I asked Chat GPT. This was its answer

To convert the provided ShaderToy fragment shader to work with Three.js, we will follow a similar process as outlined earlier. We need to create a corresponding vertex shader for Three.js and modify the fragment shader to match Three.js’s conventions. Also, we will set up the necessary uniforms and JavaScript code to render it using Three.js.

### Vertex Shader

The vertex shader can be a simple pass-through shader, as the main graphical effect is in the fragment shader.

```
void main() {
gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}
```

### Fragment Shader

In the fragment shader, we adapt the `mainImage`

function to the standard `main`

function used in Three.js shaders and use the uniforms provided by Three.js.

```
uniform float iTime;
uniform vec2 iResolution;
void main() {
vec2 uv = -1.0 + 2.0 * gl_FragCoord.xy / iResolution.xy;
uv.x *= iResolution.x / iResolution.y;
vec3 color = vec3(0.0);
for( int i = 0; i < 128; i++ ) {
float pha = sin(float(i) * 546.13 + 1.0) * 0.5 + 0.5;
float siz = pow(sin(float(i) * 651.74 + 5.0) * 0.5 + 0.5, 4.0);
float pox = sin(float(i) * 321.55 + 4.1) * iResolution.x / iResolution.y;
float rad = 0.1 + 0.5 * siz + sin(pha + siz) / 4.0;
vec2 pos = vec2(pox + sin(iTime / 15.0 + pha + siz), -1.0 - rad + (2.0 + 2.0 * rad) * mod(pha + 0.3 * (iTime / 7.0) * (0.2 + 0.8 * siz), 1.0));
float dis = length(uv - pos);
vec3 col = mix(vec3(0.194 * sin(iTime / 6.0) + 0.3, 0.2, 0.3 * pha), vec3(1.1 * sin(iTime / 9.0) + 0.3, 0.2 * pha, 0.4), 0.5 + 0.5 * sin(float(i)));
float f = length(uv - pos) / rad;
f = sqrt(clamp(1.0 + (sin(iTime * siz) * 0.5) * f, 0.0, 1.0));
color += col.zyx * (1.0 - smoothstep(rad * 0.15, rad, dis));
}
color *= sqrt(1.5 - 0.5 * length(uv));
gl_FragColor = vec4(color, 1.0);
}
```

### JavaScript/Three.js Code

Now, we set up the Three.js scene, including the uniforms, material, geometry, and mesh.

```
const uniforms = {
iTime: { value: 0 },
iResolution: { value: new THREE.Vector2(window.innerWidth, window.innerHeight) }
};
const material = new THREE.ShaderMaterial({
uniforms: uniforms,
vertexShader: vertexShader, // The vertex shader code
fragmentShader: fragmentShader // The modified fragment shader code
});
const geometry = new THREE.PlaneBufferGeometry(2, 2);
const mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);
function animate() {
requestAnimationFrame(animate);
uniforms.iTime.value += 0.05;
renderer.render(scene, camera);
}
animate();
```

Make sure to replace `vertexShader`

and `fragmentShader`

with your actual shader code strings. This setup will render the effect of the original ShaderToy shader in a Three.js context. Remember to adjust the uniforms and rendering loop to suit your specific application’s needs.

In this conversion:

- We’ve replaced
`mainImage(out vec4 fragColor, in vec2 fragCoord)`

with `void main()`

.
- We’ve modified the calculation of
`uv`

to use `gl_FragCoord`

instead of `fragCoord`

.
- The uniforms
`iTime`

and `iResolution`

are declared at the top, which you will pass from your Three.js application.

This shader should now work within a Three.js context, using a `ShaderMaterial`

with this fragment shader and a basic vertex shader. Remember to update the uniform values (`iTime`

and `iResolution`

) in your JavaScript code as your scene updates.