SDL 3

[Matei]

SimcarStunts version using SDL 3 is in the attached file, details in README.txt. Anyone intersted in testing?

[Duplode]

Nice, I'll try it out soon.

[Duplode]

Nice, I'll try it out soon.

I tried running it, but couldn't make it work while using sdl3 from the Arch Linux repo, and didn't manage investigate further so far. Running the binary from the attachment initially gives the following error:

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$ ./simcar
SDL_FRAMEBUFFER_ACCELERATION 0
>> Set BITSPERPIXEL to 24 and recompile.<<

After changing BITSPERPIXEL in graphics/grconfig.h and recompiling, the executable segfaults:

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$ ./simcar
SDL_FRAMEBUFFER_ACCELERATION 0
Set 1064x600x24
Segmentation fault         (core dumped) ./simcar


[Matei]

Code Select Expand

$ ./simcar
SDL_FRAMEBUFFER_ACCELERATION 0
Set 1064x600x24
Segmentation fault         (core dumped) ./simcar


Of course it says "Segmentation fault", the functions support only 32 and 16 bits. If the game works with SDL 2, then you probably have 16 bits, so try 16 with SDL 3, but take this version:

https://matei.one/idxscr.html#download

Version 6.2.0 supports SDL 1.2, 2.0 and 3.0, according to your preference.

If your screen is really set to 24 bits then you can only use SDL 1, but I never saw a screen working with this setting on any computer ever since I use GNU/Linux, from 2003.

[Matei]

"1064x600x24" actually looks like the screen is set to 32 bits (1064*24/32=798), so it shouldn't "Segmentation fault", unless there's a problem with "sdl3 from the Arch Linux repo". Maybe you have an older version, so you can try installing a newer SDL 3 from source code, see "SDL.txt". More details in file graphics/forsdl3/graph2d.c, lines 147...153.

[Matei]

I think I found the problem. When you started the program, it said "1064x600x24", but 1064 means a width of 798 pixels, although it was set to 800. On my computer it says "1066x600x24". The SDL function to create the window is called in file graphics/forsdl3/graph2d.c at line 139:

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SDL_CreateWindow(title,width,height,0);
The graphical functions then use variables RGLOB_width and RGLOB_height set equal to width and height, but the created window is smaller, so memory for those pixels isn't available, so "Segmentation fault". I don't know how to find the parameters of the window:

https://wiki.libsdl.org/SDL3/SDL_GetWindowSurface

Doesn't say. I can set RGLOB_width and RGLOB_height to smaller values than width and height after creating the window, but this is not reliable. Does the problem occur in the same conditions if the image is set to full screen ("fullscr=1" in file "config") or with SDL 2?

[Duplode]

Good catch; I wonder if my environment is somehow interfering with the window size (will try to find out later). Trying with the 6.2.0 from your site, both the SDL3 build and full screen always segfaults. The provided binary (which is the SDL2 one, I believe) segfaults some of the time (if I retry enough times it works somehow), and the size reported on the console for it is 798x600x32.

[Matei]

You can also try with various resolutions (file "config") and see what happens. Is the resolution set in "config" ever reported properly?

[Duplode]

Good catch; I wonder if my environment is somehow interfering with the window size (will try to find out later).

Yes, it is my environment. I normally use XMonad (a tiling window manager) on this computer; switching to a Xfce session I get no segfaults, and the expected 800x600 size is reported. Maybe the two pixels taken by the window borders are somehow being deduced from the available window size (but if so, why just from the width and not the height?). It's mostly academical now, but if I find a workaround for XMonad (and I guess there must be one) I'll post it here.

[Matei]

but if so, why just from the width and not the height?

This is why:

printf("Set %dx%dx%d\n",8*RGLOB_screen->pitch/BITSPERPIXEL,height,BITSPERPIXEL);

File graphics/forsdl3/graph2d.c, line 153. The height reported is just the value sent to the function, not the resulting height of the window, which was obviously also reduced, but as mentioned above, I don't know how to find it.

[Matei]

Possible workaround for "XMonad". Add 2 pixels to the width and height of the created window, file graphics/forsdl3/graph2d.c, line 139:

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RGLOB_window = SDL_CreateWindow(title,width+2,height+2,0);
If it doesn't work with 2 (it should), try more. I will make an update, but I have to think how. Fortunately, this problem doesn't occur very often; I never saw it and I tested:

https://matei.one/#performance

with SDL 2, but the problem also appears with SDL 2. I will have to update all my programs though and this could be a problem...

https://sourceforge.net/u/matei_v/profile/