First pass on the new SDL sensor API

src/sensor/SDL_sensor.c

@@ -0,0 +1,548 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "../SDL_internal.h"
+
+/* This is the sensor API for Simple DirectMedia Layer */
+
+#include "SDL.h"
+#include "SDL_atomic.h"
+#include "SDL_events.h"
+#include "SDL_syssensor.h"
+#include "SDL_assert.h"
+
+#if !SDL_EVENTS_DISABLED
+#include "../events/SDL_events_c.h"
+#endif
+
+static SDL_SensorDriver *SDL_sensor_drivers[] = {
+#if 0 //defined(__IPHONEOS__) || defined(__TVOS__)
+    &SDL_IOS_SensorDriver,
+#endif
+#ifdef SDL_SENSOR_ANDROID
+    &SDL_ANDROID_SensorDriver,
+#endif
+};
+static SDL_Sensor *SDL_sensors = NULL;
+static SDL_bool SDL_updating_sensor = SDL_FALSE;
+static SDL_mutex *SDL_sensor_lock = NULL; /* This needs to support recursive locks */
+static SDL_atomic_t SDL_next_sensor_instance_id;
+
+void
+SDL_LockSensors(void)
+{
+    if (SDL_sensor_lock) {
+        SDL_LockMutex(SDL_sensor_lock);
+    }
+}
+
+void
+SDL_UnlockSensors(void)
+{
+    if (SDL_sensor_lock) {
+        SDL_UnlockMutex(SDL_sensor_lock);
+    }
+}
+
+
+int
+SDL_SensorInit(void)
+{
+    int i, status;
+
+    /* Create the sensor list lock */
+    if (!SDL_sensor_lock) {
+        SDL_sensor_lock = SDL_CreateMutex();
+    }
+
+#if !SDL_EVENTS_DISABLED
+    if (SDL_InitSubSystem(SDL_INIT_EVENTS) < 0) {
+        return -1;
+    }
+#endif /* !SDL_EVENTS_DISABLED */
+
+    if (SDL_arraysize(SDL_sensor_drivers) == 0) {
+        /* What should we return here? We'll just return 0 with no sensors for now. */
+        status = 0;
+    }
+
+    status = -1;
+    for (i = 0; i < SDL_arraysize(SDL_sensor_drivers); ++i) {
+        if (SDL_sensor_drivers[i]->Init() >= 0) {
+            status = 0;
+        }
+    }
+    return status;
+}
+
+/*
+ * Count the number of sensors attached to the system
+ */
+int
+SDL_NumSensors(void)
+{
+    int i, total_sensors = 0;
+    SDL_LockSensors();
+    for (i = 0; i < SDL_arraysize(SDL_sensor_drivers); ++i) {
+        total_sensors += SDL_sensor_drivers[i]->GetCount();
+    }
+    SDL_UnlockSensors();
+    return total_sensors;
+}
+
+/*
+ * Return the next available sensor instance ID
+ * This may be called by drivers from multiple threads, unprotected by any locks
+ */
+SDL_SensorID SDL_GetNextSensorInstanceID()
+{
+    return SDL_AtomicIncRef(&SDL_next_sensor_instance_id);
+}
+
+/*
+ * Get the driver and device index for an API device index
+ * This should be called while the sensor lock is held, to prevent another thread from updating the list
+ */
+SDL_bool
+SDL_GetDriverAndSensorIndex(int device_index, SDL_SensorDriver **driver, int *driver_index)
+{
+    int i, num_sensors, total_sensors = 0;
+
+    if (device_index >= 0) {
+        for (i = 0; i < SDL_arraysize(SDL_sensor_drivers); ++i) {
+            num_sensors = SDL_sensor_drivers[i]->GetCount();
+            if (device_index < num_sensors) {
+                *driver = SDL_sensor_drivers[i];
+                *driver_index = device_index;
+                return SDL_TRUE;
+            }
+            device_index -= num_sensors;
+            total_sensors += num_sensors;
+        }
+    }
+
+    SDL_SetError("There are %d sensors available", total_sensors);
+    return SDL_FALSE;
+}
+
+/*
+ * Get the implementation dependent name of a sensor
+ */
+const char *
+SDL_SensorGetDeviceName(int device_index)
+{
+    SDL_SensorDriver *driver;
+    const char *name = NULL;
+
+    SDL_LockSensors();
+    if (SDL_GetDriverAndSensorIndex(device_index, &driver, &device_index)) {
+        name = driver->GetDeviceName(device_index);
+    }
+    SDL_UnlockSensors();
+
+    /* FIXME: Really we should reference count this name so it doesn't go away after unlock */
