-uniform sampler2D tex;
-uniform float smoothness;
-uniform float height;
-
-varying vec2 local_pt;
-
-void gradcurves(float t, out float over, out float under);
-
-#define HALF_PI 1.570796326794897
-
-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);
-
- // --- face gradients ---
- float t = local_pt.y / height;
-
- float c_over, c_under;
- float tlow = min(2.0 * t, 1.0);
- gradcurves(tlow, c_over, c_under);
- vec3 color_low = vec3(c_over, c_under, c_over);
-
- float thigh = max(2.0 * t - 1.0, 0.0);
- gradcurves(thigh, c_over, c_under);
- vec3 color_high = vec3(c_under, c_under, c_over);
-
- vec3 color = mix(color_low, color_high, step(0.5, t));
-
- // --- bevel gradients ---
- float bv_shade = mod(1.0 * dot(grad, normalize(vec2(0.1, 1.0))) * 0.5 + 0.5, 1.0);
-
- gradcurves(1.0 - bv_shade, c_over, c_under);
- vec3 bv_col = vec3(c_under, c_under, c_over);
-
- gl_FragColor.rgb = mix(bv_col, color, outline);
- gl_FragColor.a = glyph;
-}
-
-void gradcurves(float t, out float over, out float under)
-{
- over = cos(t * HALF_PI);
- under = cos(t * HALF_PI + HALF_PI) + 1.0;
-}