[Mesa-dev] MESA and KOTOR

Tue Mar 14 16:30:49 UTC 2017

Hello again,

After further investigation it seems to me that wglMakeContextCurrentARB 
is not implemented by gallium llvmpipe, that's why it gets a null pointer.

Can we add a stub or something?

Il 2017-03-14 03:44, Brian Paul ha scritto:
> 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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>>
>>
>