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Mailing lists / lazarus / 2008-02

Lazarus and GLScene, bug in polygon rendering

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Unknown author

Hi all,

I have a bug with GLScene when executing on Windows, compiled with Lazarus and FPC.
GLScene's version is Lazarus', version 1.0.0.2 (Delphi's version's needs a lot more fixes to work on Lazarus).

The program is very simple, see attached zip file, basically a polygon viewed from above in a GLSceneViewer. When I connect the viewer to the camera, the program hangs with a SIGSEGV signal in the ialmgicd!DrvSetContext procedure, it seems the GLU library transmits back bizarre pointers into the TGLNodes.RenderTesselatedPolygon procedure in GLMisc. I've printed out a copy of the values in the GLSceneDebug.Text file.

Needless to say, the same code work perfectly with Delphi7 and the latest stable GLScene.

Has anyone seen this before and could help with information to debug this?

Thanks a lot
Thierry

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Burkhard Carstens
to Unknown author
Show quoted text 20 lines
Hi all, I have a bug with GLScene when executing on Windows, compiled with Lazarus and FPC. GLScene's version is Lazarus', version 1.0.0.2 (Delphi's version's needs a lot more fixes to work on Lazarus). The program is very simple, see attached zip file, basically a polygon viewed from above in a GLSceneViewer. When I connect the viewer to the camera, the program hangs with a SIGSEGV signal in the ialmgicd!DrvSetContext procedure, it seems the GLU library transmits back bizarre pointers into the TGLNodes.RenderTesselatedPolygon procedure in GLMisc. I've printed out a copy of the values in the GLSceneDebug.Text file. Needless to say, the same code work perfectly with Delphi7 and the latest stable GLScene. Has anyone seen this before and could help with information to debug this?

Could you please retest with svn version of glscene4lazarus? I just checked glmisc.pas and it is exactly identical to the GLMisc.pas from original glscene (current cvs). So if the error still persists, it must be somewhere else ..

regards
Burkhard

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Burkhard Carstens
to Unknown author: I have a bug with GLScene when executing on Windows, compiled with Lazarus and FPC.…
Show quoted text 17 lines
Hi all, I have a bug with GLScene when executing on Windows, compiled with Lazarus and FPC. GLScene's version is Lazarus', version 1.0.0.2 (Delphi's version's needs a lot more fixes to work on Lazarus). The program is very simple, see attached zip file, basically a polygon viewed from above in a GLSceneViewer. When I connect the viewer to the camera, the program hangs with a SIGSEGV signal in the ialmgicd!DrvSetContext procedure, it seems the GLU library transmits back bizarre pointers into the TGLNodes.RenderTesselatedPolygon procedure in GLMisc. I've printed out a copy of the values in the GLSceneDebug.Text file. Needless to say, the same code work perfectly with Delphi7 and the latest stable GLScene.

I just learned "it's pure luck" that/if it works .. I'll submit a patch to original glscene as soon as you confirm the fix. ( I don't have windows to test, however in linux your test program works now )

Has anyone seen this before and could help with information to debug this?

fixed in svn.

regards
Burkhard

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Unknown author

Hi all,

downloaded glscene from svn and checked, the bug is corrected, I have a nice polygon on screen. Fixed.
Thx a lot, Burkhard :-)
Thierry

Show quoted text 17 lines
> Hi all, > > I have a bug with GLScene when executing on Windows, compiled with > Lazarus and FPC. > GLScene's version is Lazarus', version 1.0.0.2 (Delphi's version's > needs a lot more fixes to work on Lazarus). > > The program is very simple, see attached zip file, basically a > polygon viewed from above in a GLSceneViewer. When I connect the > viewer to the camera, the program hangs with a SIGSEGV signal in the > ialmgicd!DrvSetContext procedure, it seems the GLU library transmits > back bizarre pointers into the TGLNodes.RenderTesselatedPolygon > procedure in GLMisc. > I've printed out a copy of the values in the GLSceneDebug.Text file. > > Needless to say, the same code work perfectly with Delphi7 and the > latest stable GLScene.

I just learned "it's pure luck" that/if it works .. I'll submit a patch to original glscene as soon as you confirm the fix. ( I don't have windows to test, however in linux your test program works now )

> > Has anyone seen this before and could help with information to debug > this?

fixed in svn.

regards
Burkhard

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