Thanks guys ! Another cool way of using the Amiga. I thought you wouldn't be able to zoom bigger than the original image but using that technique you could. I wonder if the planet zoom at the start of Desert Dream uses it.
We've talked about Mr Pets 1*1 rotator before on here which is also used in the game Brian The Lion.
"As I write below, under chunky rotation, effects such as rotations are normally done in a "chunky" way. This program, however, performs an increasing skew of the image (think of it as a square slowly becoming a parallelogram), both horizontally and simultaneously vertically. The horizontal skew is accomplished by stepping the shift registers and bitplane pointers, while the vertical skew is done by an intricate blitter minterm and a table of masks that, for every degree of vertical shift, for every 16 bit word along the image's span from left to right, describe what pixels, in that word, are to be plotted one line below all the other ones. The table of masks were precalculated beforehand with a Pascal program that calculates the horizontal positions where the image will be "broken up" during the increasing shift, and aligns the data to 16-pixel segments, for blits. According to Pythagoras' Theorem, "the square of the hypotenuse equals the sum of the squares of the other two sides". Thus, the image has to be shrinked a bit in addition to the skewing, to preserve its shape. (This is done the usual way by making a copper list that skips certain scan lines). "
http://ada.untergrund.net/forum/index.php?action=v thread&forum=4&topic=140
Scroll down to full planar rotation:-
http://legolas.mdh.se/~dat95jed/prog/?prog68000.ht m