I am looking at this and I have no clue why there’s that artifact in the output. The code is identical. (you missed a sign on bb, if should be -sin, but it doesn’t change much)
I can’t offer an explanation, but I can tell you it is not you doing something wrong, I don’t think.
A bit of testing tells me maybe the 43758.5453123 factor is way too big for some reason.
Further testing implies the fault is somewhere around the b c d factors in the noise function.
I used Artificial Intelligence Assistant - ARIA to convert the source code for that shader and I don’t see these diff.
… fixed, that sign of sin, multiplication, and SCREEN_UV, works better with UV :
shader_type canvas_item;
uniform vec2 u_resolution;
uniform vec2 u_mouse;
uniform float p_time; // this will * TIME in fragment()
float random (vec2 _st) {
return fract(sin(dot(_st.xy, vec2(1.29898,7.8233)))* 4.37585453123);
}
float noise (vec2 _st) {
vec2 i = floor(_st);
vec2 f = fract(_st);
float a = random(i);
float b = random(i + vec2(1.0, 0.0));
float c = random(i + vec2(0.0, 1.0));
float d = random(i + vec2(1.0, 1.0));
vec2 u = f * f * (3.0 - 2.0 * f);
return mix(a, b, u.x) + (c - a)* u.y * (1.0 - u.x) + (d - b) * u.x * u.y;
}
#define NUM_OCTAVES 5
float fbm (vec2 _st) {
float v = 0.0;
float a = 0.5;
vec2 shift = vec2(100.0);
vec2 aa = vec2(cos(0.5), sin(0.5));
vec2 bb = vec2(-sin(0.5), cos(0.50));
mat2 rot = mat2(aa, bb);
for (int i = 0; i < NUM_OCTAVES; ++i) {
v += a * noise(_st);
_st = rot * _st * 2.0 + shift;
a *= 0.5;
}
return v;
}
void fragment() {
vec2 st = UV * 1.14;
//vec2 st = SCREEN_UV * 1.14;
vec3 color = vec3(0.0);
float u_time = p_time * TIME;
vec2 q = vec2(0.0);
q.x = fbm(st + 0.00*u_time);
q.y = fbm(st + vec2(1.0));
vec2 r = vec2(0.0);
r.x = fbm(st + 1.0*q + vec2(1.7,9.2)+ 0.15*u_time);
r.y = fbm(st + 1.0*q + vec2(8.3,2.8)+ 0.126*u_time);
float f = fbm(st+r);
color = mix(vec3(0.101961,0.619608,0.666667), vec3(0.666667,0.666667,0.498039), clamp((f*f)*4.0,0.0,1.0));
color = mix(color, vec3(0,0,0.164706), clamp(length(q),0.0,1.0));
color = mix(color, vec3(0.666667,1,1), clamp(length(r.x),0.0,1.0));
COLOR = vec4((f*f*f + 0.6*f*f + 0.5*f) * color, 1.0);
}