From ccadcdd238ad8e6913315760349eea63eee38ca8 Mon Sep 17 00:00:00 2001
From: Sascha Willems <webmaster@saschawillems.de>
Date: Sat, 5 Sep 2020 14:10:02 +0200
Subject: [PATCH] Shading rate pattern and colorization

---
 .../glsl/variablerateshading/scene.frag       | 29 +++++++++++++++----
 .../variablerateshading.cpp                   | 25 ++++++++++------
 2 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/data/shaders/glsl/variablerateshading/scene.frag b/data/shaders/glsl/variablerateshading/scene.frag
index ddc21bdb..1236713a 100644
--- a/data/shaders/glsl/variablerateshading/scene.frag
+++ b/data/shaders/glsl/variablerateshading/scene.frag
@@ -53,13 +53,32 @@ void main()
 
 	if (uboScene.colorShadingRates == 1) {
 		if (gl_FragmentSizeNV.x == 1 && gl_FragmentSizeNV.y == 1) {
-			outFragColor.rgb *= vec3(0.5, 1.0, 0.5);
+			outFragColor.rgb *= vec3(0.0, 0.8, 0.4);
+			return;
 		}
-		if (gl_FragmentSizeNV.x == 2 || gl_FragmentSizeNV.y == 2) {
-			outFragColor.rgb *= vec3(1.0, 1.0, 0.5);
+		if (gl_FragmentSizeNV.x == 2 && gl_FragmentSizeNV.y == 1) {
+			outFragColor.rgb *= vec3(0.2, 0.6, 1.0);
+			return;
 		}
-		if (gl_FragmentSizeNV.x == 4 || gl_FragmentSizeNV.y == 4) {
-			outFragColor.rgb *= vec3(1.0, 0.5, 0.5);
+		if (gl_FragmentSizeNV.x == 1 && gl_FragmentSizeNV.y == 2) {
+			outFragColor.rgb *= vec3(0.0, 0.4, 0.8);
+			return;
+		}
+		if (gl_FragmentSizeNV.x == 2 && gl_FragmentSizeNV.y == 2) {
+			outFragColor.rgb *= vec3(1.0, 1.0, 0.2);
+			return;
+		}
+		if (gl_FragmentSizeNV.x == 4 && gl_FragmentSizeNV.y == 2) {
+			outFragColor.rgb *= vec3(0.8, 0.8, 0.0);
+			return;
+		}
+		if (gl_FragmentSizeNV.x == 2 && gl_FragmentSizeNV.y == 4) {
+			outFragColor.rgb *= vec3(1.0, 0.4, 0.2);
+			return;
+		}
+		if (gl_FragmentSizeNV.x == 4 && gl_FragmentSizeNV.y == 4) {
+			outFragColor.rgb *= vec3(0.8, 0.0, 0.0);
+			return;
 		}
 	}
 }
\ No newline at end of file
diff --git a/examples/variablerateshading/variablerateshading.cpp b/examples/variablerateshading/variablerateshading.cpp
index 7d92b44e..1fa83579 100644
--- a/examples/variablerateshading/variablerateshading.cpp
+++ b/examples/variablerateshading/variablerateshading.cpp
@@ -171,24 +171,31 @@ void VulkanExample::prepareShadingRateImage()
 	imageViewCI.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
 	VK_CHECK_RESULT(vkCreateImageView(device, &imageViewCI, nullptr, &shadingRateImage.view));
 
-	// Populate with shading rate pattern
-	uint8_t val = VK_SHADING_RATE_PALETTE_ENTRY_NO_INVOCATIONS_NV;
+	// Populate with lowest possible shading rate pattern
+	uint8_t val = VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_4X4_PIXELS_NV;
 	uint8_t* shadingRatePatternData = new uint8_t[bufferSize];
 	memset(shadingRatePatternData, val, bufferSize);
 
+	// Create a circular pattern with decreasing sampling rates outwards (max. range, pattern)
+	std::map<float, VkShadingRatePaletteEntryNV> patternLookup = {
+		{ 8.0f, VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_PIXEL_NV },
+		{ 12.0f, VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X1_PIXELS_NV },
+		{ 16.0f, VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_1X2_PIXELS_NV },
+		{ 18.0f, VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X2_PIXELS_NV },
+		{ 20.0f, VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_4X2_PIXELS_NV },
+		{ 24.0f, VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X4_PIXELS_NV }
+	};
+
 	uint8_t* ptrData = shadingRatePatternData;
 	for (uint32_t y = 0; y < imageExtent.height; y++) {
 		for (uint32_t x = 0; x < imageExtent.width; x++) {
 			const float deltaX = (float)imageExtent.width / 2.0f - (float)x;
 			const float deltaY = (float)imageExtent.height / 2.0f - (float)y;
 			const float dist = std::sqrt(deltaX * deltaX + deltaY * deltaY);
-			if (dist <= 8.0f) {
-				*ptrData = VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_PIXEL_NV;
-			} else {
-				if (dist <= 16.0f) {
-					*ptrData = VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_2X2_PIXELS_NV;
-				} else {
-					*ptrData = VK_SHADING_RATE_PALETTE_ENTRY_1_INVOCATION_PER_4X4_PIXELS_NV;
+			for (auto pattern : patternLookup) {
+				if (dist <= pattern.first) {
+					*ptrData = pattern.second;
+					break;
 				}
 			}
 			ptrData++;