unprojectOnTbPlane method

Vector3 unprojectOnTbPlane(Camera camera, double cursorX, double cursorY, [ bool initialDistance = false, ])

• Unproject the cursor on the plane passing through the center of the trackball orthogonal to the camera
• camera The virtual camera
• cursorX Cursor horizontal coordinate on screen
• cursorY Cursor vertical coordinate on screen
• initialDistance If initial distance between camera and gizmos should be used for calculations instead of current (Perspective only)
• returns Vector3 The unprojected point on the trackball plane

Implementation

Vector3 unprojectOnTbPlane(Camera camera, double cursorX, double cursorY,[bool initialDistance = false]) {
    if (camera is OrthographicCamera) {
      _v2_1.setFrom(getCursorPosition(cursorX, cursorY));
      _v3_1.setValues(_v2_1.x, _v2_1.y, 0);

      return _v3_1.clone();
    }
    else if (camera is PerspectiveCamera) {
      _v2_1.setFrom(getCursorNDC(cursorX, cursorY));

      //unproject cursor on the near plane
      _v3_1.setValues(_v2_1.x, _v2_1.y, -1);
      _v3_1.applyMatrix4(camera.projectionMatrixInverse);

      final rayDir = _v3_1.clone().normalize(); //unprojected ray direction

      //	  camera
      //		|\
      //		| \
      //		|  \
      //	h	|	\
      //		| 	 \
      //		| 	  \
      //	_ _ | _ _ _\ _ _  near plane
      //			l

      final h = _v3_1.z;
      final l = math.sqrt(math.pow(_v3_1.x, 2) + math.pow(_v3_1.y, 2));
      dynamic cameraGizmoDistance;

      if (initialDistance) {
        cameraGizmoDistance = _v3_1
            .setFromMatrixPosition(_cameraMatrixState0)
            .distanceTo(
                _v3_2.setFromMatrixPosition(_gizmoMatrixState0));
      }
      else {
        cameraGizmoDistance = camera.position.distanceTo(_gizmos.position);
      }

      /*
		 * calculate intersection point between unprojected ray and the plane
		 *|y = mx + q
		 *|y = 0
		 *
		 * x = -q/m
		*/
      if (l == 0) {
        //ray aligned with camera
        rayDir.setValues(0, 0, 0);
        return rayDir;
      }

      final m = h / l;
      final q = cameraGizmoDistance;
      final x = -q / m;

      final rayLength = math.sqrt(math.pow(q, 2) + math.pow(x, 2));
      rayDir.scale(rayLength);
      rayDir.z = 0;
      return rayDir;
    }
    return Vector3();
  }