ue里对 UBMT_SRV和UBMT_TEXTURE的封装

texture 如果要被采样就该绑成srv这里封成两种就很奇怪了 跟了下看

使用时比如

这里

	// Custom Depth / Stencil
	SHADER_PARAMETER_TEXTURE(Texture2D<float>, CustomDepthTextureNonMS)
	SHADER_PARAMETER_TEXTURE(Texture2D, CustomDepthTexture)
	SHADER_PARAMETER_SAMPLER(SamplerState, CustomDepthTextureSampler)
	SHADER_PARAMETER_SRV(Texture2D<uint2>, CustomStencilTexture)
	SHADER_PARAMETER_SRV(Texture2D<uint2>, SceneStencilTexture)

　　stencil仅仅bind成srv 而不是像上面depth那样 texture+sampler

从使用上能看到这种patten

 最底层这两者封装差异能看到

inline void SetTexture(uint8 DescriptorSet, uint32 BindingIndex, const FVulkanTextureBase* TextureBase, VkImageLayout Layout)
	{
		check(TextureBase && TextureBase->PartialView);
		MarkDirty(DSWriter[DescriptorSet].WriteImage(BindingIndex, *TextureBase->PartialView, Layout));
	}

	inline void SetSRVBufferViewState(uint8 DescriptorSet, uint32 BindingIndex, const FVulkanBufferView* View)
	{
		check(View && (View->Flags & VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT) == VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT);
		MarkDirty(DSWriter[DescriptorSet].WriteUniformTexelBuffer(BindingIndex, View));
	}

	inline void SetSRVTextureView(uint8 DescriptorSet, uint32 BindingIndex, const FVulkanTextureView& TextureView, VkImageLayout Layout)
	{
		MarkDirty(DSWriter[DescriptorSet].WriteImage(BindingIndex, TextureView, Layout));
	}　　

上面是pipeline那层的封装

中间省略100层封装

最后

descriptorSets层的封装差异

	template <VkDescriptorType DescriptorType>
	bool WriteTextureView(uint32 DescriptorIndex, const FVulkanTextureView& TextureView, VkImageLayout Layout)
	{
		check(DescriptorIndex < NumWrites);
		if (DescriptorType == VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE)
		{
			check(WriteDescriptors[DescriptorIndex].descriptorType == VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE || WriteDescriptors[DescriptorIndex].descriptorType == VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
			ensureMsgf(Layout == VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR ||
				  Layout == VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL ||
				  Layout == VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL ||
				  Layout == VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL || 
				  Layout == VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL ||
				  Layout == VK_IMAGE_LAYOUT_GENERAL, TEXT("Invalid Layout %d, Index %d, Type %d
"), Layout, DescriptorIndex, WriteDescriptors[DescriptorIndex].descriptorType);
		}
		else
		{
			check(WriteDescriptors[DescriptorIndex].descriptorType == DescriptorType);
		}
		VkDescriptorImageInfo* ImageInfo = const_cast<VkDescriptorImageInfo*>(WriteDescriptors[DescriptorIndex].pImageInfo);
		check(ImageInfo);

		bool bChanged = false;
		if (UseVulkanDescriptorCache())
		{
			FVulkanHashableDescriptorInfo& HashableInfo = HashableDescriptorInfos[DescriptorIndex];
			check(TextureView.ViewId > 0);
			if (HashableInfo.Image.ImageViewId != TextureView.ViewId)
			{
				HashableInfo.Image.ImageViewId = TextureView.ViewId;
				ImageInfo->imageView = TextureView.View;
				bChanged = true;
			}
			if (HashableInfo.Image.ImageLayout != static_cast<uint32>(Layout))
			{
				HashableInfo.Image.ImageLayout = static_cast<uint32>(Layout);
				ImageInfo->imageLayout = Layout;
				bChanged = true;
			}
			bIsKeyDirty |= bChanged;
		}
		else
		{
			bChanged = CopyAndReturnNotEqual(ImageInfo->imageView, TextureView.View);
			bChanged |= CopyAndReturnNotEqual(ImageInfo->imageLayout, Layout);
		}

		return bChanged;
	}

	template <VkDescriptorType DescriptorType>
	bool WriteBufferView(uint32 DescriptorIndex, const FVulkanBufferView* View)
	{
		check(DescriptorIndex < NumWrites);
		check(WriteDescriptors[DescriptorIndex].descriptorType == DescriptorType);
		WriteDescriptors[DescriptorIndex].pTexelBufferView = &View->View;
		BufferViewReferences[DescriptorIndex] = View;
		
		if (UseVulkanDescriptorCache())
		{
			bool bChanged = false;
			FVulkanHashableDescriptorInfo& HashableInfo = HashableDescriptorInfos[DescriptorIndex];
			check(View->ViewId > 0);
			if (HashableInfo.BufferView.Id != View->ViewId)
			{
				HashableInfo.BufferView.Id = View->ViewId;
				bChanged = true;
			}
			bIsKeyDirty |= bChanged;
			return bChanged;
		}
		else
		{
			return true;
		}
	}

descriptor更新 view更新

除此中间还有些buffer flag的差异 

总结：

 rhi层封装为texture view和buffer view的区分