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From: Owen K. <Owe...@sc...> - 2009-11-17 03:57:36
Attachments:
point_dist_basic.c
snapshot.png
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Hello, I'm having trouble with point distance attenuation using OSMesa. I'm rendering a lot of depth sorted, alpha blended, textured points and dark bands are appearing that are not there when I render with the system GL. I found the problem only occurs with point distance attenuation turned on. If you look at the attached image you can see there are clearly defined bands, possibly the point size calculation is incorrect at certain distances resulting in size jumps. I've attached a sample program that reproduces the problem. Also tried the latest Mesalib code (Mesa-7.7-devel-20091105) and is still occurring. Thanks, Owen. |
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From: Brian P. <br...@vm...> - 2009-11-17 23:29:59
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Owen Kaluza wrote: > Hello, > I'm having trouble with point distance attenuation using OSMesa. > I'm rendering a lot of depth sorted, alpha blended, textured points and > dark bands are appearing that are not there when I render with the > system GL. > > I found the problem only occurs with point distance attenuation turned on. > If you look at the attached image you can see there are clearly defined > bands, possibly the point size calculation is incorrect at certain > distances resulting in size jumps. > > I've attached a sample program that reproduces the problem. Also tried > the latest Mesalib code (Mesa-7.7-devel-20091105) and is still occurring. Could you prune down your test program a bit? Perhaps you could draw a series of points between the min/max Z positions and see how they look. -Brian |
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From: Owen K. <Owe...@sc...> - 2009-11-18 02:20:07
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Hi Brian, Sure, here is the best illustration of the issue I could produce: 1000 points, aligned as you suggested. If I bring the point size up from 1.0 the issue isn't as obvious although still noticeable. The attenuation seems to drop the point size then gradually increase, you can see the points towards the back disappear then reappear. Attached modified program and two screen shots, one using osmesa and the other with glut+video card gl drivers. Thanks, Owen. Brian Paul wrote: > Owen Kaluza wrote: >> Hello, >> I'm having trouble with point distance attenuation using OSMesa. >> I'm rendering a lot of depth sorted, alpha blended, textured points and >> dark bands are appearing that are not there when I render with the >> system GL. >> >> I found the problem only occurs with point distance attenuation >> turned on. >> If you look at the attached image you can see there are clearly defined >> bands, possibly the point size calculation is incorrect at certain >> distances resulting in size jumps. >> >> I've attached a sample program that reproduces the problem. Also tried >> the latest Mesalib code (Mesa-7.7-devel-20091105) and is still >> occurring. > > Could you prune down your test program a bit? Perhaps you could draw > a series of points between the min/max Z positions and see how they look. > > -Brian > |
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From: Brian P. <br...@vm...> - 2009-11-18 15:54:36
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OK, the problem is we're not doing sub-pixel adjustment of texcoords in the sprite rasterization code. Look in sprite_point() in s_points.c if interested. This can be fixed but it will take some work. I'll see if I can fix it when I get some spare time. -Brian Owen Kaluza wrote: > Hi Brian, > > Sure, here is the best illustration of the issue I could produce: 1000 > points, aligned as you suggested. > If I bring the point size up from 1.0 the issue isn't as obvious > although still noticeable. > The attenuation seems to drop the point size then gradually increase, > you can see the points towards the back disappear then reappear. > Attached modified program and two screen shots, one using osmesa and the > other with glut+video card gl drivers. > > Thanks, > Owen. > > Brian Paul wrote: >> Owen Kaluza wrote: >>> Hello, >>> I'm having trouble with point distance attenuation using OSMesa. >>> I'm rendering a lot of depth sorted, alpha blended, textured points and >>> dark bands are appearing that are not there when I render with the >>> system GL. >>> >>> I found the problem only occurs with point distance attenuation >>> turned on. >>> If you look at the attached image you can see there are clearly defined >>> bands, possibly the point size calculation is incorrect at certain >>> distances resulting in size jumps. >>> >>> I've attached a sample program that reproduces the problem. Also tried >>> the latest Mesalib code (Mesa-7.7-devel-20091105) and is still >>> occurring. >> Could you prune down your test program a bit? Perhaps you could draw >> a series of points between the min/max Z positions and see how they look. >> >> -Brian >> >> >> ------------------------------------------------------------------------ >> >> >> ------------------------------------------------------------------------ >> |
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From: Owen K. <Owe...@sc...> - 2009-11-19 03:07:35
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Ah no worries, thanks for checking it out. Not a priority, mainly just reporting as a bug or in case it was a very easy fix. Owen. Brian Paul wrote: > OK, the problem is we're not doing sub-pixel adjustment of texcoords > in the sprite rasterization code. Look in sprite_point() in > s_points.c if interested. This can be fixed but it will take some > work. I'll see if I can fix it when I get some spare time. > > -Brian > > > Owen Kaluza wrote: > >> Hi Brian, >> >> Sure, here is the best illustration of the issue I could produce: 1000 >> points, aligned as you suggested. >> If I bring the point size up from 1.0 the issue isn't as obvious >> although still noticeable. >> The attenuation seems to drop the point size then gradually increase, >> you can see the points towards the back disappear then reappear. >> Attached modified program and two screen shots, one using osmesa and the >> other with glut+video card gl drivers. >> >> Thanks, >> Owen. >> >> Brian Paul wrote: >> >>> Owen Kaluza wrote: >>> >>>> Hello, >>>> I'm having trouble with point distance attenuation using OSMesa. >>>> I'm rendering a lot of depth sorted, alpha blended, textured points and >>>> dark bands are appearing that are not there when I render with the >>>> system GL. >>>> >>>> I found the problem only occurs with point distance attenuation >>>> turned on. >>>> If you look at the attached image you can see there are clearly defined >>>> bands, possibly the point size calculation is incorrect at certain >>>> distances resulting in size jumps. >>>> >>>> I've attached a sample program that reproduces the problem. Also tried >>>> the latest Mesalib code (Mesa-7.7-devel-20091105) and is still >>>> occurring. >>>> >>> Could you prune down your test program a bit? Perhaps you could draw >>> a series of points between the min/max Z positions and see how they look. >>> >>> -Brian >>> >>> >>> ------------------------------------------------------------------------ >>> >>> >>> ------------------------------------------------------------------------ >>> >>> > > > ------------------------------------------------------------------------------ > Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day > trial. Simplify your report design, integration and deployment - and focus on > what you do best, core application coding. Discover what's new with > Crystal Reports now. http://p.sf.net/sfu/bobj-july > _______________________________________________ > Mesa3d-users mailing list > Mes...@li... > https://lists.sourceforge.net/lists/listinfo/mesa3d-users > |
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