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100 lines
3.2 KiB
GLSL
100 lines
3.2 KiB
GLSL
// By Si Ping Lim ( http://www.handson.sg )
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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 drawRectAbs (vec2 pixel, vec2 center, vec2 size) {
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//vec2 t = vec2 (size.x , size.y);
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vec2 r = abs( pixel.xy - center.xy - size.xy / 2. );
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float sX = step(size.x/2., r.x );
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float sY = step(size.y/2., r.y );
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float s = max( sX, sY ) ;
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return s;
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}
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float drawRectOutlineAbs (vec2 pixel, vec2 center, vec2 size, float thickness) {
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float s = drawRectAbs(pixel, center, size);
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s += (1. - drawRectAbs(pixel , center + thickness, size - (thickness * 2.) ));
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// s = step(.4, s) * step( s, .3);
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return s;
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}
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float drawPoly (vec2 pixel, vec2 center, float size, int sides) {
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pixel /= u_resolution.xy;
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center /= u_resolution.xy;
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pixel -= center;
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pixel.x *= u_resolution.x/u_resolution.y;
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size /= u_resolution.y;
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// Angle and radius from the current pixel
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vec2 pos = pixel ;
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float a = atan(pos.x,pos.y)+PI ;
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float r = TWO_PI/float( sides) ;
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// Shaping function that modulate the distance
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float d = cos(floor(.5 + a/r) * r - a ) * length(pixel );
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return 1.0 - smoothstep(size, size +.005, d) ;
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}
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float drawPolyOutline (vec2 pixel, vec2 center, float size, int sides, float thickness) {
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pixel /= u_resolution.xy;
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center /= u_resolution.xy;
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pixel -= center;
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pixel.x *= u_resolution.x/u_resolution.y;
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size /= u_resolution.y;
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thickness /= u_resolution.y;
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// Angle and radius from the current pixel
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vec2 pos = pixel ;
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float a = atan(pos.x,pos.y)+PI ;
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float r = TWO_PI/float( sides) ;
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// Shaping function that modulate the distance
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float d = cos(floor(.5 + a/r) * r - a ) * length(pixel );
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return (smoothstep(size- thickness -.005, size-thickness, d) - smoothstep(size, size +.005, d) ) ;
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}
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float drawCirclePixelOutline (vec2 pixel, vec2 center, float radius, float thickness) {
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float dist = length(center - pixel) ;
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thickness /= radius;
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float antiAlias = 2./radius;
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dist = smoothstep (1. -thickness - antiAlias, 1.- thickness , dist / (radius)) - smoothstep ( 1.,1. + antiAlias, dist / (radius)) ;
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return dist;
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}
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float drawCircleRings (vec2 pixel, vec2 center, float radius, int count) {
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float spacing = 0.02;
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float dist = length(center - pixel) ;
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float antiAlias = 2./radius;
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float thickness = 1./float(count) -spacing;
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float t = 0.;
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for(int i=0;i<count;++i)
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{
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//result += uLightsPos[i];
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float myThickness = thickness * fract (abs ( sin(u_time*2. + float(i)/6. ) * (cos(u_time/4.)) ) );
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float sI = max (thickness * float(i) , 0. ) + (spacing* float(i) );
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t += smoothstep ( sI - antiAlias, sI , dist / (radius)) - smoothstep ( sI+myThickness, sI+ myThickness + antiAlias, dist / (radius)) ;
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}
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return t;
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}
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void main(){
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vec3 color1 = vec3(1., 0.3, 0.5);
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vec3 color = vec3 (0.);
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float pct3 = drawCircleRings(gl_FragCoord.xy, u_resolution.xy/2., 250. , 20);
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color = vec3 ( color1*pct3);
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gl_FragColor = vec4(color,1.0);
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} |