English Amiga Board Amiga Lore


Go Back   English Amiga Board > Main > Retrogaming General Discussion

 
 
Thread Tools
Old 08 December 2015, 20:25   #1
albino
Registered User
albino's Avatar
 
Join Date: Dec 2006
Location: france
Age: 38
Posts: 95
gods scrolling question

Hi everyone, i was wondering why gods's scrolling is not smoother as it doesn't use any parallax! is an amiga hardware problem or a programmer skills one?
albino is offline  
AdSense AdSense  
Old 08 December 2015, 20:27   #2
Retro1234
5150

Retro1234's Avatar
 
Join Date: Jun 2006
Location: Sycophantazia
Posts: 3,702
No No no no no no no,so so so so wrong
I guess it uses the same scrolling as ST and Amiga parallax before AGA is shite and even with AGA...............
Retro1234 is offline  
Old 08 December 2015, 20:31   #3
Mrs Beanbag
Glastonbridge Software
Mrs Beanbag's Avatar
 
Join Date: Jan 2012
Location: Edinburgh/Scotland
Posts: 2,202
so many Bitmap Brothers' games on Amiga were just straight Atari-ST ports, or i suspect, it was designed from the outset to be available for both machines so there is the lowest-common-denominator factor. Making the scrolling smoother would have meant changing all the game dynamics to cope with the higher frame rate!

I don't know what method they are using for the scrolling, maybe Codetapper can fill us in on the details...
Mrs Beanbag is offline  
Old 08 December 2015, 21:28   #4
gimbal
cheeky scoundrel
gimbal's Avatar
 
Join Date: Nov 2004
Location: Spijkenisse/Netherlands
Age: 36
Posts: 2,932
Quote:
Originally Posted by albino View Post
Hi everyone, i was wondering why gods's scrolling is not smoother as it doesn't use any parallax! is an amiga hardware problem or a programmer skills one?
Or just a design choice, it doesn't have to be rooted in negativity.
gimbal is offline  
Old 08 December 2015, 21:44   #5
Mrs Beanbag
Glastonbridge Software
Mrs Beanbag's Avatar
 
Join Date: Jan 2012
Location: Edinburgh/Scotland
Posts: 2,202
i think the question is about why the scrolling is not smooth, rather than why there is not parallax. It seems the assumption is that parallax would slow it down, so it would be an excuse if it were present...

Well there are (at least) two ways to achieve parallax on the Amiga, the most obvious way is "dual playfield mode" which allows you to have two screens superimposed in hardware, with one showing through the gaps in the other. There is not much performance hit, because it is a hardware mode, but you only get to use 3 bitplanes (i.e. 8 colours) per screen, so it really limits your graphics (on AGA this is better because you get two 16-colour playfields, so a lot of AGA versions of games could "easily" put a parallax layer in since the main graphics were already 16 colours anyway). There are some games that make it work, Kid Chaos and Soccer Kid are two that spring to mind, but Bitmap Brothers have their graphical style which maybe wouldn't translate very well.

Another way to achieve it is to use the blitter, to copy the background layer behind the foreground layer on every frame. You can use any colours you like with this method of course, but there is a speed penalty of actually having to copy a screen-sized graphic every frame. It's do-able with how bad the scrolling is on Gods (it appears to scroll about every 3 vbls) but on the whole there's not many gaps in the foreground for a background to show through anyway. More likely they just didn't want to do any extra work for the Amiga version over the ST version that they didn't have to.

I believe Agony uses a combination of the two above approaches to achieve 3 parallax layers.

another way to get parallax effects is to use sprites to do it, since they can be placed above, below or between the playfields. Jim Power uses sprites to achieve a third (stationary) parallax layer at the back. But you have to re-use sprites across the screen so you need a very heavy copper list, and usually a repetitive pattern.
Mrs Beanbag is offline  
Old 08 December 2015, 22:12   #6
albino
Registered User
albino's Avatar
 
Join Date: Dec 2006
Location: france
Age: 38
Posts: 95
Quote:
Originally Posted by Mrs Beanbag View Post
i think the question is about why the scrolling is not smooth, rather than why there is not parallax. It seems the assumption is that parallax would slow it down, so it would be an excuse if it were present...
That's exactly what i mean....
As the amiga hardware is pretty good in smooth scrolling why this game does'nt follow the logic?
albino is offline  
Old 08 December 2015, 22:18   #7
Retro1234
5150

Retro1234's Avatar
 
Join Date: Jun 2006
Location: Sycophantazia
Posts: 3,702
Chaos Engine and Speedball 2 got AGA rehash I wonder if Bitmap Brothers considered Gods.
Retro1234 is offline  
Old 08 December 2015, 22:18   #8
Mrs Beanbag
Glastonbridge Software
Mrs Beanbag's Avatar
 
Join Date: Jan 2012
Location: Edinburgh/Scotland
Posts: 2,202
maybe, *maybe* the Amiga version spends 2 VBLs out of every 3 just sitting there doing nothing, because if it ran at full speed it would just be silly.
Mrs Beanbag is offline  
Old 08 December 2015, 22:33   #9
s2325
Zone Friend

s2325's Avatar
 
Join Date: Jun 2006
Location: Gargore
Age: 37
Posts: 17,546
Yes, console version is faster and smoother and almost unplayable for me.
s2325 is online now  
Old 08 December 2015, 22:34   #10
Predseda
Puttymoon inhabitant
Predseda's Avatar
 
Join Date: Mar 2007
Location: The City of Townsville
Age: 39
Posts: 4,443
Bingo!
Predseda is offline  
Old 08 December 2015, 22:38   #11
Mrs Beanbag
Glastonbridge Software
Mrs Beanbag's Avatar
 
Join Date: Jan 2012
Location: Edinburgh/Scotland
Posts: 2,202
i watched a review of Gods for Megadrive, it looks to be 25fps rather than the ~16fps the Amiga version gets. It does look a bit like the Charlie Chaplin version, still the reviewer complained of bad frame rate, because Megadrive gamers typically expect 50fps.

