diff --git a/src/definition/AtmosphereDefinition.cpp b/src/definition/AtmosphereDefinition.cpp
index cd7935f..e96c8cd 100644
--- a/src/definition/AtmosphereDefinition.cpp
+++ b/src/definition/AtmosphereDefinition.cpp
@@ -3,10 +3,12 @@
 #include "PackStream.h"
 #include "RandomGenerator.h"
 #include "FloatNode.h"
+#include "GodRaysDefinition.h"
 
 AtmosphereDefinition::AtmosphereDefinition(DefinitionNode* parent):
     DefinitionNode(parent, "atmosphere", "atmosphere")
 {
+    godrays = new GodRaysDefinition(this);
     daytime = new FloatNode(this, "daytime");
     humidity = new FloatNode(this, "humidity");
     sun_radius = new FloatNode(this, "sun_radius");
diff --git a/src/definition/AtmosphereDefinition.h b/src/definition/AtmosphereDefinition.h
index 0d61340..20f43ee 100644
--- a/src/definition/AtmosphereDefinition.h
+++ b/src/definition/AtmosphereDefinition.h
@@ -45,6 +45,7 @@ public:
 
     virtual void copy(DefinitionNode* destination) const override;
 
+    inline GodRaysDefinition *childGodRays() const {return godrays;}
     inline FloatNode *propDayTime() const {return daytime;}
     inline FloatNode *propHumidity() const {return humidity;}
     inline FloatNode *propSunRadius() const {return sun_radius;}
@@ -78,6 +79,7 @@ public:
     std::vector<Star> stars;
 
 private:
+    GodRaysDefinition *godrays;
     FloatNode *humidity;
     FloatNode *daytime;
     FloatNode *sun_radius;
diff --git a/src/definition/GodRaysDefinition.cpp b/src/definition/GodRaysDefinition.cpp
new file mode 100644
index 0000000..94ec938
--- /dev/null
+++ b/src/definition/GodRaysDefinition.cpp
@@ -0,0 +1,12 @@
+#include "GodRaysDefinition.h"
+
+#include "FloatNode.h"
+
+GodRaysDefinition::GodRaysDefinition(DefinitionNode *parent):
+    DefinitionNode(parent, "godrays", "godrays")
+{
+    penetration = new FloatNode(this, "penetration", 0.01);
+    resistance = new FloatNode(this, "resistance", 0.3);
+    boost = new FloatNode(this, "boost", 8.0);
+}
+
diff --git a/src/definition/GodRaysDefinition.h b/src/definition/GodRaysDefinition.h
new file mode 100644
index 0000000..52775ec
--- /dev/null
+++ b/src/definition/GodRaysDefinition.h
@@ -0,0 +1,29 @@
+#ifndef GODRAYSDEFINITION_H
+#define GODRAYSDEFINITION_H
+
+#include "definition_global.h"
+
+#include "DefinitionNode.h"
+
+namespace paysages {
+namespace definition {
+
+class DEFINITIONSHARED_EXPORT GodRaysDefinition: public DefinitionNode
+{
+public:
+    GodRaysDefinition(DefinitionNode *parent);
+
+    inline FloatNode *propPenetration() const {return penetration;}
+    inline FloatNode *propResistance() const {return resistance;}
+    inline FloatNode *propBoost() const {return boost;}
+
+private:
+    FloatNode *penetration;
+    FloatNode *resistance;
+    FloatNode *boost;
+};
+
+}
+}
+
+#endif // GODRAYSDEFINITION_H
diff --git a/src/definition/definition.pro b/src/definition/definition.pro
index 7105ccf..c831134 100644
--- a/src/definition/definition.pro
+++ b/src/definition/definition.pro
@@ -37,7 +37,8 @@ SOURCES += \
     DiffManager.cpp \
     DefinitionWatcher.cpp \
     IntNode.cpp \
-    IntDiff.cpp
+    IntDiff.cpp \
+    GodRaysDefinition.cpp
 