+    return name;
+}
+
+SDL_SensorType
+SDL_SensorGetDeviceType(int device_index)
+{
+    SDL_SensorDriver *driver;
+    SDL_SensorType type = SDL_SENSOR_INVALID;
+
+    SDL_LockSensors();
+    if (SDL_GetDriverAndSensorIndex(device_index, &driver, &device_index)) {
+        type = driver->GetDeviceType(device_index);
+    }
+    SDL_UnlockSensors();
+
+    return type;
+}
+
+SDL_SensorType
+SDL_SensorGetDeviceNonPortableType(int device_index)
+{
+    SDL_SensorDriver *driver;
+    int type = -1;
+
+    SDL_LockSensors();
+    if (SDL_GetDriverAndSensorIndex(device_index, &driver, &device_index)) {
+        type = driver->GetDeviceNonPortableType(device_index);
+    }
+    SDL_UnlockSensors();
+
+    return type;
+}
+
+SDL_SensorID
+SDL_SensorGetDeviceInstanceID(int device_index)
+{
+    SDL_SensorDriver *driver;
+    SDL_SensorID instance_id = -1;
+
+    SDL_LockSensors();
+    if (SDL_GetDriverAndSensorIndex(device_index, &driver, &device_index)) {
+        instance_id = driver->GetDeviceInstanceID(device_index);
+    }
+    SDL_UnlockSensors();
+
+    return instance_id;
+}
+
+/*
+ * Open a sensor for use - the index passed as an argument refers to
+ * the N'th sensor on the system.  This index is the value which will
+ * identify this sensor in future sensor events.
+ *
+ * This function returns a sensor identifier, or NULL if an error occurred.
+ */
+SDL_Sensor *
+SDL_SensorOpen(int device_index)
+{
+    SDL_SensorDriver *driver;
+    SDL_SensorID instance_id;
+    SDL_Sensor *sensor;
+    SDL_Sensor *sensorlist;
+    const char *sensorname = NULL;
+
+    SDL_LockSensors();
+
+    if (!SDL_GetDriverAndSensorIndex(device_index, &driver, &device_index)) {
+        SDL_UnlockSensors();
+        return NULL;
+    }
+
+    sensorlist = SDL_sensors;
+    /* If the sensor is already open, return it
+     * it is important that we have a single sensor * for each instance id
+     */
+    instance_id = driver->GetDeviceInstanceID(device_index);
+    while (sensorlist) {
+        if (instance_id == sensorlist->instance_id) {
+                sensor = sensorlist;
+                ++sensor->ref_count;
+                SDL_UnlockSensors();
+                return sensor;
+        }
+        sensorlist = sensorlist->next;
+    }
+
+    /* Create and initialize the sensor */
+    sensor = (SDL_Sensor *) SDL_calloc(sizeof(*sensor), 1);
+    if (sensor == NULL) {
+        SDL_OutOfMemory();
+        SDL_UnlockSensors();
+        return NULL;
+    }
+    sensor->driver = driver;
+    sensor->instance_id = instance_id;
+    sensor->type = driver->GetDeviceType(device_index);
+    sensor->non_portable_type = driver->GetDeviceNonPortableType(device_index);
+
+    if (driver->Open(sensor, device_index) < 0) {
+        SDL_free(sensor);
+        SDL_UnlockSensors();
+        return NULL;
+    }
+
+    sensorname = driver->GetDeviceName(device_index);
+    if (sensorname) {
+        sensor->name = SDL_strdup(sensorname);
+    } else {
+        sensor->name = NULL;
+    }
+
+    /* Add sensor to list */
+    ++sensor->ref_count;
+    /* Link the sensor in the list */
+    sensor->next = SDL_sensors;
+    SDL_sensors = sensor;
+
+    SDL_UnlockSensors();
+
+    driver->Update(sensor);
+
+    return sensor;
+}
+
+/*
+ * Find the SDL_Sensor that owns this instance id
+ */
+SDL_Sensor *
+SDL_SensorFromInstanceID(SDL_SensorID instance_id)
+{
+    SDL_Sensor *sensor;
+
+    SDL_LockSensors();
+    for (sensor = SDL_sensors; sensor; sensor = sensor->next) {
+        if (sensor->instance_id == instance_id) {
+            break;
+        }
+    }
+    SDL_UnlockSensors();
+    return sensor;
+}
+
+/*
+ * Checks to make sure the sensor is valid.
