mirror of
https://github.com/bvanroll/shaders.git
synced 2025-08-29 20:12:48 +00:00
56 lines
1.3 KiB
GLSL
56 lines
1.3 KiB
GLSL
#ifdef GL_ES
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precision mediump float;
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#endif
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uniform vec2 u_resolution;
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uniform vec2 u_mouse;
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uniform float u_time;
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#define PI 3.14159265359
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const vec3 uAColor = vec3(.5,.5,.5);
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const vec3 uBColor = vec3(.5,.5,.5);
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const vec3 uCColor = vec3(1.,1.,1.);
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const vec3 uDColor = vec3(.0,.33,.67);
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//get colors from http://dev.thi.ng/gradients/
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vec3 cosPalette(float t) {
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return uAColor + uBColor*cos(6.28318*(uCColor*t+uDColor));
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}
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float rectSDF(vec2 st, vec2 s) {
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st = st*2.-1.;
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return max(abs(st.x/s.x),abs(st.y/s.y));
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}
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float crossSDF(vec2 st, float s) {
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vec2 size = vec2(.25, s);
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return min(rectSDF(st,size.xy),rectSDF(st,size.yx));
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}
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float fill(float x, float size) {
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return 1.-step(size, x);
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}
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float stroke(in float x_coor, float s, float width){
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float d = step(s,x_coor+width*.5)-step(s,x_coor-width*.5);
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return clamp(d, 0.,1.);
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}
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void main() {
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vec2 st = gl_FragCoord.xy/u_resolution;
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vec3 color = vec3(0.0,0.0,0.0);
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float alpha = 1.0;
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float rect = rectSDF(st,vec2(1.));
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color += fill(rect,.5);
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float cross = crossSDF(st,1.);
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//i don't understand what happens here
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//it has to be fract causing this to look like that
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color *= step(.5,fract(cross*4.));
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color *= step(1.,cross);
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color += fill(cross,.5);
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color += stroke(rect,.65,.05);
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color += stroke(rect,.75,.025);
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gl_FragColor = vec4(color, alpha);
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}
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