2d cellular noise

Author: gam0022

Assets/Demoscene/Projects/2018-07-12-Lava/Lava.shader

@@ -53,11 +53,11 @@ float _Power;
 
 inline float DistanceFunction(float3 pos)
 {
-    float2 c = cellular(float3(pos.xz, _Time.y));
+    float2 c = cellular(float2(pos.xz));
     float h = c.y - c.x;
     h = pow(h, _Power);
 
-    float2 c2 = cellular(float3(3.0 * pos.xz, 0.0));
+    float2 c2 = cellular(float2(3.0 * pos.xz));
     h += 0.5 * pow((c2.y - c2.x), _Power);
 
     h += 0.001 * snoise(50.0 * pos.xz);

Assets/Demoscene/Shaders/Includes/Noise.cginc

@@ -80,10 +80,62 @@ float snoise(vec2 v) {
 }
 
 
+// https://thebookofshaders.com/edit.php#12/2d-cnoise.frag
+
+// Permutation polynomial: (34x^2 + x) mod 289
+// vec3 permute(vec3 x) {
+//   return mod((34.0 * x + 1.0) * x, 289.0);
+// }
+
+// Cellular noise, returning F1 and F2 in a vec2.
+// Standard 3x3 search window for good F1 and F2 values
+vec2 cellular(vec2 P) {
+	#define K 0.142857142857 // 1/7
+	#define Ko 0.428571428571 // 3/7
+	#define jitter 1.0 // Less gives more regular pattern
+    vec2 Pi = mod(floor(P), 289.0);
+    vec2 Pf = fract(P);
+	vec3 oi = vec3(-1.0, 0.0, 1.0);
+	vec3 of = vec3(-0.5, 0.5, 1.5);
+	vec3 px = permute(Pi.x + oi);
+	vec3 p = permute(px.x + Pi.y + oi); // p11, p12, p13
+	vec3 ox = fract(p*K) - Ko;
+	vec3 oy = mod(floor(p*K),7.0)*K - Ko;
+	vec3 dx = Pf.x + 0.5 + jitter*ox;
+	vec3 dy = Pf.y - of + jitter*oy;
+	vec3 d1 = dx * dx + dy * dy; // d11, d12 and d13, squared
+	p = permute(px.y + Pi.y + oi); // p21, p22, p23
+	ox = fract(p*K) - Ko;
+	oy = mod(floor(p*K),7.0)*K - Ko;
+	dx = Pf.x - 0.5 + jitter*ox;
+	dy = Pf.y - of + jitter*oy;
+	vec3 d2 = dx * dx + dy * dy; // d21, d22 and d23, squared
+	p = permute(px.z + Pi.y + oi); // p31, p32, p33
+	ox = fract(p*K) - Ko;
+	oy = mod(floor(p*K),7.0)*K - Ko;
+	dx = Pf.x - 1.5 + jitter*ox;
+	dy = Pf.y - of + jitter*oy;
+	vec3 d3 = dx * dx + dy * dy; // d31, d32 and d33, squared
+	// Sort out the two smallest distances (F1, F2)
+	vec3 d1a = min(d1, d2);
+	d2 = max(d1, d2); // Swap to keep candidates for F2
+	d2 = min(d2, d3); // neither F1 nor F2 are now in d3
+	d1 = min(d1a, d2); // F1 is now in d1
+	d2 = max(d1a, d2); // Swap to keep candidates for F2
+	d1.xy = (d1.x < d1.y) ? d1.xy : d1.yx; // Swap if smaller
+	d1.xz = (d1.x < d1.z) ? d1.xz : d1.zx; // F1 is in d1.x
+	d1.yz = min(d1.yz, d2.yz); // F2 is now not in d2.yz
+	d1.y = min(d1.y, d1.z); // nor in  d1.z
+	d1.y = min(d1.y, d2.x); // F2 is in d1.y, we're done.
+	return sqrt(d1.xy);
+}
+
+
 // https://thebookofshaders.com/edit.php#12/3d-cnoise.frag
-//vec3 permute(vec3 x) {
-//    return mod((34.0 * x + 1.0) * x, 289.0);
-//}
+
+// vec3 permute(vec3 x) {
+//     return mod((34.0 * x + 1.0) * x, 289.0);
+// }
 
 // Cellular noise, returning F1 and F2 in a vec2.
 // 3x3x3 search region for good F2 everywhere, but a lot