shader-with-for-loop.html

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<title>WebGL GLSL Conformance Tests</title>

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<script id="fragmentShader" type="text/something-not-javascript">

// fragment shader with for loop should succeed

// TODO(gman): trim to min size to test bug.

precision mediump float;

uniform float time;

uniform vec2 resolution;

// Saw-tooth function that is synced with the demo music (128bpm)

float gBeat;

// Calculate the surface color

vec3 surfColor(vec2 p)

    vec2 q=vec2(sin(.08*p.x),4.*p.y);

    vec3 c=vec3(0);

    for(float i=0.;i<15.;i++)

      c+=(1.+sin(i*sin(time)+vec3(0.,1.3,2.2)))*.2/length(q-vec2(sin(i),12.*sin(.3*time+i)));

    return c+vec3(mix(mod(floor(p.x*.2)+floor(p.y*2.2),2.),.2,gBeat));

// Ray trace (cylinder)

vec3 trace(vec3 o,vec3 d)

    d.y*=.65+.1*sin(.5*time);

    float D=1./(d.y*d.y+d.z*d.z),

          a=(o.y*d.y+o.z*d.z)*D,

          b=(o.y*o.y+o.z*o.z-36.)*D,

          t=-a-sqrt(a*a-b);

    o+=t*d;

    return surfColor(vec2(o.x,atan(o.y,o.z)))*(1.+.01*t);

void main()

    gBeat=fract(time*3.2/3.);

    // Screen setup

    vec2 p=(2.*gl_FragCoord.xy-resolution)/resolution.y,

         q=2.*gl_FragCoord.xy/resolution-1.;

    // Camera setup

    vec3 cp=vec3(-time*20.+1.,1.6*sin(time*1.2),2.+2.*cos(time*.3)),

         ct=cp+vec3(1.,.3*cos(time),-.2),

         cd=normalize(ct-cp),

         cr=normalize(cross(cd,vec3(.5*cos(.3*time),0.,1.))),

         cu=cross(cr,cd),

         rd=normalize(2.*cd+cr*p.x+cu*p.y);

    // Trace! (+some funky lens/raster effects)

    vec3 c=trace(cp,rd)*

           min(1.,1.8-dot(q,q))*

           (.9+.1*sin(3.*sin(gBeat)*gl_FragCoord.y));

    gl_FragColor=vec4(c,1);

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"use strict";

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