Mike Gorchak
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Re: devg-extreme2 is omitting points when glDrawArrays() is executing.
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Mike Gorchak
04/09/2009 4:53 AM
post26498
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Re: devg-extreme2 is omitting points when glDrawArrays() is executing.
Additional information. Problem with points disappearing using devg-extreme2 graphics driver could be reproduced if
current display color depth is 15 bpp (1555) or 16 bpp (565). But while using 32 bpp depth (8888 format) all works fine.
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Logan Fraser
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Re: devg-extreme2 is omitting points when glDrawArrays() is executing.
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Logan Fraser
04/22/2009 4:14 PM
post27828
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Re: devg-extreme2 is omitting points when glDrawArrays() is executing.
Hi I work with Kevin Raymond and I came across the problem of invisible points in i830 in QNX 6.4 with a core duo
machine while writing a program that uses OpenGL to draw a simple set of points in 2D. I modified the photon GL gears
app to showcase this problem, if you run it with gma9xx you can see one of the gears, in i830 you see nothing. I will
attach the program and quote the included README:
---------------------------------------------------------------------
This code demonstrates the issue with the i830 driver in QNX. Tested in i830 display on a Core Duo with intel 945
integrated graphics.
When run in i830 with 16M color (we have found this configuration the most stable) you will see a black screen.
When run with gma9xx with 32K color (16M crashes QNX sometimes..) you do see the green gear in the bottom right part of
the screen drawn as faint points.
The problem at hand seems to be that in the i830 driver QNX will not render GL_POINTS on plane z=0. This is incorrect
behaviour as all other OpenGL implementations render GL_POINTS at z=0. Doing a glTranslatef(0.0, 0.0, -1.0) will allow
the points to show up but in some cases it is important to render with 0 depth.
--- Card from pci -v -------
Class = Display (VGA)
Vendor ID = 8086h, Intel Corporation
Device ID = 2772h, 82945G/GZ Integrated Graphics Controller
PCI index = 0h
PCI Mem Address = ffa80000h enabled
PCI IO Address = ec00h enabled
PCI Mem Address = e0000000h enabled
PCI Mem Address = ffa40000h enabled
PCI Int Pin = INT A
Interrupt line = 5
CPU Interrupt = 5h
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