--- /dev/null
+uniform sampler2D tex;
+uniform float smoothness;
+
+void main()
+{
+ const vec2 pix_sz = vec2(1.0 / 512.0, 1.0 / 256.0); // TODO: uniform
+
+ vec2 uv = gl_TexCoord[0].st;
+ float dist = texture2D(tex, uv).a;
+
+ float dfdu = texture2D(tex, uv + vec2(pix_sz.x, 0.0)).a - dist;
+ float dfdv = texture2D(tex, uv + vec2(0.0, pix_sz.y)).a - dist;
+ vec2 grad = normalize(vec2(dfdu, dfdv));
+
+ float glyph = smoothstep(0.47 - smoothness, 0.47 + smoothness, dist);
+ float outline = smoothstep(0.54 - smoothness, 0.54 + smoothness, dist);
+
+ float beveldot = max(dot(grad, normalize(vec2(1.0, 1.0))), 0.0);
+ vec3 bevelcol = mix(vec3(0.05, 0.1, 0.6), vec3(1.0, 0.2, 0.8), beveldot);
+
+ gl_FragColor.rgb = mix(bevelcol, vec3(1.0), outline);
+ gl_FragColor.a = glyph;
+}