diff --git a/cli/main.c b/cli/main.c
index 98cdb25..7dfb02a 100644
--- a/cli/main.c
+++ b/cli/main.c
@@ -120,7 +120,7 @@ int main(int argc, char** argv)
 
     printf("Initializing ...\n");
     paysagesInit();
-    
+
     if (conf_file_path)
     {
         paysagesLoad(conf_file_path);
@@ -131,14 +131,14 @@ int main(int argc, char** argv)
 
     for (outputcount = 0; outputcount < conf_nb_pictures; outputcount++)
     {
-        autoSetDaytimeFraction(conf_daytime_start);
+        /*autoSetDaytimeFraction(conf_daytime_start);*/ /* TODO */
 
         sprintf(outputpath, "output/pic%05d.png", outputcount);
         startRender(&renderer, outputpath, conf_render_params);
 
         conf_daytime_start += conf_daytime_step;
     }
-    
+
     printf("Cleaning up ...\n");
     rendererDelete(&renderer);
     paysagesQuit();
diff --git a/gui_qt/dialognoise.cpp b/gui_qt/dialognoise.cpp
index 6b47782..1465369 100644
--- a/gui_qt/dialognoise.cpp
+++ b/gui_qt/dialognoise.cpp
@@ -20,7 +20,7 @@ public:
         _noise_original = noise;
         _noise_preview = noiseCreateGenerator();
         _level = -1;
-        
+
         configScaling(0.15, 6.0, 0.09, 6.0);
     }
 
@@ -58,7 +58,7 @@ public:
     {
         _noise_original = noise;
         _noise_preview = noiseCreateGenerator();
-        
+
         configScaling(0.15, 6.0, 0.09, 6.0);
     }
 protected:
@@ -108,7 +108,7 @@ DialogNoise::DialogNoise(QWidget *parent, NoiseGenerator* value):
     label->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
     previews->layout()->addWidget(label);
     previews->layout()->addWidget(previewLevel);
-    
+
     previewTotal = new PreviewTotal(previews, _current);
     label = new QLabel(tr("Total preview"));
     label->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
@@ -118,11 +118,11 @@ DialogNoise::DialogNoise(QWidget *parent, NoiseGenerator* value):
     form = new QWidget(this);
     form->setLayout(new QVBoxLayout());
     layout()->addWidget(form);
-    
+
     function = new QWidget(form);
     function->setLayout(new QHBoxLayout());
     form->layout()->addWidget(function);
-    
+
     function->layout()->addWidget(new QLabel(tr("Noise function")));
     function_algo = new QComboBox(function);
     function_algo->addItems(QStringList(tr("Simplex (best)")) << tr("Perlin (fast)") << tr("Naive (slow)"));
@@ -222,7 +222,7 @@ bool DialogNoise::getNoise(QWidget* parent, NoiseGenerator* noise)
     return (result != 0) ? true : false;
 }
 
-void DialogNoise::closeEvent(QCloseEvent* e)
+void DialogNoise::closeEvent(QCloseEvent*)
 {
     reject();
 }
@@ -245,7 +245,7 @@ void DialogNoise::revertToCurrent()
     int i, n;
     int selected;
     NoiseFunction function;
-    
+
     selected = levels->currentRow();
 
     levels->clear();
@@ -254,7 +254,7 @@ void DialogNoise::revertToCurrent()
     {
         levels->addItem(QString(tr("Component %1")).arg(i + 1));
     }
-    
+
     if (n > 0)
     {
         if (selected < 0)
@@ -267,7 +267,7 @@ void DialogNoise::revertToCurrent()
         }
         levels->setCurrentRow(selected);
     }
-    
+
     function = noiseGetFunction(_current);
     function_algo->setCurrentIndex((int)function.algorithm);
     function_ridge->setValue(round(function.ridge_factor * 20.0));
@@ -279,7 +279,7 @@ void DialogNoise::revertToCurrent()
 void DialogNoise::addLevel()
 {
     NoiseLevel level;
-    
+
     level.height = 0.1;
     level.scaling = 0.1;
     level.xoffset = 0.0;
@@ -288,20 +288,20 @@ void DialogNoise::addLevel()
     noiseAddLevel(_current, level);
 
