Much improved cube map visualization

Now displays all six cube map faces as a single cross

data/shaders/shadowmapomni/cubemapdisplay.frag

@@ -2,12 +2,53 @@
 
 layout (binding = 1) uniform samplerCube shadowCubeMap;
 
-layout (location = 0) in vec3 inUVW;
+layout (location = 0) in vec2 inUV;
 
 layout (location = 0) out vec4 outFragColor;
 
 void main() 
 {
-	float dist = length(texture(shadowCubeMap, inUVW).rgb) * 0.005;
+	outFragColor.rgb = vec3(0.0, 0.0, 0.2);
-	outFragColor = vec4(vec3(dist), 1.0);
+	
+	vec3 samplePos = vec3(0.0f);
+	
+	// Crude statement to visualize different cube map faces based on UV coordinates
+	int x = int(floor(inUV.x / 0.25f));
+	int y = int(floor(inUV.y / (1.0 / 3.0))); 
+	if (y == 1) {
+		vec2 uv = vec2(inUV.x * 4.0f, (inUV.y - 1.0/3.0) * 3.0);
+		uv = 2.0 * vec2(uv.x - float(x) * 1.0, uv.y) - 1.0;
+		switch (x) {
+			case 0:	// NEGATIVE_X
+				samplePos = vec3(-1.0f, uv.y, uv.x);
+				break;
+			case 1: // POSITIVE_Z				
+				samplePos = vec3(uv.x, uv.y, 1.0f);
+				break;
+			case 2: // POSITIVE_X
+				samplePos = vec3(1.0, uv.y, -uv.x);
+				break;				
+			case 3: // NEGATIVE_Z
+				samplePos = vec3(-uv.x, uv.y, -1.0f);
+				break;
+		}
+	} else {
+		if (x == 1) { 
+			vec2 uv = vec2((inUV.x - 0.25) * 4.0, (inUV.y - float(y) / 3.0) * 3.0);
+			uv = 2.0 * uv - 1.0;
+			switch (y) {
+				case 0: // NEGATIVE_Y
+					samplePos = vec3(uv.x, -1.0f, uv.y);
+					break;
+				case 2: // POSITIVE_Y
+					samplePos = vec3(uv.x, 1.0f, -uv.y);
+					break;
+			}
+		}
+	}
+
+	if ((samplePos.x != 0.0f) && (samplePos.y != 0.0f)) {
+		float dist = length(texture(shadowCubeMap, samplePos).xyz) * 0.005;
+		outFragColor = vec4(vec3(dist), 1.0);
+	}
 }

data/shaders/shadowmapomni/cubemapdisplay.vert

@@ -1,7 +1,5 @@
 #version 450
 
-layout (location = 0) in vec3 inPos;
-
 layout (binding = 0) uniform UBO 
 {
 	mat4 projection;
@@ -9,16 +7,11 @@ layout (binding = 0) uniform UBO
 	mat4 model;
 } ubo;
 
-layout (location = 0) out vec3 outUVW;
+layout (location = 0) out vec2 outUV;
-
-out gl_PerVertex 
-{
-	vec4 gl_Position;
-};
 
 void main() 
 {
-	outUVW = inPos;
+	outUV = vec2((gl_VertexIndex << 1) & 2, gl_VertexIndex & 2);
-	gl_Position = ubo.projection * ubo.model * vec4(inPos.xyz, 1.0);
+	gl_Position = vec4(outUV.xy * 2.0f - 1.0f, 0.0f, 1.0f);
 }
 

examples/shadowmappingomni/shadowmappingomni.cpp

@@ -78,7 +78,7 @@ public:
 	struct {
 		VkPipeline scene;
 		VkPipeline offscreen;
-		VkPipeline cubeMap;
+		VkPipeline cubemapDisplay;
 	} pipelines;
 
 	struct {
@@ -154,7 +154,7 @@ public:
 		// Pipelibes
 		vkDestroyPipeline(device, pipelines.scene, nullptr);
 		vkDestroyPipeline(device, pipelines.offscreen, nullptr);
-		vkDestroyPipeline(device, pipelines.cubeMap, nullptr);
+		vkDestroyPipeline(device, pipelines.cubemapDisplay, nullptr);
 
 		vkDestroyPipelineLayout(device, pipelineLayouts.scene, nullptr);
 		vkDestroyPipelineLayout(device, pipelineLayouts.offscreen, nullptr);
@@ -552,10 +552,12 @@ public:
 
 				if (displayCubeMap)
 				{
-					vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.cubeMap);
+					// Display all six sides of the shadow cube map
+					// Note: Visualization of the different faces is done in the fragment shader, see cubemapdisplay.frag
+					vkCmdBindPipeline(drawCmdBuffers[i], VK_PIPELINE_BIND_POINT_GRAPHICS, pipelines.cubemapDisplay);
 					vkCmdBindVertexBuffers(drawCmdBuffers[i], 0, 1, &models.skybox.vertices.buffer, offsets);
 					vkCmdBindIndexBuffer(drawCmdBuffers[i], models.skybox.indices.buffer, 0, VK_INDEX_TYPE_UINT32);
-					vkCmdDrawIndexed(drawCmdBuffers[i], models.skybox.indexCount, 1, 0, 0, 0);
+					vkCmdDraw(drawCmdBuffers[i], 3, 1, 0, 0);
 				}
 				else
 				{
@@ -752,15 +754,16 @@ public:
 		// Cube map display pipeline
 		shaderStages[0] = loadShader(getAssetPath() + "shaders/shadowmapomni/cubemapdisplay.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
 		shaderStages[1] = loadShader(getAssetPath() + "shaders/shadowmapomni/cubemapdisplay.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
-		rasterizationState.cullMode = VK_CULL_MODE_FRONT_BIT;
+		VkPipelineVertexInputStateCreateInfo emptyInputState = vks::initializers::pipelineVertexInputStateCreateInfo();
-		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfo, nullptr, &pipelines.cubeMap));
+		pipelineCreateInfo.pVertexInputState = &emptyInputState;
+		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfo, nullptr, &pipelines.cubemapDisplay));
 
 		// Offscreen pipeline
 		shaderStages[0] = loadShader(getAssetPath() + "shaders/shadowmapomni/offscreen.vert.spv", VK_SHADER_STAGE_VERTEX_BIT);
 		shaderStages[1] = loadShader(getAssetPath() + "shaders/shadowmapomni/offscreen.frag.spv", VK_SHADER_STAGE_FRAGMENT_BIT);
-		rasterizationState.cullMode = VK_CULL_MODE_BACK_BIT;
 		pipelineCreateInfo.layout = pipelineLayouts.offscreen;
 		pipelineCreateInfo.renderPass = offscreenPass.renderPass;
+		pipelineCreateInfo.pVertexInputState = &vertexInputState;
 		VK_CHECK_RESULT(vkCreateGraphicsPipelines(device, pipelineCache, 1, &pipelineCreateInfo, nullptr, &pipelines.offscreen));
 	}