Clouds still bad

fancy1.cpp

@@ -29,9 +29,10 @@ int main()
 {
     FastScene scene;
     scene.setBackgroundColor(Color(0.529f, 0.808f, 0.922f) * 1.0f);
+//    scene.setBackgroundColor(Color(1, 0.79f, 0.62f) * 0.8f);
 
     // Add lights
-    auto mainLight = std::make_shared<SunLight>(Vector3d(-1.0f, -0.5f, -1.0f), 5.0f, Color(1, 0.79f, 0.62f));
+    auto mainLight = std::make_shared<SunLight>(Vector3d(-1.0f, -0.5f, -1.0f), 2.0f, Color(1,1,1));//Color(1, 0.79f, 0.62f));
     scene.add(mainLight);
 //    scene.add(std::make_shared<AmbientLight>(0.3f));
 //    auto light = std::make_shared<PointLight>(Vector3d(25.0f, 10.0f, 25.0f), 100.0f);
@@ -43,10 +44,10 @@ int main()
 //                 busShader);
 
     // Refraction boxes
-    auto boxShader = std::make_shared<RefractionShader>(1.05f, 1, Color(1,1,0), 0.7f);
+//    auto boxShader = std::make_shared<RefractionShader>(1.05f, 1, Color(1,1,0), 0.7f);
-    scene.add(std::make_shared<Box>(Vector3d(5.0f, 3.0f, 10.0f), Vector3d(3.0f, 3.0f, 3.0f), boxShader));
+//    scene.add(std::make_shared<Box>(Vector3d(5.0f, 3.0f, 10.0f), Vector3d(3.0f, 3.0f, 3.0f), boxShader));
-    auto boxShader1 = std::make_shared<RefractionShader>(1.05f, 1, Color(0,1,1), 0.7f);
+//    auto boxShader1 = std::make_shared<RefractionShader>(1.05f, 1, Color(0,1,1), 0.7f);
-    scene.add(std::make_shared<Box>(Vector3d(9.0f, 3.0f, 12.0f), Vector3d(3.0f, 3.0f, 3.0f), boxShader1));
+//    scene.add(std::make_shared<Box>(Vector3d(9.0f, 3.0f, 12.0f), Vector3d(3.0f, 3.0f, 3.0f), boxShader1));
 
     // Add floor
     auto floorShader = std::make_shared<SimpleShadowShader>(Color(0.9f, 0.9f, 0.9f));

shader/cloudshader.cpp

@@ -33,10 +33,10 @@ Color CloudShader::shade(const Scene &scene, const Ray &ray) const
 
     // Calculate step length
     int noiseSamples = settings.densitySamples;
-    float stepLength = cloudLength / noiseSamples;
+    float stepLength = cloudLength / (float) noiseSamples;
 
     // Step through cloud
-    float transmittance = 1;
+    float accumulatedDensity = 0.0f;
     Color cloudColor = Color(0, 0, 0);
     for (int i = 0; i < noiseSamples; ++i)
     {
@@ -49,14 +49,14 @@ Color CloudShader::shade(const Scene &scene, const Ray &ray) const
 
         if (sampleDensity > 0)
         {
-            cloudColor += lightMarch(scene, samplePoint, lengthDirection) * stepLength * sampleDensity;
+            cloudColor += lightMarch(scene, samplePoint, lengthDirection, ray.primitive) * sampleDensity;
         }
 
-        transmittance *= exp(-sampleDensity * stepLength * settings.lightAbsorptionThroughCloud);
+        accumulatedDensity += sampleDensity;
-
-        if (transmittance < TRANSMITTANCE_BREAK) break; // Cloud is effectively opaque
     }
 
+    float transmittance = exp(-accumulatedDensity * settings.lightAbsorptionThroughCloud);
+
     return background * transmittance + cloudColor;
 }
 
@@ -84,15 +84,17 @@ float CloudShader::getCloudDensity(Vector3d point) const
     return density;
 }
 
-Color CloudShader::lightMarch(const Scene &scene, Vector3d currentInCloudPosition, Vector3d lengthDistance) const
+Color CloudShader::lightMarch(const Scene &scene, Vector3d currentInCloudPosition, Vector3d lengthDistance,
+                              const Primitive *cloudObject) const
 {
-    Color cloudColor;
+    Color cloudColor = Color(0, 0, 0);
 
     // For alle lights
     for (const auto &light: scene.lights())
     {
         Ray ray = Ray(currentInCloudPosition - lengthDistance, normalized(lengthDistance));
         ray.length = length(lengthDistance);
+        ray.primitive = cloudObject;
         auto illumination = light->illuminate(scene, ray);
 