     revertToCurrent();
-    
+
     levels->setCurrentRow(levels->count() - 1);
 }
 
 void DialogNoise::removeLevel()
 {
     int row;
-    
+
     row = levels->currentRow();
-    
+
     noiseRemoveLevel(_current, _current_level);
 
     revertToCurrent();
-    
+
     if (row >= levels->count())
     {
         row--;
@@ -312,13 +312,13 @@ void DialogNoise::removeLevel()
 void DialogNoise::functionChanged()
 {
     NoiseFunction function;
-    
+
     function.algorithm = (NoiseFunctionAlgorithm)function_algo->currentIndex();
     function.ridge_factor = (double)function_ridge->value() * 0.05;
-    
+
     noiseSetFunction(_current, &function);
     noiseValidate(_current);
-    
+
     previewLevel->redraw();
     previewTotal->redraw();
 }
diff --git a/gui_qt/explorerchunksky.cpp b/gui_qt/explorerchunksky.cpp
index 1449571..e73d6d3 100644
--- a/gui_qt/explorerchunksky.cpp
+++ b/gui_qt/explorerchunksky.cpp
@@ -8,12 +8,12 @@ ExplorerChunkSky::ExplorerChunkSky(Renderer* renderer, double size, SkyboxOrient
 {
     _box_size = size;
     _orientation = orientation;
-    
+
     setMaxTextureSize(256);
     maintain();
 }
 
-void ExplorerChunkSky::onRenderEvent(QGLWidget* widget)
+void ExplorerChunkSky::onRenderEvent(QGLWidget*)
 {
     double size = _box_size;
     Vector3 camera = renderer()->camera_location;
@@ -85,7 +85,7 @@ void ExplorerChunkSky::onRenderEvent(QGLWidget* widget)
     glEnd();
 }
 
-double ExplorerChunkSky::getDisplayedSizeHint(CameraDefinition* camera)
+double ExplorerChunkSky::getDisplayedSizeHint(CameraDefinition*)
 {
     return 1000.0;
 }
@@ -93,10 +93,10 @@ double ExplorerChunkSky::getDisplayedSizeHint(CameraDefinition* camera)
 Color ExplorerChunkSky::getTextureColor(double x, double y)
 {
     Vector3 location;
-    
+
     x -= 0.5;
     y -= 0.5;
-    
+
     switch(_orientation)
     {
         case SKYBOX_NORTH:
diff --git a/gui_qt/explorerchunkterrain.cpp b/gui_qt/explorerchunkterrain.cpp
index 354b2cb..80c3bfc 100644
--- a/gui_qt/explorerchunkterrain.cpp
+++ b/gui_qt/explorerchunkterrain.cpp
@@ -94,7 +94,7 @@ void ExplorerChunkTerrain::onCameraEvent(CameraDefinition* camera)
     _lock_data.unlock();
 }
 
-void ExplorerChunkTerrain::onRenderEvent(QGLWidget* widget)
+void ExplorerChunkTerrain::onRenderEvent(QGLWidget*)
 {
     _lock_data.lock();
     int tessellation_size = _tessellation_current_size;
diff --git a/gui_qt/formatmosphere.cpp b/gui_qt/formatmosphere.cpp
index 5f42e8a..a8abca3 100644
--- a/gui_qt/formatmosphere.cpp
+++ b/gui_qt/formatmosphere.cpp
@@ -77,7 +77,8 @@ FormAtmosphere::FormAtmosphere(QWidget *parent):
     addPreview(previewEast, QString(tr("East preview")));
 
