Strange banding

General discussion about the development of the open source Blender

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Friday13
Posts: 54
Joined: Wed Oct 16, 2002 10:40 pm

Post by Friday13 » Thu Sep 16, 2004 9:01 pm

levon wrote:um actualy no you cant use blender with out a video card
Really? My video card doesn't accelerate OpenGL, and I'm having no problems with software OpenGL.
levon wrote: in fact you cant even use windows or dos with out a video card.
your video card is what displays things to the monitor
Windows displays the interface using GDI/GID+ and DirectDraw to display things (and can be accelerated if/when a video card is present, though it still works without the video card). As for the DOS thing....a video card is not a requirement for it (otherwise my old 286 wouldn't have worked, because it didn't have one (just plain old software acceleration :P ).

levon
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Location: adelaide

Post by levon » Fri Sep 17, 2004 4:45 am

ok Friday13 you will find that your old 286 had a video card, it was not 3D card but a 2D video card.

for anything to be displayed to a monitor it must go through the 2d card as well as the 3d, if you want openGL acceleration. and anything directx is done with you 3D card if its a directX 3D card, like most the geforce and radeons are now, if not all.

back in the voodoo 2 days, when they were only a 3d card and not a 2d card, you had to plug your 2d card into your 3d card, then your 3d card to the monitor.

these days the 2d card is built into your 3d card, and for anything to be drawn on the monitor it must go through it.

Friday13
Posts: 54
Joined: Wed Oct 16, 2002 10:40 pm

Post by Friday13 » Fri Sep 17, 2004 7:50 pm

levon wrote: for anything to be displayed to a monitor it must go through the 2d card as well as the 3d, if you want openGL acceleration.
Aaah, IF you want OpenGL acceleration. But a 3D card is not necessary, as opengl runs in software.
levon wrote:...and anything directx is done with you 3D card if its a directX 3D card, like most the geforce and radeons are now, if not all.
If there's no 3D card present, DirectX/Direct3D calls for a primary display driver and accelerates everything in software mode (and that's rather slow).
levon wrote:back in the voodoo 2 days, when they were only a 3d card and not a 2d card, you had to plug your 2d card into your 3d card, then your 3d card to the monitor. these days the 2d card is built into your 3d card, and for anything to be drawn on the monitor it must go through it.
Aaah, if it's a 2D VGA card, then it's obviously needed (to convert data into color) but 3D acceleration is not anything mandatory.

Let's just drop the subject. I don't feel like fighting today or any day.


What could be the cause of the banding? Maybe a dithered render display feature might help, but I'm not sure.
Don't miss the sequel: "I still see dead people"

joeedh
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Post by joeedh » Mon Sep 20, 2004 1:26 pm

Uhh. . .your all talking about the 3D window, right? Because hardware acceleration has nothing at all to do with the renderer. The Blender (along with most free CG scanline or raytrace renderers) internal renderer is 100% software, to my knolwedge it doesn't support any of those fancy CG hardware raytracer-accelerated cards out there (normal 3D acceration isn't useful for CG rendering purposes, although that's changing).

joeedh

joeri
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Post by joeri » Mon Sep 20, 2004 3:09 pm

This thing is getting confussing.
Videocard. Card used to display text/images from your computer.
Yes you can use blender without a video card. In a renderfarm that is.
There a 2 mayor types of video cards.
With 3d hardware acceleration and without.
For displaying realtime 3d graphics you need a good 3d hardware accelerated video card.
For displaying renderd 3d images you need a card that is able to display images in 24bits color. 8bits for the red, 8 for the green and 8 for the blue.
Blender renders to 24 bits images. The realtime renderer renders to whatever you set it to render to (most of the time 16bit, for fast rendering). I think the model shade mode is 24 bit, or whatever your current video mode is in.
16 bit will give more banding then 24 bit. But all 'bits' will give banding depending on the size of the rendering.

Friday13
Posts: 54
Joined: Wed Oct 16, 2002 10:40 pm

Post by Friday13 » Mon Sep 20, 2004 11:57 pm

Thank you, joeri, for clearing things up.

Mats78: try using 32bit if you can.
Don't miss the sequel: "I still see dead people"

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