Converting Camera-Relative to World Coordinates in Three.js

Based on the information provided, you're trying to convert coordinates from camera-relative space to world space in your shader. This is a common challenge when working with Three.js shaders.

To convert from camera-relative coordinates to world coordinates, you need to understand the relationship between the different coordinate spaces in Three.js.

Matrix Transformations

In Three.js, there are several important matrices involved in transformations:

1. modelMatrix: Transforms from object space to world space
2. viewMatrix: Transforms from world space to camera space
3. modelViewMatrix: Combined model and view matrices (object space to camera space)
4. projectionMatrix: Transforms from camera space to clip space

To convert from camera-relative to world coordinates, you need to:

1. Start with your camera-relative position
2. Apply the inverse of the view matrix to get world coordinates

Shader Implementation

Here's how you might modify your shader code:

GLSLCopied
// To convert a camera-relative position to world space
vec3 cameraRelativePos = position; // Your camera-relative position
vec4 worldPos = inverse(viewMatrix) * vec4(cameraRelativePos, 1.0);

// If you need to go from world space to scene/object space
vec4 objectPos = inverse(modelMatrix) * worldPos;

// For your final position calculation
gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);

If you're specifically trying to make points stay fixed in world space rather than moving with the camera, you'll need to:

1. Get the world position of your points
2. Apply the appropriate transformations in your vertex shader

Note that in your current code:

GLSLCopied
scene0 = inverse(modelMatrix) * vec4(.0, .0, .0, 1.0);

You're transforming the origin (0,0,0) rather than your actual point positions, which might be causing the issue.

For points that should be fixed in world space, you'll need to ensure they're properly transformed through the entire matrix chain, taking into account the camera's movement.