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3DFX Accelerators and glRasterPos/glDrawPixels

Started by Jean-Philip Desjardins Apr 30, 2000 at 12:52 PM 2 replies 1.2k views

Original Post

Apr 30, 2000 at 12:52 PM

I''m using glRasterPos and glDrawPixels to write an bitmap directly in the frame buffer. When I''m using my program in software mode, everything runs fast, but when I''m telling my program to use my 3DFX card to render the scene, the program becomes really slow. The same thing happened when trying the 13th Tutorial (Bitmap Fonts) with my 3DFX card. Is there something I can do about it? I have an Creative 3D Blaster 12MB and my program runs on the Win32 platform. Thanxs.

Demon Lord

May 1, 2000 at 12:16 PM

It has been largely discussed in a previous topic (Background... how?) about the ugly performances of rasterizing functions. It is also known that 3dFX OpenGL drivers are far from being perfect. That might explain some of your performances.

Eric Laberge

Bad Monkey

May 1, 2000 at 9:06 PM

Yes, sadly, using these raster functions in your program is akin to taking a large blunt object and beating the living shite out of it... it will thrash and moan and kick and scream, and eventually limp off into a corner to lick it''s wounds.

Most OpenGL bandits will recommend you avoid them and use texture-mapped quads to show bitmaps instead.

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squirrels are a remarkable source of protein...

Scootr7481

May 5, 2000 at 1:46 AM

Just so everybody knows, the reason that glRasterPos and glDrawPixels used in this was is because of this.

Just like when you use DirectX, you lose all hardware acceleration (and you will with any card out there, not just the voodoo) when you write your own blitter (bitmap drawing algorithm).

That''s why everyone''s performance sucks when they try. My reccomendation is to stick with the plain, and incredibly fast, harware blitter.

-- John d8?)

"No, really, I DO know it all!" <-- Yeah, Right!!

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