+ */
+static int
+SDL_PrivateSensorValid(SDL_Sensor * sensor)
+{
+    int valid;
+
+    if (sensor == NULL) {
+        SDL_SetError("Sensor hasn't been opened yet");
+        valid = 0;
+    } else {
+        valid = 1;
+    }
+
+    return valid;
+}
+
+/*
+ * Get the friendly name of this sensor
+ */
+const char *
+SDL_SensorGetName(SDL_Sensor * sensor)
+{
+    if (!SDL_PrivateSensorValid(sensor)) {
+        return NULL;
+    }
+
+    return sensor->name;
+}
+
+/*
+ * Get the type of this sensor
+ */
+SDL_SensorType
+SDL_SensorGetType(SDL_Sensor * sensor)
+{
+    if (!SDL_PrivateSensorValid(sensor)) {
+        return SDL_SENSOR_INVALID;
+    }
+
+    return sensor->type;
+}
+
+/*
+ * Get the platform dependent type of this sensor
+ */
+int
+SDL_SensorGetNonPortableType(SDL_Sensor * sensor)
+{
+    if (!SDL_PrivateSensorValid(sensor)) {
+        return -1;
+    }
+
+    return sensor->non_portable_type;
+}
+
+/*
+ * Get the instance id for this opened sensor
+ */
+SDL_SensorID
+SDL_SensorGetInstanceID(SDL_Sensor * sensor)
+{
+    if (!SDL_PrivateSensorValid(sensor)) {
+        return -1;
+    }
+
+    return sensor->instance_id;
+}
+
+/*
+ * Get the current state of this sensor
+ */
+int
+SDL_SensorGetData(SDL_Sensor * sensor, float *data, int num_values)
+{
+    if (!SDL_PrivateSensorValid(sensor)) {
+        return -1;
+    }
+
+    num_values = SDL_min(num_values, SDL_arraysize(sensor->data));
+    SDL_memcpy(data, sensor->data, num_values*sizeof(*data));
+    return 0;
+}
+
+/*
+ * Close a sensor previously opened with SDL_SensorOpen()
+ */
+void
+SDL_SensorClose(SDL_Sensor * sensor)
+{
+    SDL_Sensor *sensorlist;
+    SDL_Sensor *sensorlistprev;
+
+    if (!SDL_PrivateSensorValid(sensor)) {
+        return;
+    }
+
+    SDL_LockSensors();
+
+    /* First decrement ref count */
+    if (--sensor->ref_count > 0) {
+        SDL_UnlockSensors();
+        return;
+    }
+
+    if (SDL_updating_sensor) {
+        SDL_UnlockSensors();
+        return;
+    }
+
+    sensor->driver->Close(sensor);
+    sensor->hwdata = NULL;
+
+    sensorlist = SDL_sensors;
+    sensorlistprev = NULL;
+    while (sensorlist) {
+        if (sensor == sensorlist) {
+            if (sensorlistprev) {
+                /* unlink this entry */
+                sensorlistprev->next = sensorlist->next;
+            } else {
+                SDL_sensors = sensor->next;
+            }
+            break;
+        }
+        sensorlistprev = sensorlist;
+        sensorlist = sensorlist->next;
+    }
+
+    SDL_free(sensor->name);
+
+    /* Free the data associated with this sensor */
+    SDL_free(sensor);
+
+    SDL_UnlockSensors();
+}
+
+void
+SDL_SensorQuit(void)
+{
+    int i;
+
+    /* Make sure we're not getting called in the middle of updating sensors */
+    SDL_assert(!SDL_updating_sensor);
+
+    SDL_LockSensors();
+
+    /* Stop the event polling */
+    while (SDL_sensors) {
+        SDL_sensors->ref_count = 1;
+        SDL_SensorClose(SDL_sensors);
+    }
+
+    /* Quit the sensor setup */
+    for (i = 0; i < SDL_arraysize(SDL_sensor_drivers); ++i) {
+       SDL_sensor_drivers[i]->Quit();
+    }
+
+    SDL_UnlockSensors();
+
+#if !SDL_EVENTS_DISABLED
+    SDL_QuitSubSystem(SDL_INIT_EVENTS);
+#endif
+
+    if (SDL_sensor_lock) {
+        SDL_DestroyMutex(SDL_sensor_lock);
+        SDL_sensor_lock = NULL;
+    }
+}
+
+
+/* These are global for SDL_syssensor.c and SDL_events.c */
+
+int
+SDL_PrivateSensorUpdate(SDL_Sensor *sensor, float *data, int num_values)
+{
+    int posted;
+
+    /* Allow duplicate events, for things like steps and heartbeats */
+
+    /* Update internal sensor state */
