On 29.06.2009 19:09, Maciej Cencora wrote: > Dnia poniedziałek, 29 czerwca 2009 o 17:52:30 Roland Scheidegger napisał(a): >> On 27.06.2009 23:57, Maciej Cencora wrote: >>> Hi, >>> >>> while playing with r300 driver I've stumbled upon a problem with >>> splitting vertexes. >>> >>> Let's say we get rendering operation where number of indexes in index >>> buffer is 80000 and max_index is 20000. We are calling vbo_split_prims >>> because number of indexes exceeds hw limit. >>> In flush_vertex (vbo_split_inplace.c) function the split->ib is not null, >>> so the max_index (20000) won't be changed. In the end the draw_prims >>> functions will be called with inappropriate max_index number. >>> >>> I'm seeing this behaviour with UT2004 demo on current r300 driver. >>> >>> I think the solution would be to always calculate min/max_index numbers >>> just like in the !split->ib path but I want to be sure before I commit >>> the patch. >>> >>> Any comments? >> Apart from this problem, I think the limits in the r300 driver set are >> maybe not really hw limits. I'm not sure why max_verts is limited at all >> (though maybe limited by buffer size?), and max_indices could be bumped >> at least for r500. (I always considered it odd that even r200 could >> accept 23 bits worth of indices for the INDX_BUFFER command but only 16 >> bit number of amount of vertices in vertex fetch control, and this >> finally seems fixed in r500 - 24 bits possible with VAP_ALT_NUM_VERTICES.) > > On <= r300 we are limited by VAP_VF_CNLT_.NUM_VERTICES field size (16 bit) > for > both indices and vertices list. I tried using VAP_ALT_NUM_VERTICES reg on > r500 > by programming it right before 3D_DRAW_VBUF2 packet, but it always ended in > GPU hang. John Bridgman was going to try to dig out some info about it, but > no > luck so far.
I don't see why that NUM_VERTICES field limits max_verts. This is only the number of vertices the chip fetches after all, and it shouldn't matter how many vertices are in the buffer. BTW there's also a comment in the code that rebase should be done if there's more than 8192 / 16384 indices per primitive. I believe though the docs are wrong wrt this as it doesn't really make sense as far as I can see (says 8192 / 16384 max as per max buffer size, but max buffer size is 23bit number of dwords). Roland ------------------------------------------------------------------------------ _______________________________________________ Mesa3d-dev mailing list Mesa3d-dev@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
