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55 lines
1.4 KiB
GLSL
55 lines
1.4 KiB
GLSL
9 years ago
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// By Udit Mahajan ( uditmahajan.com / @mahajan_udit )
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// For Shader Studio Course https://github.com/patriciogonzalezvivo/ss2015
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//Choose a geometric logo to replicate using distance fields.
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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 field(float n, float x, float y, vec2 st){
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st = st-vec2(2.*x-1.,2.*y-1.);
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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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return (cos(floor(.5+a/r)*r-a)*length(st));
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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,d2,d3,d4 = 0.0;
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float a = 0.0;
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float r = 0.0;
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// Remap the space to -1. to 1.
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st = st *2.-1.;
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// Number of sides of your shape
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int N = 9;
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// Shaping function that modulate the distance
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d = field(3.,0.5,0.5,st); // Number of sides, x position, y position, st
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d2 = field(3.,0.68,0.65,st);
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d3 = field(3.,0.32,0.65,st);
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d4 = field(3.,0.5,0.33,st);
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color = vec3(smoothstep(.4,.41,d2*2.));
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color *= vec3(smoothstep(.4,.41,d3*2.));
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color *= vec3(smoothstep(.4,.41,d4*2.));
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color *= vec3(0.2,1.,1.);
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color -= vec3(smoothstep(.4,.41,d));
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// color = vec3(d);
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gl_FragColor = vec4(1.-color,1.0);
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}
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