simon-svn: puzzles: simon

[Commits to Tartarus CVS repository.]

SVN root:       svn://svn.tartarus.org/sgt
Changes by:     simon
Revision:       9168
Date:           2011-05-06 18:09:03 +0100 (Fri, 06 May 2011)

Log message (16 lines):
Apply the rotation in Penrose grid descriptions by rotating in the
4-vector representation, rather than mucking about with sines and
cosines after grid generation. _Should_ make no difference in the
generated grids (there's a theoretical risk of an unlucky rounding
error just about managing to push some point in or out of bounds, but
I think it's vanishingly small), but simplifies the coordinate-
flattening procedure, and in particular increases its chance of
getting vertical lines actually vertical.

(Prior to this change, the game ID
10x10t12:G2554,-31,108_a3b12h0a212a3d102b2a23a2e3b01b0a2c2a0c0 was
generating a not-quite-vertical edge at top left, in the Java port but
not on Linux; I suspect differences in sin and cos as the cause of the
discrepancy. With the rotation done like this, the points'
x-coordinates are now computed without reference to their
y-coordinates.)

Modified files:
U   puzzles/grid.c
U   puzzles/penrose.c
U   puzzles/penrose.h

Links:
http://svn.tartarus.org/sgt/?rev=9168&view=rev
http://svn.tartarus.org/sgt/puzzles/grid.c?rev=9168&r1=9167&r2=9168
http://svn.tartarus.org/sgt/puzzles/penrose.c?rev=9168&r1=9167&r2=9168
http://svn.tartarus.org/sgt/puzzles/penrose.h?rev=9168&r1=9167&r2=9168