assimp/tools/assimp_view/MeshRenderer.cpp

/*
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Open Asset Import Library (ASSIMP)
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Copyright (c) 2006-2008, ASSIMP Development Team

All rights reserved.

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  following disclaimer.

* Redistributions in binary form must reproduce the above
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  derived from this software without specific prior
  written permission of the ASSIMP Development Team.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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*/

#include "stdafx.h"
#include "assimp_view.h"

#include <map>

namespace AssimpView {


CMeshRenderer CMeshRenderer::s_cInstance;

//-------------------------------------------------------------------------------
int CMeshRenderer::DrawUnsorted(unsigned int iIndex)
{
	ai_assert(iIndex < g_pcAsset->pcScene->mNumMeshes);

	// set vertex and index buffer
	g_piDevice->SetStreamSource(0,g_pcAsset->apcMeshes[iIndex]->piVB,0,
		sizeof(AssetHelper::Vertex));

	g_piDevice->SetIndices(g_pcAsset->apcMeshes[iIndex]->piIB);

	// and draw the mesh
	g_piDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,
		0,0,
		g_pcAsset->pcScene->mMeshes[iIndex]->mNumVertices,0,
		g_pcAsset->pcScene->mMeshes[iIndex]->mNumFaces);

	return 1;
}
//-------------------------------------------------------------------------------
int CMeshRenderer::DrawSorted(unsigned int iIndex,const aiMatrix4x4& mWorld)
{
	ai_assert(iIndex < g_pcAsset->pcScene->mNumMeshes);

	AssetHelper::MeshHelper* pcHelper = g_pcAsset->apcMeshes[iIndex]; 
	const aiMesh* pcMesh = g_pcAsset->pcScene->mMeshes[iIndex];

	// only resort the tree of the rotation/position of the object
	// or camera have been changed
	if (this->m_bRotationChanged)
	{
		if (AI_VIEW_ALPHA_SORT_DELTA == ++this->m_iFrameCount)
		{
			this->m_iFrameCount = 0;

			// compute the position of the camera in worldspace
			aiMatrix4x4 mWorldInverse = mWorld;
			mWorldInverse.Inverse();
			mWorldInverse.Transpose();
			const aiVector3D vLocalCamera = mWorldInverse * g_sCamera.vPos;

			// 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
	g_piDevice->SetStreamSource(0,pcHelper->piVB,0,sizeof(AssetHelper::Vertex));

	// and draw the mesh
	g_piDevice->SetIndices(pcHelper->piIB);
	g_piDevice->DrawIndexedPrimitive(D3DPT_TRIANGLELIST,
		0,0,
		pcMesh->mNumVertices,0,
		pcMesh->mNumFaces);

	return 1;
}
};