1 /*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /////////////////////////////////////////////////////////////////////////
18 /*
19 * This module contains vector math utilities for the following datatypes:
20 * -) Vec3 structures for 3-dimensional vectors
21 * -) Vec4 structures for 4-dimensional vectors
22 * -) floating point arrays for N-dimensional vectors.
23 *
24 * Note that the Vec3 and Vec4 utilties were ported from the Android
25 * repository and maintain dependenices in that separate codebase. As a
26 * result, the function signatures were left untouched for compatibility with
27 * this legacy code, despite certain style violations. In particular, for this
28 * module the function argument ordering is outputs before inputs. This style
29 * violation will be addressed once the full set of dependencies in Android
30 * have been brought into this repository.
31 */
32 #ifndef LOCATION_LBS_CONTEXTHUB_NANOAPPS_COMMON_MATH_VEC_H_
33 #define LOCATION_LBS_CONTEXTHUB_NANOAPPS_COMMON_MATH_VEC_H_
34
35 #ifdef NANOHUB_NON_CHRE_API
36 #include <nanohub_math.h>
37 #else
38 #include <math.h>
39 #endif // NANOHUB_NON_CHRE_API
40
41 #include <stddef.h>
42 #include "util/nano_assert.h"
43
44 #ifdef __cplusplus
45 extern "C" {
46 #endif
47
48 struct Vec3 {
49 float x, y, z;
50 };
51
52 struct Vec4 {
53 float x, y, z, w;
54 };
55
56 #define NANO_PI (3.14159265359f)
57
58 #define NANO_ABS(x) ((x) > 0 ? (x) : -(x))
59
60 #define NANO_MAX(a, b) ((a) > (b)) ? (a) : (b)
61
62 #define NANO_MIN(a, b) ((a) < (b)) ? (a) : (b)
63
64 // 3-DIMENSIONAL VECTOR MATH ///////////////////////////////////////////
initVec3(struct Vec3 * v,float x,float y,float z)65 static inline void initVec3(struct Vec3 *v, float x, float y, float z) {
66 ASSERT_NOT_NULL(v);
67 v->x = x;
68 v->y = y;
69 v->z = z;
70 }
71
72 // Updates v as the sum of v and w.
vec3Add(struct Vec3 * v,const struct Vec3 * w)73 static inline void vec3Add(struct Vec3 *v, const struct Vec3 *w) {
74 ASSERT_NOT_NULL(v);
75 ASSERT_NOT_NULL(w);
76 v->x += w->x;
77 v->y += w->y;
78 v->z += w->z;
79 }
80
81 // Updates v as the subtraction of w from v.
vec3Sub(struct Vec3 * v,const struct Vec3 * w)82 static inline void vec3Sub(struct Vec3 *v, const struct Vec3 *w) {
83 ASSERT_NOT_NULL(v);
84 ASSERT_NOT_NULL(w);
85 v->x -= w->x;
86 v->y -= w->y;
87 v->z -= w->z;
88 }
89
90 // Scales v by the scalar c, i.e. v = c * v.
vec3ScalarMul(struct Vec3 * v,float c)91 static inline void vec3ScalarMul(struct Vec3 *v, float c) {
92 ASSERT_NOT_NULL(v);
93 v->x *= c;
94 v->y *= c;
95 v->z *= c;
96 }
97
98 // Returns the dot product of v and w.
vec3Dot(const struct Vec3 * v,const struct Vec3 * w)99 static inline float vec3Dot(const struct Vec3 *v, const struct Vec3 *w) {
100 ASSERT_NOT_NULL(v);
101 ASSERT_NOT_NULL(w);
102 return v->x * w->x + v->y * w->y + v->z * w->z;
103 }
104
105 // Returns the square of the L2-norm of the given vector.
vec3NormSquared(const struct Vec3 * v)106 static inline float vec3NormSquared(const struct Vec3 *v) {
107 ASSERT_NOT_NULL(v);
108 return vec3Dot(v, v);
109 }
110
111 // Returns the L2-norm of the given vector.
