More tweaks on milky way galaxy volume rendering.

data/assets/customization/volumes.asset

@@ -8,9 +8,9 @@ local MilkyWayVolumeGalaxy = {
     Parent = transforms.SolarSystemBarycenter.Identifier,
     Renderable = {
         Type = "RenderableGalaxy",
-        StepSize = 0.015,
-		AbsorptionMultiply = 100,
-		EmissionMultiply = 500,
+        StepSize = 0.01,
+		AbsorptionMultiply = 10,
+		EmissionMultiply = 100,
 		Translation = {0.17, 0, 0},
         Volume = {
 			Type = "Volume",

modules/galaxy/rendering/renderablegalaxy.cpp

@@ -104,8 +104,8 @@ namespace openspace {
     RenderableGalaxy::RenderableGalaxy(const ghoul::Dictionary& dictionary)
     : Renderable(dictionary)
     , _stepSize(StepSizeInfo, 0.01f, 0.0005f, 0.05f, 0.001f)
-    , _absorptionMultiply(AbsorptionMultiplyInfo, 50.f, 0.0f, 500.0f)
-    , _emissionMultiply(EmissionMultiplyInfo, 1500.f, 0.0f, 3000.0f)
+    , _absorptionMultiply(AbsorptionMultiplyInfo, 40.f, 0.0f, 100.0f)
+    , _emissionMultiply(EmissionMultiplyInfo, 400.f, 0.0f, 1000.0f)
     //, _pointStepSize(PointStepSizeInfo, 0.01f, 0.01f, 0.1f)
     //, _enabledPointsRatio(EnabledPointsRatioInfo, 0.2f, 0.f, 1.f)
     , _translation(TranslationInfo, glm::vec3(0.f), glm::vec3(0.f), glm::vec3(1.f))

modules/galaxy/shaders/galaxyraycast.glsl

@@ -41,7 +41,8 @@ void sample#{id}(vec3 samplePos,
     
     vec4 sampledColor = texture(galaxyTexture#{id}, samplePos.xyz);
 
-    float STEP_SIZE = maxStepSize#{id};
+    //float STEP_SIZE = maxStepSize#{id}*0.5;
+	float STEP_SIZE = 1 / 256.0;
 
     vec3 alphaTint = vec3(0.3, 0.54, 0.85);
 
@@ -50,28 +51,23 @@ void sample#{id}(vec3 samplePos,
     sampledColor = sampledColor*sampledColor;
 	
 	// fudge for the dust "spreading"
+	sampledColor.a = clamp(sampledColor.a, 0.0, 1.0) * opacityCoefficient#{id};
     sampledColor.a = pow(sampledColor.a, 0.7);
 	
 	// absorption probability
-	float scaled_density = sampledColor.a * STEP_SIZE * absorptionMultiply#{id} * 10;
+	float scaled_density = sampledColor.a * STEP_SIZE * absorptionMultiply#{id};
 	vec3 absorption = alphaTint * scaled_density;
 	
 	// extinction
 	vec3 extinction = exp(-absorption);
-	sampledColor.rgb = sampledColor.rgb * extinction;
+	accumulatedColor.rgb *= extinction;
 	
 	// emission
-	sampledColor.rgb += sampledColor.rgb * STEP_SIZE * emissionMultiply#{id};
-	
-    //sampledColor.a = sampledColor.a * 50; //1.0;
-	
-	vec3 backAlpha = sampledColor.aaa * 10.0;
-    sampledColor.rgb = sampledColor.rgb * backAlpha;
+	accumulatedColor.rgb += sampledColor.rgb * STEP_SIZE * emissionMultiply#{id};
 
-    sampledColor.a = clamp(sampledColor.a, 0.0, 1.0) * opacityCoefficient#{id};
 	vec3 oneMinusFrontAlpha = vec3(1.0) - accumulatedAlpha;
-    accumulatedColor += oneMinusFrontAlpha * sampledColor.rgb;
-	accumulatedAlpha += oneMinusFrontAlpha * sampledColor.a;
+    //accumulatedColor += oneMinusFrontAlpha * sampledColor.rgb;
+	accumulatedAlpha += oneMinusFrontAlpha * sampledColor.rgb;
 }
 
 float stepSize#{id}(vec3 samplePos, vec3 dir) {