public void HandleCameraMovement()
 {
     if (WindowLayer.GetKey(ctx, 'I'))
     {
         camera2D.position += vec2.UnitY * CAMERA_SPEED * deltaTime;
     }
     if (WindowLayer.GetKey(ctx, 'K'))
     {
         camera2D.position += -vec2.UnitY * CAMERA_SPEED * deltaTime;
     }
     if (WindowLayer.GetKey(ctx, 'J'))
     {
         camera2D.position += -vec2.UnitX * CAMERA_SPEED * deltaTime;
     }
     if (WindowLayer.GetKey(ctx, 'L'))
     {
         camera2D.position += vec2.UnitX * CAMERA_SPEED * deltaTime;
     }
 }
        // --

        public void HandleQuadMovement()
        {
            if (WindowLayer.GetKeyDown(ctx, 'W') && Math.Abs(quad.body.GetVelocity().y) <= 0.01f)
            {
                quad.body.ApplyImpulse(IMPULSE_POWER);
            }
            if (WindowLayer.GetKey(ctx, 'A'))
            {
                quad.Move(-vec2.UnitX * deltaTime);
            }
            if (WindowLayer.GetKey(ctx, 'D'))
            {
                quad.Move(vec2.UnitX * deltaTime);
            }
            if (WindowLayer.GetKey(ctx, 'Q'))
            {
                quad.Rotate(deltaTime * (float)Math.PI);
            }
            if (WindowLayer.GetKey(ctx, 'E'))
            {
                quad.Rotate(-deltaTime * (float)Math.PI);
            }
        }