diff --git a/lib_paysages/auto.c b/lib_paysages/auto.c
index be4c441..f5eee69 100644
--- a/lib_paysages/auto.c
+++ b/lib_paysages/auto.c
@@ -178,7 +178,7 @@ void autoGenRealisticLandscape(int seed)
     texture->thickness = 0.02;
     texture->slope_range = 0.03;
     texture->thickness_transparency = 0.005;
-    texture = texturesGetLayer(&textures, texturesAddLayer(&textures));
+    /*texture = texturesGetLayer(&textures, texturesAddLayer(&textures));
     zoneAddHeightRangeQuick(texture->zone, 1.0, 4.0, 5.0, 100.0, 100.0);
     zoneAddSlopeRangeQuick(texture->zone, 1.0, 0.0, 0.0, 0.2, 1.0);
     noiseGenerateBaseNoise(texture->bump_noise, 102400);
@@ -192,7 +192,7 @@ void autoGenRealisticLandscape(int seed)
     texture->material.shininess = 0.6;
     texture->thickness = 0.05;
     texture->slope_range = 0.3;
-    texture->thickness_transparency = 0.015;
+    texture->thickness_transparency = 0.015;*/
     scenerySetTextures(&textures);
     texturesDeleteDefinition(&textures);
 
diff --git a/lib_paysages/clouds.c b/lib_paysages/clouds.c
index c759f7e..2b377e3 100644
--- a/lib_paysages/clouds.c
+++ b/lib_paysages/clouds.c
@@ -154,20 +154,20 @@ CloudsLayerDefinition cloudsLayerCreateDefinition()
 {
     CloudsLayerDefinition result;
 
-    result.ymin = 10.0;
-    result.ycenter = 40.0;
-    result.ymax = 100.0;
+    result.ymin = 4.0;
+    result.ycenter = 6.0;
+    result.ymax = 10.0;
     result.material.base.r = 0.7;
     result.material.base.g = 0.7;
     result.material.base.b = 0.7;
-    result.material.reflection = 0.1;
-    result.material.shininess = 2.0;
-    result.hardness = 0.1;
-    result.transparencydepth = 20.0;
-    result.lighttraversal = 50.0;
-    result.minimumlight = 0.5;
-    result.scaling = 50.0;
-    result.coverage = 0.5;
+    result.material.reflection = 0.3;
+    result.material.shininess = 0.8;
+    result.hardness = 0.15;
+    result.transparencydepth = 1.5;
+    result.lighttraversal = 3.0;
+    result.minimumlight = 0.4;
+    result.scaling = 3.5;
+    result.coverage = 0.45;
     result.noise = noiseCreateGenerator();
     noiseGenerateBaseNoise(result.noise, 262144);
     noiseAddLevelSimple(result.noise, 1.0, 1.0);
@@ -408,7 +408,16 @@ static int _findSegments(CloudsLayerDefinition* definition, Renderer* renderer,
         return 0;
     }
 
-    render_precision = 3.3 - 0.3 * (double)renderer->render_quality;
+    render_precision = 15.2 - 1.5 * (double)renderer->render_quality;
+    render_precision = render_precision * definition->scaling / 50.0;
+    if (render_precision > max_total_length / 10.0)
+    {
+        render_precision = max_total_length / 10.0;
+    }
+    else if (render_precision < max_total_length / 2000.0)
+    {
+        render_precision = max_total_length / 2000.0;
+    }
 
     segment_count = 0;
     current_total_length = 0.0;
diff --git a/lib_paysages/textures.c b/lib_paysages/textures.c
index effc7a6..dbb8075 100644
--- a/lib_paysages/textures.c
+++ b/lib_paysages/textures.c
@@ -17,11 +17,10 @@ static TextureLayerDefinition _NULL_LAYER;
 
 typedef struct
 {
+    double thickness;
     Vector3 location;
     Vector3 normal;
-    double thickness;
-    Color color;
-    double thickness_transparency;
+    TextureLayerDefinition* definition;
 } TextureResult;
 
