I want to position a cube relative to the camera instead of relative to the scene. However, in order to display it in the scene, I need to determine the scene coordinates that align with the cube's camera space coordinates. I came across the function "projectionMatrixInverse" in THREE.Camera, which contains a useful method called "multiplyVector3" that I thought would allow me to convert a vector (1,1,1) back to scene space like so:
var camera, myvec, multvec; // (and others)
camera = new THREE.OrthographicCamera( window.innerWidth / - 2, window.innerWidth / 2, window.innerHeight / 2, window.innerHeight / - 2, - 2000, 1000 );
camera.position.x = 200;
camera.position.y = 100;
camera.position.z = 200;
myvec = new THREE.Vector3(1,1,1);
console.log("myvec: ", myvec);
multvec = camera.projectionMatrixInverse.multiplyVector3(THREE.Vector3(1,1,1));
console.log("multvec: ", multvec);
However, when I check the console, I encounter the following:
myvec: Object { x=1, y=1, z=1}
TypeError: v is undefined
var vx = v.x, vy = v.y, vz = v.z;
It seems that multiplyVector3 does not recognize my myvec or indicates that it is undefined, even though the console confirms that it is an object. This is quite puzzling to me.