Improve Lambert shading in splatting : actually use the sun direction

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@10438 178a84e3-b1eb-0310-8ba1-8eac791a3b58

data/shaders/splatting.frag

@@ -23,5 +23,5 @@ void main()
                     layout.b * detail2 +
                     (1.0 - layout.r - layout.g - layout.b) * detail3 +
                     (1.0 - layout.a) * detail4)
-                    * min(1.0, 0.2 + 1.5*dot(lightdir2, normal)); // 0.2 is the ambient light. *1.5 is from trial are error to make it look nice :)
+                    * min(1.0, 0.2 + dot(lightdir2, normal)); // 0.2 is the ambient light.
 }

src/graphics/material.cpp

@@ -31,6 +31,8 @@
 #include "io/file_manager.hpp"
 #include "io/xml_node.hpp"
 #include "utils/string_utils.hpp"
+#include "modes/world.hpp"
+#include "tracks/track.hpp"
 
 #include <IGPUProgrammingServices.h>
 #include <IMaterialRendererServices.h>
@@ -73,13 +75,27 @@ public:
 
 class SplattingProvider : public video::IShaderConstantSetCallBack
 {
+    core::vector3df m_light_direction;
+    bool m_light_dir_calculated;
+    
 public:
     LEAK_CHECK()
     
+    SplattingProvider()
+    {
+        m_light_dir_calculated = false;
+    }
+    
     virtual void OnSetConstants(
                                 irr::video::IMaterialRendererServices *services,
                                 s32 userData)
     {
+        if (!m_light_dir_calculated)
+        {
+            m_light_dir_calculated = true;
+            m_light_direction = -World::getWorld()->getTrack()->getSunRotation().rotationToDirection();
+        }
+        
         // Irrlicht knows this is actually a GLint and makes the conversion
         int tex_layout = 0;
         services->setPixelShaderConstant("tex_layout", (float*)&tex_layout, 1);
@@ -100,10 +116,7 @@ public:
         int tex_detail3 = 4;
         services->setPixelShaderConstant("tex_detail3", (float*)&tex_detail3, 1);
         
-        // TODO: check the position of the sun
-        core::vector3df lightdir(-0.1f, 0.1f, 0.0f);
-        lightdir.normalize();
-        services->setVertexShaderConstant("lightdir", &lightdir.X, 3);
+        services->setVertexShaderConstant("lightdir", &m_light_direction.X, 3);
     }
 };
 

src/tracks/track.cpp

@@ -1631,3 +1631,10 @@ std::vector< std::vector<float> > Track::buildHeightMap()
     
     return out;
 }
+
+// ----------------------------------------------------------------------------
+
+core::vector3df Track::getSunRotation()
+{
+    return m_sun->getRotation();
+}

src/tracks/track.hpp

@@ -387,6 +387,8 @@ public:
     CheckManager* getCheckManager() { return m_check_manager; }
 
     
+    core::vector3df getSunRotation();
+    
     TrackObjectManager* getTrackObjectManager() { return m_track_object_manager; }
     
 };   // class Track