I was able to squeeze in a little work on the new game between trips to various shopping centers for Christmas presents. One thing I wanted to research is how collision detection is done in these overhead perspective retro games. I fired up the Atari 800 KRAZY Shootout first to look at this closer. In this game, if any part of the player touches a wall, the player if killed. It is very basic, but because the perspective in these games is not a true ‘ or a true overhead, it actually comes out playing odd. See the diagram below.

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The red circle shows the head of the player. If this was a true ‘ perspective, the player would not be injured or hurt until his feet touch the blue wall. In this game, even the player’s head touching the wall results in a lost life. I will investigate trying to remedy this in my game.

The Berzerk games play basically the same. Marauder remedies this situation somewhat by using a true top-down perspective. It looks odd, and player even more odd (for other reasons), but is actually more realistic in a simple way.  Since I plan to pattern my player movement after Berzerk (KRazy Shootout’s running player looks silly), I will need to either accept or remedy the all collisions.

My next step was to create some simple frames of animation for the player. The Berkerk Atari 800 player has two basic frames. One is a standing frame, and the other is a running frame. It doesn’t make for very fluid animation, but for this test, those two will be fine. A modification I want to make in my game is to have the gun arm controlled by the mouse. It won’t be 100% realistic, but moving the mouse left and right will rotate the gun to 8 different firing positions. This will allow the player to run in one direction and fire in the other.