A.D.A. Amiga Demoscene Archive

  Welcome guest! Please register a new account or log in

  

  

  

log in with SceneID

  

Demos Amiga Demoscene Archive Forum / Coding / Planar Pixel Plotting
 Page:  ««  1  2  
Author Message
Azure
Member
#1 - Posted: 5 Jan 2010 01:55
Reply Quote
Hardcode not hardcore. Well, it is hardcore after all...
klipper
Member
#2 - Posted: 7 Jan 2010 01:08
Reply Quote
happy hardcore ravers in the house ...put your hands in the air and blow your whistles!!
Rebb
Member
#3 - Posted: 23 Feb 2010 04:15 - Edited
Reply Quote
ZEROblue:
By extending your bitplanes to f.ex 64 bytes wide for faster addressing you can do:

Little bit puzzled what this means in real life use.
Many many thanks to Kalms,d0DgE and rest for great tips so far.
ZEROblue
Member
#4 - Posted: 23 Feb 2010 05:16
Reply Quote
It just means there's a 64 byte span between one bitplane line and the next, and so you can address individual lines very fast by using a single shift instruction to multiply the Y coordinate by 64.

For a typical lowres screen you would have 64*256 bytes per bitplane and set data fetch registers as usual, but set the bitplane modulos to 24 so it reads the usual 40 bytes and then skips over the last 24 to get to the next line.

Those extra bytes between the lines are not lost or anything, they are fully useable like any other chipmem, just in a poor arrangement.
d0DgE
Member
#5 - Posted: 23 Feb 2010 14:30
Reply Quote
Actually, I will adjust my introsystem to such aligned bitplanes.
To only have to do an "lsr.w #6,dx" to determine the Y coordinate speeds up the pixel drawing
considerably.

But ATM I'll stick to standard 40-byte aligned planes b/c it would be too much of a work to change my framework by now.
 Page:  ««  1  2  

  Please register a new account or log in to comment

  

  

  

 

A.D.A. Amiga Demoscene Archive, Version 3.0