     addInputEnum(tr("Color model"), (int*)&_definition->model, QStringList(tr("Preetham/Shirley analytic model")) << tr("Bruneton/Neyret precomputed model"));
-    addInputDouble(tr("Day time"), &_definition->daytime, 0.14, 0.86, 0.002, 0.1);
+    addInputInt(tr("Day time (hour)"), &_definition->hour, 0, 23, 1, 10);
+    addInputInt(tr("Day time (minute)"), &_definition->minute, 0, 59, 1, 10);
     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);
diff --git a/gui_qt/formclouds.cpp b/gui_qt/formclouds.cpp
index 7a1c64e..760f9c7 100644
--- a/gui_qt/formclouds.cpp
+++ b/gui_qt/formclouds.cpp
@@ -47,7 +47,7 @@ protected:
     {
         cloudsLayerCopyDefinition(_original_layer, _preview_layer);
     }
-    static Color _applyLightStatus(Renderer* renderer, LightStatus* status, Vector3 location, Vector3 normal, SurfaceMaterial material)
+    static Color _applyLightStatus(Renderer*, LightStatus*, Vector3, Vector3, SurfaceMaterial)
     {
         return COLOR_WHITE;
     }
diff --git a/gui_qt/mainwindow.cpp b/gui_qt/mainwindow.cpp
index 85c828f..eaa8086 100644
--- a/gui_qt/mainwindow.cpp
+++ b/gui_qt/mainwindow.cpp
@@ -56,7 +56,7 @@ int main(int argc, char** argv)
         app.installTranslator(&qtTranslator);
     }
 
-    splash->showMessage(app.tr("Preloading..."), Qt::AlignCenter, Qt::white);
+    //splash->showMessage(app.tr("Preloading..."), Qt::AlignCenter, Qt::white);
     app.processEvents();
 
     paysagesInit();
@@ -184,7 +184,6 @@ void MainWindow::fileNew()
     if (QMessageBox::question(this, tr("Paysages 3D - New scenery"), tr("Do you want to start a new scenery ? Any unsaved changes will be lost."), QMessageBox::Yes | QMessageBox::No, QMessageBox::No) == QMessageBox::Yes)
     {
         autoGenRealisticLandscape(0);
-        autoSetDaytime(8, 30);
         refreshAll();
     }
 }
diff --git a/lib_paysages/atmosphere/basic.c b/lib_paysages/atmosphere/basic.c
new file mode 100644
index 0000000..db6b128
--- /dev/null
+++ b/lib_paysages/atmosphere/basic.c
@@ -0,0 +1,41 @@
+#include "private.h"
+
+#include <assert.h>
+#include <math.h>
+#include "../renderer.h"
+
+Color basicApplyAerialPerspective(Renderer* renderer, Vector3 location, Color base)
+{
+    Vector3 direction = v3Sub(location, renderer->camera_location);
+    double distance = v3Norm(direction);
+    AtmosphereDefinition* definition = renderer->atmosphere->definition;
+    double near = 10.0 - definition->humidity * 10.0;
+    double far = 100.0 - definition->humidity * 90.0;
+    double max = 0.85 + definition->humidity * 0.12;
+
+    assert(near < far);
+
+    if (distance < near)
+    {
+        return base;
+    }
+    else
+    {
+        if (distance > far)
+        {
+            distance = far;
+        }
+        double factor = (distance - near) / (far - near);
+
+        /* TODO Get sky color without celestial objects (sun, stars...) */
+        double angle = (1.0 - factor) * (1.0 - factor) * (1.0 - factor) * (1.0 - factor) * M_PI_4;
+        direction = v3Normalize(direction);
+        direction.y = sin(angle);
+        Color sky = renderer->atmosphere->getSkyColor(renderer, v3Normalize(direction));
+
+        sky.a = max * factor;
+        colorMask(&base, &sky);
+
+        return base;
+    }
+}
diff --git a/lib_paysages/atmosphere/bruneton.c b/lib_paysages/atmosphere/bruneton.c
index d47acca..8502559 100644
--- a/lib_paysages/atmosphere/bruneton.c
+++ b/lib_paysages/atmosphere/bruneton.c
@@ -25,7 +25,7 @@ static const double exposure = 0.4;
 static const double ISun = 100.0;
 static const double AVERAGE_GROUND_REFLECTANCE = 0.1;
 