+    num_values = SDL_min(num_values, SDL_arraysize(sensor->data));
+    SDL_memcpy(sensor->data, data, num_values*sizeof(*data));
+
+    /* Post the event, if desired */
+    posted = 0;
+#if !SDL_EVENTS_DISABLED
+    if (SDL_GetEventState(SDL_JOYAXISMOTION) == SDL_ENABLE) {
+        SDL_Event event;
+        event.type = SDL_SENSORUPDATE;
+        event.sensor.which = sensor->instance_id;
+        num_values = SDL_min(num_values, SDL_arraysize(event.sensor.data));
+        SDL_memset(event.sensor.data, 0, sizeof(event.sensor.data));
+        SDL_memcpy(event.sensor.data, data, num_values*sizeof(*data));
+        posted = SDL_PushEvent(&event) == 1;
+    }
+#endif /* !SDL_EVENTS_DISABLED */
+    return posted;
+}
+
+void
+SDL_SensorUpdate(void)
+{
+    int i;
+    SDL_Sensor *sensor;
+
+    SDL_LockSensors();
+
+    if (SDL_updating_sensor) {
+        /* The sensors are already being updated */
+        SDL_UnlockSensors();
+        return;
+    }
+
+    SDL_updating_sensor = SDL_TRUE;
+
+    /* Make sure the list is unlocked while dispatching events to prevent application deadlocks */
+    SDL_UnlockSensors();
+
+    for (sensor = SDL_sensors; sensor; sensor = sensor->next) {
+        sensor->driver->Update(sensor);
+    }
+
+    SDL_LockSensors();
+
+    SDL_updating_sensor = SDL_FALSE;
+
+    /* If any sensors were closed while updating, free them here */
+    for (sensor = SDL_sensors; sensor; sensor = sensor->next) {
+        if (sensor->ref_count <= 0) {
+            SDL_SensorClose(sensor);
+        }
+    }
+
+    /* this needs to happen AFTER walking the sensor list above, so that any
+       dangling hardware data from removed devices can be free'd
+     */
+    for (i = 0; i < SDL_arraysize(SDL_sensor_drivers); ++i) {
+        SDL_sensor_drivers[i]->Detect();
+    }
+
+    SDL_UnlockSensors();
+}
+
+/* vi: set ts=4 sw=4 expandtab: */

src/sensor/SDL_sensor_c.h

@@ -0,0 +1,38 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+struct _SDL_SensorDriver;
+
+/* Useful functions and variables from SDL_sensor.c */
+#include "SDL_sensor.h"
+
+/* Function to get the next available sensor instance ID */
+extern SDL_SensorID SDL_GetNextSensorInstanceID(void);
+
+/* Initialization and shutdown functions */
+extern int SDL_SensorInit(void);
+extern void SDL_SensorQuit(void);
+
+/* Internal event queueing functions */
+extern int SDL_PrivateSensorUpdate(SDL_Sensor *sensor, float *data, int num_values);
+
+/* vi: set ts=4 sw=4 expandtab: */

src/sensor/SDL_syssensor.h

@@ -0,0 +1,97 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+/* This is the system specific header for the SDL sensor API */
+
+#include "SDL_sensor.h"
+#include "SDL_sensor_c.h"
+
+/* The SDL sensor structure */
+struct _SDL_Sensor
+{
+    SDL_SensorID instance_id;       /* Device instance, monotonically increasing from 0 */
+    char *name;                     /* Sensor name - system dependent */
+    SDL_SensorType type;            /* Type of the sensor */
+    int non_portable_type;          /* Platform dependent type of the sensor */
+
+    float data[16];                 /* The current state of the sensor */
+
+    struct _SDL_SensorDriver *driver;
+
+    struct sensor_hwdata *hwdata;   /* Driver dependent information */
+
+    int ref_count;                  /* Reference count for multiple opens */
+
+    struct _SDL_Sensor *next;       /* pointer to next sensor we have allocated */
+};
+
+typedef struct _SDL_SensorDriver
+{
+    /* Function to scan the system for sensors.
+     * sensor 0 should be the system default sensor.
+     * This function should return 0, or -1 on an unrecoverable fatal error.
