Attempt to fix compilation of the motion blur shader for Intel cards...

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@9351 178a84e3-b1eb-0310-8ba1-8eac791a3b58

data/shaders/motion_blur.frag

@@ -21,7 +21,7 @@ void main()
 	vec2 texcoords = gl_TexCoord[0].st;
 	
 	// Sample the color buffer
-	vec3 color = texture2D(color_buffer, texcoords);
+	vec3 color = texture2D(color_buffer, texcoords).rgb;
 	
 	// Compute the blur direction.
 	// IMPORTANT: we don't normalize it so that it avoids a glitch around BLUR_DIR_CENTER,
@@ -45,15 +45,15 @@ void main()
 	blur_dir *= blur_factor;
 	
 	// Compute the blur
-	vec2 inc_vec = blur_dir / NB_SAMPLES;
+	vec2 inc_vec = blur_dir / vec2(NB_SAMPLES);
 	vec2 blur_texcoords = texcoords + inc_vec;
 	for(int i=1 ; i < NB_SAMPLES ; i++)
 	{
 		color += texture2D(color_buffer, blur_texcoords);
 		blur_texcoords += inc_vec;
 	}
-	color /= NB_SAMPLES;
-	gl_FragColor = vec4(color, 0.0);
+	color /= vec3(NB_SAMPLES);
+	gl_FragColor = vec4(color, 1.0);
 
 	// Keep this commented line for debugging:
 //	gl_FragColor = vec4(blur_factor, blur_factor, blur_factor, 0.0);