Using GridHelper in Three.js for Alignment

To align a 3D grid with your background image in Three.js, you can use the GridHelper class to create a visual reference grid that matches the perspective of your pre-rendered plaza image.

GridHelper Implementation

The GridHelper creates a two-dimensional grid that can help you visualize and align your 3D space with the 2D background. Here's how you might implement it:

JAVASCRIPTCopied
// Create a grid helper
// Parameters: size, divisions, colorCenterLine, colorGrid
const size = 10; // Adjust based on your scene scale
const divisions = 10;
const gridHelper = new THREE.GridHelper(size, divisions);

// Rotate the grid to match your isometric view
gridHelper.rotation.x = Math.PI / 6; // Adjust these angles to match your background perspective
gridHelper.rotation.y = Math.PI / 4; // Common for isometric view

// Position the grid to align with your background image
gridHelper.position.set(0, 0, 0); // Adjust as needed

// Add the grid to your scene
scene.add(gridHelper);

Alignment Tips

1. Adjust the Camera: Position your camera to match the perspective of the background image.

2. Use AxesHelper: Add an AxesHelper alongside your grid to better understand the orientation:

JAVASCRIPTCopied
const axesHelper = new THREE.AxesHelper(5);
scene.add(axesHelper);

3. Iterative Adjustment: You'll likely need to iteratively adjust the grid's position, rotation, and scale until it visually aligns with your background image.

4. Create Invisible Boundaries: Once aligned, you can create invisible collision boundaries that match the buildings in your background image to prevent your character from walking into them.

By using these helper tools, you should be able to create a 3D grid that aligns properly with your pre-rendered background, allowing for accurate character movement while maintaining the visual benefits of your background image.