distance fractal shader

src/logic/pool/Shader.tsx

@@ -58,7 +58,7 @@ vec2 pos = ((gl_FragCoord.xy + position / escale) / resol.xy + vec2(-0.5)) * esc
 vec2 zi = pos;
 for (int i = 0; i < MAX_ITS; i++) {
 	if (i == max_its) {break;}
-	zi = zi - cmul(cdiv(cpow(zi, n) - vec2(100., 0.), float(n) * cpow(zi, n-1)), point_a);
+	zi = zi - cmul(cdiv(cpow(zi, n) - vec2(100., 0.), float(n) * cpow(zi, n-1)), point_a) + point_a;
 	// zi = zi - cmul(cdiv(sin(zi) - vec2(1., 0.), cos(zi)), point_a);
 }
 
@@ -90,5 +90,99 @@ gl_FragColor = vec4(color / 255., 1);
 // }
 // if (colors[0].x == 0.) {gl_FragColor = vec4(0.2, 0.4, 0.6, 1);}
 
+}
+`;
+
+export const Alter = `
+	
+precision highp float;
+
+uniform vec2 resol;
+uniform int n;
+uniform float scale;
+uniform float roots[12];
+uniform vec2 position;
+uniform vec3 colors[12];
+uniform int max_its;
+uniform vec2 point_a;
+
+const int MAX_ITS = 300;
+
+float sigm(float x) {
+    return 1. / (1. + exp(-abs(x / 10.)+2.));
+}
+
+vec2 cmul(vec2 x, vec2 y) {
+	return vec2(x.x * y.x - x.y * y.y, x.x * y.y + x.y * y.x);
+}
+
+vec2 cdiv(vec2 x, vec2 y) {
+	float d = (y.x * y.x + y.y * y.y);
+	return vec2((x.x * y.x + x.y * y.y) / d, (y.x * x.y - x.x * y.y) / d);
+	
+}
+
+vec2 cpow(vec2 x, int p) {
+	vec2 res = vec2(1, 0);
+	for (int i = 0; i <= MAX_ITS; i++) {
+		if (i == p) {break;}
+		res = cmul(res, x);
+	}
+	return res;
+}
+
+vec2 transform(float phi) {
+	return vec2(cos(phi), sin(phi));
+}
+
+float cdist(vec2 x, vec2 y) {
+	return length((x-y));
+}
+
+void main( void ) {
+
+float escale = exp(scale - 1.);
+vec2 pos = ((gl_FragCoord.xy + position / escale) / resol.xy + vec2(-0.5)) * escale;
+
+
+vec2 zi = pos;
+for (int i = 0; i < MAX_ITS; i++) {
+	if (i == max_its) {break;}
+	zi = zi - cmul(cdiv(cpow(zi, n) - vec2(100., 0.), float(n) * cpow(zi, n-1)), point_a);
+	// zi = zi - cmul(cdiv(sin(zi) - vec2(1., 0.), cos(zi)), point_a);
+}
+
+int mi = 0;
+float md =  cdist(transform(roots[0]), zi);
+for (int i = 0; i < MAX_ITS; i++) {
+	if (i == n) { break; }
+
+	vec2 point = transform(roots[i]);
+
+	float dst = cdist(point, zi);
+	
+	if (dst < md) {
+		md = dst;
+		mi = i;
+	}
+}
+vec3 color = vec3(1.0);
+for (int i = 0; i < 12; i++) {
+    if (i == mi) {
+        color = colors[i];
+        break;
+    }
+}
+float dst = cdist(zi, pos + md );
+// float dst = md;
+color = vec3(sigm(dst));
+
+// if (pos.x < 0.1 && pos.x > -0.1 && pos.y < 0.1 && pos.y > -0.1) {
+//     gl_FragColor = vec4(vec3(1.,0.,0.), 1);
+// } else {
+    gl_FragColor = vec4(color, 1.);
+// }
+if (colors[0].x == 0.) {gl_FragColor = vec4(0.2, 0.4, 0.6, 1);}
+
 }
 `;