vec3Norm(const struct Vec3 * v)112 static inline float vec3Norm(const struct Vec3 *v) {
113 ASSERT_NOT_NULL(v);
114 return sqrtf(vec3NormSquared(v));
115 }
116
117 // Normalizes the provided vector to unit norm. If the provided vector has a
118 // norm of zero, the vector will be unchanged.
vec3Normalize(struct Vec3 * v)119 static inline void vec3Normalize(struct Vec3 *v) {
120 ASSERT_NOT_NULL(v);
121 float norm = vec3Norm(v);
122 ASSERT(norm > 0);
123 // Only normalize if norm is non-zero.
124 if (norm > 0) {
125 float invNorm = 1.0f / norm;
126 v->x *= invNorm;
127 v->y *= invNorm;
128 v->z *= invNorm;
129 }
130 }
131
132 // Updates u as the cross product of v and w.
vec3Cross(struct Vec3 * u,const struct Vec3 * v,const struct Vec3 * w)133 static inline void vec3Cross(struct Vec3 *u, const struct Vec3 *v,
134 const struct Vec3 *w) {
135 ASSERT_NOT_NULL(u);
136 ASSERT_NOT_NULL(v);
137 ASSERT_NOT_NULL(w);
138 u->x = v->y * w->z - v->z * w->y;
139 u->y = v->z * w->x - v->x * w->z;
140 u->z = v->x * w->y - v->y * w->x;
141 }
142
143 // Finds a vector orthogonal to the vector [inX, inY, inZ] and returns
144 // this in the components [outX, outY, outZ]. The vector is chosen such
145 // that the smallest component of [inX, inY, inZ] is set to zero in the
146 // output vector. For example, for the in vector [0.01, 4.0, 5.0], this
147 // function will return [0, 5.0, -4.0].
148 void findOrthogonalVector(float inX, float inY, float inZ, float *outX,
149 float *outY, float *outZ);
150
151
152 // 4-DIMENSIONAL VECTOR MATH ///////////////////////////////////////////
153 // Initialize the Vec4 structure with the provided component values.
initVec4(struct Vec4 * v,float x,float y,float z,float w)154 static inline void initVec4(struct Vec4 *v, float x, float y, float z,
155 float w) {
156 ASSERT_NOT_NULL(v);
157 v->x = x;
158 v->y = y;
159 v->z = z;
160 v->w = w;
161 }
162
163 // N-DIMENSIONAL VECTOR MATH ///////////////////////////////////////////
164 // Dimension specified by the last argument in all functions below.
165
166 // Adds two vectors and returns the sum in the provided vector, i.e.
167 // u = v + w.
168 void vecAdd(float *u, const float *v, const float *w, int dim);
169
170 // Adds two vectors and returns the sum in the first vector, i.e.
171 // v = v + w.
172 void vecAddInPlace(float *v, const float *w, int dim);
173
174 // Subtracts two vectors and returns in the provided vector, i.e.
175 // u = v - w.
176 void vecSub(float *u, const float *v, const float *w, int dim);
177
178 // Scales vector by a scalar and returns in the provided vector, i.e.
179 // u = c * v.
180 void vecScalarMul(float *u, const float *v, float c, int dim);
181
182 // Scales vector by a scalar and returns in the same vector, i.e.
183 // v = c * v.
184 void vecScalarMulInPlace(float *v, float c, int dim);
185
186 // Returns the L2-norm of the given vector.
187 float vecNorm(const float *v, int dim);
188
189 // Returns the square of the L2-norm of the given vector.
190 float vecNormSquared(const float *v, int dim);
191
192 // Returns the dot product of v and w.
193 float vecDot(const float *v, const float *w, int dim);
194
195 // Returns the maximum absolute value in vector.
196 float vecMaxAbsoluteValue(const float *v, int dim);
197
198 #ifdef __cplusplus
199 }
200 #endif
201
202 #endif // LOCATION_LBS_CONTEXTHUB_NANOAPPS_COMMON_MATH_VEC_H_
203