         // Handle ambient lights
@@ -106,22 +108,30 @@ Color CloudShader::lightMarch(const Scene &scene, Vector3d currentInCloudPositio
         Ray lightRay;
         lightRay.origin = currentInCloudPosition;
         lightRay.direction = illumination.direction;
+        lightRay.primitive = cloudObject;
         lightRay.length = 0;    // Starting in cloud itself
 
         float density = this->rayDensity(lightRay, illumination.distance);
         density *= settings.lightAbsorptionTowardsLight;
 
         // Proper light calculation
-        float transmittance = exp(-density) * (1 - exp(-density * 2));
+        float transmittance = getDensityTransmittance(density);
         float scatter = scatterFactor(normalized(lengthDistance), illumination.direction);
 
-        float factor = settings.darknessThreshold + (scatter * transmittance) * (1 - settings.darknessThreshold);   // (transmittance * scatter)
+        // TODO: Back to default
+        float factor = settings.darknessThreshold +
+                       (1.0f - settings.darknessThreshold) * (1);   // (transmittance * scatter)
         cloudColor += factor * illumination.color;
     }
 
     return cloudColor;
 }
 
+float CloudShader::getDensityTransmittance(float density) const
+{
+    return exp(-density) * (1 - exp(-density * 2)) / 0.4f;
+}
+
 Color CloudShader::transparency(const Scene &scene, const Ray &ray, float maxLength) const
 {
     float density = rayDensity(ray, maxLength);
@@ -163,9 +173,7 @@ float CloudShader::rayDensity(const Ray &ray, float maxLength) const
         Vector3d samplePoint = startPoint + i * stepLength * ray.direction;
 
         // Get data at point
-        float sampleDensity = getCloudDensity(samplePoint) * stepLength;
+        density += getCloudDensity(samplePoint) * stepLength;
-
-        density += sampleDensity * stepLength;
     }
 
     // If there is length left, check if it is in the cloud recursively
@@ -189,14 +197,14 @@ float CloudShader::rayDensity(const Ray &ray, float maxLength) const
 float CloudShader::scatterFactor(Vector3d visualRay, Vector3d illuminationRay) const
 {
     // The asymmetry parameter
-    float g = 0.7f;
+    float g = settings.scatterWeight;
 
     // The angle between the visual and illumination rays
     float cosTheta = dotProduct(visualRay, illuminationRay);
 
     // The Dual-Lob Henyey-Greenstein function
     float blend = .5;
-    float scatter = HenyeyGreenstein(cosTheta,g) * (1-blend) + HenyeyGreenstein(cosTheta,-g) * blend;
+    float scatter = HenyeyGreenstein(cosTheta, g) * (1 - blend) + HenyeyGreenstein(cosTheta, -g) * blend;
 
     // Clamp the result to the range [0, 1]
     scatter = std::max(std::min(scatter, 1.0f), 0.0f);

shader/cloudshader.h

@@ -16,12 +16,13 @@ struct CloudSettings
     int lightSamples = 100;
     float scale = 10;
     float densityOffset = -0.57f;
-    float densityIntensity = 7.0f;
+    float densityIntensity = 7.0f; // 7.0f
-    float darknessThreshold = 0.07f;
+    float darknessThreshold = 0.2f;    // 0.07f
-    float shadowIntensity = 0.8f;
+    float shadowIntensity = 0.6f;
     float shadowLightAbsorption = 1;
-    float lightAbsorptionTowardsLight = 0.94f;
+    float lightAbsorptionTowardsLight = 1.0f;
-    float lightAbsorptionThroughCloud = 0.85f;
+    float lightAbsorptionThroughCloud = 0.5f;
+    float scatterWeight = 0.5f;
 };
 
 class CloudShader : public Shader
@@ -43,13 +44,15 @@ private:
 
     float getCloudDensity(Vector3d point) const;
 
-    Color lightMarch(const Scene &scene, Vector3d currentInCloudPosition, Vector3d lengthDistance) const;
+    Color lightMarch(const Scene &scene, Vector3d currentInCloudPosition, Vector3d lengthDistance, const Primitive *cloudObject) const;
 
     float rayDensity(const Ray &ray, float maxLength) const;
 
     float scatterFactor(Vector3d visualRay, Vector3d illuminationRay) const;
 
     float HenyeyGreenstein(float cosTheta, float g) const;
+
+    float getDensityTransmittance(float density) const;
 };