// Adds this vertex index and returns the highest-scoring triangle index
u32 add(u16 vert, bool updatetris = false)
{
bool found = false;
// Mark existing pos as empty
for (u16 i = 0; i < cachesize; i++)
{
if (cache[i] == vert)
{
// Move everything down
for (u16 j = i; j; j--)
{
cache[j] = cache[j - 1];
}
found = true;
break;
}
}
if (!found)
{
if (cache[cachesize-1] != -1)
vc[cache[cachesize-1]].cachepos = -1;
// Move everything down
for (u16 i = cachesize - 1; i; i--)
{
cache[i] = cache[i - 1];
}
}
cache[0] = vert;
u32 highest = 0;
float hiscore = 0;
if (updatetris)
{
// Update cache positions
for (u16 i = 0; i < cachesize; i++)
{
if (cache[i] == -1)
break;
vc[cache[i]].cachepos = i;
vc[cache[i]].score = FindVertexScore(&vc[cache[i]]);
}
// Update triangle scores
for (u16 i = 0; i < cachesize; i++)
{
if (cache[i] == -1)
break;
const u16 trisize = vc[cache[i]].tris.size();
for (u16 t = 0; t < trisize; t++)
{
tcache *tri = &tc[vc[cache[i]].tris[t]];
tri->score =
vc[tri->ind[0]].score +
vc[tri->ind[1]].score +
vc[tri->ind[2]].score;
if (tri->score > hiscore)
{
hiscore = tri->score;
highest = vc[cache[i]].tris[t];
}
}
}
}
return highest;
}
/**
Vertex cache optimization according to the Forsyth paper:
http://home.comcast.net/~tom_forsyth/papers/fast_vert_cache_opt.html
The function is thread-safe (read: you can optimize several meshes in different threads)
\param mesh Source mesh for the operation. */
scene::IMesh* createForsythOptimizedMesh(const scene::IMesh *mesh)
{
if (!mesh)
return 0;
scene::SMesh *newmesh = new scene::SMesh();
newmesh->BoundingBox = mesh->getBoundingBox();
const u32 mbcount = mesh->getMeshBufferCount();
for (u32 b = 0; b < mbcount; ++b)
{
const scene::IMeshBuffer *mb = mesh->getMeshBuffer(b);
if (mb->getIndexType() != video::EIT_16BIT)
{
//os::Printer::log("Cannot optimize a mesh with 32bit indices", ELL_ERROR);
newmesh->drop();
return 0;
}
const u32 icount = mb->getIndexCount();
const u32 tcount = icount / 3;
const u32 vcount = mb->getVertexCount();
const u16 *ind = mb->getIndices();
vcache *vc = new vcache[vcount];
tcache *tc = new tcache[tcount];
f_lru lru(vc, tc);
// init
for (u16 i = 0; i < vcount; i++)
{
vc[i].score = 0;
vc[i].cachepos = -1;
vc[i].NumActiveTris = 0;
}
// First pass: count how many times a vert is used
for (u32 i = 0; i < icount; i += 3)
{
vc[ind[i]].NumActiveTris++;
vc[ind[i + 1]].NumActiveTris++;
vc[ind[i + 2]].NumActiveTris++;
const u32 tri_ind = i/3;
tc[tri_ind].ind[0] = ind[i];
tc[tri_ind].ind[1] = ind[i + 1];
tc[tri_ind].ind[2] = ind[i + 2];
}
// Second pass: list of each triangle
for (u32 i = 0; i < tcount; i++)
{
vc[tc[i].ind[0]].tris.push_back(i);
vc[tc[i].ind[1]].tris.push_back(i);
vc[tc[i].ind[2]].tris.push_back(i);
tc[i].drawn = false;
}
// Give initial scores
for (u16 i = 0; i < vcount; i++)
{
vc[i].score = FindVertexScore(&vc[i]);
}
for (u32 i = 0; i < tcount; i++)
{
tc[i].score =
vc[tc[i].ind[0]].score +
vc[tc[i].ind[1]].score +
vc[tc[i].ind[2]].score;
}
switch(mb->getVertexType())
{
case video::EVT_STANDARD:
{
video::S3DVertex *v = (video::S3DVertex *) mb->getVertices();
scene::SMeshBuffer *buf = new scene::SMeshBuffer();
buf->Material = mb->getMaterial();
buf->Vertices.reallocate(vcount);
buf->Indices.reallocate(icount);
core::map<const video::S3DVertex, const u16> sind; // search index for fast operation
typedef core::map<const video::S3DVertex, const u16>::Node snode;
// Main algorithm
u32 highest = 0;
