Hi Alex, Oh well... sounds very much like a driver bug then.
Perhaps the best thing you could do is pre-process your scene graphs so that they only contain a single DrawElementsUShort() rather than multiple separate primitive sets. Robert. On Wed, Sep 14, 2011 at 2:59 PM, Alexander Irion <[email protected]> wrote: > Helllo Robert, > > we use OSG-3.0 and this time its not the alignment problem, that we had on > the Intel EMGD before. > > The offset of the ushort array is 300 - so it is already dividable by 4, I > also already tested with some other alignment values. > > With my tests, I verified that the content of the element buffer is valid for > both draw calls, and if I have only one of the draw calls, the right > triangles are rendered - it only fails, when both glDrawElements are called. > > I hacked in two lines in the DrawElementsUByte::draw() method for testing. > > So, this fails with rendering garbage triangles: > > glDrawElements(GL_TRIANGLES, 300, GL_UNSIGNED_BYTE, 0); > glDrawElements(GL_TRIANGLES, 861, GL_UNSIGNED_SHORT, 300); > > but this: > > glDrawElements(GL_TRIANGLES, 300, GL_UNSIGNED_BYTE, 0); > //glDrawElements(GL_TRIANGLES, 861, GL_UNSIGNED_SHORT, 300); > > or this: > > //glDrawElements(GL_TRIANGLES, 300, GL_UNSIGNED_BYTE, 0); > glDrawElements(GL_TRIANGLES, 861, GL_UNSIGNED_SHORT, 300); > > > works well and draws the right triangles of either the indices 0-299 or > 300-1160. (Nothing else in the program is changed, so buffer contents is the > same for all three test cases.) > > When each glDrawElements() is doing right, calling both glDrawElements() in > direct sequence would be expected to do also right and to show the "sum" of > each render calls, which it is not doing. > > So, in the meantime I will kick out the Intel graphics and go for a new > Nvidia card ... > > --Alex > > > > > > > > robertosfield wrote: >> Hi Alex, >> >> Which version of the OSG are you using? Just prior to the OSG-3.0 >> release I checked in code that aligned arrays within a buffer object >> to 4 byte boundaries, this was done to address problems in Intel >> drivers. >> >> Robert. >> >> On Wed, Sep 14, 2011 at 1:35 PM, Alexander Irion <> wrote: >> >> > Hello, >> > >> > I have a quiet weird problem with Intel Core i5 integrated graphics under >> > Ubuntu: >> > >> > When I have an element buffer object, that consists of an byte index >> > array, followed by an ushort index array, wrong triangles will be >> > rendered. (See wrong_rendering.png, compared to right_rendering.png). >> > >> > The attached osgt model file consists of two GL_TRIANGLES draw calls, that >> > use the same buffer object for indices. >> > >> > DrawElementsUByte::draw size:300 offset: 0 >> > DrawElementsUShort::draw size:861 offset: 300 >> > >> > I modified the code to draw only once of them - either the ubyte array or >> > the ushort array and in both cases the right triangles are rendered, >> > whereas rendering fails, when both draw calls are made. >> > >> > It looks like the driver interprets the ushort indices as byte indices, >> > that would explain the fan looking triangles, that are drawn. The high >> > byte (0) of an ushort index would then often be taken as vertex 0 for one >> > of the three triangle vertices, so their would be many wrong triangles >> > starting from vertex 0 to some other vertices - exactly, as it looks in >> > the attached screen shot of the wrong rendering. >> > >> > The same model looks good on a system with Nvidia graphics, it also works >> > on the Intel GPU, when the arrays reside in different buffer objects, or >> > when element buffer objects are not used for the vertex indices. >> > >> > From the application side, everything looks good inside osg, so I think >> > this is a driver bug. >> > >> > Does anyone who also has integrated Intel grahics under linux can confirm >> > this bug? >> > (To verify, just start the osgviewerapp with the attached model file). >> > >> > Would that samething for the Mesa guys to look at? >> > >> > Regards, >> > --Alex >> > >> > >> > My spec: >> > >> > Ubuntu 11.04 >> > >> > OpenGL vendor string: Tungsten Graphics, Inc >> > OpenGL renderer string: Mesa DRI Intel(R) Ironlake Desktop GEM 20100330 >> > DEVELOPMENT x86/MMX/SSE2 >> > OpenGL version string: 2.1 Mesa 7.10.2 >> > OpenGL shading language version string: 1.20 >> > >> > VGA compatible controller: >> > product: Core Processor Integrated Graphics Controller >> > vendor: Intel Corporation >> > physical id: 2 >> > bus info: pci@0000:00:02.0 >> > version: 02 >> > width: 64 bits >> > clock: 33MHz >> > capabilities: msi pm vga_controller bus_master cap_list rom >> > configuration: driver=i915 latency=0 >> > resources: irq:42 memory:f0000000-f03fffff >> > memory:e0000000-efffffff ioport:1170(size=8) >> > >> > CPU: >> > product: Intel(R) Core(TM) i5 CPU 660 @ 3.33GHz >> > vendor: Intel Corp. >> > physical id: 5 >> > bus info: cpu@0 >> > version: 6.5.5 >> > serial: 0002-0655-0000-0000-0000-0000 >> > slot: XU1 PROCESSOR >> > size: 1199MHz >> > capacity: 1199MHz >> > width: 64 bits >> > clock: 133MHz >> > capabilities: x86-64 boot fpu fpu_exception wp vme de pse tsc msr >> > pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr >> > sse sse2 ss ht tm pbe nx rdtscp constant_tsc arch_perfmon pebs bts >> > xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx >> > smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt aes lahf_lm ida arat >> > tpr_shadow vnmi flexpriority ept vpid cpufreq >> > configuration: cores=2 enabledcores=2 id=1 threads=4 >> > >> > ------------------ >> > Read this topic online here: >> > http://forum.openscenegraph.org/viewtopic.php?p=42748#42748 >> > >> > >> > >> > >> > Attachments: >> > http://forum.openscenegraph.org//files/optosgt_211.gz >> > http://forum.openscenegraph.org//files/right_rendering_125.png >> > http://forum.openscenegraph.org//files/wrong_rendering_148.png >> > >> > >> > _______________________________________________ >> > osg-users mailing list >> > >> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >> > >> > >> _______________________________________________ >> osg-users mailing list >> >> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >> >> ------------------ >> Post generated by Mail2Forum > > > ------------------ > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=42754#42754 > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
