Bullet Convex Hull Crashes on Win32 with SSE #35071

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Francisco De La Cruz · 2013-04-25T03:00:56+02:00

2013-04-25 03:00:56 +02:00

Category: Physics

%%%--- Operating System, Graphics card ---
Windows Vista 32-bit, Intel 495

- Blender version with error, and version that worked ---

trunk @ r56277 crashes when starting the game engine with the attached .blend

- Short description of error ---

Loading the attached .blend and starting the Game Engine crashes Blender (~ 80% of the time)
The scene consists of static body and a dynamic body with a Convex Hull collision box.

- Steps for others to reproduce the error (preferably based on attached .blend file) ---

Open attached .blend
Game->Start Game Engine

Note 1: If the collision box for Suzanne is changed to a non Convex Hull type there is no crash.

Note 2: Tracing shows that the crash seems to be related to SSE support in bullet WHEN embedding bullet aligned-classes (btVector etc) in non-aligned external classes.

Note 3: From the btScalar.h header
//---snip--
- define BT_USE_SSE
- ifdef BT_USE_SSE
BT_USE_SSE_IN_API is disabled under Windows by default, becauseit makes it harder to integrate Bullet into your application under Windows
*(structured embedding Bullet structs/classes need to be 16-byte aligned)*with relatively little performance gain
If you are not embedded Bullet data in your classes, or make sure that you align those classes on 16-byte boundariesyou can manually enable this line or set it in the build system for a bit of performance gain (a few percent, dependent on usage)
#define BT_USE_SSE_IN_API---snip---

   
 Nonetheless BT_USE_SSE_IN_API is defined in other places as such:

if defined (_WIN32) || defined (i386)
define BT_USE_SSE_IN_API
#endif

A Proof-of-Concept patch that fixes the crashing under Win32 is also attached.

%%%

**Category**: Physics %%%--- Operating System, Graphics card --- Windows Vista 32-bit, Intel 495 - Blender version with error, and version that worked --- trunk @ r56277 crashes when starting the game engine with the attached .blend - Short description of error --- Loading the attached .blend and starting the Game Engine crashes Blender (~ 80% of the time) The scene consists of static body and a dynamic body with a Convex Hull collision box. - Steps for others to reproduce the error (preferably based on attached .blend file) --- 1) Open attached .blend 2) Game->Start Game Engine Note 1: If the collision box for Suzanne is changed to a non Convex Hull type there is no crash. Note 2: Tracing shows that the crash seems to be related to SSE support in bullet WHEN embedding bullet aligned-classes (btVector etc) in non-aligned external classes. Note 3: From the btScalar.h header //---snip-- - define BT_USE_SSE - ifdef BT_USE_SSE *BT_USE_SSE_IN_API is disabled under Windows by default, because*it makes it harder to integrate Bullet into your application under Windows *(structured embedding Bullet structs/classes need to be 16-byte aligned)*with relatively little performance gain *If you are not embedded Bullet data in your classes, or make sure that you align those classes on 16-byte boundaries*you can manually enable this line or set it in the build system for a bit of performance gain (a few percent, dependent on usage) *#define BT_USE_SSE_IN_API*---snip--- ``` Nonetheless BT_USE_SSE_IN_API is defined in other places as such: ``` - if defined (_WIN32) || defined (__i386__) - define BT_USE_SSE_IN_API #endif ``` A Proof-of-Concept patch that fixes the crashing under Win32 is also attached. ``` ``` ``` %%%

Francisco De La Cruz commented

2013-04-25 03:00:56 +02:00

Changed status to: 'Open'

Francisco De La Cruz commented

2013-04-25 03:01:38 +02:00

%%%This issue might be related to http://projects.blender.org/tracker/index.php?func=detail&aid=35048&group_id=9&atid=306%%%

%%%This issue *might* be related to http://projects.blender.org/tracker/index.php?func=detail&aid=35048&group_id=9&atid=306%%%

Sergej Reich commented

2013-04-25 22:04:05 +02:00

%%%Hmm, this looks fishy.
Seems like those defines were added in this commit: http://code.google.com/p/bullet/source/detail?r=2634
Don't really see why though.
As far as I can see it should be safe to remove them.

In my tests using SSE had only small benefits, but that depends on the scene and the processor of course.%%%

%%%Hmm, this looks fishy. Seems like those defines were added in this commit: http://code.google.com/p/bullet/source/detail?r=2634 Don't really see why though. As far as I can see it should be safe to remove them. In my tests using SSE had only small benefits, but that depends on the scene and the processor of course.%%%

Thomas Szepe commented

2013-05-02 19:21:19 +02:00

%%%I downloaded an actual version from the Buildbot and it works without crash.
But when I building Blender (Windows XP 32 bit with Microsoft Visual C++ and SCons) from the actual trunk, Blender will crash without this fix.%%%

%%%I downloaded an actual version from the Buildbot and it works without crash. But when I building Blender (Windows XP 32 bit with Microsoft Visual C++ and SCons) from the actual trunk, Blender will crash without this fix.%%%

Sergej Reich commented

2013-05-07 00:53:43 +02:00

%%%I committed Francisco's fix in svn r56519.
Could you test if the problem is fixed now?%%%

%%%I committed Francisco's fix in svn r56519. Could you test if the problem is fixed now?%%%

Sergej Reich commented

2013-05-17 20:36:03 +02:00

%%%It seems the problem is fixed, closing.%%%

Sergej Reich commented

2013-05-17 20:36:03 +02:00

Changed status from 'Open' to: 'Resolved'

Sergej Reich closed this issue

2013-05-17 20:36:03 +02:00

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Bullet Convex Hull Crashes on Win32 with SSE #35071