Texture mapping animation! (2600)
Here's a little animation routine that would be quite suitable for use as a title screen in a banked game (this demo is just under 3K and would probably take about 2-2.5K if written more efficiently). The technique I use here has some limitations, but allows some magic unlike anything the 2600 has seen before.
- A text logo scrolls up like the Star Wars opening crawl, scrolling off the top of the screen.
- The logo then zooms out from the center of the screen, then shrinks diagonally to the center.
- Another trapezoid crawl, but when the text reaches the middle of the screen the top of the text stretches until the text is rectangular, whereupon it shrinks to the top center.
- Finally the text does a really cool move combining the Star Wars crawl with the stretch and then "melts" down toward the center of the screen.
The demo repeats the above sequence of animations. The text itself is multi-colored and drawn flicker-free in a 48x66 window which is outlined by a single-pixel yellow box (itself an interesting trick).The basic drawing routine allow mapping the text on any trapezoidal(*) area of the screen; it could be easily adapted for certain other mappings as well. The primary requirement is that horizontal lines must remain horizontal, and the text must grow and shrink about the vertical centerline. It might be possible to accommodate left-right mirroring (e.g. for text that spins about the horizontal axis) but it would be tricky. Vertical mirroring, however, should pose no problem.(*) A trapezoid whose parallel sides are horizontal and which is symmetric about the vertical centerline.

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