Asteriods in C# Using GDI+
By Danna Boneheart

Summary

For my first experiment in game design, rather than using some kind of directX wrapper I wanted to see what was possible with GDI+. GDI+ has a lot of nice features but is slow, so not very practical for fast paced games, in this example you can see why. The game also includes sound...hey, it wouldn't be much of a game otherwise!

Overview

3 Classes, 1 for each on screen object to be represented:
SpaceShip
Asteroid
Bullet

These classes do have many common methods and properties so they could inherit from the same base class.

The windows form object pulls all these classes together into the same playing field, handles collision detection and player interaction. Everything is treated on a tick by tick basis via the use of a timer object.

Installation

All source/compiled files and resources should be in the same directory.

Collision Detection
Simple use of a rectangle object that represents the space occupied by the on screen object, using the "IntersectsWith" Method we can find if other rectangles overlap.

Physics

The in game physics are rudimentary at this stage, Basic Trigonometry is used to determine the new point location of each object based on speed and direction.

Sound

winmm.dll is imported using InteropServices and its PlaySound Method is used for in game sound.

Performance

The performance is bad very bad, if you try to play full screen you will experience significant lag unless you've got a high end PC, and if you play with 4 starting asteroids... well don't say I didn't warn you!
The killer lines are in the form constructor:

			SetStyle(ControlStyles.UserPaint, true);
			SetStyle(ControlStyles.AllPaintingInWmPaint, true);
			SetStyle(ControlStyles.DoubleBuffer, true);