1 /*
2 Copyright (c) 2009 Andrew Caudwell (acaudwell@gmail.com)
3 All rights reserved.
4
5 Redistribution and use in source and binary forms, with or without
6 modification, are permitted provided that the following conditions
7 are met:
8 1. Redistributions of source code must retain the above copyright
9 notice, this list of conditions and the following disclaimer.
10 2. Redistributions in binary form must reproduce the above copyright
11 notice, this list of conditions and the following disclaimer in the
12 documentation and/or other materials provided with the distribution.
13 3. The name of the author may not be used to endorse or promote products
14 derived from this software without specific prior written permission.
15
16 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include "stringhash.h"
29
30 int gStringHashSeed = 31;
31
stringHash(const std::string & str)32 int stringHash(const std::string& str) {
33
34 int val = 0;
35 int n = str.size();
36
37 for (int i = 0; i < n; i++) {
38 val = val + str[i] * (gStringHashSeed^(n-i));
39 }
40
41 if(val<0) {
42 val = -val;
43 }
44
45 return val;
46 }
47
vec2Hash(const std::string & str)48 vec2 vec2Hash(const std::string& str) {
49 int hash = stringHash(str);
50
51 int x = ((hash/7) % 255) - 127;
52 int y = ((hash/3) % 255) - 127;
53
54 vec2 v = normalise(vec2(x, y));
55
56 return v;
57 }
58
vec3Hash(const std::string & str)59 vec3 vec3Hash(const std::string& str) {
60 int hash = stringHash(str);
61
62 int x = ((hash/7) % 255) - 127;
63 int y = ((hash/3) % 255) - 127;
64 int z = hash % 255;
65
66 vec3 v = normalise(vec3(x, y, z));
67
68 return v;
69 }
70
colourHash(const std::string & str)71 vec3 colourHash(const std::string& str) {
72 int hash = stringHash(str);
73
74 if(hash == 0) hash++;
75
76 int r = (hash/7) % 255;
77 int g = (hash/3) % 255;
78 int b = hash % 255;
79
80 vec3 colour = normalise(vec3(r, g, b));
81
82 return colour;
83 }
84