diff options
Diffstat (limited to 'Stars45/Random.cpp')
-rw-r--r-- | Stars45/Random.cpp | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/Stars45/Random.cpp b/Stars45/Random.cpp new file mode 100644 index 0000000..57752e9 --- /dev/null +++ b/Stars45/Random.cpp @@ -0,0 +1,172 @@ +/* Starshatter OpenSource Distribution + Copyright (c) 1997-2004, Destroyer Studios LLC. + All Rights Reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are met: + + * Redistributions of source code must retain the above copyright notice, + this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above copyright notice, + this list of conditions and the following disclaimer in the documentation + and/or other materials provided with the distribution. + * Neither the name "Destroyer Studios" nor the names of its contributors + may be used to endorse or promote products derived from this software + without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + POSSIBILITY OF SUCH DAMAGE. + + SUBSYSTEM: nGenEx.lib + FILE: Random.cpp + AUTHOR: John DiCamillo + + + OVERVIEW + ======== + Utility functions for generating random numbers and locations. +*/ + +#include "MemDebug.h" +#include "Random.h" + +// +----------------------------------------------------------------------+ + +void RandomInit() +{ + srand(timeGetTime()); +} + +// +----------------------------------------------------------------------+ + +Point RandomDirection() +{ + Point p = Point(rand() - 16384, rand() - 16384, 0); + p.Normalize(); + return p; +} + +// +----------------------------------------------------------------------+ + +Point RandomPoint() +{ + Point p = Point(rand() - 16384, rand() - 16384, 0); + p.Normalize(); + p *= 15e3 + rand()/3; + return p; +} + +// +----------------------------------------------------------------------+ + +Vec3 RandomVector(double radius) +{ + Vec3 v = Vec3(rand() - 16384, rand() - 16384, rand() - 16384); + v.Normalize(); + + if (radius > 0) + v *= (float) radius; + else + v *= (float) Random(radius/3, radius); + + return v; +} + +// +----------------------------------------------------------------------+ + +double Random(double min, double max) +{ + double delta = max - min; + double r = delta * rand() / 32768.0; + + return min + r; +} + +// +----------------------------------------------------------------------+ + +int RandomIndex() +{ + static int index = 0; + static int table[16] = { 0, 9, 4, 7, 14, 11, 2, 12, 1, 5, 13, 8, 6, 10, 3, 15 }; + + int r = 1 + ((rand() & 0x0700) >> 8); + index += r; + if (index > 1e7) index = 0; + return table[index % 16]; +} + +// +----------------------------------------------------------------------+ + +bool RandomChance(int wins, int tries) +{ + double fraction = 256.0 * wins / tries; + double r = (rand() >> 4) & 0xFF; + + return r < fraction; +} + +// +----------------------------------------------------------------------+ + +int RandomSequence(int current, int range) +{ + if (range > 1) { + int step = (int) Random(1, range-1); + return (current + step) % range; + } + + return current; +} + +// +----------------------------------------------------------------------+ + +int RandomShuffle(int count) +{ + static int set_size = -1; + static BYTE set[256]; + static int index = -1; + + if (count < 0 || count > 250) + return 0; + + if (set_size != count) { + set_size = count; + index = -1; + } + + // need to reshuffle + if (index < 0 || index > set_size-1) { + // set up the deck + int tmp[256]; + for (int i = 0; i < 256; i++) + tmp[i] = i; + + // shuffle the cards + for (int i = 0; i < set_size; i++) { + int n = (int) Random(0, set_size); + int tries = set_size; + while (tmp[n] < 0 && tries--) { + n = (n+1) % set_size; + } + + if (tmp[n] >= 0) { + set[i] = tmp[n]; + tmp[n] = -1; + } + else { + set[i] = 0; + } + } + + index = 0; + } + + return set[index++]; +} |