paysages : Preetham approximation for sky (WIP).

git-svn-id: https://subversion.assembla.com/svn/thunderk/paysages@356 b1fd45b6-86a6-48da-8261-f70d1f35bdcc

TODO

@@ -1,5 +1,13 @@
 Technology Preview 2 :
+- Finalize Preetham's model usage
+   => Add enumarate to choose model in formsky
+   => Hide fields based on chosen model
+   => Update all fields when "auto from daytime" is selected
+   => Apply the skydome lighting by directly sampling it (no more amplitude in lights)
+   => Apply model to atmosphere (aerial perspective)
+   => Find a proper model for night sky (maybe Shirley)
 - InputInt doesn't honor small_step.
+- Disable form fields when no layer is selected.
 - Remove color gradations (replace with automatic boolean and simple colors).
 - Replace zone ranges with curves (with curve input and curve dialog).
 - Interface for textures thickness, slope_range and thickness_transparency (and correct slider ranges).

gui_qt/formmaterial.cpp

@@ -10,7 +10,7 @@ FormMaterial::FormMaterial(QWidget* parent, SurfaceMaterial* material) : BaseFor
     
     addInputColor(tr("Base color"), &_material.base);
     addInputDouble(tr("Light reflection"), &_material.reflection, 0.0, 1.0, 0.01, 0.1);
-    addInputDouble(tr("Light reflection shininess"), &_material.shininess, 0.0, 20.0, 0.1, 1.0);
+    addInputDouble(tr("Light reflection shininess"), &_material.shininess, 0.0, 30.0, 0.1, 1.0);
     
     _preview_color = new PreviewMaterial(this, &_material);
     addPreview(_preview_color, tr("Lighting preview"));

gui_qt/formsky.cpp

@@ -104,15 +104,17 @@ FormSky::FormSky(QWidget *parent):
     previewEast = new PreviewSkyEast(this);
     addPreview(previewEast, QString(tr("East preview")));
 
-    addInputDouble(tr("Day time"), &_definition.daytime, 0.0, 1.0, 0.01, 0.1);
+    addInputDouble(tr("Day time"), &_definition.daytime, 0.0, 1.0, 0.002, 0.1);
-    addInputColorGradation(tr("Sun color"), _definition.sun_color);
+    addInputColor(tr("Sun color"), &_definition.sun_color);
     addInputDouble(tr("Sun radius"), &_definition.sun_radius, 0.0, 0.4, 0.004, 0.04);
     addInputDouble(tr("Sun halo radius"), &_definition.sun_halo_size, 0.0, 0.4, 0.004, 0.04);
     addInputCurve(tr("Sun halo profile"), _definition.sun_halo_profile, 0.0, 1.0, 0.0, 1.0);
-    addInputColorGradation(tr("Zenith color"), _definition.zenith_color);
+    addInputBoolean(tr("Auto from daytime"), &_definition.model_custom.auto_from_daytime);
-    addInputColorGradation(tr("Haze color"), _definition.haze_color);
+    addInputColor(tr("Zenith color"), &_definition.model_custom.zenith_color);
-    addInputDouble(tr("Haze height"), &_definition.haze_height, 0.0, 1.0, 0.01, 0.1);
+    addInputColor(tr("Haze color"), &_definition.model_custom.haze_color);
-    addInputDouble(tr("Haze smoothing"), &_definition.haze_smoothing, 0.0, 1.0, 0.01, 0.1);
+    addInputDouble(tr("Haze height"), &_definition.model_custom.haze_height, 0.0, 1.0, 0.01, 0.1);
+    addInputDouble(tr("Haze smoothing"), &_definition.model_custom.haze_smoothing, 0.0, 1.0, 0.01, 0.1);
+    addInputDouble(tr("Turbidity"), &_definition.model_preetham.turbidity, 1.8, 6.0, 0.05, 0.5);
 
