r = mergeRanges[i];
                PxI32 start = r.start;
                for (PxI32 j = r.start + 1; j < r.end; ++j)
                {
                    //PxF64 delta = PxAbs(points[start][dimIndex] - points[j - 1][dimIndex]);
                    S delta = PxAbs(points[indexer[j]][dimIndex] - points[indexer[j - 1]][dimIndex]);
                    if (delta > tol)
                    {
                        if (j - start > 1)
                            newMergeRanges.pushBack(Range(start, j));
                        start = j;
                    }
                }
                if (r.end - start > 1)
                    newMergeRanges.pushBack(Range(start, r.end));
            }
 
            mergeRanges.clear();
            for (PxU32 i = 0; i < newMergeRanges.size(); ++i)
                mergeRanges.pushBack(newMergeRanges[i]);
        }
 
        template<typename T>
        struct Comparer
        {
            const PxArray<T>& points;
            const PxU32 dimension;
 
            Comparer(const PxArray<T>& points_, const PxU32 dimension_) : points(points_), dimension(dimension_) {}
 
            bool operator()(const PxI32& a, const PxI32& b) const
            {
                return points[a][dimension] > points[b][dimension];
            }
 
        private:
            PX_NOCOPY(Comparer)
        };
 
    public:
        template<typename T, typename S>
        static void mapDuplicatePoints(const PxArray<T>& points, PxArray<PxI32>& result, S duplicateDistanceManhattanMetric = static_cast<S>(1e-6))
        {
            PxArray<PxI32> indexer;
            indexer.reserve(points.size());
            indexer.forceSize_Unsafe(points.size());
            for (PxU32 i = 0; i < points.size(); ++i)
            {
                indexer[i] = i;
                result[i] = i;
            }
 
            PxSort(indexer.begin(), indexer.size(), Comparer<T>(points, 0));
 
            PxArray<Range> mergeRanges;
            mergeRanges.pushBack(Range(0, points.size()));
            splitRanges<T>(mergeRanges, indexer, points, 0, duplicateDistanceManhattanMetric);
 
            for (PxU32 i = 0; i < mergeRanges.size(); ++i)
            {
                const Range& r = mergeRanges[i];
                PxSort(indexer.begin() + r.start, r.Length(), Comparer<T>(points, 1));
            }
            splitRanges<T>(mergeRanges, indexer, points, 1, duplicateDistanceManhattanMetric);
 
            for (PxU32 i = 0; i < mergeRanges.size(); ++i)
            {
                const Range& r = mergeRanges[i];
                PxSort(indexer.begin() + r.start, r.Length(), Comparer<T>(points, 2));
            }
            splitRanges<T>(mergeRanges, indexer, points, 2, duplicateDistanceManhattanMetric);
 
            //Merge the ranges
            for (PxU32 i = 0; i < mergeRanges.size(); ++i)
            {
                const Range& r = mergeRanges[i];
                PxSort(indexer.begin() + r.start, r.Length());
                for (PxI32 j = r.start + 1; j < r.end; ++j)
                    result[indexer[j]] = result[indexer[r.start]];
            }
        }
 
        PX_PHYSX_COMMON_API static bool buildTriangleAdjacency(const Triangle* tris, PxU32 numTriangles, PxArray<PxI32>& result, PxHashMap<PxU64, PxI32>& edges);
        PX_PHYSX_COMMON_API static bool checkConsistentTriangleOrientation(const Triangle* tris, PxU32 numTriangles, PxArray<bool>& flip, PxHashMap<PxU64, PxI32>& edges);
        PX_PHYSX_COMMON_API static bool makeTriOrientationConsistent(Triangle* tris, PxU32 numTriangles, bool invertOrientation = false);
        PX_PHYSX_COMMON_API static bool checkMeshWatertightness(const Triangle* tris, PxU32 numTriangles);
    };
}
}
 
#endif