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/computeshader/edgedetect.comp

@@ -0,0 +1,40 @@
+// Copyright 2020 Google LLC
+
+Texture2D inputImage : register(t0);
+RWTexture2D<float4> resultImage : register(u1);
+
+float conv(float kernel[9], in float data[9], in float denom, in float offset)
+{
+   float res = 0.0;
+   for (int i=0; i<9; ++i)
+   {
+      res += kernel[i] * data[i];
+   }
+   return saturate(res/denom + offset);
+}
+
+[numthreads(16, 16, 1)]
+void main(uint3 GlobalInvocationID : SV_DispatchThreadID)
+{
+	float imageData[9];
+	// Fetch neighbouring texels
+	int n = -1;
+	for (int i=-1; i<2; ++i)
+	{
+		for(int j=-1; j<2; ++j)
+		{
+			n++;
+			float3 rgb = inputImage[uint2(GlobalInvocationID.x + i, GlobalInvocationID.y + j)].rgb;
+			imageData[n] = (rgb.r + rgb.g + rgb.b) / 3.0;
+		}
+	}
+
+	float kernel[9];
+	kernel[0] = -1.0/8.0; kernel[1] = -1.0/8.0; kernel[2] = -1.0/8.0;
+	kernel[3] = -1.0/8.0; kernel[4] =  1.0;     kernel[5] = -1.0/8.0;
+	kernel[6] = -1.0/8.0; kernel[7] = -1.0/8.0; kernel[8] = -1.0/8.0;
+
+	float4 res = float4(conv(kernel, imageData, 0.1, 0.0).xxx, 1.0);
+
+	resultImage[int2(GlobalInvocationID.xy)] = res;
+}

data/hlsl/computeshader/emboss.comp

@@ -0,0 +1,40 @@
+// Copyright 2020 Google LLC
+
+Texture2D inputImage : register(t0);
+RWTexture2D<float4> resultImage : register(u1);
+
+float conv(in float kernel[9], in float data[9], in float denom, in float offset)
+{
+   float res = 0.0;
+   for (int i=0; i<9; ++i)
+   {
+      res += kernel[i] * data[i];
+   }
+   return saturate(res/denom + offset);
+}
+
+[numthreads(16, 16, 1)]
+void main(uint3 GlobalInvocationID : SV_DispatchThreadID)
+{
+	float imageData[9];
+	// Fetch neighbouring texels
+	int n = -1;
+	for (int i=-1; i<2; ++i)
+	{
+		for(int j=-1; j<2; ++j)
+		{
+			n++;
+			float3 rgb = inputImage[uint2(GlobalInvocationID.x + i, GlobalInvocationID.y + j)].rgb;
+			imageData[n] = (rgb.r + rgb.g + rgb.b) / 3.0;
+		}
+	}
+
+	float kernel[9];
+	kernel[0] = -1.0; kernel[1] =  0.0; kernel[2] =  0.0;
+	kernel[3] = 0.0; kernel[4] = -1.0; kernel[5] =  0.0;
+	kernel[6] = 0.0; kernel[7] =  0.0; kernel[8] = 2.0;
+
+	float4 res = float4(conv(kernel, imageData, 1.0, 0.50).xxx, 1.0);
+
+	resultImage[int2(GlobalInvocationID.xy)] = res;
+}

data/hlsl/computeshader/sharpen.comp

@@ -0,0 +1,49 @@
+// Copyright 2020 Google LLC
+
+Texture2D inputImage : register(t0);
+RWTexture2D<float4> resultImage : register(u1);
+
+float conv(in float kernel[9], in float data[9], in float denom, in float offset)
+{
+   float res = 0.0;
+   for (int i=0; i<9; ++i)
+   {
+      res += kernel[i] * data[i];
+   }
+   return saturate(res/denom + offset);
+}
+
+[numthreads(16, 16, 1)]
+void main(uint3 GlobalInvocationID : SV_DispatchThreadID)
+{
+	float r[9];
+	float g[9];
+	float b[9];
+
+	// Fetch neighbouring texels
+	int n = -1;
+	for (int i=-1; i<2; ++i)
+	{
+		for(int j=-1; j<2; ++j)
+		{
+			n++;
+			float3 rgb = inputImage[uint2(GlobalInvocationID.x + i, GlobalInvocationID.y + j)].rgb;
+			r[n] = rgb.r;
+			g[n] = rgb.g;
+			b[n] = rgb.b;
+		}
+	}
+
+	float kernel[9];
+	kernel[0] = -1.0; kernel[1] = -1.0; kernel[2] = -1.0;
+	kernel[3] = -1.0; kernel[4] =  9.0; kernel[5] = -1.0;
+	kernel[6] = -1.0; kernel[7] = -1.0; kernel[8] = -1.0;
+
+	float4 res = float4(
+		conv(kernel, r, 1.0, 0.0),
+		conv(kernel, g, 1.0, 0.0),
+		conv(kernel, b, 1.0, 0.0),
+		1.0);
+
+	resultImage[int2(GlobalInvocationID.xy)] = res;
+}

data/hlsl/computeshader/texture.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/computeshader/texture.vert

@@ -0,0 +1,29 @@
+// Copyright 2020 Google LLC
+
+struct VSInput
+{
+[[vk::location(0)]] float3 Pos : POSITION0;
+[[vk::location(1)]] float2 UV : TEXCOORD0;
+};
+
+struct UBO
+{
+	float4x4 projection;
+	float4x4 model;
+};
+
+cbuffer ubo : register(b0) { UBO ubo; }
+
+struct VSOutput
+{
+	float4 Pos : SV_POSITION;
+	[[vk::location(0)]] float2 UV : TEXCOORD0;
+};
+
+VSOutput main(VSInput input)
+{
+	VSOutput output = (VSOutput)0;
+	output.UV = input.UV;
+	output.Pos = mul(ubo.projection, mul(ubo.model, float4(input.Pos.xyz, 1.0)));
+	return output;
+}