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 <[email protected]> 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 > [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
