Using copyTextureToTexture with CubeTexture

Based on the WebGLRenderer documentation, the copyTextureToTexture method allows you to copy pixel data from one texture to another. When working with a CubeTexture, there are some specific considerations to keep in mind.

Method Signature

JAVASCRIPTCopied
renderer.copyTextureToTexture(
  srcRegion,      // Box2 or Box3 defining the source region
  dstPosition,    // Vector2 or Vector3 defining the destination position
  srcTexture,     // Source Texture
  dstTexture,     // Destination Texture
  srcLevel,       // Source mipmap level (optional)
  dstLevel        // Destination mipmap level (optional)
)

Working with CubeTexture

When copying to a CubeTexture, you need to:

1. Specify which face of the cube you're updating (CubeTexture has 6 faces)
2. Ensure your source and destination regions are properly defined
3. Make sure both textures are initialized

From your screenshots, it appears you're trying to update a specific face of a CubeTexture. Here's how you might correctly implement this:

JAVASCRIPTCopied
// Assuming you have:
// - renderer: WebGLRenderer
// - sourceTex: The texture containing the new data
// - cubeTexture: The CubeTexture you want to update
// - faceIndex: Which face of the cube to update (0-5)

// Define source region (the entire source texture)
const srcRegion = new THREE.Box2(
  new THREE.Vector2(0, 0),
  new THREE.Vector2(sourceTex.image.width, sourceTex.image.height)
);

// Define destination position (starting at 0,0)
const dstPosition = new THREE.Vector2(0, 0);

// Make sure both textures are initialized
renderer.initTexture(sourceTex);
renderer.initTexture(cubeTexture);

// Copy the texture data to the specific face of the cube
renderer.copyTextureToTexture(
  srcRegion,
  dstPosition,
  sourceTex,
  cubeTexture,
  0,  // Source level
  0   // Destination level
);

// Make sure to update the cube texture
cubeTexture.needsUpdate = true;

For CubeTexture specifically, you might need to update each face individually, as the CubeTexture consists of 6 separate textures (one for each face). The documentation indicates that both 2D and 3D textures are supported, so you may need to adjust your approach based on how your CubeTexture is structured.

If you're still encountering issues, ensure that:

1. Your source texture is valid and loaded
2. The dimensions match or are properly accounted for
3. You're targeting the correct face of the CubeTexture
4. Both textures have been properly initialized

Remember that for render target textures, you must initialize them with renderer.initRenderTarget() before copying.