u32 drawcalls = 0;
for (;;)
{
if (tc[highest].drawn)
{
bool found = false;
float hiscore = 0;
for (u32 t = 0; t < tcount; t++)
{
if (!tc[t].drawn)
{
if (tc[t].score > hiscore)
{
highest = t;
hiscore = tc[t].score;
found = true;
}
}
}
if (!found)
break;
}
// Output the best triangle
u16 newind = buf->Vertices.size();
snode *s = sind.find(v[tc[highest].ind[0]]);
if (!s)
{
buf->Vertices.push_back(v[tc[highest].ind[0]]);
buf->Indices.push_back(newind);
sind.insert(v[tc[highest].ind[0]], newind);
newind++;
}
else
{
buf->Indices.push_back(s->getValue());
}
s = sind.find(v[tc[highest].ind[1]]);
if (!s)
{
buf->Vertices.push_back(v[tc[highest].ind[1]]);
buf->Indices.push_back(newind);
sind.insert(v[tc[highest].ind[1]], newind);
newind++;
}
else
{
buf->Indices.push_back(s->getValue());
}
s = sind.find(v[tc[highest].ind[2]]);
if (!s)
{
buf->Vertices.push_back(v[tc[highest].ind[2]]);
buf->Indices.push_back(newind);
sind.insert(v[tc[highest].ind[2]], newind);
}
else
{
buf->Indices.push_back(s->getValue());
}
vc[tc[highest].ind[0]].NumActiveTris--;
vc[tc[highest].ind[1]].NumActiveTris--;
vc[tc[highest].ind[2]].NumActiveTris--;
tc[highest].drawn = true;
for (u16 j = 0; j < 3; j++)
{
vcache *vert = &vc[tc[highest].ind[j]];
for (u16 t = 0; t < vert->tris.size(); t++)
{
if (highest == vert->tris[t])
{
vert->tris.erase(t);
break;
}
}
}
lru.add(tc[highest].ind[0]);
lru.add(tc[highest].ind[1]);
highest = lru.add(tc[highest].ind[2], true);
drawcalls++;
}
buf->setBoundingBox(mb->getBoundingBox());
newmesh->addMeshBuffer(buf);
buf->drop();
}
break;
case video::EVT_2TCOORDS:
{
video::S3DVertex2TCoords *v = (video::S3DVertex2TCoords *) mb->getVertices();
scene::SMeshBufferLightMap *buf = new scene::SMeshBufferLightMap();
buf->Material = mb->getMaterial();
buf->Vertices.reallocate(vcount);
buf->Indices.reallocate(icount);
core::map<const video::S3DVertex2TCoords, const u16> sind; // search index for fast operation
typedef core::map<const video::S3DVertex2TCoords, const u16>::Node snode;
// Main algorithm
u32 highest = 0;
u32 drawcalls = 0;
for (;;)
{
if (tc[highest].drawn)
{
bool found = false;
float hiscore = 0;
for (u32 t = 0; t < tcount; t++)
{
if (!tc[t].drawn)
{
if (tc[t].score > hiscore)
{
highest = t;
hiscore = tc[t].score;
found = true;
}
}
}
if (!found)
break;
}
// Output the best triangle
u16 newind = buf->Vertices.size();
snode *s = sind.find(v[tc[highest].ind[0]]);
if (!s)
{
buf->Vertices.push_back(v[tc[highest].ind[0]]);
buf->Indices.push_back(newind);
sind.insert(v[tc[highest].ind[0]], newind);
newind++;
}
else
{
buf->Indices.push_back(s->getValue());
}
s = sind.find(v[tc[highest].ind[1]]);
if (!s)
{
buf->Vertices.push_back(v[tc[highest].ind[1]]);
buf->Indices.push_back(newind);
sind.insert(v[tc[highest].ind[1]], newind);
newind++;
}
else
{
buf->Indices.push_back(s->getValue());
}
s = sind.find(v[tc[highest].ind[2]]);
if (!s)
{
buf->Vertices.push_back(v[tc[highest].ind[2]]);
buf->Indices.push_back(newind);
sind.insert(v[tc[highest].ind[2]], newind);
}
else
{
buf->Indices.push_back(s->getValue());
}
vc[tc[highest].ind[0]].NumActiveTris--;
vc[tc[highest].ind[1]].NumActiveTris--;
vc[tc[highest].ind[2]].NumActiveTris--;
tc[highest].drawn = true;
for (u16 j = 0; j < 3; j++)
{
vcache *vert = &vc[tc[highest].ind[j]];
for (u16 t = 0; t < vert->tris.size(); t++)
{
if (highest == vert->tris[t])
{
vert->tris.erase(t);
break;
}
}
}
lru.add(tc[highest].ind[0]);
lru.add(tc[highest].ind[1]);
