Scrolling Game Development Kit Forum

SGDK Version 2 => Help, Errors, FAQ => Topic started by: SmartBoy16 on 2007-08-25, 05:55:05 AM

Title: 24 bit vs 32 bit
Post by: SmartBoy16 on 2007-08-25, 05:55:05 AM

i was just wondering, if SGDK2 involves having alpha transparency, shouldn't a 32 bit graphics card be required for running SGDK2. My (outdated) graphics card only supports up to 24 bit color and cannot correctly view PNG graphics without clogging up my system. (usually i can have up to two large size pictures doing this)

Title: Re: 24 bit vs 32 bit
Post by: bluemonkmn on 2007-08-25, 09:59:09 AM

Sometimes alpha translucency can be emulated in software, I think, depending on the driver.  I'm not sure how this works.  Does SGDK2 work on your video card?

Title: Re: 24 bit vs 32 bit
Post by: SmartBoy16 on 2007-08-25, 03:58:36 PM

it does, only the map editor doesn't work. the graphics editor works, but really slows down my system. my compute is a 98se with only 256 MB of memory. I'm planning to get a new one soon anyway.

Title: Re: 24 bit vs 32 bit
Post by: bluemonkmn on 2007-08-26, 06:33:50 AM

I suspect the slowness might be DirectX emulating alpha translucency in software.

Title: Re: 24 bit vs 32 bit
Post by: SmartBoy16 on 2007-08-26, 01:08:38 PM

i just went through the dxdiag thing and it worked just fine. i also noticed i get two diferent messages whether im in 16 bit or 24 bit (see attatchments) the error message is the same

Title: Re: 24 bit vs 32 bit
Post by: durnurd on 2007-08-26, 06:00:30 PM

The 16-Bit mode would never work. The error message displayed makes sense, in that case, since the 16-bit hardware mode doesn't even support the full color range.

Title: Re: 24 bit vs 32 bit
Post by: SmartBoy16 on 2007-08-27, 08:51:22 AM

there are some image files that support 16 bit color with transparency, 15bit is color and 1bit is the alpha channel

Title: Re: 24 bit vs 32 bit
Post by: durnurd on 2007-08-27, 03:30:39 PM

If 1 bit is the alpha channel, it's not very alpha.  More like boolean transparency in that case, in which case it would be better to just define some color that doesn't show up in the image as the transparent color like GIF does.  Anyway, PNG is not one of those formats, and PNG is the format that SGDK2 uses.