示例#1
0
	/*求对象rend和射线ray的全部交点到射线原点的距离
	*/
	vector<Ogre::Real> BaseManager::Intersect(const Ogre::Ray& ray,Ogre::Renderable *rend){
		Ogre::RenderOperation op;
		Ogre::VertexElementType vtype;
		size_t offset,pkgsize,source,indexNums,vertexNums;
		vector<Ogre::Real> result;

		rend->getRenderOperation( op );

		if( !op.indexData || 
			op.operationType==Ogre::RenderOperation::OT_LINE_LIST || 
			op.operationType==Ogre::RenderOperation::OT_LINE_STRIP ||
			op.operationType==Ogre::RenderOperation::OT_POINT_LIST )
			return result;

		Ogre::VertexDeclaration* pvd = op.vertexData->vertexDeclaration;

		source = -1;
		for( size_t i = 0;i < pvd->getElementCount();++i ){
			if( pvd->getElement(i)->getSemantic()==Ogre::VES_POSITION ){
				source = pvd->getElement(i)->getSource();
				offset = pvd->getElement(i)->getOffset();
				vtype = pvd->getElement(i)->getType();
				break;
			}
		}
		if( source == - 1 || vtype != Ogre::VET_FLOAT3 ) //别的格式目前没有考虑
			return result;

		/*source对应与一个缓存区
		  getVertexSize(source)求缓存区中一个紧密数据包的大小
		  例如:一个数据包里面包括POSITION,COLOR,NORMAL,TEXCROOD然后在这个缓冲
			区中循环。而getVertexSize求出这个包的字节大小
		  例如POSITION(FLOAT3) TEXCROOD(FLOAT2) 这样前面的是12字节后面的是8字节
			getVertexSize返回20
		*/
		pkgsize = pvd->getVertexSize(source);

		Ogre::HardwareVertexBufferSharedPtr hvb = op.vertexData->vertexBufferBinding->getBuffer(source);
		Ogre::HardwareIndexBufferSharedPtr ivb = op.indexData->indexBuffer;
		Ogre::HardwareIndexBuffer::IndexType indexType = op.indexData->indexBuffer->getType();
		/*先将顶点数据复制一份,然后变换到世界坐标系
		*/
		vertexNums = hvb->getNumVertices();
		indexNums = ivb->getNumIndexes();
		 
		boost::scoped_array<float> vp( new float[3*vertexNums] );
		boost::scoped_array<unsigned int> ip( new unsigned int[indexNums] );
		
		{
			Ogre::Vector3 p3;
			Ogre::Matrix4 mat;
			rend->getWorldTransforms( &mat );
			float* preal = (float*)hvb->lock( Ogre::HardwareBuffer::HBL_READ_ONLY );
			float* ptarget = vp.get();
			//这里考虑到对齐,我假设offset和pkgsize都可以被sizeof(float)整除
			preal += offset/sizeof(float);
			size_t strip = pkgsize/sizeof(float);
			for( size_t i = 0; i < vertexNums;++i ){
				p3.x = *preal;
				p3.y = *(preal+1);
				p3.z = *(preal+2);
				p3 = mat * p3;
				*ptarget++ = p3.x;
				*ptarget++ = p3.y;
				*ptarget++ = p3.z;
				preal += strip;
			}
			hvb->unlock();
		}
		//拷贝出顶点数据
		
		{
			unsigned int* pindex32 = ip.get();
			
			if( indexType==Ogre::HardwareIndexBuffer::IT_16BIT ){
				unsigned short* pi16 = (unsigned short*)ivb->lock( Ogre::HardwareBuffer::HBL_READ_ONLY );
				copy( pi16,pi16+indexNums,pindex32 );
			}else
				memcpy( pindex32,ivb->lock( Ogre::HardwareBuffer::HBL_READ_ONLY ),ivb->getSizeInBytes() );
			ivb->unlock();
		}
		/*数据都准备好了,vp保存了变换好的顶点,ip保存了顶点索引
			下面根据情况求交点
		*/
		switch( op.operationType ){
			case Ogre::RenderOperation::OT_TRIANGLE_LIST:
				{ /* 0,1,2 组成一个三角 3,4,5 下一个...
				  */
					Ogre::Vector3 a[3],n;
					int index,k = 0;
					float* preal = vp.get();
					unsigned int* pindex = ip.get();
					for( size_t i = 0;i<indexNums;++i ){
						if( pindex[i] < vertexNums ){
							index = pindex[i]*3; //对应与格式VET_FLOAT3
							a[k].x = preal[index];
							a[k].y = preal[index+1];
							a[k].z = preal[index+2];
							if( k == 2 ){//三个点都填满了
								//这里使用的是Math3d的求交函数,而不是Ogre::Math的
								//原因就在于Ogre::Math的求交点函数不能得到射线背面那个负的交点
								std::pair<bool,Ogre::Real> res = Math3d::intersects(ray,a[0],a[1],a[2],true,true);
								if( res.first )
									result.push_back( res.second );
								k = 0;
							}else
								k++;
						}else{
							WARNING_LOG("Game::Intersect"<<" Invalid index rang out" << " pindex["<<i<<"]="<<pindex[i] << "("<<vertexNums<<")");
							return result;
						}
					}
				}
				break;
			case Ogre::RenderOperation::OT_TRIANGLE_FAN:
				{/* 0,1,2组成一个三角 0,2,3 组成下一个 0,3,4...
				 */
					assert( false||"Game::Intersect can't support OT_TRIANGLE_FAN " );
				}
				break;
			case Ogre::RenderOperation::OT_TRIANGLE_STRIP:
				{//0,1,2组成第一个三角 1,2,3 组成下一个 2,3,4...
					assert( false||"Game::Intersect can't support OT_TRIANGLE_STRIP " );
				}
				break;
			default:;
		}
		return result;
	}
bool ShaderParticleRenderer::allocateBuffers(size_t iNumParticles)
{
    // prepare vertex declaration
    if (mVertexData->vertexDeclaration->getElementCount() == 0) {
        VertexDeclaration* pDecl = mVertexData->vertexDeclaration;
        size_t ofs = 0;
        ofs += pDecl->addElement(0, ofs, VET_FLOAT4, VES_POSITION).getSize();				// position
        if (mVertexFormatColour)
            ofs += pDecl->addElement(0, ofs, VET_FLOAT4, VES_DIFFUSE).getSize();			// diffuse colour