 HEADERS +=\
         definition_global.h \
@@ -64,7 +65,8 @@ HEADERS +=\
     DiffManager.h \
     DefinitionWatcher.h \
     IntNode.h \
-    IntDiff.h
+    IntDiff.h \
+    GodRaysDefinition.h
 
 unix:!symbian {
     maemo5 {
diff --git a/src/definition/definition_global.h b/src/definition/definition_global.h
index 9f2d446..e2e6903 100644
--- a/src/definition/definition_global.h
+++ b/src/definition/definition_global.h
@@ -30,6 +30,7 @@ namespace definition {
     class CloudsDefinition;
     class CloudLayerDefinition;
     class AtmosphereDefinition;
+    class GodRaysDefinition;
     class TexturesDefinition;
     class TextureLayerDefinition;
     class TerrainDefinition;
diff --git a/src/interface/commandline/tests.cpp b/src/interface/commandline/tests.cpp
index c71702f..6260484 100644
--- a/src/interface/commandline/tests.cpp
+++ b/src/interface/commandline/tests.cpp
@@ -5,6 +5,7 @@
 #include "TerrainDefinition.h"
 #include "AtmosphereDefinition.h"
 #include "TexturesDefinition.h"
+#include "GodRaysDefinition.h"
 #include "TextureLayerDefinition.h"
 #include "WaterDefinition.h"
 #include "SurfaceMaterial.h"
@@ -157,11 +158,37 @@ static void testGodRays()
     TestLightFilter filter;
     renderer.getLightingManager()->clearFilters();
     renderer.getLightingManager()->registerFilter(&filter);
+
+    // quality
     for (int i = 0; i < 6; i++)
     {
         renderer.setQuality((double)i / 5.0);
         rasterizer->setQuality(0.2);
-        startTestRender(&renderer, "god_rays", i);
+        startTestRender(&renderer, "god_rays_quality", i);
+    }
+    renderer.setQuality(0.5);
+
+    // penetration
+    for (int i = 0; i < 3; i++)
+    {
+        scenery.getAtmosphere()->childGodRays()->propPenetration()->setValue(0.01 + 0.02 * (double)i);
+        startTestRender(&renderer, "god_rays_penetration", i);
+    }
+
+    // resistance
+    scenery.getAtmosphere()->childGodRays()->propPenetration()->setValue(0.01);
+    for (int i = 0; i < 3; i++)
+    {
+        scenery.getAtmosphere()->childGodRays()->propResistance()->setValue(0.1 + 0.1 * (double)i);
+        startTestRender(&renderer, "god_rays_resistance", i);
+    }
+
+    // boost
+    scenery.getAtmosphere()->childGodRays()->propResistance()->setValue(0.3);
+    for (int i = 0; i < 3; i++)
+    {
+        scenery.getAtmosphere()->childGodRays()->propBoost()->setValue(2.0 + 4.0 * (double)i);
+        startTestRender(&renderer, "god_rays_boost", i);
     }
 }
 
diff --git a/src/render/software/GodRaysResult.cpp b/src/render/software/GodRaysResult.cpp
index 27ea188..5a629ae 100644
--- a/src/render/software/GodRaysResult.cpp
+++ b/src/render/software/GodRaysResult.cpp
@@ -5,7 +5,7 @@ GodRaysResult::GodRaysResult(double inside_length, double full_length):
 {
 }
 
-Color GodRaysResult::apply(const Color &raw, const Color &atmosphered)
+Color GodRaysResult::apply(const Color &raw, const Color &atmosphered, const GodRaysParams &params)
 {
     if (inside_length == 0.0)
     {
@@ -14,14 +14,16 @@ Color GodRaysResult::apply(const Color &raw, const Color &atmosphered)
     else if (inside_length < full_length)
     {
         double diff = full_length - inside_length;
-        double factor = 1.0 - 0.01 * diff;
-        if (factor < 0.3)
+        double factor = 1.0 - params.penetration * diff;
+        double minimum = params.resistance;
+        double complement = 1.0 - minimum;
+        if (factor < minimum)
         {
-            factor = 0.3;
+            factor = minimum;
         }
         else
         {
-            factor = pow((factor - 0.3) / 0.7, 8.0) * 0.7 + 0.3;
+            factor = pow((factor - minimum) / complement, params.boost) * complement + minimum;
         }
 