+     */
+    int (*Init)(void);
+
+    /* Function to return the number of sensors available right now */
+    int (*GetCount)(void);
+
+    /* Function to check to see if the available sensors have changed */
+    void (*Detect)(void);
+
+    /* Function to get the device-dependent name of a sensor */
+    const char *(*GetDeviceName)(int device_index);
+
+    /* Function to get the type of a sensor */
+    SDL_SensorType (*GetDeviceType)(int device_index);
+
+    /* Function to get the platform dependent type of a sensor */
+    int (*GetDeviceNonPortableType)(int device_index);
+
+    /* Function to get the current instance id of the sensor located at device_index */
+    SDL_SensorID (*GetDeviceInstanceID)(int device_index);
+
+    /* Function to open a sensor for use.
+       The sensor to open is specified by the device index.
+       It returns 0, or -1 if there is an error.
+     */
+    int (*Open)(SDL_Sensor * sensor, int device_index);
+
+    /* Function to update the state of a sensor - called as a device poll.
+     * This function shouldn't update the sensor structure directly,
+     * but instead should call SDL_PrivateSensorUpdate() to deliver events
+     * and update sensor device state.
+     */
+    void (*Update)(SDL_Sensor * sensor);
+
+    /* Function to close a sensor after use */
+    void (*Close)(SDL_Sensor * sensor);
+
+    /* Function to perform any system-specific sensor related cleanup */
+    void (*Quit)(void);
+
+} SDL_SensorDriver;
+
+/* The available sensor drivers */
+extern SDL_SensorDriver SDL_ANDROID_SensorDriver;
+
+/* vi: set ts=4 sw=4 expandtab: */

src/sensor/android/SDL_androidsensor.c

@@ -0,0 +1,211 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "SDL_config.h"
+
+#ifdef SDL_SENSOR_ANDROID
+
+/* This is the system specific header for the SDL sensor API */
+#include <android/sensor.h>
+
+#include "SDL_error.h"
+#include "SDL_sensor.h"
+#include "SDL_androidsensor.h"
+#include "../SDL_syssensor.h"
+#include "../SDL_sensor_c.h"
+//#include "../../core/android/SDL_android.h"
+
+#ifndef LOOPER_ID_USER
+#define LOOPER_ID_USER  3
+#endif
+
+typedef struct
+{
+    ASensorRef asensor;
+    SDL_SensorID instance_id;
+} SDL_AndroidSensor;
+
+static ASensorManager* SDL_sensor_manager;
+static ALooper* SDL_sensor_looper;
+static SDL_AndroidSensor *SDL_sensors;
+static int SDL_sensors_count;
+
+static int
+SDL_ANDROID_SensorInit(void)
+{
+    int i, sensors_count;
+    ASensorList sensors;
+
+    SDL_sensor_manager = ASensorManager_getInstance();
+    if (!SDL_sensor_manager) {
+        return SDL_SetError("Couldn't create sensor manager");
+    }
+
+    SDL_sensor_looper = ALooper_forThread();
+    if (!SDL_sensor_looper) {
+        SDL_sensor_looper = ALooper_prepare(ALOOPER_PREPARE_ALLOW_NON_CALLBACKS);
+        if (!SDL_sensor_looper) {
+            return SDL_SetError("Couldn't create sensor event loop");
+        }
+    }
+
+    /* FIXME: Is the sensor list dynamic? */
+    sensors_count = ASensorManager_getSensorList(SDL_sensor_manager, &sensors);
+    if (sensors_count > 0) {
+        SDL_sensors = (SDL_AndroidSensor *)SDL_calloc(sensors_count, sizeof(*SDL_sensors));
+        if (!SDL_sensors) {
+            return SDL_OutOfMemory();
+        }
+
+        for (i = 0; i < sensors_count; ++i) {
+            SDL_sensors[i].asensor = sensors[i];
+            SDL_sensors[i].instance_id = SDL_GetNextSensorInstanceID();
+        }
+        SDL_sensors_count = sensors_count;
+    }
+    return 0;
+}
+
+static int
+SDL_ANDROID_SensorGetCount(void)
+{
+    return SDL_sensors_count;