        // other data are stored in vertex as texture coordinates
        ushort ix = 0;
        if (mVertexFormatTexture)
            ofs += pDecl->addElement(0, ofs, VET_FLOAT2, VES_TEXTURE_COORDINATES, ix++).getSize();	// general texture coord

        if (mVertexFormatSize)
            ofs += pDecl->addElement(0, ofs, VET_FLOAT2, VES_TEXTURE_COORDINATES, ix++).getSize();	// particle size

        if (mVertexFormatRotation || mVertexFormatRotationSpeed) {
            if (mVertexFormatRotation && mVertexFormatRotationSpeed)
                ofs += pDecl->addElement(0, ofs, VET_FLOAT2, VES_TEXTURE_COORDINATES, ix++).getSize();	// current rotation and rotation speed
            else
                ofs += pDecl->addElement(0, ofs, VET_FLOAT1, VES_TEXTURE_COORDINATES, ix++).getSize();	// current rotation or rotation speed
        }

        if (mVertexFormatDirection)
            ofs += pDecl->addElement(0, ofs, VET_FLOAT3, VES_TEXTURE_COORDINATES, ix++).getSize();	// particle direction (as speed)

        // add packed times
        size_t iNumTimes = 0;
        if (mVertexFormatTTL) iNumTimes++;
        if (mVertexFormatTotalTTL) iNumTimes++;
        if (mVertexFormatTimeFragment) iNumTimes++;
        if (mVertexFormatTimeFragmentInv) iNumTimes++;
        switch(iNumTimes) {
            case 1:
                ofs += pDecl->addElement(0, ofs, VET_FLOAT1, VES_TEXTURE_COORDINATES, ix++).getSize();
                break;
            case 2:
                ofs += pDecl->addElement(0, ofs, VET_FLOAT2, VES_TEXTURE_COORDINATES, ix++).getSize();
                break;
            case 3:
                ofs += pDecl->addElement(0, ofs, VET_FLOAT3, VES_TEXTURE_COORDINATES, ix++).getSize();
                break;
            case 4:
                ofs += pDecl->addElement(0, ofs, VET_FLOAT4, VES_TEXTURE_COORDINATES, ix++).getSize();
                break;
        }

        // add custom parameters
        ofs += pDecl->addElement(0, ofs, VET_FLOAT4, VES_TEXTURE_COORDINATES, ix++).getSize();
        assert(ix <= 8);

        // cache vertex size
        mVertexSize = pDecl->getVertexSize(0);
    }

    Ogre::HardwareVertexBufferSharedPtr pVB;
    if (mVertexData->vertexBufferBinding->isBufferBound(0))
        pVB = mVertexData->vertexBufferBinding->getBuffer(0);

    // prepare vertex buffer
    if (pVB.isNull() || pVB->getNumVertices() < iNumParticles * 4) {
        assert(iNumParticles * 4 < 65536); // we are using 16bit index buffer
        pVB = Ogre::HardwareBufferManager::getSingleton().createVertexBuffer(mVertexSize, 4 * iNumParticles, Ogre::HardwareBuffer::HBU_DYNAMIC_WRITE_ONLY_DISCARDABLE);
        if (pVB.isNull())
            return false;

        mVertexData->vertexBufferBinding->setBinding(0, pVB);
    }

    // prepare index buffer
    Ogre::HardwareIndexBufferSharedPtr pIB = mIndexData->indexBuffer;
    if (pIB.isNull() || pIB->getNumIndexes() < iNumParticles * 6) {
        pIB = Ogre::HardwareBufferManager::getSingleton().createIndexBuffer(Ogre::HardwareIndexBuffer::IT_16BIT, iNumParticles * 6, Ogre::HardwareBuffer::HBU_STATIC_WRITE_ONLY);
        if (pIB.isNull())
            return false;

        mIndexData->indexBuffer = pIB;

        // fill
        Ogre::uint16* pDataIB = reinterpret_cast<Ogre::uint16*>(pIB->lock(Ogre::HardwareBuffer::HBL_NORMAL));
        for (Ogre::uint16 k=0; k<static_cast<Ogre::uint16>(iNumParticles); ++k) {
            pDataIB[0] = k*4 + 0;
            pDataIB[1] = k*4 + 1;
            pDataIB[2] = k*4 + 2;

            pDataIB[3] = k*4 + 0;
            pDataIB[4] = k*4 + 2;
            pDataIB[5] = k*4 + 3;
            pDataIB += 6;
        }
        pIB->unlock();
    }

    return true;
}