         return Color(raw.r + (atmosphered.r - raw.r) * factor,
diff --git a/src/render/software/GodRaysResult.h b/src/render/software/GodRaysResult.h
index bc6f952..15102f4 100644
--- a/src/render/software/GodRaysResult.h
+++ b/src/render/software/GodRaysResult.h
@@ -13,6 +13,13 @@ namespace software {
  */
 class SOFTWARESHARED_EXPORT GodRaysResult
 {
+public:
+    typedef struct {
+        double penetration;
+        double resistance;
+        double boost;
+    } GodRaysParams;
+
 public:
     GodRaysResult() = default;
     GodRaysResult(double inside_length, double full_length);
@@ -20,7 +27,7 @@ public:
     /**
      * Apply the result on a base color.
      */
-    Color apply(const Color &raw, const Color &atmosphered);
+    Color apply(const Color &raw, const Color &atmosphered, const GodRaysParams &params);
 
 private:
     double inside_length;
diff --git a/src/render/software/GodRaysSampler.cpp b/src/render/software/GodRaysSampler.cpp
index 75ee606..39c6e67 100644
--- a/src/render/software/GodRaysSampler.cpp
+++ b/src/render/software/GodRaysSampler.cpp
@@ -1,10 +1,13 @@
 #include "GodRaysSampler.h"
 
+#include "GodRaysDefinition.h"
+#include "AtmosphereDefinition.h"
 #include "SoftwareRenderer.h"
 #include "Vector3.h"
 #include "SpaceSegment.h"
 #include "GodRaysResult.h"
 #include "LightingManager.h"
+#include "FloatNode.h"
 #include "LightStatus.h"
 #include "Scenery.h"
 #include "TerrainDefinition.h"
@@ -16,6 +19,7 @@ GodRaysSampler::GodRaysSampler()
 {
     enabled = true;
     bounds = new SpaceSegment();
+    definition = new GodRaysDefinition(NULL);
     camera_location = new Vector3(0, 0, 0);
     lighting = NULL;
     low_altitude = -1.0;
@@ -28,6 +32,7 @@ GodRaysSampler::GodRaysSampler()
 
 GodRaysSampler::~GodRaysSampler()
 {
+    delete definition;
     delete bounds;
     delete camera_location;
     delete[] data;
@@ -38,6 +43,7 @@ void GodRaysSampler::prepare(SoftwareRenderer *renderer)
     setCameraLocation(renderer->getCameraLocation(VECTOR_ZERO));
     setLighting(renderer->getLightingManager());
     setAltitudes(renderer->getScenery()->getTerrain()->getHeightInfo().min_height, renderer->getCloudsRenderer()->getHighestAltitude());
+    renderer->getScenery()->getAtmosphere()->childGodRays()->copy(definition);
     reset();
 }
 
@@ -178,7 +184,13 @@ Color GodRaysSampler::apply(const Color &raw, const Color &atmosphered, const Ve
     if (enabled)
     {
         GodRaysResult result = getResult(SpaceSegment(*camera_location, location));
-        return result.apply(raw, atmosphered);
+
+        GodRaysResult::GodRaysParams params;
+        params.penetration = definition->propPenetration()->getValue();
+        params.resistance = definition->propResistance()->getValue();
+        params.boost = definition->propBoost()->getValue();
+
+        return result.apply(raw, atmosphered, params);
     }
     else
     {
diff --git a/src/render/software/GodRaysSampler.h b/src/render/software/GodRaysSampler.h
index a3e4954..27efc67 100644
--- a/src/render/software/GodRaysSampler.h
+++ b/src/render/software/GodRaysSampler.h
@@ -99,6 +99,8 @@ private:
     bool enabled;
     SpaceSegment *bounds;
 
+    GodRaysDefinition *definition;
+
     double sampling_step;
     double max_length;
     double walk_step;
diff --git a/src/render/software/NightSky.cpp b/src/render/software/NightSky.cpp
index 6cb4bd9..d70923e 100644
--- a/src/render/software/NightSky.cpp
+++ b/src/render/software/NightSky.cpp
@@ -95,7 +95,7 @@ const Color NightSky::getColor(double altitude, const Vector3 &direction)
 
 }
 
-bool NightSky::getLightsAt(std::vector<LightComponent> &result, const Vector3 &location) const
+bool NightSky::getLightsAt(std::vector<LightComponent> &result, const Vector3 &) const
 {
     LightComponent moon, sky;