     revertConfig();
 }

i18n/paysages_fr.ts

@@ -628,21 +628,31 @@ Maintenir Ctrl : Plus rapide</translation>
     </message>
     <message>
         <location filename="../gui_qt/formsky.cpp" line="112"/>
+        <source>Auto from daytime</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location filename="../gui_qt/formsky.cpp" line="117"/>
+        <source>Turbidity</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <location filename="../gui_qt/formsky.cpp" line="113"/>
         <source>Zenith color</source>
         <translation>Couleur du ciel au zénith</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formsky.cpp" line="113"/>
+        <location filename="../gui_qt/formsky.cpp" line="114"/>
         <source>Haze color</source>
         <translation>Couleur de la brume</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formsky.cpp" line="114"/>
+        <location filename="../gui_qt/formsky.cpp" line="115"/>
         <source>Haze height</source>
         <translation>Hauteur apparente de la brume</translation>
     </message>
     <message>
-        <location filename="../gui_qt/formsky.cpp" line="115"/>
+        <location filename="../gui_qt/formsky.cpp" line="116"/>
         <source>Haze smoothing</source>
         <translation>Facteur de lissage de la brume</translation>
     </message>

lib_paysages/atmosphere.c

@@ -77,7 +77,7 @@ void atmosphereValidateDefinition(AtmosphereDefinition* definition)
     {
         sky = skyCreateDefinition();
         sceneryGetSky(&sky);
-        definition->color = colorGradationGet(sky.haze_color, sky.daytime);
+        definition->color = sky.model_custom.haze_color;
         skyDeleteDefinition(&sky);
     }
 }

lib_paysages/auto.c

@@ -82,17 +82,17 @@ void autoGenRealisticLandscape(int seed)
     water = waterCreateDefinition();
     water.height = -5.0;
     water.transparency = 0.5;
-    water.reflection = 0.3;
+    water.reflection = 0.4;
     water.transparency_depth = 6.0;
-    water.material.base.r = 0.1;
+    water.material.base.r = 0.05;
-    water.material.base.g = 0.3;
+    water.material.base.g = 0.15;
-    water.material.base.b = 0.4;
+    water.material.base.b = 0.2;
     water.material.base.a = 1.0;
     water.material.reflection = 1.0;
-    water.material.shininess = 12.0;
+    water.material.shininess = 16.0;
     water.depth_color.r = 0.0;
-    water.depth_color.g = 0.2;
+    water.depth_color.g = 0.1;
-    water.depth_color.b = 0.3;
+    water.depth_color.b = 0.1;
     water.depth_color.a = 1.0;
     water.lighting_depth = 3.0;
     water.waves_noise_height = 0.005;
@@ -106,32 +106,30 @@ void autoGenRealisticLandscape(int seed)
 
     /* Sky */
     sky = skyCreateDefinition();
-    colorGradationQuickAddRgb(sky.sun_color, 0.3, 1.0, 0.91, 0.8);
+    sky.model = SKY_MODEL_PREETHAM;
-    colorGradationQuickAddRgb(sky.sun_color, 0.5, 1.0, 0.95, 0.9);
-    colorGradationQuickAddRgb(sky.sun_color, 0.7, 1.0, 0.91, 0.8);
-    colorGradationQuickAddRgb(sky.zenith_color, 0.2, 0.03, 0.03, 0.05);
-    colorGradationQuickAddRgb(sky.zenith_color, 0.25, 0.25, 0.33, 0.37);
-    colorGradationQuickAddRgb(sky.zenith_color, 0.35, 0.52, 0.63, 0.8);
-    colorGradationQuickAddRgb(sky.zenith_color, 0.65, 0.52, 0.63, 0.8);
-    colorGradationQuickAddRgb(sky.zenith_color, 0.75, 0.25, 0.33, 0.37);
-    colorGradationQuickAddRgb(sky.zenith_color, 0.8, 0.03, 0.03, 0.05);
-    colorGradationQuickAddRgb(sky.haze_color, 0.2, 0.05, 0.05, 0.08);
-    colorGradationQuickAddRgb(sky.haze_color, 0.25, 0.55, 0.42, 0.42);
-    colorGradationQuickAddRgb(sky.haze_color, 0.3, 0.6, 0.6, 0.6);
-    colorGradationQuickAddRgb(sky.haze_color, 0.4, 0.92, 0.93, 1.0);
-    colorGradationQuickAddRgb(sky.haze_color, 0.6, 0.92, 0.93, 1.0);
-    colorGradationQuickAddRgb(sky.haze_color, 0.7, 0.6, 0.6, 0.8);
-    colorGradationQuickAddRgb(sky.haze_color, 0.75, 0.62, 0.50, 0.42);
-    colorGradationQuickAddRgb(sky.haze_color, 0.8, 0.05, 0.05, 0.08);
     sky.daytime = 0.0;
-    sky.haze_height = 0.75;
+    sky.sun_color.r = 1.0;
-    sky.haze_smoothing = 0.3;
+    sky.sun_color.g = 0.95;
+    sky.sun_color.b = 0.9;
+    sky.sun_color.a = 1.0;
     sky.sun_radius = 0.02;
     sky.sun_halo_size = 0.3;
     curveClear(sky.sun_halo_profile);
     curveQuickAddPoint(sky.sun_halo_profile, 0.0, 1.0);
     curveQuickAddPoint(sky.sun_halo_profile, 0.1, 0.2);
     curveQuickAddPoint(sky.sun_halo_profile, 1.0, 0.0);
+    sky.model_custom.auto_from_daytime = 1;
+    sky.model_custom.zenith_color.r = 0.52;
+    sky.model_custom.zenith_color.g = 0.63;
+    sky.model_custom.zenith_color.b = 0.8;
+    sky.model_custom.zenith_color.a = 1.0;
+    sky.model_custom.haze_color.r = 0.92;
+    sky.model_custom.haze_color.g = 0.93;
+    sky.model_custom.haze_color.b = 1.0;
+    sky.model_custom.haze_color.a = 1.0;
+    sky.model_custom.haze_height = 0.75;
+    sky.model_custom.haze_smoothing = 0.3;
+    sky.model_preetham.turbidity = 2.0;
     scenerySetSky(&sky);
     skyDeleteDefinition(&sky);
 

