[comp.os.msdos.programmer] Reference for Smooth Animation Algorithm

davecarr@tove.cs.umd.edu (David Carr) (06/20/91)

Hello,

Does anyone know were to find an algorithm to do smooth animation
of a sprite across an arbitrary background.  By smooth I mean that
I don't want to see the background flicker through the sprite. 
Examples of existing programs with this type of animation are Windows
Solitare and any mouse driver.  I would appreciate a reference or
algorithm description.

Thanks in advance.

David Carr (davecarr@cs.umd.edu)

sorrow@oak.circa.ufl.edu (06/21/91)

Mouse cursors use two bit masks (monochrome) via XOR then an AND of a 
screen mask and a cursor mask.  The Logitech Mouse PRogrammer's Reference
describes this.  This is flicker free mostly because it is all done using
1-bit plane logic (monochrome).

As for good full screen animation, a technique called double buffering is
used, where you draw to hidden page while looking at another one, then you
swap pages when ready, etc.

As for solitaire, it seems to use a standard XOR technique much like the
mouse cursor.  If you have a Microsoft C or Borland compiler, look at the
getimage() and putimage() functions.  MSC is _getimage() and _putimage().

Brian
/*
Brian Hook -- MS-DOS Programmer for Contract
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