1 /**************************************************************************
2 *
3 * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28
29
30 #include "util/u_math.h"
31
32
33 /** 2^x, for x in [-1.0, 1.0) */
34 float pow2_table[POW2_TABLE_SIZE];
35
36
37 static void
init_pow2_table(void)38 init_pow2_table(void)
39 {
40 int i;
41 for (i = 0; i < POW2_TABLE_SIZE; i++)
42 pow2_table[i] = (float) pow(2.0, (i - POW2_TABLE_OFFSET) / POW2_TABLE_SCALE);
43 }
44
45
46 /** log2(x), for x in [1.0, 2.0) */
47 float log2_table[LOG2_TABLE_SIZE];
48
49
50 static void
init_log2_table(void)51 init_log2_table(void)
52 {
53 unsigned i;
54 for (i = 0; i < LOG2_TABLE_SIZE; i++)
55 log2_table[i] = (float) log2(1.0 + i * (1.0 / LOG2_TABLE_SCALE));
56 }
57
58
59 /**
60 * One time init for math utilities.
61 */
62 void
util_init_math(void)63 util_init_math(void)
64 {
65 static boolean initialized = FALSE;
66 if (!initialized) {
67 init_pow2_table();
68 init_log2_table();
69 initialized = TRUE;
70 }
71 }
72
73
74