Add support for using a second UV layer for normal maps

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@10486 178a84e3-b1eb-0310-8ba1-8eac791a3b58

data/shaders/normalmap2uv.frag

@@ -0,0 +1,26 @@
+// By http://content.gpwiki.org/index.php/OpenGL:Tutorials:GLSL_Bump_Mapping
+// Released under GNU FDL license, without invariant (so DFSG-compliant, see
+// http://wiki.debian.org/DFSGLicenses#Exception)
+
+uniform sampler2D BumpTex; //The bump-map 
+ uniform sampler2D DecalTex; //The texture
+ varying vec4 passcolor; //Receiving the vertex color from the vertex shader
+ varying vec3 LightDir; //Receiving the transformed light direction 
+ void main() 
+ {
+   vec4 LightDirTransformed4 = gl_ProjectionMatrix * gl_ModelViewMatrix * vec4(LightDir[0], LightDir[1], LightDir[2], 0);
+   vec3 LightDirTransformed = vec3(LightDirTransformed4[0], LightDirTransformed4[1], LightDirTransformed4[2]);
+   
+   //Get the color of the bump-map
+   vec3 BumpNorm = vec3(texture2D(BumpTex, gl_TexCoord[1].xy));
+   //Get the color of the texture
+   vec3 DecalCol = vec3(texture2D(DecalTex, gl_TexCoord[0].xy));
+   //Expand the bump-map into a normalized signed vector
+   BumpNorm = (BumpNorm -0.5) * 2.0;
+   //Find the dot product between the light direction and the normal
+   float NdotL = max(dot(BumpNorm, LightDirTransformed), 0.0) / 3.0 * 2.1 + 0.5;
+   //Calculate the final color gl_FragColor
+   vec3 diffuse = NdotL * passcolor.xyz * DecalCol;
+   //Set the color of the fragment...  If you want specular lighting or other types add it here
+   gl_FragColor = vec4(diffuse, passcolor.w);
+ }

data/shaders/normalmap2uv.vert

@@ -0,0 +1,25 @@
+// By http://content.gpwiki.org/index.php/OpenGL:Tutorials:GLSL_Bump_Mapping
+// Released under GNU FDL license, without invariant (so DFSG-compliant, see
+// http://wiki.debian.org/DFSGLicenses#Exception)
+
+varying vec4 passcolor; //The vertex color passed
+ varying vec3 LightDir; //The transformed light direction, to pass to the fragment shader
+ attribute vec3 tangent; //The inverse tangent to the geometry
+ attribute vec3 binormal; //The inverse binormal to the geometry
+ uniform vec3 lightdir; //The direction the light is shining
+ void main() 
+ {
+   //Put the color in a varying variable
+   passcolor = gl_Color;
+   //Put the vertex in the position passed
+   gl_Position = ftransform(); 
+   //Construct a 3x3 matrix from the geometry’s inverse tangent, binormal, and normal
+   mat3 rotmat = mat3(tangent,binormal,gl_Normal);
+   //Rotate the light into tangent space
+   LightDir = rotmat * normalize(lightdir);
+   //Normalize the light
+   normalize(LightDir); 
+   //Use the first set of texture coordinates in the fragment shader 
+   gl_TexCoord[0] = gl_MultiTexCoord0;
+   gl_TexCoord[1] = gl_MultiTexCoord1;
+ }

src/graphics/material.cpp

@@ -188,10 +188,26 @@ Material::Material(const XMLNode *node, int index)
         node->get("crash-reset-particles", &m_crash_reset_particles);
     }
     
+    bool use_normal_map = false;
+    node->get("use-normal-map",  &use_normal_map);
+    
+    if (use_normal_map)
+    {
         if (node->get("normal-map",  &m_normal_map_tex))
         {
             m_normal_map = true;
         }
+        else
+        {
+            fprintf(stderr, "[Material] WARNING: could not find normal map image in materials.xml\n");
+        }
+        
+        m_normal_map_uv2 = false;
+        node->get("normal-map-uv2",  &m_normal_map_uv2);
+
+        
+        // TODO: add support for parallax maps?
+        /*
         else if (node->get("normal-heightmap",  &m_normal_map_tex))
         {
             m_is_heightmap = true;
@@ -210,6 +226,8 @@ Material::Material(const XMLNode *node, int index)
             m_parallax_height = 0.2f;
             node->get("parallax-height", &m_parallax_height);
         }
+         */
+    }
     
     s="";
     node->get("graphical-effect", &s                   );
@@ -341,6 +359,7 @@ void Material::init(unsigned int index)
     m_zipper_max_speed_increase = -1.0f;
     m_zipper_speed_gain         = -1.0f;
     m_normal_map                = false;
+    m_normal_map_uv2            = false;
     m_parallax_map              = false;
     m_is_heightmap              = false;
     m_alpha_to_coverage         = false;
@@ -655,16 +674,21 @@ void  Material::setMaterialProperties(video::SMaterial *m)
                 m_normal_map_provider = new NormalMapProvider();
             }
                         
+            const char* vertex_shader = (m_normal_map_uv2 ?
+                                            "shaders/normalmap2uv.vert" :
+                                            "shaders/normalmap.vert");
+            const char* pixel_shader  = (m_normal_map_uv2 ?
+                                            "shaders/normalmap2uv.frag" :
+                                            "shaders/normalmap.frag");
+
             // Material and shaders
             IGPUProgrammingServices* gpu = 
                 video_driver->getGPUProgrammingServices();
             s32 material_type = gpu->addHighLevelShaderMaterialFromFiles(
-                                  (file_manager->getDataDir() + 
+                                   (file_manager->getDataDir() + vertex_shader).c_str(),
-                                       "shaders/normalmap.vert").c_str(), 
                                    "main",
                                    video::EVST_VS_2_0,
-                                   (file_manager->getDataDir() + 
+                                   (file_manager->getDataDir() + pixel_shader).c_str(), 
-                                       "shaders/normalmap.frag").c_str(), 
                                    "main",
                                    video::EPST_PS_2_0,
                                    m_normal_map_provider,

src/graphics/material.hpp

@@ -101,6 +101,7 @@ private:
     /** For normal maps */
     bool             m_normal_map;
     std::string      m_normal_map_tex;
+    bool             m_normal_map_uv2; //!< Whether to use a second UV layer for normal map
     bool             m_is_heightmap;
     bool             m_parallax_map;
     float            m_parallax_height;