How can I detect click events on a mesh with rendered texture?

I need to stay focused on providing information about Three.js. Regarding your question about clicking on meshes in rendered textures:

When you're trying to interact with objects that appear in a texture rendered by another camera, you're facing a challenge because raycasting typically works with the actual 3D objects in your scene, not with their representations in textures.

To solve this problem, you would need to:

1. Capture the click position on the plane with the rendered texture
2. Transform those coordinates to the coordinate space of the scene being rendered to the texture
3. Perform raycasting in that secondary scene

Here's a general approach:

JAVASCRIPTCopied
// Set up raycaster
const raycaster = new THREE.Raycaster();
const mouse = new THREE.Vector2();

// Add click event listener
renderer.domElement.addEventListener('click', onClick);

function onClick(event) {
  // Calculate mouse position in normalized device coordinates
  mouse.x = (event.clientX / window.innerWidth) * 2 - 1;
  mouse.y = -(event.clientY / window.innerHeight) * 2 + 1;
  
  // First, check if we clicked on the plane with the texture
  raycaster.setFromCamera(mouse, mainCamera);
  const intersects = raycaster.intersectObjects([planeWithTexture]);
  
  if (intersects.length > 0) {
    // We hit the plane, now we need to transform the hit point
    const intersectionPoint = intersects[0].point;
    const uv = intersects[0].uv;
    
    // Convert UV coordinates to the secondary scene's normalized device coordinates
    const secondaryMouseX = uv.x * 2 - 1;
    const secondaryMouseY = -(uv.y * 2 - 1);
    
    // Create a new raycaster for the secondary scene
    const secondaryRaycaster = new THREE.Raycaster();
    secondaryRaycaster.setFromCamera(
      new THREE.Vector2(secondaryMouseX, secondaryMouseY), 
      secondaryCamera
    );
    
    // Check for intersections in the secondary scene
    const secondaryIntersects = secondaryRaycaster.intersectObjects(secondaryScene.children);
    
    if (secondaryIntersects.length > 0) {
      // Handle the click on the object in the secondary scene
      console.log("Clicked on:", secondaryIntersects[0].object);
    }
  }
}

This is a conceptual approach - you'll need to adapt it to your specific setup, especially regarding how your scenes and cameras are organized.

Another alternative would be to use a render target with a unique color for each object (off-screen rendering), then use the pixel color at the click position to identify which object was clicked.