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Quaternions.cpp
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1 /* Copyright (c) 2014-2017, ARM Limited and Contributors
2  *
3  * SPDX-License-Identifier: MIT
4  *
5  * Permission is hereby granted, free of charge,
6  * to any person obtaining a copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation the rights to
8  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
9  * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
12  *
13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
14  * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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17  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
19  */
20 
21 #include <cstdio>
22 #include <cstdlib>
23 #include <cmath>
24 #include "Quaternions.h"
25 
26 /* Please see the header for specification */
27 Quaternion construct_quaternion(float x, float y, float z, float degs)
28 {
29  Quaternion init = { 0.0f, 0.0f, 0.0f, 0.0f };
30 
31  float ang = (float) M_PI * degs / 180.0f;
32  float res = sin(ang / 2.0f);
33 
34  init.w = cos(ang / 2.0f);
35  init.x = x * res;
36  init.y = y * res;
37  init.z = z * res;
38 
39  return init;
40 }
41 
42 /* Please see the header for specification */
43 void construct_modelview_matrix(Quaternion quaternion, float* mat)
44 {
45  if (mat == 0)
46  {
47  fprintf(stderr, "Pointer to a modelview matrix points to NULL.\n");
48 
49  exit(EXIT_FAILURE);
50  }
51 
52  mat[ 0] = 1.0f - 2.0f * (quaternion.y * quaternion.y + quaternion.z * quaternion.z);
53  mat[ 1] = 2.0f * (quaternion.x * quaternion.y + quaternion.z * quaternion.w);
54  mat[ 2] = 2.0f * (quaternion.x * quaternion.z - quaternion.y * quaternion.w);
55  mat[ 3] = 0.0f;
56  mat[ 4] = 2.0f * (quaternion.x * quaternion.y - quaternion.z * quaternion.w);
57  mat[ 5] = 1.0f - 2.0f * (quaternion.x * quaternion.x + quaternion.z * quaternion.z);
58  mat[ 6] = 2.0f * (quaternion.z * quaternion.y + quaternion.x * quaternion.w);
59  mat[ 7] = 0.0f;
60  mat[ 8] = 2.0f * ( quaternion.x * quaternion.z + quaternion.y * quaternion.w);
61  mat[ 9] = 2.0f * ( quaternion.y * quaternion.z - quaternion.x * quaternion.w);
62  mat[10] = 1.0f - 2.0f * ( quaternion.x * quaternion.x + quaternion.y * quaternion.y);
63  mat[11] = 0.0f;
64  mat[12] = 0.0f;
65  mat[13] = 0.0f;
66  mat[14] = 0.0f;
67  mat[15] = 1.0f;
68 }
69 
70 /* Please see the header for specification */
72 {
73  Quaternion res;
74 
75  res.w = a.w * b.w - a.x * b.x - a.y * b.y - a.z * b.z;
76  res.x = a.w * b.x + a.x * b.w + a.y * b.z - a.z * b.y;
77  res.y = a.w * b.y + a.y * b.w + a.z * b.x - a.x * b.z;
78  res.z = a.w * b.z + a.z * b.w + a.x * b.y - a.y * b.x;
79 
80  return res;
81 }
GLboolean GLboolean GLboolean GLboolean a
Definition: gl2ext.h:306
Quaternion multiply_quaternions(Quaternion a, Quaternion b)
Definition: Quaternions.cpp:71
Quaternion construct_quaternion(float x, float y, float z, float degs)
Definition: Quaternions.cpp:27
GLfloat GLfloat f
Definition: gl2ext.h:2707
#define M_PI
The value of pi.
Definition: Mathematics.h:37
void construct_modelview_matrix(Quaternion quaternion, float *mat)
Definition: Quaternions.cpp:43
GLint GLint GLint GLint GLint x
Definition: gl2ext.h:574
precision highp float
Definition: hiz_cull.cs:37
GLboolean GLboolean GLboolean b
Definition: gl2ext.h:306
GLint y
Definition: gl2ext.h:179