Lighting in Bullet Devil

Welcome back to another episode of lighting in games! Today's special we will be serving up lighting from the game Bullet Devil, produced by Studio 8 for the game development workshop (GDW). We will be taking a look at the difference lighting makes in the game using shaders. Then we will go into some detail on the code (just the shaders) on how we go about doing this. Let's get to it.


So lets start by showing the game as it was before we introduced it to the magical world of shaderland. The image below shows a very plain and almost 2D looking game without any source of shader power. The main character model is textured red as a temporary texture because the models are changing anyways for the game.

Now it's hard to see in these pictures because they are so small, so I recommend you go and play the game, but there is shading on a per fragment basis applied to the models in the game. Now if you don't know what per fragment lighting is then i suggest you go back to my previous blog and do some reading! 

Time for the fun details on how this was accomplished. Again, the theory is all explained in my previous blog so I'm just going to jump into how we did it. Most of the reference for how we did this comes from what we learned in the tutorial with some modifications. Those modifications were to change the per vertex lighting model shown in class and make it per fragment lighting. We also have shadow mapping developed into the shader but won't be used until the FBO's are properly working. If you don't know what an FBO is read on to my next blog where i discuss frame buffer objects. 

Alright, now when we were taught this the version used is 120. We plan to continue to use 120 to the end of the semester. Next year our team will step up to a better version like 330 or 420 but for now, 120 is doing the job for us. Here is some sample code of our vertex shader:

Next is the sample code for our fragment shader:

So as you can see, it stays very close to what I explained in the last blog. Only thing that's there that I haven't explained in detail is the shadow mapping. I did touch on it in my post processing blog but when it is actually in game I will have a blog for that. At the end of the day it has it's own math for the algorithm and it can simply be added to the end result of the per fragment lighting in game to give the proper results.