It is currently Thu Oct 19, 2017 6:41 pm

All times are UTC - 7 hours





Post new topic Reply to topic  [ 9 posts ] 
Author Message
PostPosted: Mon Sep 24, 2012 5:41 pm 
Offline

Joined: Wed Feb 23, 2011 4:14 pm
Posts: 21
Location: Belo Horizonte, Minas Gerais, Brazil
Here's an experiment I have been making:
http://www.smspower.org/forums/viewtopic.php?t=13923
It's an 64x48 2bpp 10fps video player; so far, I have only implemented it on the Sega Master System but the algorithm is pretty simple to implement, specially for systems that use a tile based background.


Top
 Profile  
 
PostPosted: Tue Sep 25, 2012 4:11 am 
Offline

Joined: Sun Sep 19, 2004 11:12 pm
Posts: 19104
Location: NE Indiana, USA (NTSC)
Sounds like Chris Covell's "Motion" demo or the Bad Apple video.


Top
 Profile  
 
PostPosted: Tue Sep 25, 2012 4:04 pm 
Offline

Joined: Wed Feb 23, 2011 4:14 pm
Posts: 21
Location: Belo Horizonte, Minas Gerais, Brazil
Yes, it's about the same idea.


Top
 Profile  
 
PostPosted: Fri Sep 28, 2012 10:09 pm 
Offline
Site Admin
User avatar

Joined: Mon Sep 20, 2004 6:04 am
Posts: 3470
Location: Indianapolis
The "move your feet" video converted pretty well. I like how it handled the colors, I thought it looked good.


Top
 Profile  
 
PostPosted: Sat Sep 29, 2012 7:40 am 
Offline

Joined: Wed Feb 23, 2011 4:14 pm
Posts: 21
Location: Belo Horizonte, Minas Gerais, Brazil
Thanks but, to be sincere, I still think the color conversion needs some tweaking. :P
Currently, for each pixel, it calculates it's brightness, which is what is actually used for choosing the background tile patterns; then, for each level of brightness, its calculated an average color, which is what's used for the frame's palette. The end result is a video with accurate brightness, but very innacurate colors. I've also experimented with a pallete-per-line encoding scheme that gives slightly better results, but haven't implemented that as a ROM, yet.


Top
 Profile  
 
PostPosted: Sat Nov 24, 2012 9:34 pm 
Offline
User avatar

Joined: Sat Feb 12, 2005 9:43 pm
Posts: 10063
Location: Rio de Janeiro - Brazil
Today I was messing with my Mega Everdrive (Genesis/MD flashcart that also runs Master System games) and decided to test this just because. It didn't work, there were just some random squares and some "snow". Does the program by any chance use something that a Genesis/MD in SMS mode doesn't support, like the old video modes? Did you test this on a Master System?


Top
 Profile  
 
PostPosted: Sun Nov 25, 2012 2:48 pm 
Offline

Joined: Wed Feb 23, 2011 4:14 pm
Posts: 21
Location: Belo Horizonte, Minas Gerais, Brazil
Unfortunately, I didn't test it on real hardware; in fact, it doesn't take into account the VDP bandwidth: it should take about 4 VBLANKs to upload everything to the VRAM.


Top
 Profile  
 
PostPosted: Sun Nov 25, 2012 4:56 pm 
Offline
User avatar

Joined: Sat Feb 12, 2005 9:43 pm
Posts: 10063
Location: Rio de Janeiro - Brazil
I don't know much about SMS programming, but I remember reading that you can write to VRAM during rendering, is that correct? But you have to do it slower than you'd do during VBlank, right?


Top
 Profile  
 
PostPosted: Mon Nov 26, 2012 3:23 am 
Offline
User avatar

Joined: Wed Feb 13, 2008 9:10 am
Posts: 577
Location: Estonia, Rapla city (50 and 60Hz compatible :P)
Z80 can never saturate VRAM bandwidth in VBL but during active display there is minimally only 8 slots and Z80 has no problems doing too many writes.

_________________
http://www.tmeeco.eu


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group