Add specular highlights to the trophy shader. Something is not 100% right since the highlights move around, nonetheless the effect is reaosnably good

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@10860 178a84e3-b1eb-0310-8ba1-8eac791a3b58

data/shaders/spheremap.frag

@@ -4,6 +4,8 @@ uniform sampler2D texture;
 varying vec3 normal;
 uniform vec3 lightdir;
 varying vec4 vertex_color;
+varying vec3 eyeVec;
+varying vec3 lightVec;
 
 void main()
 {
@@ -20,5 +22,27 @@ void main()
     vec4 detail0 = texture2D(texture, vec2(0.5 + sin_theta_x*0.5, 0.5 + sin_theta_y*0.5));
 
     gl_FragColor = detail0 * (0.5 + dot(lightdir, normal)) * vertex_color; // 0.5 is the ambient light.    
-    //gl_FragColor = vec4(sin_theta_y*0.5 + 0.5, 0.0, 1.0 - (sin_theta_y*0.5 + 0.5), 1.0);
+    //gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
+    
+    // specular (phong)
+    vec3 R = normalize(reflect(lightVec, normal));
+    float specular = max(dot(R,eyeVec),0.0);
+    
+    //gl_FragColor = vec4(specular, specular, specular, 1.0);
+    
+    if (specular > 0.0)
+    {
+        // weak specular
+        specular = specular*specular;
+        specular = specular*specular;
+        float specular_weak = specular*2.0; //max(specular*1.1, 1.0);
+        gl_FragColor += vec4(specular_weak, specular_weak, specular_weak, 0.0);
+        
+        /*
+        // strong specular
+        specular = specular*specular;
+        float specular_strong = specular;
+        gl_FragColor += vec4(specular_strong, specular_strong, specular_strong, 0.0);
+        */
+    }
 }

data/shaders/spheremap.vert

@@ -1,5 +1,8 @@
 varying vec3 normal;
 varying vec4 vertex_color;
+varying vec3 eyeVec;
+varying vec3 lightVec;
+uniform vec3 lightdir;
 
 void main()
 {
@@ -11,5 +14,18 @@ void main()
     //vec4 normal4 = vec4(normal3.x, normal3.y, normal3.z, 0.0)*gl_ModelViewMatrix;
     //normal = normal4.xyz;
     
+    eyeVec = normalize(-gl_Position).xyz; // we are in Eye Coordinates, so EyePos is (0,0,0)  
     normal = normalize(gl_NormalMatrix*gl_Normal);
+    
+    // Building the matrix Eye Space -> Tangent Space
+    // gl_MultiTexCoord1.xyz
+	vec3 t = normalize (gl_NormalMatrix * vec3(0.0, 0.0, 1.0)); // tangent
+	vec3 b = cross (normal, t);
+	    
+	// transform light and half angle vectors by tangent basis
+	vec3 v;
+	v.x = dot(lightdir, t);
+	v.y = dot(lightdir, b);
+	v.z = dot(lightdir, normal);
+	lightVec = normalize (v);
 }