English Amiga Board


Go Back   English Amiga Board > Main > Retrogaming General Discussion

 
 
Thread Tools
Old 30 January 2012, 06:47   #1
mc6809e
Registered User
 
Join Date: Jan 2012
Location: USA
Posts: 281
Did Starglider use the blitter?

I remember how disappointed I was with the frame rate of Starglider. I always suspected that it was a direct port and that none of the blitter's features were used.

Does anyone know if the game used the blitter's line draw or area clear functions or anything else Amiga specific?
mc6809e is offline  
AdSense AdSense  
Old 30 January 2012, 11:48   #2
StingRay
move.l #$c0ff33,throat

StingRay's Avatar
 
Join Date: Dec 2005
Location: Berlin/Joymoney
Posts: 5,593
The game does use the blitter.
StingRay is offline  
Old 30 January 2012, 13:54   #3
fishyfish
Banned
 
Join Date: Jul 2010
Location: Australia
Posts: 475
It is quite slow, but Id hardly call the framerate bad. It's quite smooth even on a stock a500.
fishyfish is offline  
Old 01 February 2012, 02:23   #4
Lord Riton
Registered User
Lord Riton's Avatar
 
Join Date: Jan 2011
Location: France
Age: 45
Posts: 490
Starglider 2 was much much better ! An incredible game !

Only played starglider 1 on an Amstrad cpc, and it was rather a good game too, for that computer at that time, of course.
Lord Riton is offline  
Old 03 February 2012, 11:37   #5
Oscar Castillo
Junior Member
Oscar Castillo's Avatar
 
Join Date: Nov 2001
Location: New Jersey, USA
Posts: 282
Send a message via AIM to Oscar Castillo
It did slow when more enemies were in the frame, but it was decent on a stock 500 from what I remember.
Oscar Castillo is offline  
Old 03 February 2012, 16:03   #6
Adropac2
Zone Friend
 
Join Date: Jan 2006
Location: Kent
Age: 45
Posts: 834
I don't think Starglider2 is an amazing game actually but it's a convincing enough game world that i love to be in

A really good example of how the load/save sytem pretty much ruined any sense of tension you might oherwise have had though- i simply just saved prior to a difficult spot and loaded back in each time if i messed up, which ruins the experience. Even now this stupid save system exists

I recall Jez San saying saying something about the blitter and Starglider1 but it's not something you can use for filled in polygons? and so that's why the ST had ever so slightly faster 3d generally- which frankly the differences there i still don't see
Adropac2 is offline  
Old 03 February 2012, 16:29   #7
AmigaFriend
Registered User
AmigaFriend's Avatar
 
Join Date: Sep 2008
Location: CLI
Posts: 1,464
I never played Starglider 1 but I can say for the time, in 1988, Starglider 2 was an incredible game. I still remember the 'wow' moment I had when I heard that whale for the first couple of times. I played for weeks that game an amazing experience, very immersive game.

Also concerning the subject of this thread, although a different game, I think it was fast enough giving a good experience to the player.
AmigaFriend is offline  
Old 04 February 2012, 07:08   #8
mc6809e
Registered User
 
Join Date: Jan 2012
Location: USA
Posts: 281
Quote:
Originally Posted by Adropac2 View Post
I recall Jez San saying saying something about the blitter and Starglider1 but it's not something you can use for filled in polygons? and so that's why the ST had ever so slightly faster 3d generally- which frankly the differences there i still don't see
Many multiplications are needed each frame to determine the positions of all vertices. These calculations dominate in situations where rendering is wireframe. The Amiga's blitter doesn't help much. Calculations on the ST are going to be about 12% faster.

Filled polygons are another story. The Amiga's blitter definitely makes a difference there.

Of course if someone could come up with a series of blits that used a variety of logic functions to perform binary multiplies, that might really help. Sounds ridiculous, but consider Gerald Hull who used a 9 blit combination to perform additions in a blitter accelerated implementation of Conway's LIFE. Maybe using the blitter to accelerate 3d calculations isn't impossible.

Start with 16 blits to create an 16x16 bit array of partial products for each pair of values. That's easy. Coming up with a quick way to sum them properly is more challenging. Maybe Wallace-tree. I think I remember 64 full adders were needed with Wallace tree for 16x16 mult. A full adder with the blitter takes two blits. So we're up to at least 16+64*2=134 blits.

At least nine MULs are required per vertex for handling rotations and maybe a couple of DIVs when mapping from 3d space to screen coordinates. That's a lot of cycles. The nine MULs on the 68000 are going to cost around 360 to 630 cycles. That's for each vertex, but most of it is internal processing. If the blitter were calculating in parallel, even inefficiently, it might still speed things up overall. If the 134 blits number is correct, then the total number of cycles per multiply is slightly over 1000. Nine times that for each vertex and it's near 10000 cycles. So the blitter would be about 1/20th the speed of the CPU. That's disappointing. It would only be a tiny increase in speed -- and probably wiped-out by the overhead of setting up the blitter.

Maybe there are some tricks that can be used to reduce the total number of blits. It's possible the area fill logic can be exploited to help with the additions (the high bit of every nibble can do the mod 2 sum of the previous three bits).

Computers are so fast now maybe the optimal sequence of blits can be determined by brute force.
mc6809e is offline  
Old 04 February 2012, 16:19   #9
Supamax
Da Digger :)

Supamax's Avatar
 
Join Date: Nov 2008
Location: Monza, Italy
Posts: 2,509
Quote:
Originally Posted by xpect View Post
I can say for the time, in 1988, Starglider 2 was an incredible game. I still remember the 'wow' moment I had when I heard that whale for the first couple of times. I played for weeks that game an amazing experience, very immersive game.
I agree, especially with the "wow" moment hearing&seeing the whales .
I loved the Stardrive (do I recall the name exactly?) too.
Supamax 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
How Starglider 2 became Starfox kamelito Nostalgia & memories 8 14 April 2013 01:49
Starglider 2 Novella Retro-Nerd request.Other 9 30 June 2010 01:25
about Starglider dlfrsilver HOL contributions 4 18 May 2007 21:15
Starglider - Gamemap Carcharias HOL contributions 2 09 September 2006 20:44
Starglider 2 WHDload v1.2.1 killergorilla request.Old Rare Games 2 03 August 2005 14:09

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 19:30.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Page generated in 0.28806 seconds with 11 queries