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 // 3-DIMENSIONAL VECTOR MATH ///////////////////////////////////////////
initVec3(struct Vec3 * v,float x,float y,float z)57 static inline void initVec3(struct Vec3 *v, float x, float y, float z) {
58 ASSERT_NOT_NULL(v);
59 v->x = x;
60 v->y = y;
61 v->z = z;
62 }
63
64 // Updates v as the sum of v and w.
vec3Add(struct Vec3 * v,const struct Vec3 * w)65 static inline void vec3Add(struct Vec3 *v, const struct Vec3 *w) {
66 ASSERT_NOT_NULL(v);
67 ASSERT_NOT_NULL(w);
68 v->x += w->x;
69 v->y += w->y;
70 v->z += w->z;
71 }
72
73 // Sets u as the sum of v and w.
vec3AddVecs(struct Vec3 * u,const struct Vec3 * v,const struct Vec3 * w)74 static inline void vec3AddVecs(struct Vec3 *u, const struct Vec3 *v,
75 const struct Vec3 *w) {
76 ASSERT_NOT_NULL(u);
77 ASSERT_NOT_NULL(v);
78 ASSERT_NOT_NULL(w);
79 u->x = v->x + w->x;
80 u->y = v->y + w->y;
81 u->z = v->z + w->z;
82 }
83
84 // Updates v as the subtraction of w from v.
vec3Sub(struct Vec3 * v,const struct Vec3 * w)85 static inline void vec3Sub(struct Vec3 *v, const struct Vec3 *w) {
86 ASSERT_NOT_NULL(v);
87 ASSERT_NOT_NULL(w);
88 v->x -= w->x;
89 v->y -= w->y;
90 v->z -= w->z;
91 }
92
93 // Sets u as the difference of v and w.
vec3SubVecs(struct Vec3 * u,const struct Vec3 * v,const struct Vec3 * w)94 static inline void vec3SubVecs(struct Vec3 *u, const struct Vec3 *v,
95 const struct Vec3 *w) {
96 ASSERT_NOT_NULL(u);
97 ASSERT_NOT_NULL(v);
98 ASSERT_NOT_NULL(w);
99 u->x = v->x - w->x;
100 u->y = v->y - w->y;
101 u->z = v->z - w->z;
102 }
103
104 // Scales v by the scalar c, i.e. v = c * v.
vec3ScalarMul(struct Vec3 * v,float c)105 static inline void vec3ScalarMul(struct Vec3 *v, float c) {
106 ASSERT_NOT_NULL(v);
107 v->x *= c;
108 v->y *= c;
109 v->z *= c;
110 }
111
112 // Returns the dot product of v and w.
vec3Dot(const struct Vec3 * v,const struct Vec3 * w)113 static inline float vec3Dot(const struct Vec3 *v, const struct Vec3 *w) {
114 ASSERT_NOT_NULL(v);
115 ASSERT_NOT_NULL(w);
116 return v->x * w->x + v->y * w->y + v->z * w->z;
117 }
118
119 // Returns the square of the L2-norm of the given vector.
vec3NormSquared(const struct Vec3 * v)120 static inline float vec3NormSquared(const struct Vec3 *v) {
121 ASSERT_NOT_NULL(v);
122 return vec3Dot(v, v);
123 }
124
125 // Returns the L2-norm of the given vector.
vec3Norm(const struct Vec3 * v)126 static inline float vec3Norm(const struct Vec3 *v) {
127 ASSERT_NOT_NULL(v);
128 return sqrtf(vec3NormSquared(v));
129 }
130
131 // Normalizes the provided vector to unit norm. If the provided vector has a
132 // norm of zero, the vector will be unchanged.
vec3Normalize(struct Vec3 * v)133 static inline void vec3Normalize(struct Vec3 *v) {
134 ASSERT_NOT_NULL(v);
135 float norm = vec3Norm(v);
136 ASSERT(norm > 0);
137 // Only normalize if norm is non-zero.
138 if (norm > 0) {
139 float invNorm = 1.0f / norm;
140 v->x *= invNorm;
141 v->y *= invNorm;
142 v->z *= invNorm;
143 }
144 }
145
146 // Updates u as the cross product of v and w.
vec3Cross(struct Vec3 * u,const struct Vec3 * v,const struct Vec3 * w)147 static inline void vec3Cross(struct Vec3 *u, const struct Vec3 *v,
148 const struct Vec3 *w) {
149 ASSERT_NOT_NULL(u);
150 ASSERT_NOT_NULL(v);
151 ASSERT_NOT_NULL(w);
152 u->x = v->y * w->z - v->z * w->y;
153 u->y = v->z * w->x - v->x * w->z;
154 u->z = v->x * w->y - v->y * w->x;
155 }
156
157 // Finds a vector orthogonal to the vector [inX, inY, inZ] and returns
158 // this in the components [outX, outY, outZ]. The vector is chosen such
159 // that the smallest component of [inX, inY, inZ] is set to zero in the
160 // output vector. For example, for the in vector [0.01, 4.0, 5.0], this
161 // function will return [0, 5.0, -4.0].
162 void findOrthogonalVector(float inX, float inY, float inZ, float *outX,
163 float *outY, float *outZ);
164
165
166 // 4-DIMENSIONAL VECTOR MATH ///////////////////////////////////////////
167 // Initialize the Vec4 structure with the provided component values.
initVec4(struct Vec4 * v,float x,float y,float z,float w)168 static inline void initVec4(struct Vec4 *v, float x, float y, float z,
169 float w) {
170 ASSERT_NOT_NULL(v);
171 v->x = x;
172 v->y = y;
173 v->z = z;
174 v->w = w;
175 }
176
177 // N-DIMENSIONAL VECTOR MATH ///////////////////////////////////////////
178 // Dimension specified by the last argument in all functions below.
179
180 // Adds two vectors and returns the sum in the provided vector, i.e.
181 // u = v + w.
182 void vecAdd(float *u, const float *v, const float *w, size_t dim);
183
184 // Adds two vectors and returns the sum in the first vector, i.e.
185 // v = v + w.
186 void vecAddInPlace(float *v, const float *w, size_t dim);
187
188 // Subtracts two vectors and returns in the provided vector, i.e.
189 // u = v - w.
190 void vecSub(float *u, const float *v, const float *w, size_t dim);
191
192 // Scales vector by a scalar and returns in the provided vector, i.e.
193 // u = c * v.
194 void vecScalarMul(float *u, const float *v, float c, size_t dim);
195
196 // Scales vector by a scalar and returns in the same vector, i.e.
197 // v = c * v.
198 void vecScalarMulInPlace(float *v, float c, size_t dim);
199
200 // Returns the L2-norm of the given vector.
201 float vecNorm(const float *v, size_t dim);
202
203 // Returns the square of the L2-norm of the given vector.
204 float vecNormSquared(const float *v, size_t dim);
205
206 // Returns the dot product of v and w.
207 float vecDot(const float *v, const float *w, size_t dim);
208
209 // Returns the maximum absolute value in vector.
210 float vecMaxAbsoluteValue(const float *v, size_t dim);
211
212 #ifdef __cplusplus
213 }
214 #endif
215
216 #endif // LOCATION_LBS_CONTEXTHUB_NANOAPPS_COMMON_MATH_VEC_H_
217