[Godot4] 水底气泡的 gdshader

水底气泡的 gdshader

来自 shadertoy 的代码

在这里，我添加了 x 方向和 y 方向上的 uv 位移

但是还是感觉太弱智

shader_type canvas_item;
// Created by greenbird10
// License Creative Commons Attribution-NonCommercial-ShareAlike 3.0

uniform float bubble_size = 0.1;   // Size of the bubbles
uniform float upward_speed = 0.2;  // Speed at which bubbles rise
uniform float movable_x = 0.0;
uniform float movable_y = 0.0;

float hash(vec2 p) {
	return 0.5*(
    sin(dot(p, vec2(271.319, 413.975)) + 1217.13*p.x*p.y)
    ) + 0.5;
}

float noise(vec2 p) {
  vec2 w = fract(p);
  w = w * w * (3.0 - 2.0*w);
  p = floor(p);
  return mix(
    mix(hash(p+vec2(0,0)), hash(p+vec2(1,0)), w.x),
    mix(hash(p+vec2(0,1)), hash(p+vec2(1,1)), w.x), w.y);
}

// wave octave inspiration
// Alexander Alekseev - Seascape
// https://www.shadertoy.com/view/Ms2SD1
float map_octave(vec2 uv) {
  uv = (uv + noise(uv)) / 2.5;
  uv = vec2(uv.x*0.6-uv.y*0.8, uv.x*0.8+uv.y*0.6);
  vec2 uvsin = 1.0 - abs(sin(uv));
  vec2 uvcos = abs(cos(uv));
  uv = mix(uvsin, uvcos, uvsin);
  float val = 1.0 - pow(uv.x * uv.y, 0.65);
  return val;
}

float map(vec3 p) {
  vec2 uv = p.xz + TIME/2.;
  float amp = 0.6, freq = 2.0, val = 0.0;
  for(int i = 0; i < 3; ++i) {
    val += map_octave(uv) * amp;
    amp *= 0.3;
    uv *= freq;
    // uv = vec2(uv.x*0.6-uv.y*0.8, uv.x*0.8+uv.y*0.6);
  }
  uv = p.xz - 1000. - TIME/2.;
  amp = 0.6;
  freq = 2.0;
  for(int i = 0; i < 3; ++i) {
    val += map_octave(uv) * amp;
    amp *= 0.3;
    uv *= freq;
    // uv = vec2(uv.x*0.6-uv.y*0.8, uv.x*0.8+uv.y*0.6);
  }
  return val + 3.0 - p.y;
}

vec3 getNormal(vec3 p, vec2 resolution) {
  float eps = 1./resolution.x;
  vec3 px = p + vec3(eps, 0, 0);
  vec3 pz = p + vec3(0, 0, eps);
  return normalize(vec3(map(px),eps,map(pz)));
}

// raymarch inspiration
// Alexander Alekseev - Seascape
// https://www.shadertoy.com/view/Ms2SD1
float raymarch(vec3 ro, vec3 rd, vec2 resolution, out vec3 outP, out float outT) {
    float l = 0., r = 26.;
    int i = 0, steps = 16;
    float dist = 1000000.;
    for(int i = 0; i < steps; ++i) {
        float mid = (r+l)/2.;
        float mapmid = map(ro + rd*mid);
        dist = min(dist, abs(mapmid));
        if(mapmid > 0.) {
        	l = mid;
        }
        else {
        	r = mid;
        }
        if(r - l < 1./resolution.x) break;
    }
    outP = ro + rd*l;
    outT = l;
    return dist;
}

float fbm(vec2 n) {
	float total = 0.0, amplitude = 1.0;
	for (int i = 0; i < 5; i++) {
		total += noise(n) * amplitude; 
		n += n;
		amplitude *= 0.4; 
	}
	return total;
}

float lightShafts(vec2 st) {
    float angle = -0.2;