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/inputattachments/attachmentread.frag

@@ -0,0 +1,35 @@
+// Copyright 2020 Google LLC
+
+[[vk::input_attachment_index(0)]][[vk::binding(0)]] SubpassInput inputColor;
+[[vk::input_attachment_index(1)]][[vk::binding(1)]] SubpassInput inputDepth;
+
+struct UBO  {
+	float2 brightnessContrast;
+	float2 range;
+	int attachmentIndex;
+};
+
+cbuffer ubo : register(b2) { UBO ubo; }
+
+float3 brightnessContrast(float3 color, float brightness, float contrast) {
+	return (color - 0.5) * contrast + 0.5 + brightness;
+}
+
+float4 main() : SV_TARGET
+{
+	// Apply brightness and contrast filer to color input
+	if (ubo.attachmentIndex == 0) {
+		// Read color from previous color input attachment
+		float3 color = inputColor.SubpassLoad().rgb;
+		return float4(brightnessContrast(color, ubo.brightnessContrast[0], ubo.brightnessContrast[1]), 1);
+	}
+
+	// Visualize depth input range
+	if (ubo.attachmentIndex == 1) {
+		// Read depth from previous depth input attachment
+		float depth = inputDepth.SubpassLoad().r;
+		return float4((depth - ubo.range[0]) * 1.0 / (ubo.range[1] - ubo.range[0]).xxx, 1);
+	}
+
+	return 0.xxxx;
+}