3D Game Engine Design: A Practical Approach to Real-Time Computer Graphics by David H. Eberly was an quite a read, at slightly over 1,000 pages. However, after a few chapters in I was already getting fatigued and I really had to push my way to the end. That’s not to say that the book was bad, it was not, however it was nothing like what I expected. Let me explain. Imagine you walk into a restaurant and sit down with a friend. After several minutes of thought, you decide to order a steak. The waiter comes, takes your order, and about 15 minutes later returnsRead More →

  Spent the last couple days adding in skybox support into the engine. Currently it’s a little hard-coded, but it does seem to be working well. I also bumped the field of view (FOV) up to 90 (from 45) so you can see more of the sky. I wanted to make sure I was only using my own artwork for this engine demo. Unfortunately, it would have been rather difficult to take panoramic photos myself. So I generated the sky texture using Terragen. Somewhat of a cheat, but I did technically “create” it myself, so I can live with that. Ran into one issue that hadRead More →

  While getting models loaded was pretty exciting, I ended up dealing with major load times on the demo. Granted, my XML parsing code is probably slow as all hell, but I don’t think COLLADA is really designed for real-time engine use. With simple plane and cube shapes the loading wasn’t that bad, but with my soda can model (around 600 triangles) the loading was nearing 10 seconds (totally unacceptable). I can only imagine what would happen with a really complex model. Something had to be done. So I decided to switch to a binary format with basically only exactly what I needed to pumpRead More →

What you see above is a custom model I made in 3ds Max, exported as a COLLADA *.dae file, and imported into my DirectX engine. I figured I’d start with something simple, like a soda can, and I plan to make a lot more models going forward. Although I hadn’t touched Max in years, I found it to be a comfortable experience and was able to put the model together in a few hours. Now, actually getting that model into DirectX was a different story. First off, the COLLADA documentation is vast, but they fail to explain basic things about the format. The examples theyRead More →

Programmer art is great and all, but I’d really like to see some complex models inside the engine. Unfortunately, DirectX 11 does not include a built-in way to load in 3D models. As I’ve mentioned before, I am interested in using COLLADA has the import format. Since COLLADA is based on XML, I will need a way to load and parse XML files. While there are tons of XML parsing libraries out there, I decided to write my own. Why would I do that? A few reasons. First, I don’t want my engine to be encumbered with 3rd party licenses, forcing me to do thingsRead More →

After some more testing, it looks like OGRE is not the savior it seemed like yesterday. While the static geometry boosted frame-rates greatly, it’s only useful for, well, static objects. Meaning the models can’t move or animate. I did find another option, instancing, which initially looked promising. It allows rendering of large amounts of identical objects faster than just having them be individual. Sounds good. The implementation seemed complex at first, but then I found the InstanceManager which simplified things a whole lot. However, after getting it working, I wasn’t as impressed with the performance. Just rendering the same 13k still cubes I was getting a littleRead More →

Looks like I spoke too soon. While OGRE was getting pretty slow with the naive implementation, I was able to find some code on what they call StaticGeometry, which is a system to batch together lots of similar meshes that don’t move (great for my cube example project). With this feature added, the frame rate has sky-rocketed to over 2,600 fps. Most impressive. Keep in mind a blank DirectX window on my machine will get around 3,600 fps. So getting around 2,600 with over 13,000 cubes is very nice. That still doesn’t help me with my physics simulation, since static objects won’t cut it. But itRead More →

Seeing as performance has been on my mind recently, I tweaked the core render loop a bit and saw some reasonable gains. The one thing I realized is that most of the objects in the scene are static, and don’t need their combined transformed matrices recalculated every frame. I expected to see wild improvements after caching the values. What I received was a decent 50% gain. Not monster, but certainly substantial. Now the average framerates are in the upper 200’s to lower 300’s. More acceptable but still maybe not where I want it to be. Just as a sanity check I decided to recreate the sameRead More →

I don’t have much time, so I will be brief. Basically for the past few days I have been trying to optimize the engine. With the stress test you see above (around 13K cubes) I was only getting around 200 fps. Just slightly above my target of 120 fps, and with such a simple scene I was expecting more. So I got to hacking, fully realizing that early optimization is evil… yeah, yeah. In any case, I needed to know if the engine architecture was flawed in some way, and if I was going down the wrong path. Through some crude debugging I found that myRead More →

  Today I have gotten the camera system to a decent place, and made a simple free look demo. Most of the code had already been implemented, inside the vector and matrix classes, I just had to piece it together into a camera object. I also added a grid of cubes, to better see the camera working. Sadly these extra 200 cubes slowed down the performance by a good chunk. Previously I was getting around 3,500 FPS (with 3 cubes), now I’m only getting around 2,000 FPS (with around 220 cubes). Granted the performance is bound to drop as more objects are added, but IRead More →