lib_paysages/color.c

@@ -136,6 +136,13 @@ void colorGradationCopy(ColorGradation* source, ColorGradation* destination)
     curveCopy(source->blue, destination->blue);
 }
 
+void colorGradationClear(ColorGradation* gradation)
+{
+    curveClear(gradation->red);
+    curveClear(gradation->green);
+    curveClear(gradation->blue);
+}
+
 void colorGradationSave(PackStream* stream, ColorGradation* gradation)
 {
     curveSave(stream, gradation->red);

lib_paysages/color.h

@@ -42,6 +42,7 @@ typedef struct ColorGradation ColorGradation;
 ColorGradation* colorGradationCreate();
 void colorGradationDelete(ColorGradation* gradation);
 void colorGradationCopy(ColorGradation* source, ColorGradation* destination);
+void colorGradationClear(ColorGradation* gradation);
 
 void colorGradationSave(PackStream* stream, ColorGradation* gradation);
 void colorGradationLoad(PackStream* stream, ColorGradation* gradation);

lib_paysages/sky.c

@@ -13,6 +13,7 @@
 
 #define SPHERE_SIZE 1000.0
 
+/******************************** Configuration ********************************/
 void skyInit()
 {
 }
@@ -23,28 +24,38 @@ void skyQuit()
 
 void skySave(PackStream* stream, SkyDefinition* definition)
 {
+    packWriteInt(stream, (int*)&definition->model);
     packWriteDouble(stream, &definition->daytime);
-    colorGradationSave(stream, definition->sun_color);
+    colorSave(stream, &definition->sun_color);
     packWriteDouble(stream, &definition->sun_radius);
     packWriteDouble(stream, &definition->sun_halo_size);
     curveSave(stream, definition->sun_halo_profile);
-    colorGradationSave(stream, definition->zenith_color);
+    
-    colorGradationSave(stream, definition->haze_color);
+    packWriteInt(stream, &definition->model_custom.auto_from_daytime);
-    packWriteDouble(stream, &definition->haze_height);
+    colorSave(stream, &definition->model_custom.zenith_color);
-    packWriteDouble(stream, &definition->haze_smoothing);
+    colorSave(stream, &definition->model_custom.haze_color);
+    packWriteDouble(stream, &definition->model_custom.haze_height);
+    packWriteDouble(stream, &definition->model_custom.haze_smoothing);
+    
+    packWriteDouble(stream, &definition->model_preetham.turbidity);
 }
 
