mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-09 19:10:24 +00:00
53 lines
1.1 KiB
GLSL
53 lines
1.1 KiB
GLSL
// By Luobin Wang ( @peterobbin )
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// For Shader Studio Course https://github.com/patriciogonzalezvivo/ss2015
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#ifdef GL_ES
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precision mediump float;
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#endif
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#define PI 3.14159265359
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#define TWO_PI 6.28318530718
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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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// Reference to
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// http://thndl.com/square-shaped-shaders.html
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float triShapeDistance(vec2 st, int sides){
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// Remap the space to -1. to 1.
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st = st *2.-1.;
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float sinT = sin(u_time ) * 0.5 + 0.5;
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float cosT = cos(u_time ) * 0.5 + 0.5;
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// Number of sides of your shape
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int N = sides;
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// Angle and radius from the current pixel
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float a = atan(st.x,st.y)+PI;
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float r = TWO_PI/float(N);
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// Shaping function that modulate the distance
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float d = max(cos(floor(1.5+a/r)*r-a - sinT)*length(st), sin(floor(1.5+a/r)*r-a + cosT)*length(st));
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return d;
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}
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void main(){
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vec2 st = gl_FragCoord.xy/u_resolution.xy;
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st.x *= u_resolution.x/u_resolution.y;
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vec3 color = vec3(0.0);
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float d = 0.0;
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d = triShapeDistance(st, 5);
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color = vec3(1.0-smoothstep(.0,0.8,d));
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// color = vec3(d);
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gl_FragColor = vec4(color,1.0);
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} |