133 lines
4.5 KiB
GLSL
133 lines
4.5 KiB
GLSL
// 2016 David A Roberts <https://davidar.io>
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#define AA 4.
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#define PI 3.141592653589793
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// CRT effects (curvature, vignette, scanlines and CRT grille)
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// from <https://www.shadertoy.com/view/XtlSD7>
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vec2 CRTCurveUV( vec2 uv ) {
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uv = uv * 2.0 - 1.0;
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vec2 offset = abs( uv.yx ) / vec2( 6.0, 4.0 );
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uv = uv + uv * offset * offset;
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uv = uv * 0.5 + 0.5;
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return uv;
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}
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void DrawVignette( inout vec3 color, vec2 uv ) {
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float vignette = uv.x * uv.y * ( 1.0 - uv.x ) * ( 1.0 - uv.y );
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vignette = clamp( pow( 16.0 * vignette, 0.3 ), 0.0, 1.0 );
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color *= vignette;
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}
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void DrawScanline( inout vec3 color, vec2 uv ) {
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float scanline = clamp( 0.95 + 0.05 * cos( 3.14 * ( uv.y + 0.008 * iTime ) * 240.0 * 1.0 ), 0.0, 1.0 );
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float grille = 0.85 + 0.15 * clamp( 1.5 * cos( 3.14 * uv.x * 640.0 * 1.0 ), 0.0, 1.0 );
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color *= scanline * grille * 1.2;
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}
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float atanp(in vec2 p) { return atan(p.y,p.x); }
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float cube_root(float x) { return sign(x) * pow(abs(x), 1./3.); }
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float sq(float x) { return x*x; }
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vec3 margarita(in vec2 p) {
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float z = length(p) - 3.5 * atanp(p) + sin(p.x) + cos(p.y);
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if(mod(z,7.*PI) < PI/2.) return vec3(1,0,0);
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if(mod(z,1.*PI) < PI/2.) return vec3(0);
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return vec3(1);
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}
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vec3 digital_bacteria(in vec2 p) {
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p /= 4.;
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float x = sq(sin(p.x)+p.y) + sq(cos(p.y)+p.x);
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float y = cos(10.*p.x) + cos(10.*p.y) - sin(p.x*p.y);
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float z = sq(sin(floor(p.x))+floor(p.y)) + sq(cos(floor(p.y))+floor(p.x));
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if(17. < x && x < 21. && 17. < z && z < 21. && y < 0.)
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return vec3(1.,1.,85./256.);
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if(17. < z && z < 21.) return vec3(85./256.,0.,0.);
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if(17. < x && x < 21.) return vec3(170./256.,170./256.,0.);
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return vec3(85./256.,85./256.,0.);
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}
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vec3 threesome(in vec2 p) {
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p /= 3.;
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float z = 1.;
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z *= sin(length(p + vec2(5,0))) * cos(8.*atanp(p + vec2(5,0)));
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z *= sin(length(p - vec2(5,5))) * cos(8.*atanp(p - vec2(5,5)));
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z *= sin(length(p + vec2(0,5))) * cos(8.*atanp(p + vec2(0,5)));
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if(-0.1 < z && z < 0. || 0.2 < z) return vec3(0);
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return vec3(1);
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}
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vec3 plaid_meltdown(in vec2 p) {
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p /= 15.;
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p += 7.;
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float a = 2.*sin(p.x*sin(p.y) + p.y*sin(p.x));
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float b = cube_root(sin(2.5*sqrt(2.) * (p.x - p.y)));
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float c = cube_root(sin(2.5*sqrt(2.) * (p.x + p.y)));
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float d = sin(80.*p.x) + sin(80.*p.y);
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if(0.25 * (a + b + c) > 0.5 * d) return vec3(0);
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return vec3(1);
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}
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vec3 sunlight_revealed(in vec2 p) {
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p /= 6.;
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p.x += 2.;
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float a = length(vec2(3.-p.x,p.y)) + abs(p.y) + abs(1.-p.x);
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float f = atan(p.y,p.x-1.);
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float c = atan(p.y,p.x-3.);
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float R = sq(p.x-1.) + sq(p.y);
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vec3 col = vec3(0);
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bool mix = false;
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if(5. < a && a < 7. && mod(f,PI/7.) < PI/14.) {
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col += vec3(0.,82./256.,173./256.);
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if(mix) col /= 2.;
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mix = true;
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}
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if(5. < a && a < 7. && mod(c,PI/9.) < PI/18.) {
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col += vec3(1,0,0);
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if(mix) col /= 2.;
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mix = true;
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}
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if(5. < a && a < 7. && mod(f,PI/8.) < PI/16.) {
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col += vec3(1,1,0);
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if(mix) col /= 2.;
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mix = true;
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}
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if((45.-3.*p.x)*PI/180. < f && f < (47.-p.x)*PI/180. && p.y > 0.1*p.x
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&& mod(log(R)/log(f),2.) < 1.) {
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col += vec3(1);
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if(mix) col /= 2.;
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}
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return col;
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}
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void mainImage(out vec4 fragColor, in vec2 fragCoord) {
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float t = mod(iTime/10,10.);
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vec3 color = vec3(0);
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for(float i = 0.; i < AA*AA - 0.5; i += 1.) {
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vec2 uv = (fragCoord.xy + vec2(floor(i/AA), mod(i,AA))/AA) / iResolution.xy;
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vec2 crtUV = CRTCurveUV( uv );
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if ( crtUV.x < 0.0 || crtUV.x > 1.0 || crtUV.y < 0.0 || crtUV.y > 1.0 ) continue;
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vec2 p = 50.0 * crtUV - 25.0;
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p *= 0.75 + 0.05*mod(iTime,10.);
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p += mod(iTime,10.) - 5.;
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p.x *= iResolution.x / iResolution.y;
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if(t < 2. || 8. < t) {
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float fade = smoothstep(0.,2.,t) - smoothstep(8.,10.,t);
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float scale = iResolution.y/50.*float(AA)*fade + 1.;
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p = floor(p.xy*scale)/scale;
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}
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vec3 c;
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if (mod(0.1*iTime,5.) < 1.) c = margarita(p);
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else if(mod(0.1*iTime,5.) < 2.) c = plaid_meltdown(p);
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else if(mod(0.1*iTime,5.) < 3.) c = sunlight_revealed(p);
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else if(mod(0.1*iTime,5.) < 4.) c = threesome(p);
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else if(mod(0.1*iTime,5.) < 5.) c = digital_bacteria(p);
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DrawVignette( c, crtUV );
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DrawScanline( c, uv );
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color += c / float(AA*AA);
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}
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fragColor.xyz = color;
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fragColor.w = 1.0;
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}
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