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Diffstat (limited to 'examples/snail.frag')
-rw-r--r-- | examples/snail.frag | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/examples/snail.frag b/examples/snail.frag new file mode 100644 index 0000000..491c53a --- /dev/null +++ b/examples/snail.frag @@ -0,0 +1,41 @@ +#version 330 + +out vec4 fragColor; + +uniform vec2 res; +uniform float time; + +const float sharpness = 300; + +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); +} + +void main(void) { + vec2 m = res/2; + float s = min(m.x, m.y); + vec2 p = (gl_FragCoord.xy - m) / s; + + float scene = 0; + + for (int i = 1; i <= 50; i++) { + float c = circle_d(vec2(0.5, 0) * rot(time/500/i), 0.1 + 0.005*i, p); + scene = abs(scene - c); + } + + fragColor = vec4(vec3(1, 1, 1) * scene, 1); +} |