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/deferred/deferred.frag

@@ -0,0 +1,73 @@
+// Copyright 2020 Google LLC
+
+Texture2D textureposition : register(t1);
+SamplerState samplerposition : register(s1);
+Texture2D textureNormal : register(t2);
+SamplerState samplerNormal : register(s2);
+Texture2D textureAlbedo : register(t3);
+SamplerState samplerAlbedo : register(s3);
+
+struct Light {
+	float4 position;
+	float3 color;
+	float radius;
+};
+
+struct UBO
+{
+	Light lights[6];
+	float4 viewPos;
+};
+
+cbuffer ubo : register(b4) { UBO ubo; }
+
+
+float4 main([[vk::location(0)]] float2 inUV : TEXCOORD0) : SV_TARGET
+{
+	// Get G-Buffer values
+	float3 fragPos = textureposition.Sample(samplerposition, inUV).rgb;
+	float3 normal = textureNormal.Sample(samplerNormal, inUV).rgb;
+	float4 albedo = textureAlbedo.Sample(samplerAlbedo, inUV);
+
+	#define lightCount 6
+	#define ambient 0.0
+
+	// Ambient part
+	float3 fragcolor  = albedo.rgb * ambient;
+
+	for(int i = 0; i < lightCount; ++i)
+	{
+		// Vector to light
+		float3 L = ubo.lights[i].position.xyz - fragPos;
+		// Distance from light to fragment position
+		float dist = length(L);
+
+		// Viewer to fragment
+		float3 V = ubo.viewPos.xyz - fragPos;
+		V = normalize(V);
+
+		//if(dist < ubo.lights[i].radius)
+		{
+			// Light to fragment
+			L = normalize(L);
+
+			// Attenuation
+			float atten = ubo.lights[i].radius / (pow(dist, 2.0) + 1.0);
+
+			// Diffuse part
+			float3 N = normalize(normal);
+			float NdotL = max(0.0, dot(N, L));
+			float3 diff = ubo.lights[i].color * albedo.rgb * NdotL * atten;
+
+			// Specular part
+			// Specular map values are stored in alpha of albedo mrt
+			float3 R = reflect(-L, N);
+			float NdotR = max(0.0, dot(R, V));
+			float3 spec = ubo.lights[i].color * albedo.a * pow(NdotR, 16.0) * atten;
+
+			fragcolor += diff + spec;
+		}
+	}
+
+  return float4(fragcolor, 1.0);
+}