more shader examples

shaders/whitestar.glsl

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+
+
+//  Online implementation by kasari39 : https://www.shadertoy.com/embed/ttKGDt?gui=true&t=10&paused=false&muted=false
+
+
+precision highp float;
+
+uniform float iTime;
+uniform vec2 iResolution;
+
+mat2 rot(float a) {
+    float c = cos(a), s = sin(a);
+    return mat2(c,s,-s,c);
+}
+
+const float pi = acos(-1.0);
+const float pi2 = pi*2.0;
+
+vec2 pmod(vec2 p, float r) {
+    float a = atan(p.x, p.y) + pi/r;
+    float n = pi2 / r;
+    a = floor(a/n)*n;
+    return p*rot(-a);
+}
+
+float box( vec3 p, vec3 b ) {
+    vec3 d = abs(p) - b;
+    return min(max(d.x,max(d.y,d.z)),0.0) + length(max(d,0.0));
+}
+
+float ifsBox(vec3 p) {
+    for (int i=0; i<5; i++) {
+        p = abs(p) - 1.0;
+        p.xy *= rot(iTime*0.3);
+        p.xz *= rot(iTime*0.1);
+    }
+    p.xz *= rot(iTime);
+    return box(p, vec3(0.4,0.8,0.3));
+}
+
+float map(vec3 p, vec3 cPos) {
+    vec3 p1 = p;
+    p1.x = mod(p1.x-5., 10.) - 5.;
+    p1.y = mod(p1.y-5., 10.) - 5.;
+    p1.z = mod(p1.z, 16.)-8.;
+    p1.xy = pmod(p1.xy, 5.0);
+    return ifsBox(p1);
+}
+
+void main() {
+    vec2 p = (gl_FragCoord.xy * 1.0 - iResolution.xy) / min(iResolution.x, iResolution.y);
+
+    vec3 cPos = vec3(0.0,0.0, -3.0 * iTime);
+    // vec3 cPos = vec3(0.3*sin(iTime*0.8), 0.4*cos(iTime*0.3), -6.0 * iTime);
+    vec3 cDir = normalize(vec3(0.0, 0.0, -1.0));
+    vec3 cUp  = vec3(sin(iTime), 1.0, 0.0);
+    vec3 cSide = cross(cDir, cUp);
+
+    vec3 ray = normalize(cSide * p.x + cUp * p.y + cDir);
+
+    // Phantom Mode https://www.shadertoy.com/view/MtScWW by aiekick
+    float acc = 0.0;
+    float acc2 = 0.0;
+    float t = 0.0;
+    for (int i = 0; i < 99; i++) {
+        vec3 pos = cPos + ray * t;
+        float dist = map(pos, cPos);
+        dist = max(abs(dist), 0.02);
+        float a = exp(-dist*3.0);
+        if (mod(length(pos)+24.0*iTime, 30.0) < 3.0) {
+            a *= 2.0;
+            acc2 += a;
+        }
+        acc += a;
+        t += dist * .5;
+    }
+
+    vec3 col = vec3(acc * 0.01, acc * 0.011 + acc2*0.002, acc * 0.012+ acc2*0.005);
+    gl_FragColor = vec4(col, 1.0 - t * 0.03);
+}