SuperTuxKart 1.5 upstream source (from official release tarball)

data/shaders/sky.frag

@@ -0,0 +1,14 @@
+uniform samplerCube tex;
+
+out vec4 FragColor;
+
+void main(void)
+{
+    vec3 eyedir = vec3(mod(gl_FragCoord.xy, u_screen) / u_screen, 1.);
+    eyedir = 2.0 * eyedir - 1.0;
+    vec4 tmp = (u_inverse_projection_matrix * vec4(eyedir, 1.));
+    tmp /= tmp.w;
+    eyedir = (u_inverse_view_matrix * vec4(tmp.xyz, 0.)).xyz;
+    vec4 color = texture(tex, eyedir);
+    FragColor = vec4(color.xyz, 1.);
+}