Function OptimizeTriangleOrdering

Engine/source/gfx/util/triListOpt.cpp:31–221

{

void OptimizeTriangleOrdering(const dsize_t numVerts, const dsize_t numIndices, const U32 *indices, IndexType *outIndices)
{
   PROFILE_SCOPE(TriListOpt_OptimizeTriangleOrdering);

   if(numVerts == 0 || numIndices == 0)
   {
      dCopyArray(outIndices, indices, numIndices);
      return;
   }

   const U32 NumPrimitives = numIndices / 3;
   AssertFatal(NumPrimitives == U32(mFloor(numIndices / 3.0f)), "Number of indicies not divisible by 3, not a good triangle list.");

   //
   // Step 1: Run through the data, and initialize
   //
   FrameTemp<VertData> vertexData(numVerts);
   FrameTemp<TriData> triangleData(NumPrimitives);

   U32 curIdx = 0;
   for(S32 tri = 0; tri < NumPrimitives; tri++)
   {
      TriData &curTri = triangleData[tri];

      for(S32 c = 0; c < 3; c++)
      {  
         const U32 &curVIdx = indices[curIdx];
         AssertFatal(curVIdx < numVerts, "Out of range index.");

         // Add this vert to the list of verts that define the triangle
         curTri.vertIdx[c] = curVIdx;

         VertData &curVert = vertexData[curVIdx];

         // Increment the number of triangles that reference this vertex
         curVert.numUnaddedReferences++;

         curIdx++;
      }
   }

   // Allocate per-vertex triangle lists, and calculate the starting score of
   // each of the verts
   for(S32 v = 0; v < numVerts; v++)
   {
      VertData &curVert = vertexData[v];
      curVert.triIndex = new S32[curVert.numUnaddedReferences];
      curVert.score = FindVertexScore::score(curVert);
   }

   // These variables will be used later, but need to be declared now
   S32 nextNextBestTriIdx = -1, nextBestTriIdx = -1;
   F32 nextNextBestTriScore = -1.0f, nextBestTriScore = -1.0f;

#define _VALIDATE_TRI_IDX(idx) if(idx > -1) { AssertFatal(idx < NumPrimitives, "Out of range triangle index."); AssertFatal(!triangleData[idx].isInList, "Triangle already in list, bad."); }
#define _CHECK_NEXT_NEXT_BEST(score, idx) { if(score > nextNextBestTriScore) { nextNextBestTriIdx = idx; nextNextBestTriScore = score; } }
#define _CHECK_NEXT_BEST(score, idx) { if(score > nextBestTriScore) { _CHECK_NEXT_NEXT_BEST(nextBestTriScore, nextBestTriIdx); nextBestTriIdx = idx; nextBestTriScore = score; } _VALIDATE_TRI_IDX(nextBestTriIdx); }