Zoom on mouse

OpenGL Development
#1

Ok, here’s what I am trying to accomplish. Have you seen those applications that zoom around the mouse? AutoCAD is a really good example. The page doesn’t center on the mouse but the pointer is the focal point for the zooming action. I have a program that displays map data on and AWTGLCanvas and I need to implement that same kind of thing. Here is my idea (feel free to shoot this idea down (In fact please do there has got to be a better way)):

  1. Get the mouse location from the MouseEvent
  2. Translate that to world coords
  3. Zoom
  4. Get the new screen coords of where the mouse had been pointing
  5. Adjust to reconcile the difference vetween the two sets of screen coords

Now in pseudo-code:


Do you think that'll work?
oldX = mouseEvent.getX();
oldY = mouseEvent.getY();
gluUnProject((float)oldX, (float)oldY, zoomLevel, modelArray, projectionArray, viewportArray, result);
worldX = result[0];
worldY = result[1];
zoom();
gluProject(worldX, worldY, zoomLevel,  modelArray, projectionArray, viewportArray, result);
newX = result[0];
newY = result[1];
pan(newX - oldX, newY - oldY);