From 9d3cdc7f5ee96c3b2a9342e44b62102f5b05be3b Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Mon, 1 Feb 2016 14:03:21 +0100 Subject: Add glslwrite tool and some examples --- examples/square-in-circle.frag | 66 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 examples/square-in-circle.frag (limited to 'examples/square-in-circle.frag') diff --git a/examples/square-in-circle.frag b/examples/square-in-circle.frag new file mode 100644 index 0000000..ad6c615 --- /dev/null +++ b/examples/square-in-circle.frag @@ -0,0 +1,66 @@ +#version 330 + +out vec4 fragColor; + +uniform vec2 res; +uniform float time; + +const float sharpness = 300; + +const float PI = 3.14159265358979323846; + + +mat2 rot(float a) { + return mat2( + cos(a), -sin(a), + sin(a), cos(a) + ); +} + +float circle(vec2 m, float r, vec2 p) { + vec2 diff = m - p; + float d = sqrt(dot(diff, diff)); + + return clamp((r - d)*sharpness, 0.0, 1.0); +} + +float circle_d(vec2 m, float r, vec2 p) { + return circle(m, r, p) - circle(m, r - 1/sharpness, p); +} + +float square(vec2 m, float a, float r, vec2 p) { + vec2 diff = abs((m - p) * rot(r)); + float d = max(diff.x, diff.y); + + return clamp((a - d)*sharpness, 0.0, 1.0); +} + +void main(void) { + vec2 m = res/2; + float s = min(m.x, m.y); + vec2 p = (gl_FragCoord.xy - m) / s; + + float scene = 0; + + int n = 20; + float b = 1; + float alpha = 0; + for (int i = 0; i < n; i++) { + float c; + + c = circle_d(vec2(0, 0), b, p); + scene = abs(scene - c); + + float delta = mod(time/5000, PI/2); + alpha = mod(alpha + delta, PI/2); + b /= sqrt(2); + + c = square(vec2(0, 0), b, alpha, p); + scene = abs(scene - c); + + c = square(vec2(0, 0), b, -alpha, p); + scene = abs(scene - c); + } + + fragColor = vec4(vec3(1, 1, 1) * scene, 1); +} -- cgit v1.2.3