Add shaders re-implemented in HLSL

These were written against the shaders at revision eddd724e7.
There have been changes made since then, which will need to be mirrored.

See `data/hlsl/README.md` for the current status of each sample.

data/hlsl/conservativeraster/fullscreen.frag

@@ -0,0 +1,9 @@
+// Copyright 2020 Google LLC
+
+Texture2D textureColor : register(t1);
+SamplerState samplerColor : register(s1);
+
+float4 main([[vk::location(0)]] float2 inUV : TEXCOORD0) : SV_TARGET
+{
+	return textureColor.Sample(samplerColor, inUV);
+}

data/hlsl/conservativeraster/fullscreen.vert

@@ -0,0 +1,15 @@
+// Copyright 2020 Google LLC
+
+struct VSOutput
+{
+	float4 Pos : SV_POSITION;
+[[vk::location(0)]] float2 UV : TEXCOORD0;
+};
+
+VSOutput main(uint VertexIndex : SV_VertexID)
+{
+	VSOutput output = (VSOutput)0;
+	output.UV = float2((VertexIndex << 1) & 2, VertexIndex & 2);
+	output.Pos = float4(output.UV * 2.0f - 1.0f, 0.0f, 1.0f);
+	return output;
+}

data/hlsl/conservativeraster/triangle.frag

@@ -0,0 +1,6 @@
+// Copyright 2020 Google LLC
+
+float4 main([[vk::location(0)]] float3 Color : COLOR0) : SV_TARGET
+{
+	return float4(Color, 1);
+}

data/hlsl/conservativeraster/triangle.vert

@@ -0,0 +1,29 @@
+// Copyright 2020 Google LLC
+
+struct VSInput
+{
+[[vk::location(0)]] float3 Pos : POSITION0;
+[[vk::location(1)]] float3 Color : COLOR0;
+};
+
+struct UBO
+{
+	float4x4 projection;
+	float4x4 model;
+};
+
+cbuffer ubo : register(b0) { UBO ubo; }
+
+struct VSOutput
+{
+	float4 Pos : SV_POSITION;
+[[vk::location(0)]] float3 Color : COLOR0;
+};
+
+VSOutput main(VSInput input)
+{
+	VSOutput output = (VSOutput)0;
+	output.Color = input.Color;
+	output.Pos = mul(ubo.projection, mul(ubo.model, float4(input.Pos, 1.0)));
+	return output;
+}

data/hlsl/conservativeraster/triangleoverlay.frag

@@ -0,0 +1,6 @@
+// Copyright 2020 Google LLC
+
+float4 main() : SV_TARGET
+{
+	return float4(1.0, 1.0, 1.0, 1.0);
+}