Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!portal!cup.portal.com!Sullivan
From: Sullivan@cup.portal.com (sullivan - segall)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Bitplanes - good or bad
Message-ID: <28749@cup.portal.com>
Date: 10 Apr 90 03:02:02 GMT
References: <5917@tekig5.PEN.TEK.COM> <10432@cbmvax.commodore.com>
  <5943@tekig5.PEN.TEK.COM>
Distribution: na
Organization: The Portal System (TM)
Lines: 72

>In article <10432@cbmvax.commodore.com>, daveh@cbmvax.commodore.com (Dave Haynie) 
w
>rites: 
>> In article <5917@tekig5.PEN.TEK.COM> wayneck@tekig5.PEN.TEK.COM (Wayne C Knapp) 
w
>rites: 
>> 
>> >After many countless hours of programming on my Amiga.  I'm becoming to 
>> >realize that a major short comming of the Amiga is the fact that it uses 
>> >a bitplane memory design for graphics and any real graphics require the 
>> >processor.  
>> 
>> You have to define "graphics" considerably more carefully to make that a
>> true statement.  What you're really talking about is pixel by pixel image
>> processing.  
>
>This is a resonable point.  I didn't do a good job of choosing my words here.
>Of coarse the Amiga is an excellent platform for many kinds of graphics. 
>Everyone must be aware of how nice a job the Amiga does with windowing and
>paint type fuctions.  What I should said is,  many graphic fuctions require 
>the processor.   I'm sorry about my poor choice of wording.
>
>However, there are many things happening in the graphics field today that
>were only being touched on in 1985.  When I first read about the Amiga in 
>BYTE and read about the reasons for using bitplanes I was very impressed! 
>I rushed to get an Amiga.  Since then things like raytraceing on micros,
>image processing on micros, spline based interfaces, 3D animations, and
>many other things have started to become common place.  It is in these areas
>that the extra hardware is often of little use when dealing with bitplanes.
>Prehaps, future Amigas will be better suited to these type of problems.  The
>last 5 years has been explosive in graphics and the demands on computers is
>increasing all the time.  
>
>Pixel by pixel image processing is only one of many areas where bitplanes are
>not an aid.   
>
>Currently I'm trying to figure out how to get improved drawing speeds for
>a spline based interface.  It is hard.  I will probably end up living with
>a just barely usable system speed-wise since it is just too hard to get the
>speed I would like out of the bitplanes.  The problem is changing points.  If
>I was only using one or two colors it would be easier since I could assign a
>bitplane per color.  However, I'm at the point were I can't get more speed
>without giving up colors or other things I don't want to.  Since this is
>the user interface I force into dealing with the bitplanes.  Converting an
>image from fast RAM into the bitplanes is just too slow.
>
Wayne, I'm not going to tell you how to write your programs, but it seems 
to me that you are working the problem from the wrong end.  Rather than treating
a bit-plane based system like a pixel based system, why not draw your splines
into an empty plane, and then blit-or it into the appropriate on planes, or
blit-nand it into the inappropriate planes.  You could even draw into 16
different planes and blit combine them later.  If your splines are really 
short then perhaps it would be better to recalculate them for each plane.
Anyway, as long as you use the former method, the CPU is *NOT* required for
drawing the screen (beyond the initial calculations.)


In any case, 'of course' is spelled O-F C-O-U-R-S-E.

Sorry, it hurts my brain to see 'of coarse'. -ss
 
                           -Sullivan Segall
_________________________________________________________________
 
/V\  Sullivan  was the first to learn how to jump  without moving.
 '   Is it not proper that the student should surpass the teacher?
To Quote the immortal Socrates: "I drank what?" -Sullivan
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