From: <fra...@se...> - 2007-10-30 19:45:13
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hi to all, finally we managed to isolate the problem! it seems to be a bug in the state management of the colorMaterial in conjunction with materials using SHLChunks. here is an osb scene with the problem reproduction ( read more to discover how to test the bug! ): http://user.augmented-reality.it/~tamagni/bugtest.osb here is what happens: - there are two (or more) nodes with vertex colors assigned. now, the default to opensg is to map glColor to GL_DIFFUSE. - if i assign materials without shaders it behaves correctly (?), i.e diffuse colors from glColor and from MaterialChunk are blended. - if i use materials with shaders like in the test osb scene, which blends somehow glColor with gl_FrontMaterial.diffuse, the bug happens: i assign the material to the first object and it's ok, when i assign the material to the second one, the first one renders in an unpredictable (to me) way. how to reproduce the bug: 1 - open bugtest.osb using VRED 2 - assign to the both spheres the material blau 3 - assign to the both spheres the chunkmaterial NOTE: this bug is not reproducible with all graphics hardware, we observed the bug happening on boards with: Quadro FX 4000, Quadro FX 2500M and Quadro FX 5600 although it works correctly on Quadro FX 3000 and ATI Radeon X1300 It is "driver version independent" ! we workarounded it by mapping color material to GL_NONE (which is what we expected opensg to do by default, because we didn't know that the default is GL_DIFFUSE, sorry ;) ) thanks for your time francesco Scrive Antonio Bleile <ant...@se...>: > > Always concerning this problem..... We apply the same shader material > to two different geoemtries and they're rendered differently. This also > depends on the viewpoint, if we move around the camera, the material > assignment changes, the two objects interchange their material randomly > (althought tey're supposed to have the same material). > To me this looks like messed up material sorting or something (as long > as OpenSG minimizez state changes during rendering..). We observed that if we > render "manually" each geometry with their attached material, the rendering > is ok. As it is very hard to give you a self contained example reproducing > the problem, we'd like to know if it's possible to get a dump from > OpenSG where it states what's going on during rendering. Is there anything > I can switch on for more verbose logging? > > Here's another observation: The property that changes randomly seems to be > only the diffuse lighting... The textures, specular lighting are ok).. > > Any hints very much appreciated, > > Toni ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. |