PrBoom+ vs Chocolate Doom Fake Contrast

shoober said:

Any monitor can display black borders around an image.

Okay. Can your 4:3 monitor fill the entire screen with an image rendered in 16:10 resolution?

shoober said:

It doesn't have to have black borders, since Chocolate Doom can do this very same thing without black borders (render a 16:10 resolution with 4:3 aspect ratio correction) like I have mentioned before.

Rendering a 16:10 picture is one thing, rendering in a 16:10 resolution is another.

Anyway, this conversation is already too long while being rather pointless. I wish you the best of luck in finding the answers you're looking for.

shoober said:

Half of your confusion is not understanding the problem and not fully reading my posts (or understanding them).

Sure.

shoober said:

So, what I found is, PrBoom+ will do the aspect ratio correction, only if you choose the correct resolution to match it. For example, PrBoom+ will only correct the aspect ratio if you choose the right resolution to match the aspect ratio. Like 640x480 with 4:3, or 1280x800 with 16:10. If you choose a 4:3 resolution with a 16:10 aspect ratio, or vice versa, the aspect ratio will not be corrected.

That's because it'll assume the image stretching will be done by the monitor (pixels will not be square).

Suppose you run Doom in 640x400 (logical 16:10) on a 4:3 screen, and pixels are stretched by the monitor to be 20% taller than they are wide. If the port also stretches them to perform aspect ratio correction, they'll end up being hypercorrected -- that is to say, wrong but the other way around.


Now as for fake contrast -- you're pursuing a red herring. PrBoom+ does fake contrast in exactly the same way as vanilla Doom, Chocolate Doom, or any other Doom port. The difference isn't in fake contrast handling. Fake contrast is nothing more than increasing or decreasing a value, it'll be decreased or increased in the same way and to the same values in every Doom port out there -- even the fancy-schmancy OpenGL ones.

The difference is in rendering the result. The vanilla software renderer is extremely dependent on screen size and resolution, to the point that light levels can and will change if you reduce the screen size into a small window (remember the effect of the +/- keys?).

Which brings up the next point:

shoober said:

Regardless of if I'm in window or fullscreen mode, it doesn't have an effect on whether it stretches or not. The results are the same.

I'm not convinced. If your screen is CRT, it should stretch the image to fit itself, resulting in a physical aspect ratio correction done by the hardware. In windowed mode however, if the desktop resolution gives you square pixels, aspect ratio correction should be done in software by the port. Therefore: use 4:3 window sizes, multiples of 320x240.

Looking at your first pics, I see aspect ratio correction done by PrBoom+.

Threads where people argue for multiple pages over the difference between some shades of gray on some pixels are what keep developers like me up at night sweating.

Da Werecat said:

Okay. Can your 4:3 monitor fill the entire screen with an image rendered in 16:10 resolution?

With software aspect ratio correction, it is always possible.

Da Werecat said:

Rendering a 16:10 picture is one thing, rendering in a 16:10 resolution is another.

Technically, using a 16:10 resolution makes the 16:10 picture, so its the same thing. That's like saying a red apple is one thing, but a red apple is another. They are not different, they are the same.

Gez said:

The difference is in rendering the result. The vanilla software renderer is extremely dependent on screen size and resolution, to the point that light levels can and will change if you reduce the screen size into a small window (remember the effect of the +/- keys?).

I'm aware that aspect ratio and resolution have an important role in how the fake contrast is drawn. Its just there were some people that didn't believe this was true and thought it had to do with gamma. I bet if vanilla Doom supported higher resolutions with the ability to do a 16:10, it would do the same thing to fake contrast and make it more brighter at long distances.

But the thing is, vanilla Doom doesn't allow this, so when the fake contrast is drawn like that, its not supposed to look like that. Its not how it was ment to be. Since Doom was only 320x200, the fake contrast is supposed to look like how it does in Chocolate Doom. Any other way is wrong.

Gez said:

Looking at your first pics, I see aspect ratio correction done by PrBoom+.

PrBoom+ does aspect ratio correction only if you use a matching aspect ratio and resolution (16:10 - 1280x800 is what that picture was taken as). The problem is, it will not draw the fake contrast correctly, no matter if I use 4:3 with 640x480, or 1920x1200 with 16:10. So it does not do aspect ratio correction like Chocolate Doom does, were it will correct the aspect ratio no matter what resolution you use.

shoober said:

Technically, using a 16:10 resolution makes the 16:10 picture, so its the same thing. That's like saying a red apple is one thing, but a red apple is another. They are not different, they are the same.

Uh, yeah. Except Chocolate Doom can render 320x200 in 640x480. Go figure.

Quasar said:

Threads where people argue for multiple pages over the difference between some shades of gray on some pixels are what keep developers like me up at night sweating.

I know its very poopy to want such accuracy, but I want my Doom experience to be as close to vanilla Doom as possible (except for higher resolution).

Gez said:

I'm not convinced. If your screen is CRT, it should stretch the image to fit itself, resulting in a physical aspect ratio correction done by the hardware. In windowed mode however, if the desktop resolution gives you square pixels, aspect ratio correction should be done in software by the port. Therefore: use 4:3 window sizes, multiples of 320x240.

Well I'd be damned. You're the man Gez. You're right, about half of it at least. For the fake contrast to be drawn correctly, you must use a 320x200 multiple resolution. You also cannot use 16:10 aspect ratio, or it will always be wrong, no matter what resolution you use. So what I did was, I chose a 4:3 aspect ratio, with a resolution in the multiple of 320x200 (1920x1200). Then, upon entering fullscreen, THE ASPECT RATIO WAS CORRECTED!!! EUREKA!!! KJLBNDFUIH#$*H$F*(N$#E(UI*FHN948ernbfvg9p84hvg98p4hvfg8794bfb8n94f8h948h9f89h489hf89h4erfh89f48hbui9er4c8ih94e8hin9cvibunoeruibnocubin

shoober said:

Then, upon entering fullscreen, THE ASPECT RATIO WAS CORRECTED!!! EUREKA!!!

Well, who would have guessed?

Da Werecat said:

Well, who would have guessed?

IT RUBS THE LOTION ON ITS WEINER!!!

Why don't you just run at 1600x1200 or something?

chungy said:

Why don't you just run at 1600x1200 or something?

Do you fart when you pee?

Enough.