Actually it was probably the NTSC version so it would have been 30fps...
Mrs Beanbag is offline  
Old 08 December 2015, 22:56   #12
albino
Registered User
albino's Avatar
 
Join Date: Dec 2006
Location: france
Age: 38
Posts: 95
The amiga ntsc version run probably faster and got full screen size...but cannot find it.

the amiga game look like a straight port of the st, that's why they didn't touch the scrolling..
albino is offline  
Old 09 December 2015, 04:39   #13
ReadOnlyCat
Code Kitten

 
Join Date: Aug 2015
Location: Montreal/Canadia
Age: 46
Posts: 1,002
Quote:
Originally Posted by Mrs Beanbag View Post
maybe, *maybe* the Amiga version spends 2 VBLs out of every 3 just sitting there doing nothing, because if it ran at full speed it would just be silly.
If the code is not too ugly, maybe the scrolling speed and gameplay refresh rate could be decoupled from one another with relatively few modifications.

I suspect that the game does not use hardware scrolling at all though, otherwise the Bitmap Brothers could have made this modification themselves. I mean, if the game has a
draw_background
and a
draw_bobs
function, adapting it to the Amiga is as simple as gutting the former of most of its code except for discovered tiles and adding a scroll register update and adapting the latter to use the blitter. This should be at worst two days of work (worst case: one week) even in assembly language provided the code is modular. Just these two changes would provide a massive speed boost compared to the ST making the decoupling of gameplay and display more valuable to pursue.

We keep hearing the "didn't bother adapting for the Amiga" excuse but the amount of work needed is so low with a properly written program that I am tending to think that either these code bases were a horrible spaghetti mess (yeah for assembly) or many of the coders were blatantly incompetent. It seems hard to justify refusing even two additional weeks of coder time when the result could have run two times faster on another platform. The return on investment is definitely worth it if you can add "50 FPS" on the box.
ReadOnlyCat is offline  
Old 09 December 2015, 07:53   #14
vulture
Registered User
 
Join Date: Oct 2007
Location: Athens , Greece
Posts: 642
@albino

You can run Gods in NTSC mode (whdload tooltype) and it's indeed as fast as the mega drive version and full screen.
vulture is offline  
Old 09 December 2015, 11:42   #15
Sandro
Banned
 
Join Date: Feb 2013
Location: spain
Posts: 897
Quote:
Originally Posted by albino View Post
Hi everyone, i was wondering why gods's scrolling is not smoother as it doesn't use any parallax! is an amiga hardware problem or a programmer skills one?
because it works at 25 fps instead 50 fps

bitmap brothers used idem lame engine for games like, chaos engine,magic pockets etc
none of them are smooth
Sandro is offline  
Old 09 December 2015, 11:59   #16
vulture
Registered User
 
Join Date: Oct 2007
Location: Athens , Greece
Posts: 642
@sandro

actually, it's worse than that, it's every third frame hence the 16,66 fps figure Mrs Beanbag mentioned
vulture is offline  
Old 09 December 2015, 12:39   #17
Mrs Beanbag
Glastonbridge Software
Mrs Beanbag's Avatar
 
Join Date: Jan 2012
Location: Edinburgh/Scotland
Posts: 2,202
Quote:
Originally Posted by ReadOnlyCat View Post
If the code is not too ugly, maybe the scrolling speed and gameplay refresh rate could be decoupled from one another with relatively few modifications.
Smooth scrolling with jerky sprites can look worse imho, especially if it's the player character, it would look terrible.
Mrs Beanbag is offline  
Old 09 December 2015, 12:46   #18
Predseda
Puttymoon inhabitant
Predseda's Avatar
 
Join Date: Mar 2007
Location: The City of Townsville
Age: 39
Posts: 4,443
I have no problem with Gods as is. Scrolling is choppy, but the game is slow, so I can accept it. NTSC is not a solution as it speeds up the sound.
Predseda is offline  
Old 09 December 2015, 12:54   #19
vulture
Registered User
 
Join Date: Oct 2007
Location: Athens , Greece
Posts: 642
@Predseda

yeah, but.... in game, it's just sound fx, so, imo, no big deal
vulture is offline  
Old 09 December 2015, 12:56   #20
Muzkat
Into the Wonderful
Muzkat's Avatar
 
Join Date: Jul 2001
Location: Earthrealm
Age: 36
Posts: 1,281
While I will openly admit that Gods is my favourite Amiga game of all time, I will also go on the record to say I've never noticed any choppiness with the frame rate.

Then again, I can't tell the difference between 30FPS and 60FPS in modern day games either. It's just something I don't pick up.
Muzkat is offline  
AdSense AdSense  
 


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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Indivision 1200 AGA MK2cr scrolling question schneidas support.Hardware 45 29 July 2015 13:09
Hardware scrolling question oRBIT Coders. Asm / Hardware 3 11 April 2015 10:57
Scrolling Shoot'em'up??? K1ngArth3r Looking for a game name ? 34 20 July 2013 13:26
Which better for Scrolling Beat em up? Amiga Forever Coders. General 18 02 April 2011 19:10
smooth scrolling sink support.WinUAE 3 20 July 2007 01:16

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 00:34.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Page generated in 0.40869 seconds with 11 queries