 void skyLoad(PackStream* stream, SkyDefinition* definition)
 {
+    packReadInt(stream, (int*)&definition->model);
     packReadDouble(stream, &definition->daytime);
-    colorGradationLoad(stream, definition->sun_color);
+    colorLoad(stream, &definition->sun_color);
     packReadDouble(stream, &definition->sun_radius);
     packReadDouble(stream, &definition->sun_halo_size);
     curveLoad(stream, definition->sun_halo_profile);
-    colorGradationLoad(stream, definition->zenith_color);
+    
-    colorGradationLoad(stream, definition->haze_color);
+    packReadInt(stream, &definition->model_custom.auto_from_daytime);
-    packReadDouble(stream, &definition->haze_height);
+    colorLoad(stream, &definition->model_custom.zenith_color);
-    packReadDouble(stream, &definition->haze_smoothing);
+    colorLoad(stream, &definition->model_custom.haze_color);
+    packReadDouble(stream, &definition->model_custom.haze_height);
+    packReadDouble(stream, &definition->model_custom.haze_smoothing);
+    
+    packReadDouble(stream, &definition->model_preetham.turbidity);
 
     skyValidateDefinition(definition);
 }
@@ -53,15 +64,19 @@ SkyDefinition skyCreateDefinition()
 {
     SkyDefinition def;
 
+    def.model = SKY_MODEL_CUSTOM;
     def.daytime = 0.0;
-    def.sun_color = colorGradationCreate();
+    def.sun_color = COLOR_BLACK;
     def.sun_radius = 1.0;
     def.sun_halo_size = 0.0;
     def.sun_halo_profile = curveCreate();
-    def.zenith_color = colorGradationCreate();
+    def.model_custom.auto_from_daytime = 0;
-    def.haze_color = colorGradationCreate();
+    def.model_custom.zenith_color = COLOR_BLACK;
-    def.haze_height = 0.0;
+    def.model_custom.haze_color = COLOR_BLACK;
-    def.haze_smoothing = 0.0;
+    def.model_custom.haze_height = 0.0;
+    def.model_custom.haze_smoothing = 0.0;
+    def.model_custom._sky_gradation = colorGradationCreate();
+    def.model_preetham.turbidity = 0.0;
 
     skyValidateDefinition(&def);
 
@@ -71,39 +86,72 @@ SkyDefinition skyCreateDefinition()
 void skyDeleteDefinition(SkyDefinition* definition)
 {
     curveDelete(definition->sun_halo_profile);
-    colorGradationDelete(definition->sun_color);
+    colorGradationDelete(definition->model_custom._sky_gradation);
-    colorGradationDelete(definition->zenith_color);
-    colorGradationDelete(definition->haze_color);
 }
 
 void skyCopyDefinition(SkyDefinition* source, SkyDefinition* destination)
 {
+    destination->model = source->model;
     destination->daytime = source->daytime;
+    destination->sun_color = source->sun_color;
     destination->sun_radius = source->sun_radius;
     destination->sun_halo_size = source->sun_halo_size;
-    destination->haze_height = source->haze_height;
+    destination->model_custom.auto_from_daytime = source->model_custom.auto_from_daytime;
-    destination->haze_smoothing = source->haze_smoothing;
+    destination->model_custom.zenith_color = source->model_custom.zenith_color;
+    destination->model_custom.haze_color = source->model_custom.haze_color;
+    destination->model_custom.haze_height = source->model_custom.haze_height;
+    destination->model_custom.haze_smoothing = source->model_custom.haze_smoothing;
+    destination->model_preetham.turbidity = source->model_preetham.turbidity;
     
     curveCopy(source->sun_halo_profile, destination->sun_halo_profile);
     