-#if 0
+#if 1
 #define RES_MU 128
 #define RES_MU_S 32
 #define RES_R 32
diff --git a/lib_paysages/atmosphere/main.c b/lib_paysages/atmosphere/main.c
index a5af481..a721362 100644
--- a/lib_paysages/atmosphere/main.c
+++ b/lib_paysages/atmosphere/main.c
@@ -23,7 +23,24 @@ static int _inited = 0;
 /******************** Definition ********************/
 static void _validateDefinition(AtmosphereDefinition* definition)
 {
-    UNUSED(definition);
+    if (definition->hour < 0)
+    {
+        definition->hour = 0;
+    }
+    if (definition->hour > 23)
+    {
+        definition->hour = 23;
+    }
+    if (definition->minute < 0)
+    {
+        definition->minute = 0;
+    }
+    if (definition->minute > 59)
+    {
+        definition->minute = 59;
+    }
+
+    definition->_daytime = (double)definition->hour / 24.0 + (double)definition->minute / 1440.0;
 }
 
 static AtmosphereDefinition* _createDefinition()
@@ -54,7 +71,8 @@ static void _deleteDefinition(AtmosphereDefinition* definition)
 static void _copyDefinition(AtmosphereDefinition* source, AtmosphereDefinition* destination)
 {
     destination->model = source->model;
-    destination->daytime = source->daytime;
+    destination->hour = source->hour;
+    destination->minute = source->minute;
     destination->sun_color = source->sun_color;
     destination->sun_radius = source->sun_radius;
     destination->sun_halo_size = source->sun_halo_size;
@@ -69,7 +87,8 @@ static void _copyDefinition(AtmosphereDefinition* source, AtmosphereDefinition*
 static void _saveDefinition(PackStream* stream, AtmosphereDefinition* definition)
 {
     packWriteInt(stream, (int*)&definition->model);
-    packWriteDouble(stream, &definition->daytime);
+    packWriteInt(stream, &definition->hour);
+    packWriteInt(stream, &definition->minute);
     colorSave(stream, &definition->sun_color);
     packWriteDouble(stream, &definition->sun_radius);
     packWriteDouble(stream, &definition->sun_halo_size);
@@ -81,7 +100,8 @@ static void _saveDefinition(PackStream* stream, AtmosphereDefinition* definition
 static void _loadDefinition(PackStream* stream, AtmosphereDefinition* definition)
 {
     packReadInt(stream, (int*)&definition->model);
-    packReadDouble(stream, &definition->daytime);
+    packReadInt(stream, &definition->hour);
+    packReadInt(stream, &definition->minute);
     colorLoad(stream, &definition->sun_color);
     packReadDouble(stream, &definition->sun_radius);
     packReadDouble(stream, &definition->sun_halo_size);
@@ -175,7 +195,7 @@ static Color _getSkyColor(Renderer* renderer, Vector3 direction)
 static Vector3 _getSunDirection(Renderer* renderer)
 {
     Vector3 result;
-    double sun_angle = (renderer->atmosphere->definition->daytime + 0.75) * M_PI * 2.0;
+    double sun_angle = (renderer->atmosphere->definition->_daytime + 0.75) * M_PI * 2.0;
     result.x = cos(sun_angle);
     result.y = sin(sun_angle);
     result.z = 0.0;
@@ -207,7 +227,7 @@ static int _getSkydomeLights(Renderer* renderer, LightDefinition* lights, int ma
     {
         definition = renderer->atmosphere->definition;
 
-        sun_angle = (definition->daytime + 0.75) * M_PI * 2.0;
+        sun_angle = (definition->_daytime + 0.75) * M_PI * 2.0;
         sun_direction.x = cos(sun_angle);
         sun_direction.y = sin(sun_angle);
         sun_direction.z = 0.0;
@@ -321,14 +341,11 @@ static void _bindRenderer(AtmosphereRenderer* renderer, AtmosphereDefinition* de
 
     switch (definition->model)
     {
-        case ATMOSPHERE_MODEL_PREETHAM:
-            renderer->applyAerialPerspective = preethamApplyAerialPerspective;
-            break;
         case ATMOSPHERE_MODEL_BRUNETON:
             renderer->applyAerialPerspective = brunetonApplyAerialPerspective;
             break;
         default:
-            renderer->applyAerialPerspective = _fakeApplyAerialPerspective;
+            renderer->applyAerialPerspective = basicApplyAerialPerspective;
     }
 