highest = lru.add(tc[highest].ind[2]);
drawcalls++;
}
buf->setBoundingBox(mb->getBoundingBox());
newmesh->addMeshBuffer(buf);
buf->drop();
}
break;
case video::EVT_TANGENTS:
{
video::S3DVertexTangents *v = (video::S3DVertexTangents *) mb->getVertices();
scene::SMeshBufferTangents *buf = new scene::SMeshBufferTangents();
buf->Material = mb->getMaterial();
buf->Vertices.reallocate(vcount);
buf->Indices.reallocate(icount);
core::map<const video::S3DVertexTangents, const u16> sind; // search index for fast operation
typedef core::map<const video::S3DVertexTangents, const u16>::Node snode;
// Main algorithm
u32 highest = 0;
u32 drawcalls = 0;
for (;;)
{
if (tc[highest].drawn)
{
bool found = false;
float hiscore = 0;
for (u32 t = 0; t < tcount; t++)
{
if (!tc[t].drawn)
{
if (tc[t].score > hiscore)
{
highest = t;
hiscore = tc[t].score;
found = true;
}
}
}
if (!found)
break;
}
// Output the best triangle
u16 newind = buf->Vertices.size();
snode *s = sind.find(v[tc[highest].ind[0]]);
if (!s)
{
buf->Vertices.push_back(v[tc[highest].ind[0]]);
buf->Indices.push_back(newind);
sind.insert(v[tc[highest].ind[0]], newind);
newind++;
}
else
{
buf->Indices.push_back(s->getValue());
}
s = sind.find(v[tc[highest].ind[1]]);
if (!s)
{
buf->Vertices.push_back(v[tc[highest].ind[1]]);
buf->Indices.push_back(newind);
sind.insert(v[tc[highest].ind[1]], newind);
newind++;
}
else
{
buf->Indices.push_back(s->getValue());
}
s = sind.find(v[tc[highest].ind[2]]);
if (!s)
{
buf->Vertices.push_back(v[tc[highest].ind[2]]);
buf->Indices.push_back(newind);
sind.insert(v[tc[highest].ind[2]], newind);
}
else
{
buf->Indices.push_back(s->getValue());
}
vc[tc[highest].ind[0]].NumActiveTris--;
vc[tc[highest].ind[1]].NumActiveTris--;
vc[tc[highest].ind[2]].NumActiveTris--;
tc[highest].drawn = true;
for (u16 j = 0; j < 3; j++)
{
vcache *vert = &vc[tc[highest].ind[j]];
for (u16 t = 0; t < vert->tris.size(); t++)
{
if (highest == vert->tris[t])
{
vert->tris.erase(t);
break;
}
}
}
lru.add(tc[highest].ind[0]);
lru.add(tc[highest].ind[1]);
highest = lru.add(tc[highest].ind[2]);
drawcalls++;
}
buf->setBoundingBox(mb->getBoundingBox());
newmesh->addMeshBuffer(buf);
buf->drop();
}
break;
}
delete [] vc;
delete [] tc;
} // for each meshbuffer
return newmesh;
}
void OptimizeFaces(const uint16* indexList, uint indexCount, uint vertexCount, uint16* newIndexList, uint16 lruCacheSize)
{
std::vector<OptimizeVertexData> vertexDataList;
vertexDataList.resize(vertexCount);
// compute face count per vertex
for (uint i=0; i<indexCount; ++i)
{
uint16 index = indexList[i];
assert(index < vertexCount);
OptimizeVertexData& vertexData = vertexDataList[index];
vertexData.activeFaceListSize++;
}
std::vector<uint> activeFaceList;
const uint16 kEvictedCacheIndex = std::numeric_limits<uint16>::max();
{
// allocate face list per vertex
uint curActiveFaceListPos = 0;
for (uint i=0; i<vertexCount; ++i)
{
OptimizeVertexData& vertexData = vertexDataList[i];
vertexData.cachePos0 = kEvictedCacheIndex;
vertexData.cachePos1 = kEvictedCacheIndex;
vertexData.activeFaceListStart = curActiveFaceListPos;
curActiveFaceListPos += vertexData.activeFaceListSize;
vertexData.score = FindVertexScore(vertexData.activeFaceListSize, vertexData.cachePos0, lruCacheSize);
vertexData.activeFaceListSize = 0;
}
activeFaceList.resize(curActiveFaceListPos);
}
// fill out face list per vertex
for (uint i=0; i<indexCount; i+=3)
{
for (uint j=0; j<3; ++j)
{
uint16 index = indexList[i+j];