 void texturesInit()
@@ -275,9 +274,8 @@ static inline TextureResult _getTerrainResult(Renderer* renderer, double x, doub
     }
 
     result.location = center;
-    result.color = COLOR_GREEN;
     result.thickness = -100.0;
-    result.thickness_transparency = 0.0;
+    result.definition = NULL;
     
     return result;
 }
@@ -323,8 +321,7 @@ static inline TextureResult _getLayerResult(TextureLayerDefinition* definition,
         result_center.normal = _getNormal2(result_center.location, result_east.location, result_south.location);
     }
     
-    result_center.color = renderer->applyLightingToSurface(renderer, result_center.location, result_center.normal, definition->material);
-    result_center.thickness_transparency = definition->thickness_transparency;
+    result_center.definition = definition;
     
     return result_center;
 }
@@ -340,19 +337,23 @@ double texturesGetLayerCoverage(TextureLayerDefinition* definition, Renderer* re
     return zoneGetValue(definition->zone, base.location, base.normal);
 }
 
+static inline Color _getLayerColor(Renderer* renderer, TextureResult result)
+{
+    return renderer->applyLightingToSurface(renderer, result.location, result.normal, result.definition->material);
+}
+
 Color texturesGetLayerColor(TextureLayerDefinition* definition, Renderer* renderer, Vector3 location, double detail)
 {
-    return _getLayerResult(definition, renderer, location.x, location.z, detail).color;
+    return _getLayerColor(renderer, _getLayerResult(definition, renderer, location.x, location.z, detail));
 }
 
 Color texturesGetColor(TexturesDefinition* definition, Renderer* renderer, double x, double z, double detail)
 {
     TextureResult results[TEXTURES_MAX_LAYERS + 1];
-    Color result;
+    Color result, color;
     double thickness, last_height;
-    int i;
+    int i, start;
 
-    /* TODO Do not compute layers fully covered */
     /* TODO Optimize : each layer computes the same shadows */
     
     detail *= 0.1;
@@ -366,20 +367,65 @@ Color texturesGetColor(TexturesDefinition* definition, Renderer* renderer, doubl
     
     qsort(results, definition->nbtextures + 1, sizeof(TextureResult), _cmpResults);
 
-    result = results[0].color;
+    /* Pre compute alpha channel */
+    start = 0;
     last_height = results[0].thickness;
     for (i = 1; i <= definition->nbtextures; i++)
     {
         thickness = results[i].thickness - last_height;
         last_height = results[i].thickness;
         
-        if (thickness < results[i].thickness_transparency)
+        if (results[i].definition)
         {
-            results[i].color.a = thickness / results[i].thickness_transparency;
+            if (thickness < results[i].definition->thickness_transparency)
+            {
+                results[i].thickness = thickness / results[i].definition->thickness_transparency;
+            }
+            else
+            {
+                results[i].thickness = (thickness > 0.0) ? 1.0 : 0.0;
+            }
+        }
+        else
+        {
+            color = COLOR_GREEN;
+            results[i].thickness = 1.0;
         }
         
-        colorMask(&result, &results[i].color);
+        if (results[i].thickness >= 0.999999)
+        {
+            start = i;
+        }
+        
+        colorMask(&result, &color);
     }
 
+    /* Apply colors and alphas */
+    if (results[start].definition)
+    {
+        result = _getLayerColor(renderer, results[start]);
+    }
+    else
+    {
+        result = COLOR_GREEN;
+    }
+    for (i = start; i <= definition->nbtextures; i++)
+    {
+        if (results[i].thickness)
+        {
+            if (results[i].definition)
+            {
+                color = _getLayerColor(renderer, results[i]);
+                color.a = results[i].thickness;
+            }
+            else
+            {
+                color = COLOR_GREEN;
+            }
+
+            colorMask(&result, &color);
+        }
+    }
+    
     return result;
 }