C++ CModel::GetMaterial方法代码示例

void ShaderModelRenderer::Render(const RenderModifierPtr& modifier, const CShaderDefines& context, int cullGroup, int flags)
{
	if (m->submissions[cullGroup].empty())
		return;

	CMatrix3D worldToCam;
	g_Renderer.GetViewCamera().m_Orientation.GetInverse(worldToCam);

	/*
	 * Rendering approach:
	 * 
	 * m->submissions contains the list of CModels to render.
	 * 
	 * The data we need to render a model is:
	 *  - CShaderTechnique
	 *  - CTexture
	 *  - CShaderUniforms
	 *  - CModelDef (mesh data)
	 *  - CModel (model instance data)
	 * 
	 * For efficient rendering, we need to batch the draw calls to minimise state changes.
	 * (Uniform and texture changes are assumed to be cheaper than binding new mesh data,
	 * and shader changes are assumed to be most expensive.)
	 * First, group all models that share a technique to render them together.
	 * Within those groups, sub-group by CModelDef.
	 * Within those sub-groups, sub-sub-group by CTexture.
	 * Within those sub-sub-groups, sub-sub-sub-group by CShaderUniforms.
	 * 
	 * Alpha-blended models have to be sorted by distance from camera,
	 * then we can batch as long as the order is preserved.
	 * Non-alpha-blended models can be arbitrarily reordered to maximise batching.
	 * 
	 * For each model, the CShaderTechnique is derived from:
	 *  - The current global 'context' defines
	 *  - The CModel's material's defines
	 *  - The CModel's material's shader effect name
	 * 
	 * There are a smallish number of materials, and a smaller number of techniques.
	 * 
	 * To minimise technique lookups, we first group models by material,
	 * in 'materialBuckets' (a hash table).
	 * 
	 * For each material bucket we then look up the appropriate shader technique.
	 * If the technique requires sort-by-distance, the model is added to the
	 * 'sortByDistItems' list with its computed distance.
	 * Otherwise, the bucket's list of models is sorted by modeldef+texture+uniforms,
	 * then the technique and model list is added to 'techBuckets'.
	 * 
	 * 'techBuckets' is then sorted by technique, to improve batching when multiple
	 * materials map onto the same technique.
	 * 
	 * (Note that this isn't perfect batching: we don't sort across models in
	 * multiple buckets that share a technique. In practice that shouldn't reduce
	 * batching much (we rarely have one mesh used with multiple materials),
	 * and it saves on copying and lets us sort smaller lists.)
	 * 
	 * Extra tech buckets are added for the sorted-by-distance models without reordering.
	 * Finally we render by looping over each tech bucket, then looping over the model
	 * list in each, rebinding the GL state whenever it changes.
	 */

	Allocators::DynamicArena arena(256 * KiB);
	typedef ProxyAllocator<CModel*, Allocators::DynamicArena> ModelListAllocator;
	typedef std::vector<CModel*, ModelListAllocator> ModelList_t;
	typedef boost::unordered_map<SMRMaterialBucketKey, ModelList_t,
		SMRMaterialBucketKeyHash, std::equal_to<SMRMaterialBucketKey>,
		ProxyAllocator<std::pair<const SMRMaterialBucketKey, ModelList_t>, Allocators::DynamicArena>
	> MaterialBuckets_t;
	MaterialBuckets_t materialBuckets((MaterialBuckets_t::allocator_type(arena)));

	{
		PROFILE3("bucketing by material");

		for (size_t i = 0; i < m->submissions[cullGroup].size(); ++i)
		{
			CModel* model = m->submissions[cullGroup][i];

			uint32_t condFlags = 0;

			const CShaderConditionalDefines& condefs = model->GetMaterial().GetConditionalDefines();
			for (size_t j = 0; j < condefs.GetSize(); ++j)
			{
				const CShaderConditionalDefines::CondDefine& item = condefs.GetItem(j);
				int type = item.m_CondType;
				switch (type)
				{
					case DCOND_DISTANCE:
					{
						CVector3D modelpos = model->GetTransform().GetTranslation();
						float dist = worldToCam.Transform(modelpos).Z;
						
						float dmin = item.m_CondArgs[0];
						float dmax = item.m_CondArgs[1];
						
						if ((dmin < 0 || dist >= dmin) && (dmax < 0 || dist < dmax))
							condFlags |= (1 << j);
						
						break;
					}
				}
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