3D draggable camera does not work when the camera is rotated

Question

I am working on some sort of city builder where you can drag the camera with your mouse. It all works fine accept when you turn the camera.

Mouse drag script:

private float angleArroundTarget = 0; // rotation arround the target \\

// draggable camera \\
    if(Mouse.isButtonDown(0)){
        targetPosition.x += delta * (Mouse.getDX() * 2);
        targetPosition.z -= delta * (Mouse.getDY() * 2);
    }

If you know a calculation where it does not depend on the angleArroundTarget when you drag the camera arround please let me know.

Thanks in advance

HolyBlackCat HolyBlackCat · Accepted Answer · 2019-01-27T12:20:51

I assume you need something like:

if(Mouse.isButtonDown(0)){
    float dx =  delta * (Mouse.getDX() * 2);
    float dy = -delta * (Mouse.getDY() * 2);
    float c = Math.cos(angleArroundTarget);
    float s = Math.sin(angleArroundTarget);
    targetPosition.x += c * dx - s * dy;
    targetPosition.z += s * dx + c * dy;
}

This code rotates ( delta * (Mouse.getDX() * 2) , -delta * (Mouse.getDY() * 2)) vector by angleArroundTarget angle.

Depending on how your camera is set up, the exact code above might not work. If it happends, try negating angleArroundTarget and/or dy.

3D draggable camera does not work when the camera is rotated

1 Answers