Re: More orca/m - flicker free animation

[jlee@Bonnie.ICS.UCI.EDU (Joseph)]

In article <93161.180749KCR103@psuvm.psu.edu> Ken (something?) writes:
>I have been using the block move instructions for the animation routines I am
>working on.  First of all, are the MVP and MVN instructions the most efficient
>ways of moving data around using the 65816?  Also, there was some talk about

Yes and no. It is faster than a lda/sta/iny/iny/bne loop, rolled or
unrolled, but only on an accelerator which will cache the mvp/mvn
instruction.  It's way too inefficient on a stock GS.

A faster technique, one developed by somebody, and used in Rastan, DuelTris,
and all those superfast stuff by programmers like John Brooks, Steve Chiang,
Nathan Trost, and others, is mapping the stack to the shadow screen and
pushing graphics onto the shr screen and works best with compiled graphics.
Technique is called by most as stack blasting.

>flicker free animation recently.  If I check the scan line register and find it
>is on a different line I am about to write to, will I have flicker free
>animation as a result?  Any help will be appreciated.  Thanks.

It's actually better if it's below the line you want to draw, because what
happens if it just 2 or 1 line above the line you're drawing? The scanline
will catchup and pass your drawing and FLICKER.  The recommendations I've
gotten from Richard Witfall is to wait until the line is at least 4 lines
below what you want to draw.

Look through the demo and graphics stuff at cco.caltech.edu.  It's a good
start to learn graphics programming, besides talking to, asking, bothering
(hi Steve :) the people who are the pros at this.

Hope this helps

>Ken

Joseph