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/computecullandlod/indirectdraw.frag

@@ -0,0 +1,18 @@
+// Copyright 2020 Google LLC
+
+struct VSOutput
+{
+[[vk::location(0)]] float3 Normal : NORMAL0;
+[[vk::location(1)]] float3 Color : COLOR0;
+[[vk::location(2)]] float3 ViewVec : TEXCOORD1;
+[[vk::location(3)]] float3 LightVec : TEXCOORD2;
+};
+
+float4 main(VSOutput input) : SV_TARGET
+{
+	float3 N = normalize(input.Normal);
+	float3 L = normalize(input.LightVec);
+	float3 ambient = float3(0.25, 0.25, 0.25);
+	float3 diffuse = max(dot(N, L), 0.0).xxx;
+	return float4((ambient + diffuse) * input.Color, 1.0);
+}