raghu@unocss..unl.edu (Local Submission) (01/17/90)
Hi,
I am posting this for a friend of mine. Please send your replies to him
directly at butch@fergvax.unl.edu
Thanks
Raghu
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Hello Everyone,
I'm a fairly new Amiga user and am playing around with assembly
language. Since I couldn't afford a C compiler when I first got the
Amiga, I bought the DevPac Amiga developers assembler from HiSoft (since
I actually enjoy programming in Assembly language, sadistic as it is)
and have been very pleased with it. However, I've run into problems when
trying to build a screen by using the Amiga's graphic primitives. I've
got several books which give the procedure, but all example code is in
C. I've got the Amiga Books (Hardware Manual, Includes and Autodocs, Sybex
Programmer's Guides and the Machine Language Programmers book from
Abacus), but this still doesn't help me. I've been able to open a
screen from intuition, but that's not really what I want.
I'm able to allocate the necessary memory I need for graphic
structures (Rastport, View, Viewport, Bitmap, RasInfo, etc) and have not
had any problems initializing them to what they need to be (I've
watched the progress with my debugger). However, the trouble begins
when I create the copper lists and try to load the view. I have
struggled on this for about a month now and have exhausted most of my
ideas, so I was wondering if anyone has assembly code which builds a
display using graphic primitives (MakeVPort, MrgCop, LoadView, Init's),
or know where I can look to find the answers. I'd really appreciate any
help anyone can give me. Does Commodore have any docs on this which
they would give (or sell) to a non-developer, yet devoted owner like myself?
Also, I would like to know (or would like an opinion) if to double
buffer an animation, would one only need to have two separate bitmaps
and respective Bitmap structures, and then just switch pointers in the
RasInfo and Viewport structures when a new image is to be displayed?
I thought perhaps if only the address of the image to be displayed were
changed, this would be enough info for the Amiga...or am I just being
stupid?
Any info can be mailed to my account, butch@fergvax.unl.edu .
Thanks in advance for you help.
Charles Rosecrans, Jr.rubin@mead.UUCP (Daniel Rubin) (08/24/90)
I have a couple of technical questions.. How does a computer generate the video representation of screen memory? How does a computer update the memory that is used for the screen? I was thinking and I got stuck when I thought about a 25Mhz (fast!) processor. It seems to me that a the most memory that this processor can update at 60Hz or 60 times a second (which if I am not mistaken is the speed that a television redraws its picture and monitors are even faster) is only .417 Megabytes??? Is this correct - the most graphical data that you can malipulate is less than 1/2 of a Meg at the normal speeds of a typical television when you are using a 25Mhz processor dedicated to graphics? Is there something that I am missing - perhaps there is some sort of co-processor or something. Anybody out there who knows something about microprocessors ect.. please help me out.......... Thanks in Advance - Dan Rubin