English Amiga Board


Go Back   English Amiga Board > Support > support.Hardware

 
 
Thread Tools
Old 23 July 2013, 19:09   #1
diablothe2nd
Registered User

diablothe2nd's Avatar
 
Join Date: Dec 2011
Location: Northampton, UK
Age: 38
Posts: 1,232
AGA alpha transparency question

i know that bobs can have a transparent colour, but can they have half transparent colours? for example a shadow used to darken what is behind it on a bob/sprite? or better yet alpha used in a way that removes jaggies and to blend better with the background.
diablothe2nd is offline  
Old 23 July 2013, 19:25   #2
Thorham
Computer Nerd

Thorham's Avatar
 
Join Date: Sep 2007
Location: Rotterdam/Netherlands
Age: 43
Posts: 3,089
AGA doesn't have alpha transparency so it has to be done in software, and that's going to get slow real quick.
Thorham is offline  
Old 23 July 2013, 19:28   #3
diablothe2nd
Registered User

diablothe2nd's Avatar
 
Join Date: Dec 2011
Location: Northampton, UK
Age: 38
Posts: 1,232
can you fake it?
diablothe2nd is offline  
Old 24 July 2013, 03:55   #4
Thorham
Computer Nerd

Thorham's Avatar
 
Join Date: Sep 2007
Location: Rotterdam/Netherlands
Age: 43
Posts: 3,089
You can set up the palette (preferably in a 256 color screen) so that certain bit plane combinations show an effect like alpha blending and transparency, but you have to calculate the different combinations of fore and background objects. This limits the number of free colors you have, but it can be fast. Doesn't work for hardware sprites, only for blitter and CPU sprites.

Actually, Diablo 2 uses the palette technique for transparancy in 256 color screens, so it's certainly possible.

Real alpha blending and transparency are, however, still a pain because you 1) have to do the blending/transparency calculations, and 2) you have to do it in HAM, or there's little point.
Thorham is offline  
Old 24 July 2013, 08:42   #5
diablothe2nd
Registered User

diablothe2nd's Avatar
 
Join Date: Dec 2011
Location: Northampton, UK
Age: 38
Posts: 1,232
thanks for the info
diablothe2nd is offline  
Old 24 July 2013, 14:15   #6
pandy71
Registered User
 
Join Date: Jun 2010
Location: PL
Posts: 1,690
Quote:
Originally Posted by diablothe2nd View Post
can you fake it?

Yep, by pattern for example.
pandy71 is offline  
Old 25 July 2013, 15:06   #7
xArtx
Registered User
 
Join Date: Jun 2013
Location: Australia
Posts: 679
Quote:
Originally Posted by pandy71 View Post
Yep, by pattern for example.
Win
xArtx is offline  
 


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Indivision AGA Config Question Ebster support.Hardware 2 17 July 2016 06:43
Released: Red Wizard Island alpha v.0.24 (AGA) r0ber7 project.Amiga Game Factory 34 14 January 2016 12:19
Eye of the Beholder AGA question. Thorham support.Games 1 13 December 2011 22:32
tinymeter transparency Skellionz project.ClassicWB 1 07 August 2011 16:28
Question about AGA display data fetches FrenchShark Coders. General 7 30 December 2007 16:40

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +2. The time now is 19:51.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2020, vBulletin Solutions Inc.
Page generated in 0.07684 seconds with 15 queries