[#82] Add UI controls for volumetric lighting

projects/voxelization/resources/shaders/shader.frag

@@ -32,6 +32,13 @@ layout(set=0, binding=6) uniform VoxelInfoBuffer{
     VoxelInfo voxelInfo;
 };
 
+layout(set=0, binding=7) uniform VolumetricSettings {
+    vec3    scatteringCoefficient;
+    float   volumetricAmbientLight;
+    vec3    absorptionCoefficient;
+};
+
+
 vec3 cookTorrance(vec3 f0, float r, vec3 N, vec3 V, vec3 L){
     
     vec3 H  = normalize(L + V);
@@ -78,10 +85,7 @@ vec3 volumetricLighting(vec3 colorIn, vec3 V, vec3 pos, float d){
     int sampleCount = 48;
     float stepSize  = d / sampleCount;
     
-    vec3 scatteringCoefficient = vec3(0.005);
-    vec3 absorptionCoefficient = vec3(0.01);
     vec3 extinctionCoefficient = scatteringCoefficient + absorptionCoefficient;
-    vec3 ambientLight          = vec3(0.2);
     
     float noiseScale    = 0.1;
     pos                 += V * noiseScale * interleavedGradientNoise(gl_FragCoord.xy);
@@ -92,7 +96,7 @@ vec3 volumetricLighting(vec3 colorIn, vec3 V, vec3 pos, float d){
         vec3    light       = lightInfo.sunColor * lightInfo.sunStrength;
         float   shadow      = shadowTest(samplePoint, lightInfo, shadowMap, shadowMapSampler, vec2(0));
         light               *= shadow;
-        light               += ambientLight;
+        light               += volumetricAmbientLight;
         
         color               += phase * light * scatteringCoefficient * stepSize;
         color               *= exp(-stepSize * extinctionCoefficient);

projects/voxelization/src/main.cpp

@@ -444,12 +444,21 @@ int main(int argc, const char** argv) {
 
 	vkcv::Buffer<glm::vec3> cameraPosBuffer = core.createBuffer<glm::vec3>(vkcv::BufferType::UNIFORM, 1);
 
+	struct VolumetricSettings {
+		glm::vec3   scatteringCoefficient;
+		float       ambientLight;
+		glm::vec3   absorptionCoefficient;
+	};
+	vkcv::Buffer<VolumetricSettings> volumetricSettingsBuffer
+		= core.createBuffer<VolumetricSettings>(vkcv::BufferType::UNIFORM ,1);
+
 	// write forward pass descriptor set
 	vkcv::DescriptorWrites forwardDescriptorWrites;
 	forwardDescriptorWrites.uniformBufferWrites = {
 		vkcv::UniformBufferDescriptorWrite(0, shadowMapping.getLightInfoBuffer()),
 		vkcv::UniformBufferDescriptorWrite(3, cameraPosBuffer.getHandle()),
-		vkcv::UniformBufferDescriptorWrite(6, voxelization.getVoxelInfoBufferHandle()) };
+		vkcv::UniformBufferDescriptorWrite(6, voxelization.getVoxelInfoBufferHandle()),
+		vkcv::UniformBufferDescriptorWrite(7, volumetricSettingsBuffer.getHandle())};
 	forwardDescriptorWrites.sampledImageWrites = {
 		vkcv::SampledImageDescriptorWrite(1, shadowMapping.getShadowMap()),
 		vkcv::SampledImageDescriptorWrite(4, voxelization.getVoxelImageHandle()) };
@@ -470,6 +479,12 @@ int main(int argc, const char** argv) {
 
 	bool msaaCustomResolve = true;
 
+	glm::vec3   scatteringColor     = glm::vec3(1);
+	float       scatteringDensity   = 0.001;
+	glm::vec3   absorptionColor     = glm::vec3(1);
+	float       absorptionDensity   = 0.001;
+	float       volumetricAmbient   = 0.2;
+
 	auto start = std::chrono::system_clock::now();
 	const auto appStartTime = start;
 	while (window.isWindowOpen()) {
@@ -567,6 +582,12 @@ int main(int argc, const char** argv) {
 			mainPassMatrices.push_back({ viewProjectionCamera * m, m });
 		}
 
+		VolumetricSettings volumeSettings;
+		volumeSettings.scatteringCoefficient    = scatteringColor * scatteringDensity;
+		volumeSettings.absorptionCoefficient    = absorptionColor * absorptionDensity;
+		volumeSettings.ambientLight             = volumetricAmbient;
+		volumetricSettingsBuffer.fill({ volumeSettings });
+
 		const vkcv::PushConstantData            pushConstantData((void*)mainPassMatrices.data(), 2 * sizeof(glm::mat4));
 		const std::vector<vkcv::ImageHandle>    renderTargets = { colorBuffer, depthBuffer };
 
@@ -655,6 +676,12 @@ int main(int argc, const char** argv) {
 		voxelizationExtent = std::max(voxelizationExtent, 1.f);
 		voxelVisualisationMip = std::max(voxelVisualisationMip, 0);
 
+		ImGui::ColorEdit3("Scattering color", &scatteringColor.x);
+		ImGui::DragFloat("Scattering density", &scatteringDensity, 0.0001);
+		ImGui::ColorEdit3("Absorption color", &absorptionColor.x);
+		ImGui::DragFloat("Absorption density", &absorptionDensity, 0.0001);
+		ImGui::DragFloat("Volumetric ambient", &volumetricAmbient, 0.002);
+
 		if (ImGui::Button("Reload forward pass")) {
 
 			vkcv::ShaderProgram newForwardProgram;