486quake: Broken Blob Model Renderer? Let's Discuss!

Hey everyone,

I've been diving into some classic Quake rendering and stumbled upon a potentially interesting issue with the 486quake.exe version. It seems like the fast model renderer, often called the "blob" renderer, might be a bit wonky compared to its 586quake.exe counterpart. Let's break down what I've found and see if anyone else has experienced this.

Understanding the "Blob" Renderer in Quake

To really get into the nitty-gritty, let's first talk about the "blob" renderer. Back in the day, when hardware was less powerful, game developers had to get creative with optimization. In Quake, one such optimization was how the game rendered models at a distance. Instead of fully rendering every triangle of a model that was far away, Quake would use a simplified, approximate rendering technique. This involved essentially rendering a colored pixel for each triangle, giving the model a "blobby" or pixelated appearance. This fast rendering method helped to reduce the load on the hardware, especially on older machines like those with 486 processors, thus maintaining a smoother frame rate.

The main goal of this optimized rendering technique was to save precious processing power. Imagine trying to render a complex monster model with hundreds of triangles, even when it's a tiny speck on the horizon. That's a lot of calculations for something the player barely notices. By using the "blob" renderer, Quake could quickly draw a rough approximation, freeing up resources for other tasks, such as AI, physics, and more detailed rendering of closer objects. It's a clever trade-off between visual fidelity and performance, one that was crucial for the game to run smoothly on the hardware of the time.

This approach was particularly important for older systems, where every cycle counted. The 486 processor, while a workhorse in its day, was significantly less powerful than the Pentium (586) and other subsequent processors. As a result, the 486quake.exe version likely relied more heavily on the "blob" renderer to maintain a playable frame rate. This makes it all the more important that the "blob" renderer functions correctly, as any issues with it could have a noticeable impact on the game's visuals.

The Issue: Missing or Misplaced Pixels in 486quake.exe

So, here's the crux of the matter. When running 486quake.exe, I've noticed that the "blob" renderer seems to have some issues. Specifically, it looks like pixels are either missing or misplaced when rendering distant models. This results in the models appearing somewhat transparent or like a "see-through" pixel cloud, rather than solid objects. It's a rather strange visual effect, and definitely not how it's supposed to look. You can see a visual representation of the issue here:

https://github.com/user-attachments/assets/03b30f1d-0132-46af-89fb-3a251b3387f5

In this screenshot, you can clearly see how the model appears fragmented and partially transparent, like it's dissolving into thin air. This is not the intended behavior of the "blob" renderer, which should at least produce a solid, albeit pixelated, representation of the model. The effect is quite distracting and detracts from the overall visual experience of the game. It makes it difficult to gauge the distance and position of enemies, and it simply looks… wrong.

This visual glitch stands in stark contrast to how the models should appear. The "blob" renderer is meant to be a fast approximation, not a broken one. The fact that pixels are missing or misplaced suggests a potential bug in the rendering code specific to the 486quake.exe version. It's possible that there's an issue with how the pixels are being calculated or drawn, leading to these visual anomalies. Further investigation is needed to pinpoint the exact cause of the problem.

The Comparison: 586quake.exe Works as Expected

Now, the interesting part is that when I switch over to 586quake.exe, the "blob" renderer seems to be working just fine. Distant models are rendered with the expected pixelated appearance, but they remain solid and recognizable. This is consistent with how the "blob" renderer functions in WinQuake and other versions of the game. You can see the difference in this screenshot:

https://github.com/user-attachments/assets/633c3708-43b3-4e15-9f39-28dccd68a8be

As you can see, the model is rendered as a solid, albeit pixelated, shape. This is the expected behavior of the "blob" renderer, and it demonstrates that the underlying concept of the renderer is sound. The issue appears to be specific to the 486quake.exe version, suggesting that there might be a bug in the code that's unique to that executable.

This discrepancy between the two versions of the game is quite telling. It suggests that the problem isn't a fundamental flaw in the "blob" renderer itself, but rather a specific issue within the 486quake.exe implementation. This could be due to a variety of factors, such as compiler optimizations, differences in the code base, or even a simple coding error. Whatever the cause, it's clear that there's something amiss in the 486quake.exe version that's affecting the way distant models are rendered.

A Clear Test Case: The Grunts at the Entrance

If you want to see this issue in action for yourself, there's a really easy place to test it out. At the very beginning of the game, in the first level, there are two grunts patrolling the entrance of the base. These grunts provide a perfect opportunity to observe the behavior of the "blob" renderer. As they walk away from you, the game will naturally switch to the approximate rendering method to save on processing power.

In 486quake.exe, as the grunts move further away, you'll notice them start to "disintegrate" quite a bit. They become partially see-through, with pixels disappearing and reappearing in a rather erratic fashion. It's like they're fading in and out of existence, which is obviously not the intended effect. This is a clear manifestation of the issue with the "blob" renderer in this version of the game.

This real-world example makes the problem much more apparent. It's one thing to look at screenshots, but it's another to see the issue unfold in real-time gameplay. The way the grunts seem to fall apart as they move away is quite jarring, and it highlights the impact of this bug on the visual experience of the game. It's a readily reproducible test case that anyone can use to confirm the issue for themselves.

Testing Environment: Dosbox-X (So Far)

For my testing, I've been using Dosbox-X, which is a fantastic emulator for running classic DOS games. It provides a controlled environment that allows for consistent and repeatable results. However, it's important to note that emulation can sometimes introduce its own set of issues, so it's always best to verify findings on actual hardware if possible. That being said, the issue I'm seeing in Dosbox-X is quite pronounced and seems to be a genuine problem with the 486quake.exe version itself.

The use of Dosbox-X is a convenient way to test these old games, but it's not a perfect substitute for running them on original hardware. Emulation involves translating the instructions of one system to another, and this process can sometimes introduce subtle differences in behavior. While Dosbox-X is generally very accurate, it's always possible that it's interacting with the 486quake.exe in a way that exacerbates the issue, or even causes it to appear when it wouldn't on real hardware.

Next Steps: Testing on Original Hardware

Ideally, the next step would be to test this on an actual 486-based PC to see if the issue persists. This would provide a more definitive answer as to whether the problem is specific to 486quake.exe or if it's somehow related to the emulation environment. Unfortunately, I haven't had the chance to test on original hardware just yet, but I'm hoping to do so soon. It would be great to get confirmation from someone who has access to a 486 machine and can try running the game directly.

Testing on original hardware is crucial for validating any findings made in emulation. It's the only way to be absolutely sure that the issue is a genuine problem with the game itself, rather than an artifact of the emulation process. Running the game on a real 486 PC would eliminate any potential compatibility issues or inaccuracies introduced by Dosbox-X, providing a much clearer picture of what's going on. If the issue persists on original hardware, it would strongly suggest that there's a bug in the 486quake.exe version that needs to be addressed.

Has Anyone Else Experienced This? Let's Discuss!

So, that's what I've found so far. I'm really curious to know if anyone else has encountered this issue with the "blob" renderer in 486quake.exe. Have you noticed similar visual glitches when playing the game? Have you tested it on original hardware, and if so, what were your results? Let's discuss this and see if we can get to the bottom of it! Maybe we can even figure out what's causing this and potentially find a fix.

I'm really eager to hear your thoughts and experiences on this. It's always great to collaborate with other retro gaming enthusiasts and share knowledge. If you've got any insights, suggestions, or even just a hunch about what might be going on, please don't hesitate to chime in. Together, we can unravel this mystery and hopefully improve the experience of playing 486quake.exe.

Let's get this discussion going, guys!