+}
+
+static void
+SDL_ANDROID_SensorDetect(void)
+{
+}
+
+static const char *
+SDL_ANDROID_SensorGetDeviceName(int device_index)
+{
+    return ASensor_getName(SDL_sensors[device_index].asensor);
+}
+
+static SDL_SensorType
+SDL_ANDROID_SensorGetDeviceType(int device_index)
+{
+    switch (ASensor_getType(SDL_sensors[device_index].asensor)) {
+    case 0x00000001:
+        return SDL_SENSOR_ACCEL;
+    case 0x00000004:
+        return SDL_SENSOR_GYRO;
+    default:
+        return SDL_SENSOR_UNKNOWN;
+    }
+}
+
+static int
+SDL_ANDROID_SensorGetDeviceNonPortableType(int device_index)
+{
+    return ASensor_getType(SDL_sensors[device_index].asensor);
+}
+
+static SDL_SensorID
+SDL_ANDROID_SensorGetDeviceInstanceID(int device_index)
+{
+    return SDL_sensors[device_index].instance_id;
+}
+
+static int
+SDL_ANDROID_SensorOpen(SDL_Sensor *sensor, int device_index)
+{
+    struct sensor_hwdata *hwdata;
+
+    hwdata = (struct sensor_hwdata *)SDL_calloc(1, sizeof(*hwdata));
+    if (hwdata == NULL) {
+        return SDL_OutOfMemory();
+    }
+
+    hwdata->asensor = SDL_sensors[device_index].asensor;
+    hwdata->eventqueue = ASensorManager_createEventQueue(SDL_sensor_manager, SDL_sensor_looper, LOOPER_ID_USER, NULL, NULL);
+    if (!hwdata->eventqueue) {
+        SDL_free(hwdata);
+        return SDL_SetError("Couldn't create sensor event queue");
+    }
+
+    if (ASensorEventQueue_enableSensor(hwdata->eventqueue, hwdata->asensor) < 0) {
+        ASensorManager_destroyEventQueue(SDL_sensor_manager, hwdata->eventqueue);
+        SDL_free(hwdata);
+        return SDL_SetError("Couldn't enable sensor");
+    }
+
+    /* FIXME: What rate should we set for this sensor? 60 FPS? Let's try the default rate for now... */
+
+    sensor->hwdata = hwdata;
+    return 0;
+}
+    
+static void
+SDL_ANDROID_SensorUpdate(SDL_Sensor* sensor)
+{
+    int events;
+    ASensorEvent event;
+    struct android_poll_source* source;
+
+    if (ALooper_pollAll(0, NULL, &events, (void**)&source) == LOOPER_ID_USER) {
+        SDL_zero(event);
+        while (ASensorEventQueue_getEvents(sensor->hwdata->eventqueue, &event, 1) > 0) {
+            SDL_PrivateSensorUpdate(sensor, event.data, SDL_arraysize(event.data));
+        }
+    }
+}
+
+static void
+SDL_ANDROID_SensorClose(SDL_Sensor * sensor)
+{
+    if (sensor->hwdata) {
+        ASensorEventQueue_disableSensor(sensor->hwdata->eventqueue, sensor->hwdata->asensor);
+        ASensorManager_destroyEventQueue(SDL_sensor_manager, sensor->hwdata->eventqueue);
+        SDL_free(sensor->hwdata);
+        sensor->hwdata = NULL;
+    }
+}
+
+static void
+SDL_ANDROID_SensorQuit(void)
+{
+    if (SDL_sensors) {
+        SDL_free(SDL_sensors);
+        SDL_sensors = NULL;
+        SDL_sensors_count = 0;
+    }
+}
+
+SDL_SensorDriver SDL_ANDROID_SensorDriver =
+{
+    SDL_ANDROID_SensorInit,
+    SDL_ANDROID_SensorGetCount,
+    SDL_ANDROID_SensorDetect,
+    SDL_ANDROID_SensorGetDeviceName,
+    SDL_ANDROID_SensorGetDeviceType,
+    SDL_ANDROID_SensorGetDeviceNonPortableType,
+    SDL_ANDROID_SensorGetDeviceInstanceID,
+    SDL_ANDROID_SensorOpen,
+    SDL_ANDROID_SensorUpdate,
+    SDL_ANDROID_SensorClose,
+    SDL_ANDROID_SensorQuit,
+};
+
+#endif /* SDL_SENSOR_ANDROID */
+
+/* vi: set ts=4 sw=4 expandtab: */

src/sensor/android/SDL_androidsensor.h

@@ -0,0 +1,31 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+/* The private structure used to keep track of a sensor */
+struct sensor_hwdata
+{
+    ASensorRef asensor;
+    ASensorEventQueue *eventqueue;
+};
+
+
+/* vi: set ts=4 sw=4 expandtab: */