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Experimental UV Mapper for GP2

Posted: Thu Jun 04, 2026 10:46 pm
by rremedio
Download page
Source code

So, this has been a pain to carset creators since the 90s lol. You create a carshape that looks like the car you want to make, then you create the painting and export it to GP2 with GP2Edit, and in game many parts of your paiting look distorted because the template is for the original 1994 F1 car. The carshape has many 3D faces and GP2 uses a particular slice of the car painting to each face. So if a small square face became a wide rectangle in your carshape, its square slice of the car image will appear stretched in the game.

This tool aims to recalculate the correct slicing and update the table inside GP2.exe that keeps that data. You just need to load the exe and your carshape, select the layout you want and export it to the game. It can also export a template with a wireframe so you can paint the car with the new layout. There's a helper image too that tells the face number for each slice of the image (when in doubt, you can select the face number in the car editor texture data and see where that face is).

There are three layouts:
- GP2 Symmetric tries its best to do the same as the original template. It divides the image in three sections, one for top-down slices and one for each side of the car. It is never as good as the original cause the original was probably designed by hand and not by a software like this.
- GP2 Compact ditches the three sections and try to use more space so the faces are bigger and you can add more detail to them. I think it is the best, but it will be harder to work with them the symmetric because it is less organized
- Dense allows you to pick between 3 algorithms that don't care about organization in any way. This was my first try and they are very hard to work with. But I left them there in case someone finds any use for them

There's also an option to "recover collapsed faces". Some extreme carshapes (touring cars, 60s cars, etc) sometimes collapse/degenerate faces and my algorithms miss them. This will make another pass and find them. For each carshape you should look at the car editor and decide if you need them or not.

Side effects: loading images created with these templates into GP2Edit will make its 3D viewer look terrible. Exporting them to GP2 will make textured preview in the car editor also look terrible.

I'm not very talented at paiting cars and I take a long time to do so. That's why there is no example of this in use in the game yet (hopefully I can create one in the next few days), but I know some of our community members can create wonders from this.

Image

Example with Group C car:
Image

Re: Experimental UV Mapper for GP2

Posted: Fri Jun 05, 2026 2:27 pm
by samsepi0l
Huh - wow. There are a ton of polygons on the gp2 cars. I know in icr2 we have made new carshapes with more polygons and it really taxes the processor usage compared to using the default carset.

Very cool thank you for posting!

I really wonder if underneath the cover Gp2 works with the same style BSP tree coding that I use in ICR2. It's like there are similarities but we don't have a tool to write the source code we need to hack and hex edit.

our very first actual content post too! congratulations :D

Re: Experimental UV Mapper for GP2

Posted: Fri Jun 12, 2026 9:55 am
by eky78
This is very nice! Coincidentally, I was thinking about this thing of changing the Bitmap just a couple of days before your release.

This looks interesting although it will take some time to understand how to make a good paint. It´s gonna be hard for me as I´m not good at painting from stretch.

Do you think there may be a way to have in the future a sort of an Import function, like to load an existing Bitmap, so that you can see how a current template looks on the new one? And you could start editing from there. That could help a lot, but of course I don´t know if it´s even possible.

By the way, I want to give it a try once I´m finished with my IMSA carset, maybe starting with something easier. I was thinking the truck shape might be easier to start with.

In any case, thanks for this work and great to see you again in the GP2 community.

Re: Experimental UV Mapper for GP2

Posted: Fri Jun 12, 2026 11:43 am
by samsepi0l
eky78 wrote: Fri Jun 12, 2026 9:55 am This is very nice! Coincidentally, I was thinking about this thing of changing the Bitmap just a couple of days before your release.

This looks interesting although it will take some time to understand how to make a good paint. It´s gonna be hard for me as I´m not good at painting from stretch.

Do you think there may be a way to have in the future a sort of an Import function, like to load an existing Bitmap, so that you can see how a current template looks on the new one? And you could start editing from there. That could help a lot, but of course I don´t know if it´s even possible.

By the way, I want to give it a try once I´m finished with my IMSA carset, maybe starting with something easier. I was thinking the truck shape might be easier to start with.

In any case, thanks for this work and great to see you again in the GP2 community.
This is similar to how I paint carsets in ICR2. We have the carset MIPs (think of them like GP2's JAMs) in a file called a DAT. We extract them from the DAT and then convert the MIP to BMP. Then I can open the file with gimp and paint away at my hearts desire.

It helps to make a template to show where the lines are and it makes shadows and features of the cars shape.

Re: Experimental UV Mapper for GP2

Posted: Fri Jun 12, 2026 1:27 pm
by rremedio
eky78 wrote: Fri Jun 12, 2026 9:55 am This is very nice! Coincidentally, I was thinking about this thing of changing the Bitmap just a couple of days before your release.

This looks interesting although it will take some time to understand how to make a good paint. It´s gonna be hard for me as I´m not good at painting from stretch.

Do you think there may be a way to have in the future a sort of an Import function, like to load an existing Bitmap, so that you can see how a current template looks on the new one? And you could start editing from there. That could help a lot, but of course I don´t know if it´s even possible.

By the way, I want to give it a try once I´m finished with my IMSA carset, maybe starting with something easier. I was thinking the truck shape might be easier to start with.

In any case, thanks for this work and great to see you again in the GP2 community.
Yes, it would be possible. But the templates it creates are very different from the original one from GP2, even if you use the same original .dat shape. So I don't think it would be very helpful. One thing that I'd like to do is let the user organize the polygons as they wish. That way you could create GP2-like templates and maybe overlay them over bitmaps. Anyway, there's someone else (who knows much much more than me about this) working on a related thing, and it is looking very promissing, much better than my tool. So I'm gonna wait for now, I don't plan to add features very soon.