/*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;
}