Killer Game Programming in Java

Local Sprites

TourSprite offers a simplified interface for moving and rotating a local sprite. It communicates movements, rotations, and its initial creation to the server. The complete class appears in Example 32-1.

Example 32-1. The TourSprite class

    public class TourSprite extends Sprite3D
    {
      private final static double MOVERATE = 0.3;
      private final static double ROTATE_AMT = Math.PI / 16.0;

      PrintWriter out;    // for sending commands to the server

      public TourSprite(String userName, String fnm, Obstacles obs,
                     double xPosn, double zPosn, PrintWriter o)
      { super(userName, fnm, obs);
        setPosition(xPosn, zPosn);
        out = o;
        out.println("create " + userName + " " + xPosn + " " + zPosn);
      }

      // moves
      public boolean moveForward()
      { out.println("forward");
        return moveBy(0.0, MOVERATE);
      }

      public boolean moveBackward()
      { out.println("back");
        return moveBy(0.0, -MOVERATE);
      }

      public boolean moveLeft()
      { out.println("left");
        return moveBy(-MOVERATE,0.0);
      }

      public boolean moveRight()
      { out.println("right");

        return moveBy(MOVERATE,0.0);
      }

      // rotations in Y-axis only
      public void rotClock()
      { out.println("rotClock");
        doRotateY(-ROTATE_AMT); // clockwise
      }

      public void rotCounterClock()
      { out.println("rotCClock");
        doRotateY(ROTATE_AMT);  // counter-clockwise
      }

    }  // end of TourSprite

Creating a Local Sprite

WrapNetTour3D creates a local sprite by invoking a TourSprite object and adding it to the scene graph. As part of TourSprite's construction, a create n x z message is sent to the server; n is its client's ...