mirror of
https://github.com/patriciogonzalezvivo/thebookofshaders
synced 2024-11-08 01:10:27 +00:00
118 lines
2.9 KiB
GLSL
118 lines
2.9 KiB
GLSL
// Author @patriciogv - 2015 - patriciogonzalezvivo.com
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#ifdef GL_OES_standard_derivatives
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#extension GL_OES_standard_derivatives : enable
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#endif
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#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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vec2 skew (vec2 st) {
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vec2 r = vec2(0.0);
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r.x = 1.1547*st.x;
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r.y = st.y+0.5*r.x;
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return r;
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}
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vec3 simplexGrid (vec2 st) {
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vec3 xyz = vec3(0.0);
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vec2 p = fract(skew(st));
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if (p.x > p.y) {
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xyz.xy = 1.0-vec2(p.x,p.y-p.x);
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xyz.z = p.y;
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} else {
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// xyz.yz = 1.0-vec2(p.x-p.y,p.y);
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// xyz.x = p.x;
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xyz.zx = 1.-vec2(p.x-p.y,p.y);
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xyz.y = p.x;
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}
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return fract(xyz);
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}
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vec3 starS (vec3 S) {
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S += max(dot(S.xxx,S.zzz),max(dot(S.yyy,S.xxx),dot(S.yyy,S.zzz)));
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return S;
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}
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vec3 sakuraS (vec3 S) {
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return S + min(dot(S.xxx,S.zzz),min(dot(S.yyy,S.xxx),dot(S.yyy,S.zzz)));
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}
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float warpDF (vec3 S) {
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return dot(S.xy,S.yx);
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}
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float circleDF (vec3 S) {
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return dot(S,S);
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}
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float triangleDF (vec3 S) {
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S -= 1.04;
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return abs(min(dot(S.zz,S.yy),min(dot(S.zz,S.xx),dot(S.xx,S.yy))));
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}
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float lotusDF (vec3 S, float petals_size, float roundness) {
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S = 1.-(S)*petals_size; // above 1.
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S = pow(S,vec3(roundness));
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S = max(starS(S),sakuraS(S));
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return 1.0-fract(triangleDF(S));
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}
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// Antialiazed Step function
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// from http://webstaff.itn.liu.se/~stegu/webglshadertutorial/shadertutorial.html
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float aastep(float threshold, float value) {
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#ifdef GL_OES_standard_derivatives
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float afwidth = 0.7 * length(vec2(dFdx(value), dFdy(value)));
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return smoothstep(threshold-afwidth, threshold+afwidth, value);
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#else
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return step(threshold, value);
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#endif
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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 t = smoothstep(0.,1.,abs(sin(u_time*0.4)));
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// Scale the space to see the grid
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st *= 1.733;
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st *= 2.;
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vec3 S = simplexGrid(st);
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// Triangles
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// ------------
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// color += aastep(t,triangleDF(S));
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// color += aastep(0.5,triangleDF(smoothstep(vec3(.3,.3,.7),vec3(1.),S)));
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// color += aastep(0.99,triangleDF(pow(S,vec3(3.,3.,1.))));
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// color += aastep(1.,triangleDF(S*20.));
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// color += aastep(0.1,triangleDF(S*5.+dot(S,S)));
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// color += aastep(t*.5,triangleDF(sakuraS(S)));
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// color += aastep(-.1t*.2,triangleDF(starS(S)) );
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// color += aastep(t,triangleDF(sakuraS(starS(S))));
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color += aastep(t,triangleDF(starS(sakuraS(S))));
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// Warp
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// color += aastep(t,warpDF(sakuraS(S)));
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// color += aastep(t,warpDF(starS(S)));
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// Lotus
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// -------------
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// color += aastep(.5,lotusDF(S,2.12,0.001+t*0.6));
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// color += aastep(.5,lotusDF(S,3.,.1+t*.1));
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// color += aastep(.5,lotusDF(S,3.,.3+t*.2));
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// color += aastep(.5,lotusDF(S,5.,.1+t*.1));
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// color += aastep(.5,lotusDF(S,12.,.0001+t*.04));
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gl_FragColor = vec4(color,1.0);
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}
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