     mutexAcquire(cache->lock);
diff --git a/lib_paysages/atmosphere/preetham.c b/lib_paysages/atmosphere/preetham.c
index 5a68801..9f9650d 100644
--- a/lib_paysages/atmosphere/preetham.c
+++ b/lib_paysages/atmosphere/preetham.c
@@ -135,33 +135,3 @@ Color preethamGetSkyColor(AtmosphereDefinition* definition, Vector3 eye, Vector3
     colorMask(&result, &humidity_color);
     return result;
 }
-
-Color preethamApplyAerialPerspective(Renderer* renderer, Vector3 location, Color base)
-{
-    Vector3 ray = v3Sub(location, renderer->camera_location);
-    Vector3 direction = v3Normalize(ray);
-    double distance = v3Norm(ray);
-    AtmosphereDefinition* definition = renderer->atmosphere->definition;
-    double near = 10.0 - definition->humidity * 10.0;
-    double far = 100.0 - definition->humidity * 90.0;
-    double max = 0.85 + definition->humidity * 0.12;
-
-    assert(near < far);
-
-    if (distance < near)
-    {
-        return base;
-    }
-    else
-    {
-        Vector3 sun_position = renderer->atmosphere->getSunDirection(renderer);
-        Color sky = preethamGetSkyColor(definition, renderer->camera_location, direction, sun_position);
-        if (distance > far)
-        {
-            distance = far;
-        }
-        sky.a = max * ((distance - near) / (far - near));
-        colorMask(&base, &sky);
-        return base;
-    }
-}
diff --git a/lib_paysages/atmosphere/presets.c b/lib_paysages/atmosphere/presets.c
index e64d72e..eccdb04 100644
--- a/lib_paysages/atmosphere/presets.c
+++ b/lib_paysages/atmosphere/presets.c
@@ -22,30 +22,35 @@ void atmosphereAutoPreset(AtmosphereDefinition* definition, AtmospherePreset pre
     {
         case ATMOSPHERE_PRESET_CLEAR_DAY:
             definition->model = ATMOSPHERE_MODEL_BRUNETON;
-            definition->daytime = 0.4;
+            definition->hour = 15;
+            definition->minute = 0;
             definition->dome_lighting = 0.6;
             break;
         case ATMOSPHERE_PRESET_CLEAR_SUNSET:
             definition->model = ATMOSPHERE_MODEL_BRUNETON;
-            definition->daytime = 0.74;
+            definition->hour = 17;
+            definition->minute = 45;
             definition->dome_lighting = 0.8;
             definition->sun_radius = 0.03;
             break;
         case ATMOSPHERE_PRESET_HAZY_MORNING:
             definition->model = ATMOSPHERE_MODEL_PREETHAM;
-            definition->daytime = 0.3;
+            definition->hour = 8;
+            definition->minute = 30;
             definition->dome_lighting = 0.5;
             definition->humidity = 0.3;
             break;
         case ATMOSPHERE_PRESET_FOGGY:
             definition->model = ATMOSPHERE_MODEL_PREETHAM;
-            definition->daytime = 0.4;
+            definition->hour = 15;
+            definition->minute = 0;
             definition->dome_lighting = 0.7;
             definition->humidity = 0.6;
             break;
         case ATMOSPHERE_PRESET_STORMY:
             definition->model = ATMOSPHERE_MODEL_PREETHAM;
-            definition->daytime = 0.4;
+            definition->hour = 15;
+            definition->minute = 0;
             definition->dome_lighting = 0.3;
             definition->humidity = 0.9;
             break;
diff --git a/lib_paysages/atmosphere/private.h b/lib_paysages/atmosphere/private.h
index 35967a4..cee96cd 100644
--- a/lib_paysages/atmosphere/private.h
+++ b/lib_paysages/atmosphere/private.h
@@ -5,11 +5,12 @@
 
 #define SPHERE_SIZE 1000.0
 
+Color basicApplyAerialPerspective(Renderer* renderer, Vector3 location, Color base);
+
 void brunetonInit();
 Color brunetonGetSkyColor(AtmosphereDefinition* definition, Vector3 eye, Vector3 direction, Vector3 sun_position);
 Color brunetonApplyAerialPerspective(Renderer* renderer, Vector3 location, Color base);
 
 Color preethamGetSkyColor(AtmosphereDefinition* definition, Vector3 eye, Vector3 direction, Vector3 sun_position);
-Color preethamApplyAerialPerspective(Renderer* renderer, Vector3 location, Color base);
 
