denis@vlsisj.VLSI.COM (/) (09/07/89)
I am starting to write some code to do simple animations and am wondering
how other people are going about it. So far I have written an iff ilbm
reader and created two screens. To double buffer the display I pop one
screen to the front and then blit into the other hidden screen. I am
using ClipBlit to blit my objects onto the screen. I create the various
views of the objects in a paint program. The first thing I ran across
was that I needed an outline mask for the object so that I can clear out
the screen, using the mask, before oring the object onto the screen with
ClipBlit. To get the outline mask I just BltPattern each object bitplane
into a single bitplane. I am currenly using WaitTOF to slow down the
animation (the Amiga is just too darn fast!). Each time an new screen
is drawn each object can change its position and image.
Is this how others are doing things? Does anyone use the built in
animation stuff, BOBs? I was going to use it but it seemed like it
was kind of limited (no sound info, just has acceleration and velocity
control). The real reason I did not try it first was that it looked
like a lot of stuff to learn how to use. If anyone has some neat demo
that uses this stuff I would really like to see it!
One thing that I could not figure out how to get is the current frame
number. I wanted to save the current frame number when I pop a screen
to the front. Then I can draw into my hidden screen. Then I can wait
until at least N frames later to pop the hidden screen to the front.
That way I can make sure that the animation does not go too fast,
while going as fast as I can when there are other tasks slowing things
down. Is the current frame number available somewhere or should I
create a vertical blank counter of my own?
Anouther thing that I am not sure about is how to create two views
using one screen. I want a screen so that the user can depth arrange
the animation, but I want two views so that I can double buffer.
Leo Schwab posted a neat way to create two views for double buffering,
but I do not know how to do this with a screen. Does someone know how
to do this?
Any comments on any of the above or animation in general would be
very welcome!
Denis Bohm (usenet: decwrl!vlsisj!denis)
(internet: vlsisj!denis@decwrl.dec.com)
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Denis Bohm (usenet: decwrl!vlsisj!denis)
(internet: vlsisj!denis@decwrl.dec.com)