Xref: utzoo comp.graphics:10115 comp.sys.ibm.pc:45221
Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!zaphod.mps.ohio-state.edu!uakari!ames!ncar!tank!mimsy!nems!news
From: news@nems.dt.navy.mil (USENET News System)
Newsgroups: comp.graphics,comp.sys.ibm.pc
Subject: Re: VGA - direct memory access question
Message-ID: <1090@nems.dt.navy.mil>
Date: 26 Feb 90 12:36:25 GMT
References: <90039.091705IAP@PSUVM.BITNET>
Reply-To: flitter@dtrc.dt.navy.mil (Lance Flitter)
Followup-To: comp.graphics
Lines: 14

From: flitter@dtrc.dt.navy.mil (Flitter)
Path: dtrc!flitter

>    My question is this: where in the heck are the pixel values
>stored in memory for the VGA adapter in 640x480 16 color mode?
>Every book I've seen covers only monochrome graphics and uses
>the method above to write/read pixels.

  In 16 color mode there are four bit planes each of which are mapped into the
  same address space: A0000 - AFFFF. In order to get the value of a pixel you
  have to use the segment registers so you get all four bit planes. You will
  want to AND them together to find whether the monochrome pixel is on or off.
  I don't remember the proper settings off the top of my head. If you still
  need them write me a message and I'll look it up.