-    colorGradationCopy(source->sun_color, destination->sun_color);
+    skyValidateDefinition(destination);
-    colorGradationCopy(source->zenith_color, destination->zenith_color);
+}
-    colorGradationCopy(source->haze_color, destination->haze_color);
+
-    colorGradationCopy(source->_sky_gradation, destination->_sky_gradation);
+static void _setAutoCustomModel(SkyDefinition* definition)
+{
+    ColorGradation* zenith_gradation;
+    ColorGradation* haze_gradation;
+    
+    zenith_gradation = colorGradationCreate();
+    haze_gradation = colorGradationCreate();
+
+    colorGradationQuickAddRgb(zenith_gradation, 0.2, 0.03, 0.03, 0.05);
+    colorGradationQuickAddRgb(zenith_gradation, 0.25, 0.25, 0.33, 0.37);
+    colorGradationQuickAddRgb(zenith_gradation, 0.35, 0.52, 0.63, 0.8);
+    colorGradationQuickAddRgb(zenith_gradation, 0.65, 0.52, 0.63, 0.8);
+    colorGradationQuickAddRgb(zenith_gradation, 0.75, 0.25, 0.33, 0.37);
+    colorGradationQuickAddRgb(zenith_gradation, 0.8, 0.03, 0.03, 0.05);
+    colorGradationQuickAddRgb(haze_gradation, 0.2, 0.05, 0.05, 0.08);
+    colorGradationQuickAddRgb(haze_gradation, 0.25, 0.55, 0.42, 0.42);
+    colorGradationQuickAddRgb(haze_gradation, 0.3, 0.6, 0.6, 0.6);
+    colorGradationQuickAddRgb(haze_gradation, 0.4, 0.92, 0.93, 1.0);
+    colorGradationQuickAddRgb(haze_gradation, 0.6, 0.92, 0.93, 1.0);
+    colorGradationQuickAddRgb(haze_gradation, 0.7, 0.6, 0.6, 0.8);
+    colorGradationQuickAddRgb(haze_gradation, 0.75, 0.62, 0.50, 0.42);
+    colorGradationQuickAddRgb(haze_gradation, 0.8, 0.05, 0.05, 0.08);
+
+    definition->model_custom.zenith_color = colorGradationGet(zenith_gradation, definition->daytime);
+    definition->model_custom.haze_color = colorGradationGet(haze_gradation, definition->daytime);
+    
+    colorGradationDelete(zenith_gradation);
+    colorGradationDelete(haze_gradation);
 }
 
 void skyValidateDefinition(SkyDefinition* definition)
 {
-    Color zenith, haze;
+    if (definition->model == SKY_MODEL_CUSTOM)
-
+    {
-    zenith = colorGradationGet(definition->zenith_color, definition->daytime);
+        if (definition->model_custom.auto_from_daytime)
-    haze = colorGradationGet(definition->haze_color, definition->daytime);
+        {
-
+            _setAutoCustomModel(definition);
-    definition->_sky_gradation = colorGradationCreate();
+        }
-    colorGradationQuickAdd(definition->_sky_gradation, 0.0, &haze);
+        colorGradationClear(definition->model_custom._sky_gradation);
-    colorGradationQuickAdd(definition->_sky_gradation, definition->haze_height - definition->haze_smoothing, &haze);
+        colorGradationQuickAdd(definition->model_custom._sky_gradation, 0.0, &definition->model_custom.haze_color);
-    colorGradationQuickAdd(definition->_sky_gradation, definition->haze_height, &zenith);
+        colorGradationQuickAdd(definition->model_custom._sky_gradation, definition->model_custom.haze_height - definition->model_custom.haze_smoothing, &definition->model_custom.haze_color);
-    colorGradationQuickAdd(definition->_sky_gradation, 1.0, &zenith);
+        colorGradationQuickAdd(definition->model_custom._sky_gradation, definition->model_custom.haze_height, &definition->model_custom.zenith_color);
+        colorGradationQuickAdd(definition->model_custom._sky_gradation, 1.0, &definition->model_custom.zenith_color);
+    }
 }
 
 int skyGetLights(SkyDefinition* sky, LightDefinition* lights, int max_lights)
@@ -123,7 +171,7 @@ int skyGetLights(SkyDefinition* sky, LightDefinition* lights, int max_lights)
     {
         /* Light from the sun */
         lights[0].direction = v3Scale(sun_direction, -1.0);
-        lights[0].color = colorGradationGet(sky->sun_color, sky->daytime);
+        lights[0].color = sky->sun_color;
         lights[0].reflection = 1.0;
         lights[0].filtered = 1;
         lights[0].masked = 1;
@@ -135,7 +183,7 @@ int skyGetLights(SkyDefinition* sky, LightDefinition* lights, int max_lights)
             lights[1].direction.x = 0.0;
             lights[1].direction.y = -1.0;
             lights[1].direction.z = 0.0;
-            lights[1].color = colorGradationGet(sky->zenith_color, sky->daytime);
+            lights[1].color = sky->model_custom.zenith_color;
             lights[1].color.r *= 0.6;
             lights[1].color.g *= 0.6;
             lights[1].color.b *= 0.6;
@@ -150,6 +198,7 @@ int skyGetLights(SkyDefinition* sky, LightDefinition* lights, int max_lights)
     return nblights;
 }
 
