Three.js: converting 3d position to 2d screen position

Question

I have a 3D object with the position(x,y,z). How can I calculate the screen position(x,y) of that object?

I have search for it and one solution is that I have to fin

Answer 1

I make it done by this code at last:

Note: div parameter = canvas dom element.

function toScreenXY( position, camera, div ) {
            var pos = position.clone();
            projScreenMat = new THREE.Matrix4();
            projScreenMat.multiply( camera.projectionMatrix, camera.matrixWorldInverse );
            projScreenMat.multiplyVector3( pos );

            var offset = findOffset(div);

            return { x: ( pos.x + 1 ) * div.width / 2 + offset.left,
                 y: ( - pos.y + 1) * div.height / 2 + offset.top };

        }
function findOffset(element) { 
          var pos = new Object();
          pos.left = pos.top = 0;        
          if (element.offsetParent)  
          { 
            do  
            { 
              pos.left += element.offsetLeft; 
              pos.top += element.offsetTop; 
            } while (element = element.offsetParent); 
          } 
          return pos;
        }