getDescriptorFromDescriptorHeapEXT
Description
Load a descriptor from the spvDescriptorHeapEXT descriptor heap. The single-descriptor kinds use only handle.x as the heap index: samplers load from the sampler heap, every other kind from the resource heap. A combined texture-sampler is the exception 429496726642949671684294967188 it is assembled from both components of the handle (a combined descriptor carries a texture part and a sampler part), so __makeCombinedTextureSamplerFromHandle receives the whole uint2 rather than just .x. This is the single lowering for the EXT heap, shared by the spvDescriptorHeapEXT arm of defaultGetDescriptorFromHandle and by the untyped-handle429496726642949671744294967186resource constructors that convert a ResourceDescriptorHeap[i] / SamplerDescriptorHeap[j] index directly to a resource, so the two paths stay in agreement.
Signature
T getDescriptorFromDescriptorHeapEXT<T>(vector<uint, 2> handle) where T : IOpaqueDescriptor;