Optimized lighting of underwater terrain

The water light filter is now applied first to avoid computing
terrain shadows when no light passes through the water layer.

src/render/software/LightingManager.cpp

@@ -12,7 +12,7 @@ LightingManager::LightingManager()
 
 void LightingManager::registerFilter(LightFilter* filter)
 {
-    filters.insert(filter);
+    filters.push_back(filter);
 }
 
 bool LightingManager::alterLight(LightComponent &component, const Vector3 &location)

src/render/software/LightingManager.h

@@ -3,8 +3,6 @@
 
 #include "software_global.h"
 
-#include <set>
-
 namespace paysages {
 namespace software {
 
@@ -42,7 +40,7 @@ public:
 private:
     int specularity;
 
-    std::set<LightFilter*> filters;
+    std::vector<LightFilter*> filters;
 };
 
 }

src/render/software/SoftwareRenderer.cpp

@@ -36,8 +36,8 @@ SoftwareRenderer::SoftwareRenderer(Scenery* scenery)
     fluid_medium = new FluidMediumManager(this);
     lighting = new LightingManager();
 
-    lighting->registerFilter(terrain_renderer);
     lighting->registerFilter(water_renderer);
+    lighting->registerFilter(terrain_renderer);
     lighting->registerFilter(clouds_renderer);
 
     this->scenery = new Scenery;

src/render/software/WaterRenderer.cpp

@@ -263,7 +263,7 @@ bool WaterRenderer::applyLightFilter(LightComponent &light, const Vector3 &at)
             light.color.b *= factor;
             light.reflection *= factor;
 
-            return true;
+            return factor > 0.0;
         }
         else
         {