Atlas - SDL_emscriptensensor.c
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1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2025 Sam Lantinga <[email protected]>
4
5  This software is provided 'as-is', without any express or implied
6  warranty.  In no event will the authors be held liable for any damages
7  arising from the use of this software.
8
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12
13  1. The origin of this software must not be misrepresented; you must not
14     claim that you wrote the original software. If you use this software
15     in a product, an acknowledgment in the product documentation would be
16     appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18     misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20*/
21#include "SDL_internal.h"
22
23#ifdef SDL_SENSOR_EMSCRIPTEN
24
25#include "../SDL_syssensor.h"
26#include "SDL_emscriptensensor.h"
27#include <emscripten/html5.h>
28
29#define EMSCRIPTEN_SENSOR_COUNT 2
30
31typedef struct
32{
33    SDL_SensorType type;
34    SDL_SensorID instance_id;
35    float data[3];
36    bool new_data;
37} SDL_EmscriptenSensor;
38
39static SDL_EmscriptenSensor SDL_sensors[EMSCRIPTEN_SENSOR_COUNT];
40
41static void SDL_EMSCRIPTEN_AccelerometerCallback(const EmscriptenDeviceMotionEvent *event)
42{
43    double total_gravity;
44    double gravity[3];
45
46    // Convert from browser specific gravity constant to SDL_STANDARD_GRAVITY.
47    total_gravity = 0.0;
48    total_gravity += SDL_fabs(event->accelerationIncludingGravityX - event->accelerationX);
49    total_gravity += SDL_fabs(event->accelerationIncludingGravityY - event->accelerationY);
50    total_gravity += SDL_fabs(event->accelerationIncludingGravityZ - event->accelerationZ);
51
52    gravity[0] = (event->accelerationIncludingGravityX - event->accelerationX) / total_gravity;
53    gravity[1] = (event->accelerationIncludingGravityY - event->accelerationY) / total_gravity;
54    gravity[2] = (event->accelerationIncludingGravityZ - event->accelerationZ) / total_gravity;
55
56    SDL_sensors[0].data[0] = (float)(event->accelerationX + gravity[0] * SDL_STANDARD_GRAVITY);
57    SDL_sensors[0].data[1] = (float)(event->accelerationY + gravity[1] * SDL_STANDARD_GRAVITY);
58    SDL_sensors[0].data[2] = (float)(event->accelerationZ + gravity[2] * SDL_STANDARD_GRAVITY);
59    SDL_sensors[0].new_data = true;
60}
61
62static void SDL_EMSCRIPTEN_GyroscopeCallback(const EmscriptenDeviceMotionEvent *event)
63{
64    SDL_sensors[1].data[0] = (float)event->rotationRateAlpha * SDL_PI_F / 180.0f;
65    SDL_sensors[1].data[1] = (float)event->rotationRateBeta * SDL_PI_F / 180.0f;
66    SDL_sensors[1].data[2] = (float)event->rotationRateGamma * SDL_PI_F / 180.0f;
67    SDL_sensors[1].new_data = true;
68}
69
70static EM_BOOL SDL_EMSCRIPTEN_SensorCallback(int event_type, const EmscriptenDeviceMotionEvent *event, void *user_data)
71{
72    SDL_EMSCRIPTEN_AccelerometerCallback(event);
73    SDL_EMSCRIPTEN_GyroscopeCallback(event);
74
75    return true;
76}
77
78static bool SDL_EMSCRIPTEN_SensorInit(void)
79{
80    emscripten_set_devicemotion_callback((void *)0, false, &SDL_EMSCRIPTEN_SensorCallback);
81
82    SDL_sensors[0].type = SDL_SENSOR_ACCEL;
