Rainbow Gradient that ignores Black
Found this shader and modified it to ignore black. Though i’d share for convinience.
Shader code
shader_type canvas_item;
uniform float strength: hint_range(0., 1.) = 0.3;
uniform float speed: hint_range(0., 10.) = 0.5;
uniform float angle: hint_range(0., 360.) = 0.;
void fragment() {
float hue = UV.x * cos(radians(angle)) - UV.y * sin(radians(angle));
hue = fract(hue + fract(TIME * speed));
float x = 1. - abs(mod(hue / (1./ 6.), 2.) - 1.);
vec3 rainbow;
if(hue < 1./6.){
rainbow = vec3(1., x, 0.);
} else if (hue < 1./3.) {
rainbow = vec3(x, 1., 0);
} else if (hue < 0.5) {
rainbow = vec3(0, 1., x);
} else if (hue < 2./3.) {
rainbow = vec3(0., x, 1.);
} else if (hue < 5./6.) {
rainbow = vec3(x, 0., 1.);
} else {
rainbow = vec3(1., 0., x);
}
vec4 color = texture(TEXTURE, UV);
COLOR = mix(color, color * vec4(rainbow, color.a), strength);
}