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Bug 1129

Summary: opengl renderer bug when compiled with VLC
Product: SDL Reporter: Vittorio Giovara <vitto.giova>
Component: videoAssignee: Sam Lantinga <slouken>
Status: RESOLVED FIXED QA Contact: Sam Lantinga <slouken>
Severity: normal    
Priority: P2 CC: icculus
Version: HG 2.0   
Hardware: x86_64   
OS: Linux   
Attachments: the culprit source file

Description Vittorio Giovara 2011-02-17 00:16:39 UTC 
Created attachment 576 [details]
the culprit source file

I'm trying to port the sdl+vlc example
(http://wiki.videolan.org/LibVLC_SampleCode_SDL) to SDL 1.3 apis
I'm trying to use this code to decode some h264 videos and to do some
compositing operation on it live.

The attached code works fine on Windows, i can see the video and render with the
new apis; it works using the direct3d and software renderer, with the
opengl renderer i see only a black screen.
However on Linux, using the opengl renderer, it gets a segfault and
crashes at the first frame or so (works fine with software renderer).

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffe2da4700 (LWP 2995)]
0x00007ffff57e3629 in glGetError () from /usr/lib/nvidia-current/libGL.so.1
(gdb) bt
#0  0x00007ffff57e3629 in glGetError () from /usr/lib/nvidia-current/libGL.so.1
#1  0x00007ffff7b50533 in GL_UpdateTexture (renderer=<value optimized
out>, texture=0x88bda0, rect=0x8abfc4, pixels=0x7ffff2c29010,
pitch=7680) at src/render/opengl/SDL_render_gl.c:546
#2  0x00007ffff7b4c197 in SDL_UnlockTexture (texture=0x88bda0) at
src/render/SDL_render.c:732
#3  0x00000000004010d3 in unlock (data=0x7fffffffe0d0, id=0x0,
p_pixels=0x7fffe2da3bf0) at sdl13+vlc.c:26
#4  0x00007fffe2aa0c66 in Unlock (picture=<value optimized out>) at vmem.c:353
#5  0x00007ffff6c48532 in vout_display_Display (vout=0xa94f50,
now=<value optimized out>, deadline=<value optimized out>) at
../include/vlc_vout_wrapper.h:58
#6  ThreadDisplayRenderPicture (vout=0xa94f50, now=<value optimized
out>, deadline=<value optimized out>) at
video_output/video_output.c:1040
#7  ThreadDisplayPicture (vout=0xa94f50, now=<value optimized out>,
deadline=<value optimized out>) at video_output/video_output.c:1113
#8  0x00007ffff6c48ffd in ThreadManage (object=<value optimized out>)
at video_output/video_output.c:1125
#9  Thread (object=<value optimized out>) at video_output/video_output.c:1559
#10 0x00007ffff6ed4971 in start_thread (arg=<value optimized out>) at
pthread_create.c:304
#11 0x00007ffff765792d in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#12 0x0000000000000000 in ?? ()
Comment 1 Sam Lantinga 2013-05-21 02:07:10 UTC 
Is this still active in the latest snapshot?
http://www.libsdl.org/tmp/SDL-2.0.zip
Comment 2 Ryan C. Gordon 2013-07-12 11:21:57 UTC 
This looks like it's trying to do OpenGL calls in a background thread. Maybe set the context current on that thread and see if it helps?

--ryan.
Comment 3 Vittorio Giovara 2013-07-13 06:21:04 UTC 
Will do try again soon.
Thanks.
Comment 4 Ryan C. Gordon 2015-02-18 03:26:37 UTC 
I'm assuming this turned out to be GL calls on a background thread without a current context, and the latest SDL revisions should take care of this now (grep for "GL_ActivateRenderer" in the sources).

--ryan.