[Mesa-dev] MESA and KOTOR

[Brian Paul]

Looks like my KOTOR patch never made it to master.  I'm attaching it 
below so you can try it.  I should commit it master.  In any case, let 
me know if it helps.

-Brian

On 03/13/2017 10:55 AM, Federico Dossena wrote:
> Hi Jose, thanks for replying, I've seen your name inside many files in
> mesa ;)
>
> I have tried mesa master (previously I was using 17.0.1) but it still
> crashes for the same null pointer.
> Do you have a link to that patch you've mentioned for kotor?
>
> I have used apitrace and took traces of both the nvidia driver (which
> runs kotor) and mesa (up until the crash).
> Here's a link to them:
> https://drive.google.com/file/d/0B6qj91UlSYlYa3dIM0FtaHNULW8/view?usp=sharing
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__drive.google.com_file_d_0B6qj91UlSYlYa3dIM0FtaHNULW8_view-3Fusp-3Dsharing&d=DwMDaQ&c=uilaK90D4TOVoH58JNXRgQ&r=Ie7_encNUsqxbSRbqbNgofw0ITcfE8JKfaUjIQhncGA&m=u9OxTt6a0b4XxAVoFjjG7RmQNYLAIe3smaD2NtY0mhE&s=h5NDyV1_DsR1WIruLOfH3IDrWkYTa8VEHeC3vIiucF4&e=>
>
> I tried reading them with the dump function but it's way above my
> comprehension.
>
> I know that some applications use wglGetProcAddress to check if an
> extension if available, but I've seen KOTOR check for the
> WGL_ARB_render_texture, and when it's present it enables frame buffer
> effects and soft shadows, which use wglMakeContextCurrentARB (not
> wglBindTexImageARB, I was wrong in my previous mail), which for some
> reason is a null pointer.
>
> ////
>
>
> Il 2017-03-13 14:39, Jose Fonseca ha scritto:
>> On 13/03/17 11:09, Emil Velikov wrote:
>>> On 11 March 2017 at 11:51, Federico Dossena <dossenus91 at gmail.com>
>>> wrote:
>>>> In the last week I've been trying to bring an "old" game back to
>>>> life, Star
>>>> Wars Knights of the old republic (KOTOR, for short). It's from 2003
>>>> and uses
>>>> OpenGL 1.4.
>>>>
>>>> I have used Mesa, libtxc_dxtn and some trickery to decompress the
>>>> textures
>>>> to boost performance, and right now I have it up and running
>>>> smoothly with
>>>> Gallium on LLVMPipe, compiled on Windows. (I can upload a copy if
>>>> someone is
>>>> interested). This took me about 2 days of compiling and figuring out
>>>> stuff.
>>>>
>>>> Here's where the weirdness begins:
>>>> Turning on framebuffer effects or soft shadows make the game crash
>>>> right
>>>> after the menu. Using a disassembler and debugger and what little
>>>> knowledge
>>>> I have of reverse engineering, I managed to track down the issue to a
>>>> function which uses wglGetProcAddress to get the addresses of
>>>> several OpenGL
>>>> functions. Some of these calls return a null pointer (even if there
>>>> is a
>>>> valid context and it is current), and when the game tries to call
>>>> them, it
>>>> crashes. The first one that makes it crash is a pointer to
>>>> wglBindTexImageARB, but there are a few others. NOPing the offending
>>>> instructions did not work, and returning a nop function just makes
>>>> the game
>>>> display artifacts.
>>>>
>>> Strange - afaict mesa (st/wgl) exposes both wglBindTexImageARB and the
>>> WGL_ARB_render_texture extension.
>>> You can break on DrvGetProcAddress and trace where/how we end up with
>>> NULL function pointer.
>>>
>>> -Emil
>>> _______________________________________________
>>> mesa-dev mailing list
>>> mesa-dev at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>>>
>>
>> Federico,
>>
>> You should be using latest master for this.   There have been recent
>> changes/fixes to our WGL implementation.
>>
>>
>> Last fall Brian Paul fixed an issue with WGL extension seen on KOTOR.
>> I'm not sure the the issue has been crossported to Mesa master yet,
>> and it might be unrelated.
>>
>>
>> Generally speaking, wglGetProcAddress returning NULL by itself is not
>> a problem.  Many games wrongly rely on wglGetProcAddress NULL results
>> to detect whether an GL/WGL extension is present (which goes against
>> the spec).  Other libraries try to bindly get every possible
>> entrypoint through wglGetProcAddress, then check which ones to use
>> based on supported extensions (which is actually fine by the spec.)
>>
>>
>> For the record, getting an apitrace is usually useful to debug this
>> sort of issues.  One can use apitrace straigh from windows or with
>> WINE -- https://github.com/apitrace/apitrace/wiki/WINE
>>
>>
>> Jose
>
>
>
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