mirror of
https://github.com/bvanroll/shaders.git
synced 2025-08-29 12:02:44 +00:00
47 lines
1.1 KiB
GLSL
47 lines
1.1 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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vec2 rotate(vec2 st, float a) {
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st = mat2(cos(a),-sin(a),sin(a),cos(a))*(st-.5);
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return st+.5;
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}
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float triSDF(vec2 st) {
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st = (st*2.-1.)*2.;
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return max(abs(st.x)*.866025+st.y*.5,-st.y*.5);
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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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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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st = rotate(st, radians(-25.));
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float sdf = triSDF(st);
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//why does dividing the triangle with a larger triangle create a smaller black triangle area at the bottom?
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sdf /= triSDF(st+vec2(.0,.2));
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color += sdf; //fill(abs(sdf),.56);
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gl_FragColor = vec4(color, alpha);
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}
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