void CModelMeshNode::renderInstanced(E_PIPELINE_USAGE usage, u32 instanceCount, IMeshBuffer* instanceBuffer)
{
if (instanceCount == 0)
mMesh->bind();
else
mMesh->bind(instanceBuffer);
IPipeline* prePipeline = nullptr; /* 记录前一个流水线 */
IMaterial* preMaterial = nullptr; /* 记录前一个子集的材质 */
u32 subsetCount = mMesh->getSubsetCount();
for (u32 i = 0; i < subsetCount; i++)
{
IMaterial* material = mMaterials[i];
if (!material)
continue;
IPipeline* pipeline = material->getPipeline(usage);
if (!pipeline)
continue;
//如果当前的流水线和上一条相同，则除了材质外的其他变量不用注入
if (pipeline == prePipeline)
{
//当且仅当材质也不同于上一个时才注入
if (preMaterial != material)
{
CShaderVariableInjection::injectMaterial(material, pipeline);
pipeline->apply(usage);
}
}
else // 如果两条流水线不同，全部变量都需要更新
{
CShaderVariableInjection::inject(this, pipeline, i);
pipeline->apply(usage);
prePipeline = pipeline;
}
if (instanceCount == 0)
mMesh->drawSubset(i);
else
mMesh->drawSubsetInstanced(i, instanceCount);
preMaterial = material;
}
}
