Create Bouncing Balls Using C#

I've been a programmer for a long time (started in '81 on a Timex-Sinclair 1000) mostly for fun, sometimes for profit (wishing more was for profit!). I used to teach electronics, computer science and programming at a private technical college in California from 1989 to 2001. The languages I taught were Basic, Visual Basic, Borland Turbo C/C++ (beginning class so not much ++) and x86 assembly. Writing games has always been a source of fun and enjoyment. To try and inspire students I would reverse-engineer whatever current game was a favorite. Some got the bug and became serious about programming, some didn't.

I program in other languages and have just started learning Visual C# and enjoy it's power and flexibility. I read a blog here, but forgot who it was by (sorry) about how when learning a new language that person will write a program to bounce a ball off the walls to learn some of the basic concepts. That sounded like a good idea. I glanced at his code but not seeing many comments I didn't want to dive into it and decipher it (sorry). Since I had just gotten to the chapter in the book I'm learning from about graphics, I have started trying to write games. The book of course doesn't have much about that. One of the first game-oriented things I ran across here was Mike Gold's Space Invaders program. I realized I need to create more objects, but was struck by something I saw in a rectangle property:

 I then decided to write a bounce off the walls code and put in some of the things that anyone beginning to write games would like to learn, and commenting everywhere. I decided to write the program I wish I had found when I began to write games a long time ago. :)

The result is this small program called Bouncer. It creates a "ball cage" around the edge of the screen using flat rectangles, and places obstacle boxes (more rectangles) on the screen in random locations. The ball starts as white, moving in a random direction and when it hits a wall or a box the color changes to match what it hits. The ball bounces off in a different direction going after more boxes. If no boxes are hit after 7 seconds the ball changes back to white and changes direction. This is important when there are less boxes to hit. This makes sure that all the boxes will eventually be hit.

 Bouncer screen shot

Bouncer screen shot, using PrtScr

The boxes hit are counted, the time between hits is counted and the total time to hit all boxes is calculated and reported at the end. If the ball hits a corner directly it will leave the screen. A label pops up for a second saying "Perfect Corner Hit" and the ball gets re-started on the screen. This could be eliminated by simply checking for two intersections (special case) of a side wall and bottom wall, or side wall and top wall.

Report at end of hitting all boxes

Report at end of hitting all boxes

The basic stuff in here can be used for making games. The IntersectsWith is wonderful for collisions. This code could be easily adapted to make a Pachinko-type game, or pinball with not too much effort.

Sample code

The following is sample code to detect collisions:

private void CheckForWallHit()


   bool hitWall = false;   

   // if we hit a wall, move the ball in new direction

   // and change ball color to wall color

   if (rectBallBounds.IntersectsWith(rectCageTop))


       if (iMoveDir == (int)bounceDir.NE)

           iMoveDir = (int)bounceDir.SE;

       else if (iMoveDir == (int)bounceDir.NW)

           iMoveDir = (int)bounceDir.SW;

       brshBallBrush = new SolidBrush(aryWallColor[0]);

       hitWall = true;


   else if (rectBallBounds.IntersectsWith(rectCageRight))


I hope some of you beginning game writers out there will find this program useful or at least fun. I am always writing several things at once and have some games in progress and will post them when they are done.
I am currently torturing myself writing a 3D maze game using XAML and C#. I had one example of 3D in my book where they rotate a 3D pyramid. I have taken that and ran with it, creating a large 3D environment for a maze, with the camera moving as you walk through (of course) and making sure you don't walk through the walls. My current problem is trying to animate the camera turning instead of just snapping to the new direction (left or right). I can do it in pure C# and can do it once in XAML. Still looking for how to do it using both so I can turn left or right 90 degrees from whatever direction I am facing. Of course I know it says not to develop 3D games with XAML/C# but I'm a glutton for punishment and love challenges. I also do not currently have the internet at home to download the DirectX SDK that would make things much easier. I get an hour a day at the local library and their slow connection won't let me download anything even semi-large.

Screen shot of 3D Maze game

Screen shot of 3D Maze game I'm working on

If anyone has some knowledge of how to animate the camera look direction in XAML and C#, please help! lol.
Please add comments about this program. Since I am still learning C# I don't profess that this code is the best way of doing stuff. I've been mostly using the MSDN help file and trial and error to learn to write games.
Thanks to everyone on this great site for all the info about various topics.