////////////////////////////////////////////////////////////
// DrawUnsorted
////////////////////////////////////////////////////////////
bool MeshRender::DrawUnsorted(unsigned int iIndex)
{
ai_assert(iIndex < scene->mNumMeshes);
// set vertex and index buffer
devices.d3ddev->SetStreamSource(0,apcMeshes[iIndex]->piVB,0,
sizeof(Vertex));
devices.d3ddev->SetIndices(apcMeshes[iIndex]->piIB);
D3DPRIMITIVETYPE type;
switch (scene->mMeshes[iIndex]->mPrimitiveTypes) {
case aiPrimitiveType_POINT:
type = D3DPT_POINTLIST;break;
case aiPrimitiveType_LINE:
type = D3DPT_LINELIST;break;
case aiPrimitiveType_TRIANGLE:
type = D3DPT_TRIANGLELIST;break;
}
// and draw the mesh
devices.d3ddev->DrawIndexedPrimitive(type,
0,0,
scene->mMeshes[iIndex]->mNumVertices,0,
scene->mMeshes[iIndex]->mNumFaces);
return true;
}
////////////////////////////////////////////////////////////
// DrawSorted
////////////////////////////////////////////////////////////
bool MeshRender::DrawSorted(unsigned int iIndex,const aiMatrix4x4& mWorld)
{
ai_assert(iIndex < scene->mNumMeshes);
MeshHelper* pcHelper = apcMeshes[iIndex];
const aiMesh* pcMesh = scene->mMeshes[iIndex];
if (!pcHelper || !pcMesh || !pcHelper->piIB)
return false;
if (pcMesh->mPrimitiveTypes != aiPrimitiveType_TRIANGLE || pcMesh->HasBones())
return DrawUnsorted(iIndex);
// compute the position of the camera in worldspace
aiMatrix4x4 mWorldInverse = mWorld;
mWorldInverse.Inverse();
mWorldInverse.Transpose();
const aiVector3D vLocalCamera = mWorldInverse * aiVector3D(0.0f, 0.0f, 15.0f);
// well ... this is really funny now. We must compute their distance
// from the camera. We take the average distance of a face and add it
// to a map which sorts it
std::map<float,unsigned int, std::greater<float>> smap;
for (unsigned int iFace = 0; iFace < pcMesh->mNumFaces;++iFace)
{
const aiFace* pcFace = &pcMesh->mFaces[iFace];
float fDist = 0.0f;
for (unsigned int c = 0; c < 3;++c)
{
aiVector3D vPos = pcMesh->mVertices[pcFace->mIndices[c]];
vPos -= vLocalCamera;
fDist += vPos.SquareLength();
}
smap.insert(std::pair<float, unsigned int>(fDist,iFace));
}
// now we can lock the index buffer and rebuild it
D3DINDEXBUFFER_DESC sDesc;
pcHelper->piIB->GetDesc(&sDesc);
if (D3DFMT_INDEX16 == sDesc.Format)
{
uint16_t* aiIndices;
pcHelper->piIB->Lock(0,0,(void**)&aiIndices,D3DLOCK_DISCARD);
for (std::map<float,unsigned int, std::greater<float> >::const_iterator
i = smap.begin();
i != smap.end();++i)
{
const aiFace* pcFace = &pcMesh->mFaces[(*i).second];
*aiIndices++ = (uint16_t)pcFace->mIndices[0];
*aiIndices++ = (uint16_t)pcFace->mIndices[1];
*aiIndices++ = (uint16_t)pcFace->mIndices[2];
}
}
else if (D3DFMT_INDEX32 == sDesc.Format)
{
uint32_t* aiIndices;
pcHelper->piIB->Lock(0,0,(void**)&aiIndices,D3DLOCK_DISCARD);
for (std::map<float,unsigned int, std::greater<float>>::const_iterator
i = smap.begin();
i != smap.end();++i)
{
const aiFace* pcFace = &pcMesh->mFaces[(*i).second];
*aiIndices++ = (uint32_t)pcFace->mIndices[0];
*aiIndices++ = (uint32_t)pcFace->mIndices[1];
*aiIndices++ = (uint32_t)pcFace->mIndices[2];
}
}
pcHelper->piIB->Unlock();
// set vertex and index buffer
devices.d3ddev->SetStreamSource(0,pcHelper->piVB,0,sizeof(Vertex));
// and draw the mesh
devices.d3ddev->SetIndices(pcHelper->piIB);
devices.d3ddev->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,
0,0,
pcMesh->mNumVertices,0,
pcMesh->mNumFaces);
return true;
}