83    SDL_sensors[0].instance_id = SDL_GetNextObjectID();
84    SDL_sensors[0].new_data = false;
85    SDL_sensors[1].type = SDL_SENSOR_GYRO;
86    SDL_sensors[1].instance_id = SDL_GetNextObjectID();
87    SDL_sensors[1].new_data = false;
88
89    return true;
90}
91
92static int SDL_EMSCRIPTEN_SensorGetCount(void)
93{
94    return EMSCRIPTEN_SENSOR_COUNT;
95}
96
97static void SDL_EMSCRIPTEN_SensorDetect(void)
98{
99}
100
101static const char *SDL_EMSCRIPTEN_SensorGetDeviceName(int device_index)
102{
103    if (device_index < EMSCRIPTEN_SENSOR_COUNT) {
104        switch (SDL_sensors[device_index].type) {
105        case SDL_SENSOR_ACCEL:
106            return "Accelerometer";
107        case SDL_SENSOR_GYRO:
108            return "Gyroscope";
109        default:
110            return "Unknown";
111        }
112    }
113
114    return NULL;
115}
116
117static SDL_SensorType SDL_EMSCRIPTEN_SensorGetDeviceType(int device_index)
118{
119    if (device_index < EMSCRIPTEN_SENSOR_COUNT) {
120        return SDL_sensors[device_index].type;
121    }
122
123    return SDL_SENSOR_INVALID;
124}
125
126static int SDL_EMSCRIPTEN_SensorGetDeviceNonPortableType(int device_index)
127{
128    if (device_index < EMSCRIPTEN_SENSOR_COUNT) {
129        return SDL_sensors[device_index].type;
130    }
131
132    return -1;
133}
134
135static SDL_SensorID SDL_EMSCRIPTEN_SensorGetDeviceInstanceID(int device_index)
136{
137    if (device_index < EMSCRIPTEN_SENSOR_COUNT) {
138        return SDL_sensors[device_index].instance_id;
139    }
140
141    return -1;
142}
143
144static bool SDL_EMSCRIPTEN_SensorOpen(SDL_Sensor *sensor, int device_index)
145{
146    return true;
147}
148
149static void SDL_EMSCRIPTEN_SensorUpdate(SDL_Sensor *sensor)
150{
151    Uint64 timestamp;
152
153    switch (sensor->type) {
154    case SDL_SENSOR_ACCEL:
155        if (SDL_sensors[0].new_data) {
156            SDL_sensors[0].new_data = false;
157            timestamp = SDL_GetTicksNS();
158            SDL_SendSensorUpdate(timestamp, sensor, timestamp, SDL_sensors[0].data, SDL_arraysize(SDL_sensors[0].data));
159        }
160        break;
161    case SDL_SENSOR_GYRO:
162        if (SDL_sensors[1].new_data) {
163            SDL_sensors[1].new_data = false;
164            timestamp = SDL_GetTicksNS();
165            SDL_SendSensorUpdate(timestamp, sensor, timestamp, SDL_sensors[1].data, SDL_arraysize(SDL_sensors[1].data));
166        }
167        break;
168    default:
169        break;
170    }
171}
172
173static void SDL_EMSCRIPTEN_SensorClose(SDL_Sensor *sensor)
174{
175}
176
177static void SDL_EMSCRIPTEN_SensorQuit(void)
178{
179}
180
181SDL_SensorDriver SDL_EMSCRIPTEN_SensorDriver = {
182    SDL_EMSCRIPTEN_SensorInit,
183    SDL_EMSCRIPTEN_SensorGetCount,
184    SDL_EMSCRIPTEN_SensorDetect,
185    SDL_EMSCRIPTEN_SensorGetDeviceName,
186    SDL_EMSCRIPTEN_SensorGetDeviceType,
187    SDL_EMSCRIPTEN_SensorGetDeviceNonPortableType,
188    SDL_EMSCRIPTEN_SensorGetDeviceInstanceID,
189    SDL_EMSCRIPTEN_SensorOpen,
190    SDL_EMSCRIPTEN_SensorUpdate,
191    SDL_EMSCRIPTEN_SensorClose,
192    SDL_EMSCRIPTEN_SensorQuit,
193};
194
195#endif // SDL_SENSOR_EMSCRIPTEN
196
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