From Functional Animation
to Sprite-Based Display

Conal Elliott

Abstract

Functional animation encourages a highly modular programming style, by supplying a set of arbitrarily composable functions for building up animations. In contrast, libraries for sprite-based display impose rigid structure, in order to allow acceleration by hardware and low level software. This paper presents a method to bridge the gap between functional specification and stateful, sprite-based presentation of animation. The method's correctness is proved informally by derivation from a simple non-effective specification, exploiting algebraic properties of the animation data types that are made explicit in the functional approach. We have implemented this method in the Fran system, which is freely available.

Content:

Postscript (453K)
Animations
Expanded version with more detail
Partial C++ implementation

BibTeX:

@InProceedings{Elliott99:Spritify,
  author       = {Conal Elliott},
  title        = {From Functional Animation to Sprite-Based Display},
  url          = {http://conal.net/papers/padl99/},
  booktitle    = {Practical Aspects of Declarative Languages},
  year         = 1999
}