+/******************************** Preetham Model ********************************/
 static inline double _angleBetween(double thetav, double phiv, double theta, double phi) 
 {
     double cospsi = sin(thetav) * sin(theta) * cos(phi-phiv) + cos(thetav) * cos(theta);
@@ -158,29 +207,28 @@ static inline double _angleBetween(double thetav, double phiv, double theta, dou
     return acos(cospsi);
 }
 
-static inline Color _toColor(float x, float y, float Y)
+static inline Color _xyYToRGB(double x, double y, double Y)
 {
-	float fX, fY, fZ;
+	double fX, fY, fZ;
         Color result;
 
 	fY = Y;
 	fX = x / y * Y;
-	fZ = ((1.0f - x - y) / y) * Y;
+	fZ = ((1.0 - x - y) / y) * Y;
 
-	float r, g, b;
+	double r, g, b;
+	r =  3.2404 * fX - 1.5371 * fY - 0.4985 * fZ;
+	g = -0.9692 * fX + 1.8759 * fY + 0.0415 * fZ;
+	b =  0.0556 * fX - 0.2040 * fY + 1.0573 * fZ;
 
-	r =  3.2404f * fX - 1.5371f * fY - 0.4985f * fZ;
+	double expo = -(1.0 / 10000.0);
-	g = -0.9692f * fX + 1.8759f * fY + 0.0415f * fZ;
+	r = 1.0 - exp(expo * r);
-	b =  0.0556f * fX - 0.2040f * fY + 1.0573f * fZ;
+	g = 1.0 - exp(expo * g);
+	b = 1.0 - exp(expo * b);
 
-	float expo = -(1.0f / 10000.0f);
+	if (r < 0.0) r = 0.0;
-	r = 1.0f - exp(expo * r);
+	if (g < 0.0) g = 0.0;
-	g = 1.0f - exp(expo * g);
+	if (b < 0.0) b = 0.0;
-	b = 1.0f - exp(expo * b);
-
-	if (r < 0.0f) r = 0.0f;
-	if (g < 0.0f) g = 0.0f;
-	if (b < 0.0f) b = 0.0f;
 
 	result.r = r;
 	result.g = g;
@@ -197,7 +245,7 @@ static Color _preethamApproximate(SkyDefinition* definition, double theta, doubl
     double thetaSun;
     double phiSun;
     double gamma;
-    double turbidity = 2.0;
+    double turbidity = definition->model_preetham.turbidity;
 
     /* Handle angles */
     if (theta > M_PI / 2.0)
@@ -262,26 +310,27 @@ static Color _preethamApproximate(SkyDefinition* definition, double theta, doubl
                 (-0.04214 * suntheta3 + 0.08970 * suntheta2 - 0.04153 * suntheta + 0.00516) * T +	
                 ( 0.15346 * suntheta3 - 0.26756 * suntheta2 + 0.06670 * suntheta + 0.26688);
     
-    double X = (4.0f / 9.0f - T / 120.0f) * (M_PI - 2.0 * suntheta);		
+    double X = (4.0 / 9.0 - T / 120.0) * (M_PI - 2.0 * suntheta);		
-    double Yz = ((4.0453f * T - 4.9710) * tan(X) - 0.2155 * T + 2.4192) * 1000.0f;
+    double Yz = ((4.0453 * T - 4.9710) * tan(X) - 0.2155 * T + 2.4192) * 1000.0;
 
     double val1, val2;
 
-    val1 = ( 1 + Ax * exp(Bx / cosTheta ) ) * ( 1 + Cx * exp(Dx * gamma) + Ex * sqrt(cosGamma) );
+    val1 = (1.0 + Ax * exp(Bx / cosTheta)) * (1.0 + Cx * exp(Dx * gamma) + Ex * sqrt(cosGamma));
-    val2 = ( 1 + Ax * exp(Bx) ) * ( 1 + Cx * exp(Dx * suntheta) + Ex * sqrt(cosSTheta) );
+    val2 = (1.0 + Ax * exp(Bx)) * (1.0 + Cx * exp(Dx * suntheta) + Ex * sqrt(cosSTheta));
     double x = xz * val1 / val2;
 
