================ @@ -0,0 +1,426 @@ +==================== +HLSL Root Signatures +==================== + +.. contents:: + :local: + +Usage +===== + +In HLSL, the `root signature +<https://learn.microsoft.com/en-us/windows/win32/direct3d12/root-signatures>`_ +defines what types of resources are bound to the graphics pipeline. + +A root signature can be specified in HLSL as a `string +<https://learn.microsoft.com/en-us/windows/win32/direct3d12/specifying-root-signatures-in-hlsl#an-example-hlsl-root-signature>`_. +The string contains a collection of comma-separated clauses that describe root +signature constituent components. + +There are two mechanisms to compile an HLSL root signature. First, it is +possible to attach a root signature string to a particular shader via the +RootSignature attribute (in the following example, using the MyRS1 entry +point): + +.. code-block:: c++ + + #define RS "RootFlags( ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT | " \ + "DENY_VERTEX_SHADER_ROOT_ACCESS), " \ + "CBV(b0, space = 1, flags = DATA_STATIC), " \ + "SRV(t0), " \ + "UAV(u0), " \ + "DescriptorTable( CBV(b1), " \ + " SRV(t1, numDescriptors = 8, " \ + " flags = DESCRIPTORS_VOLATILE), " \ + " UAV(u1, numDescriptors = unbounded, " \ + " flags = DESCRIPTORS_VOLATILE)), " \ + "DescriptorTable(Sampler(s0, space=1, numDescriptors = 4)), " \ + "RootConstants(num32BitConstants=3, b10), " \ + "StaticSampler(s1)," \ + "StaticSampler(s2, " \ + " addressU = TEXTURE_ADDRESS_CLAMP, " \ + " filter = FILTER_MIN_MAG_MIP_LINEAR )" + + [RootSignature(RS)] + float4 main(float4 coord : COORD) : SV_Target + { + … + } + +The compiler will create and verify the root signature blob for the shader and +embed it alongside the shader byte code into the shader blob. + +The other mechanism is to create a standalone root signature blob, perhaps to +reuse it with a large set of shaders, saving space. The name of the define +string is specified via the usual -E argument. For example: + +.. code-block:: c++ + + dxc.exe -T rootsig_1_1 MyRS1.hlsl -E MyRS1 -Fo MyRS1.fxo + +Note that the root signature string define can also be passed on the command +line, e.g, -D MyRS1=”…”. + +Root Signature Grammar +====================== + +.. code-block:: c++ ---------------- bogner wrote:
This isn't C++. I think you could use "peg" here based on https://pygments.org/docs/lexers/#lexers-for-grammar-notations-like-bnf https://github.com/llvm/llvm-project/pull/83933 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