OptimizeVertexData& vertexData = vertexDataList[index];
activeFaceList[vertexData.activeFaceListStart + vertexData.activeFaceListSize] = i;
vertexData.activeFaceListSize++;
}
}
std::vector<byte> processedFaceList;
processedFaceList.resize(indexCount);
uint16 vertexCacheBuffer[(kMaxVertexCacheSize+3)*2];
uint16* cache0 = vertexCacheBuffer;
uint16* cache1 = vertexCacheBuffer+(kMaxVertexCacheSize+3);
uint16 entriesInCache0 = 0;
uint bestFace = 0;
float bestScore = -1.f;
const float maxValenceScore = FindVertexScore(1, kEvictedCacheIndex, lruCacheSize) * 3.f;
for (uint i = 0; i < indexCount; i += 3)
{
if (bestScore < 0.f)
{
// no verts in the cache are used by any unprocessed faces so
// search all unprocessed faces for a new starting point
for (uint j = 0; j < indexCount; j += 3)
{
if (processedFaceList[j] == 0)
{
uint face = j;
float faceScore = 0.f;
for (uint k=0; k<3; ++k)
{
uint16 index = indexList[face+k];
OptimizeVertexData& vertexData = vertexDataList[index];
assert(vertexData.activeFaceListSize > 0);
assert(vertexData.cachePos0 >= lruCacheSize);
faceScore += vertexData.score;
}
if (faceScore > bestScore)
{
bestScore = faceScore;
bestFace = face;
assert(bestScore <= maxValenceScore);
if (bestScore >= maxValenceScore)
{
break;
}
}
}
}
assert(bestScore >= 0.f);
}
processedFaceList[bestFace] = 1;
uint16 entriesInCache1 = 0;
// add bestFace to LRU cache and to newIndexList
for (uint v = 0; v < 3; ++v)
{
uint16 index = indexList[bestFace+v];
newIndexList[i+v] = index;
OptimizeVertexData& vertexData = vertexDataList[index];
if (vertexData.cachePos1 >= entriesInCache1)
{
vertexData.cachePos1 = entriesInCache1;
cache1[entriesInCache1++] = index;
if (vertexData.activeFaceListSize == 1)
{
--vertexData.activeFaceListSize;
continue;
}
}
assert(vertexData.activeFaceListSize > 0);
uint* begin = &activeFaceList[vertexData.activeFaceListStart];
uint* end = &activeFaceList[vertexData.activeFaceListStart + vertexData.activeFaceListSize];
uint* it = std::find(begin, end, bestFace);
assert(it != end);
std::swap(*it, *(end-1));
--vertexData.activeFaceListSize;
vertexData.score = FindVertexScore(vertexData.activeFaceListSize, vertexData.cachePos1, lruCacheSize);
}
// move the rest of the old verts in the cache down and compute their new scores
for (uint c0 = 0; c0 < entriesInCache0; ++c0)
{
uint16 index = cache0[c0];
OptimizeVertexData& vertexData = vertexDataList[index];
if (vertexData.cachePos1 >= entriesInCache1)
{
vertexData.cachePos1 = entriesInCache1;
cache1[entriesInCache1++] = index;
vertexData.score = FindVertexScore(vertexData.activeFaceListSize, vertexData.cachePos1, lruCacheSize);
}
}
// find the best scoring triangle in the current cache (including up to 3 that were just evicted)
bestScore = -1.f;
for (uint c1 = 0; c1 < entriesInCache1; ++c1)
{
uint16 index = cache1[c1];
OptimizeVertexData& vertexData = vertexDataList[index];
vertexData.cachePos0 = vertexData.cachePos1;
vertexData.cachePos1 = kEvictedCacheIndex;
for (uint j=0; j<vertexData.activeFaceListSize; ++j)
{
uint face = activeFaceList[vertexData.activeFaceListStart+j];
float faceScore = 0.f;
for (uint v=0; v<3; v++)
{
uint16 faceIndex = indexList[face+v];
OptimizeVertexData& faceVertexData = vertexDataList[faceIndex];
faceScore += faceVertexData.score;
}
if (faceScore > bestScore)
{
bestScore = faceScore;
bestFace = face;
}
}
}
std::swap(cache0, cache1);
entriesInCache0 = std::min(entriesInCache1, lruCacheSize);
}
}
