background shader

ripped from basic shaders from to-fujita

https://github.com/To-Fujita/Godot_v3.2-Basic_Shaders check his stuff out

Shader code

shader_type canvas_item;
// Background Noise

uniform mat2 _rot = mat2( vec2(0.5, 0.86), vec2(-0.86, 0.5));
uniform float _speed = 1.1;
uniform float _gradation : hint_range(0, 2) = 0.5;

float wave(vec2 p) {
	float v = sin(p.x+sin(p.y) + sin(p.y*.43));
	return v*v;
}

float map(float time, vec2 p) {
	float v = 0.0;
	v += wave(p);
	p.x += time * _speed;
	p = p * _rot;
	v += wave(p);
	p.x += time * _speed * .17;
	p = p * _rot;
	v += wave(p);
	v = abs(1.5 - v);

	return v;
}

void fragment()
{
	vec2 resolution = 1.0 / SCREEN_PIXEL_SIZE;
	vec2 uv = (FRAGCOORD.xy * 2.0 - resolution.xy) / min(resolution.x, resolution.y);
	vec2 p = normalize(vec3(uv.xy, 2.3)).xy * 10.0;
	p.y += TIME * _speed * 0.3;
	float v=map(TIME, p);
	
	COLOR = vec4((v * .7 + texture(SCREEN_TEXTURE,SCREEN_UV).r) / 2.0, (v * .3 + texture(SCREEN_TEXTURE,SCREEN_UV).g) / 2.0, (v * 0.49 + texture(SCREEN_TEXTURE,SCREEN_UV).b / 2.0), _gradation);
}