1/* libs/opengles/fp.cpp
2**
3** Copyright 2006, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18#include "fp.h"
19
20// ----------------------------------------------------------------------------
21
22#if !defined(__arm__)
23GGLfixed gglFloatToFixed(float v) {
24    return GGLfixed(floorf(v * 65536.0f + 0.5f));
25}
26#endif
27
28// ----------------------------------------------------------------------------
29
30namespace android {
31
32namespace gl {
33
34GLfloat fixedToFloat(GLfixed x)
35{
36#if DEBUG_USE_FLOATS
37    return x / 65536.0f;
38#else
39    if (!x) return 0;
40    const uint32_t s = x & 0x80000000;
41    union {
42        uint32_t i;
43        float f;
44    };
45    i = s ? -x : x;
46    const int c = gglClz(i) - 8;
47    i = (c>=0) ? (i<<c) : (i>>-c);
48    const uint32_t e = 134 - c;
49    i &= ~0x800000;
50    i |= e<<23;
51    i |= s;
52    return f;
53#endif
54}
55
56float sinef(float x)
57{
58    const float A =   1.0f / (2.0f*M_PI);
59    const float B = -16.0f;
60    const float C =   8.0f;
61
62    // scale angle for easy argument reduction
63    x *= A;
64
65    if (fabsf(x) >= 0.5f) {
66        // Argument reduction
67        x = x - ceilf(x + 0.5f) + 1.0f;
68    }
69
70    const float y = B*x*fabsf(x) + C*x;
71    return 0.2215f * (y*fabsf(y) - y) + y;
72}
73
74float cosinef(float x)
75{
76    return sinef(x + float(M_PI/2));
77}
78
79void sincosf(GLfloat angle, GLfloat* s, GLfloat* c) {
80    *s = sinef(angle);
81    *c = cosinef(angle);
82}
83
84}; // namespace fp_utils
85
86// ----------------------------------------------------------------------------
87}; // namespace android
88