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/texturesparseresidency/sparseresidency.frag

@@ -0,0 +1,36 @@
+// Copyright 2020 Google LLC
+
+Texture2D textureColor : register(t1);
+SamplerState samplerColor : register(s1);
+
+struct VSOutput
+{
+[[vk::location(0)]] float2 UV : TEXCOORD0;
+[[vk::location(1)]] float LodBias : TEXCOORD3;
+[[vk::location(2)]] float3 Normal : NORMAL0;
+[[vk::location(3)]] float3 ViewVec : TEXCOORD1;
+[[vk::location(4)]] float3 LightVec : TEXCOORD2;
+};
+
+float4 main(VSOutput input) : SV_TARGET
+{
+	float4 color = float4(0.0, 0.0, 0.0, 0.0);
+
+	// Fetch sparse until we get a valid texel
+	uint status;
+	float minLod = input.LodBias;
+	do
+	{
+		color = textureColor.SampleLevel(samplerColor, input.UV, minLod, 0, status);
+		minLod += 1.0f;
+	} while(!CheckAccessFullyMapped(status));
+
+	float3 N = normalize(input.Normal);
+
+	N = normalize((input.Normal - 0.5) * 2.0);
+
+	float3 L = normalize(input.LightVec);
+	float3 R = reflect(-L, N);
+	float3 diffuse = max(dot(N, L), 0.25) * color.rgb;
+	return float4(diffuse, 1.0);
+}