 #endif
diff --git a/lib_paysages/atmosphere/public.h b/lib_paysages/atmosphere/public.h
index d228c55..2d8640d 100644
--- a/lib_paysages/atmosphere/public.h
+++ b/lib_paysages/atmosphere/public.h
@@ -29,13 +29,16 @@ typedef enum
 typedef struct
 {
     AtmosphereModel model;
-    double daytime;
+    int hour;
+    int minute;
     double humidity;
     Color sun_color;
     double sun_radius;
     double sun_halo_size;
     Curve* sun_halo_profile;
     double dome_lighting;
+
+    double _daytime;
 } AtmosphereDefinition;
 
 typedef int (*FuncAtmosphereGetSkydomeLights)(Renderer* renderer, LightDefinition* array, int max_lights);
diff --git a/lib_paysages/auto.c b/lib_paysages/auto.c
index 489617f..e2ad864 100644
--- a/lib_paysages/auto.c
+++ b/lib_paysages/auto.c
@@ -16,28 +16,6 @@
 #include "water.h"
 #include "zone.h"
 
-void autoSetDaytime(int hour, int minute)
-{
-    autoSetDaytimeFraction((double)hour / 24.0 + (double)minute / 1440.0);
-}
-
-void autoSetDaytimeFraction(double daytime)
-{
-    AtmosphereDefinition* atmosphere;
-
-    daytime = fmod(daytime, 1.0);
-    if (daytime < 0.0)
-    {
-        daytime += 1.0;
-    }
-
-    atmosphere = AtmosphereDefinitionClass.create();
-    sceneryGetAtmosphere(atmosphere);
-    atmosphere->daytime = daytime;
-    scenerySetAtmosphere(atmosphere);
-    AtmosphereDefinitionClass.destroy(atmosphere);
-}
-
 void autoGenRealisticLandscape(int seed)
 {
     WaterDefinition water;
diff --git a/lib_paysages/auto.h b/lib_paysages/auto.h
index b7a9ca1..341594a 100644
--- a/lib_paysages/auto.h
+++ b/lib_paysages/auto.h
@@ -7,8 +7,6 @@
 extern "C" {
 #endif
 
-void autoSetDaytime(int hour, int minute);
-void autoSetDaytimeFraction(double daytime);
 void autoGenRealisticLandscape(int seed);
 
 #ifdef __cplusplus
diff --git a/lib_paysages/main.c b/lib_paysages/main.c
index a3440ec..e9dc38a 100644
--- a/lib_paysages/main.c
+++ b/lib_paysages/main.c
@@ -32,7 +32,6 @@ void paysagesInit()
     cameraDeleteDefinition(&camera);
 
     autoGenRealisticLandscape(0);
-    autoSetDaytime(8, 30);
 
     // DEBUG
     /*double last_height, height, x;
@@ -52,7 +51,7 @@ void paysagesQuit()
 {
     sceneryQuit();
     renderQuit();
-    
+
     openclQuit();
 }
 
@@ -60,21 +59,21 @@ FileOperationResult paysagesSave(char* filepath)
 {
     PackStream* stream = packWriteFile(filepath);
     double app_header, version_header;
-    
+
     if (!stream)
     {
         return FILE_OPERATION_IOERROR;
     }
-    
+
     app_header = (double)APP_HEADER;
     packWriteDouble(stream, &app_header);
     version_header = (double)PAYSAGES_CURRENT_DATA_VERSION;
     packWriteDouble(stream, &version_header);
-    
+
     scenerySave(stream);
-    
+
     packCloseStream(stream);
-    
+
     return FILE_OPERATION_OK;
 }
 
@@ -94,7 +93,7 @@ FileOperationResult paysagesLoad(char* filepath)
         packCloseStream(stream);
         return FILE_OPERATION_APP_MISMATCH;
     }
-    
+
     packReadDouble(stream, &version_header);
     if ((int)version_header != PAYSAGES_CURRENT_DATA_VERSION)
     {
@@ -105,6 +104,6 @@ FileOperationResult paysagesLoad(char* filepath)
     sceneryLoad(stream);
 
     packCloseStream(stream);
-    
+
     return FILE_OPERATION_OK;
 }