-    val1 = ( 1 + Ay * exp(By / cosTheta) ) * ( 1 + Cy * exp(Dy * gamma   ) + Ey * sqrt(cosGamma )  );
+    val1 = (1.0 + Ay * exp(By / cosTheta)) * (1.0 + Cy * exp(Dy * gamma) + Ey * sqrt(cosGamma));
-    val2 = ( 1 + Ay * exp(By            )  ) * ( 1 + Cy * exp(Dy * suntheta) + Ey * sqrt(cosSTheta) );
+    val2 = (1.0 + Ay * exp(By)) * (1.0 + Cy * exp(Dy * suntheta) + Ey * sqrt(cosSTheta));
     double y = yz * val1 / val2;
 
-    val1 = ( 1 + AY * exp(BY / cosTheta) ) * ( 1 + CY * exp(DY * gamma   ) + EY * sqrt(cosGamma) );
+    val1 = (1.0 + AY * exp(BY / cosTheta)) * (1.0 + CY * exp(DY * gamma) + EY * sqrt(cosGamma));
-    val2 = ( 1 + AY * exp(BY             ) ) * ( 1 + CY * exp(DY * suntheta) + EY * sqrt(cosSTheta) );
+    val2 = (1.0 + AY * exp(BY)) * (1.0 + CY * exp(DY * suntheta) + EY * sqrt(cosSTheta));
     double Y = Yz * val1 / val2;
 
-    return _toColor(x, y, Y);
+    return _xyYToRGB(x, y, Y);
 }
 
+/******************************** Rendering ********************************/
 Color skyGetColor(SkyDefinition* definition, Renderer* renderer, Vector3 eye, Vector3 look)
 {
     double dist;
@@ -293,10 +342,18 @@ Color skyGetColor(SkyDefinition* definition, Renderer* renderer, Vector3 eye, Ve
     look = v3Normalize(look);
     dist = v3Norm(v3Sub(look, sun_position));
 
+    if (definition->model == SKY_MODEL_PREETHAM)
+    {
         sky_color = _preethamApproximate(definition, M_PI/2.0 - asin(look.y), atan2(-look.z, look.x));
+    }
+    else
+    {
+        sky_color = colorGradationGet(definition->model_custom._sky_gradation, look.y * 0.5 + 0.5);
+    }
+    
     if (dist < definition->sun_radius + definition->sun_halo_size)
     {
-        sun_color = colorGradationGet(definition->sun_color, definition->daytime);
+        sun_color = definition->sun_color;
         if (dist <= definition->sun_radius)
         {
             return sun_color;
@@ -396,10 +453,10 @@ Vector3 skyGetSunDirection(SkyDefinition* definition)
 
 Color skyGetSunColor(SkyDefinition* definition)
 {
-    return colorGradationGet(definition->sun_color, definition->daytime);
+    return definition->sun_color;
 }
 
 Color skyGetZenithColor(SkyDefinition* definition)
 {
-    return colorGradationGet(definition->zenith_color, definition->daytime);
+    return definition->model_custom.zenith_color;
 }

lib_paysages/sky.h

@@ -10,18 +10,31 @@
 extern "C" {
 #endif
     
+typedef enum
+{
+    SKY_MODEL_CUSTOM = 0,
+    SKY_MODEL_PREETHAM = 1
+} SkyModel;
+
 typedef struct
 {
+    SkyModel model;
     double daytime;
-    ColorGradation* sun_color;
+    Color sun_color;
     double sun_radius;
     double sun_halo_size;
     Curve* sun_halo_profile;
-    ColorGradation* zenith_color;
+    struct {
-    ColorGradation* haze_color;
+        int auto_from_daytime;
+        Color zenith_color;
+        Color haze_color;
         double haze_height;
         double haze_smoothing;
         ColorGradation* _sky_gradation;
+    } model_custom;
+    struct {
+        double turbidity;
+    } model_preetham;
 } SkyDefinition;
 
 void skyInit();