The other thing

While working on my sprite editor I've also been working on a more consistent framework for my projects. Whereas my previous isometric engine utilised OpenGL, it was kind of thrown together with little thought for what was where with the best intentions of sorting it out later. Instead of going through the laborious process of untangling a big mess of code I decided to start from scratch and, armed with the knowledge garnered from writing my isometric engine, I was able to decide on what was needed and what was completely unnecessary. With the new framework I've separated all aspects of the basic structure into clearly defined units.

I have a utilities unit which contains the main Game class. The game class is used for storing common objects that all games would contain;

log file (Class)
quit flag
title
framerate timer (Class)
pause flag

The Utils unit also houses some commonly used functions. All subsequent units have access to the Utils unit.

The Graphics unit houses the Screen class and the Sprite and SpriteManager classes. This is the only place where direct OpenGL calls should be made.

The Input unit is used for interfacing with the mouse and keyboard. I am using SDL for input but all SDL calls are contained here and there is no reason to directly call SDL outside of this unit.

Here's a screenshot of a very simple program written to test the framework. It is approx 200 lines of code in the main program since most of the work is done behind the scenes in the framework or encoded into the sprites using my sprite editor.


(Oh yeah, I borrowed the sprites from the Internets)
Download it here.
Use arrow keys to move one of the guys and be sure to click and hold for flames galore.

My sprite editor

Since my last post I've been creating a sprite editor which allows me to load a sprite sheet and section it off into frames. I can then also anchor points so that animations are drawn smoothly and trigger frames so that when I use the animation in the game I can look out for these triggers and generate an event based on the trigger value. For instance a zero would be a null trigger since the default for all frames is a zero. However a trigger value of one might be the shoot trigger. In which case I could generate bullets whenever this trigger frame is drawn. Instead of having the bullets generated at the beginning of the shoot animation I could have them generated at the exact frame where the gun recoils. Another example would be the jump animation. Let's say we've got a Prince Of Persia-esque character walking along then the player hits the jump button and this begins the jump animation. Now in this version there's a few frames of pre jump action where the character compresses his body then explodes into the jump. It would seem a bit odd to have the character jumping the instant this animation starts so instead I add a trigger frame at frame 4 and the animation is much more convincing. Now this could all be hard coded but the problem with hard coding things like this is that it's much more effort and should the need arise to change the animation then the code would need editing and recompiling, also the code tends to look like crap when there's special case stuff like that dotted all over the place.