SuperTuxKart 1.5 upstream source (from official release tarball)

data/shaders/mlaa_color1.frag

@@ -0,0 +1,32 @@
+uniform sampler2D colorMapG;
+
+const float threshold = 0.1;
+
+out vec4 FragColor;
+
+void main() {
+	vec3 weights = vec3(0.2126,0.7152, 0.0722); // ITU-R BT. 709
+
+	vec2 uv = gl_FragCoord.xy / u_screen;
+	vec2 uv_left = uv + vec2(-1., 0.) / u_screen;
+	vec2 uv_top = uv + vec2(0., 1.) / u_screen;
+	vec2 uv_right = uv + vec2(1., 0.) / u_screen;
+	vec2 uv_bottom = uv + vec2(0., -1.) / u_screen;
+
+	/**
+	 * Luma calculation requires gamma-corrected colors:
+	 */
+	float L = dot(texture(colorMapG, uv).rgb, weights);
+	float Lleft = dot(texture(colorMapG, uv_left).rgb, weights);
+	float Ltop = dot(texture(colorMapG, uv_top).rgb, weights);
+	float Lright = dot(texture(colorMapG, uv_right).rgb, weights);
+	float Lbottom = dot(texture(colorMapG, uv_bottom).rgb, weights);
+
+	vec4 delta = abs(vec4(L) - vec4(Lleft, Ltop, Lright, Lbottom));
+	vec4 edges = step(vec4(threshold), delta);
+
+	if (dot(edges, vec4(1.0)) == 0.0)
+		discard;
+
+	FragColor = edges;
+}