8K section of memory on the TV screen. When in bit map mode, you can directly control whether an individual dot on the screen is on or off.
There are two types of bit mapping available on the Commodore 64. They are:
Each is very similar to the character type it is named for: standard has greater resolution, but fewer color selections. On the other hand, multi-color bit mapping trades horizontal resolution for a greater number of colors in an 8-dot by 8-dot square.
Standard bit map mode gives you a 320 horizontal dot by 200 vertical dot resolution, with a choice of 2 colors in each 8-dot by 8-dot section. Bit map mode is selected (turned ON) by setting bit 5 of the VIC-II control register to a 1 at location 53265 ($D011 in HEX). The following POKE will do this:
POKE 53265,PEEK(53265)OR 32Bit map mode is turned OFF by setting bit 5 of the VIC-II control register to 0 at location 53265 ($D011), like this:
POKE 53265,PEEK(53265)AND 223Before we get into the details of the bit map mode, there is one more issue to tackle, and that is where to locate the bit map area.
If you remember the PROGRAMMABLE CHARACTERS section you will recall that you were able to set the bit pattern of a character stored in RAM to almost anything you wanted. If at the same time you change the character that is displayed on the screen, you would be able to change a single dot, and watch it happen. This is the basis of bit-mapping. The entire
|This page has been created by Sami Rautiainen.|
|Read the small print.||Last updated May 12, 2002.|