what is RenderTargetView/DepthStencilView/ShaderResourceView means
A resource view (a.k.a descriptor or descriptor view) is an object that allows us to tell the GPU how to interpret our data in a resource into something it could use in a shader or pipeline
Example
A recent work of me can explain this very easy, example you want to use a texture2Darray to store your cascade shadow map.
then you need to fill DepthOrArraySize in D3D12_RESOURCE_DESC when create the texture.
typedef struct D3D12_RESOURCE_DESC {
D3D12_RESOURCE_DIMENSION Dimension;
UINT64 Alignment;
UINT64 Width;
UINT Height;
UINT16 DepthOrArraySize;
UINT16 MipLevels;
DXGI_FORMAT Format;
DXGI_SAMPLE_DESC SampleDesc;
D3D12_TEXTURE_LAYOUT Layout;
D3D12_RESOURCE_FLAGS Flags;
} D3D12_RESOURCE_DESC;
the texture is used for shadowmap pass, so you need create a depthstencilview for it
typedef struct D3D12_DEPTH_STENCIL_VIEW_DESC {
DXGI_FORMAT Format;
D3D12_DSV_DIMENSION ViewDimension;
D3D12_DSV_FLAGS Flags;
union {
D3D12_TEX1D_DSV Texture1D;
D3D12_TEX1D_ARRAY_DSV Texture1DArray;
D3D12_TEX2D_DSV Texture2D;
D3D12_TEX2D_ARRAY_DSV Texture2DArray;
D3D12_TEX2DMS_DSV Texture2DMS;
D3D12_TEX2DMS_ARRAY_DSV Texture2DMSArray;
};
} D3D12_DEPTH_STENCIL_VIEW_DESC;
typedef struct D3D12_TEX2D_ARRAY_DSV {
UINT MipSlice;
UINT FirstArraySlice;
UINT ArraySize;
} D3D12_TEX2D_ARRAY_DSV;
we want to render the each cascade with one render pass, so fill the Texture2DArray.FirstArraySlice with cascade index, and Texture2DArray.ArraySize with 1.(another way is to fill them with 0, N and use a geometry shader)
debug your program with a renderdoc framecap
to use the shadowmap in shading pass, you need to create a shaderresoureview for it, when you fill D3D12_SHADER_RESOURCE_VIEW_DESC , you should fill the Texture2DArray.FirstArraySlice with 0, and Texture2DArray.ArraySize with N. to access all slices in you texture2darray.