DirectXShaderCompiler/tools/clang/test/CodeGenHLSL/Samples/MiniEngine/ScreenQuadVS.hlsl

// RUN: %dxc -E main -T vs_6_0 %s | FileCheck %s

//
// Copyright (c) Microsoft. All rights reserved.
// This code is licensed under the MIT License (MIT).
// THIS CODE IS PROVIDED *AS IS* WITHOUT WARRANTY OF
// ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY
// IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR
// PURPOSE, MERCHANTABILITY, OR NON-INFRINGEMENT.
//
// Developed by Minigraph
//
// Author:  James Stanard
//
// A vertex shader for full-screen effects without a vertex buffer.  The
// intent is to output an over-sized triangle that encompasses the entire
// screen.  By doing so, we avoid rasterization inefficiency that could
// result from drawing two triangles with a shared edge.
//
// Use null input layout
// Draw(3)

#include "PresentRS.hlsli"

[RootSignature(Present_RootSig)]
void main(
	in uint VertID : SV_VertexID,
	out float4 Pos : SV_Position,
	out float2 Tex : TexCoord0
)
{
// For VertID << 1
// CHECK: shl i32
// For & 2
// CHECK: and i32
// CHECK: and i32
// For float2(uint2
// CHECK: uitofp
// CHECK: uitofp
	// Texture coordinates range [0, 2], but only [0, 1] appears on screen.
	Tex = float2(uint2(VertID, VertID << 1) & 2);
	Pos = float4(lerp(float2(-1, 1), float2(1, -1), Tex), 0, 1);
}