Hook up sensors API in libretro.

There are still many FIXMEs to be resolved before the interface
can lose its experimental status.

android/native/jni/input_android.c

@@ -82,7 +82,7 @@ typedef struct android_input
 } android_input_t;
 
 void (*engine_handle_dpad)(void *data, AInputEvent*, size_t, int, char*, size_t, int, bool, unsigned);
-static void android_input_set_sensor_state(void *data, unsigned port, unsigned action, unsigned event_rate);
+static bool android_input_set_sensor_state(void *data, unsigned port, enum retro_sensor_action action, unsigned event_rate);
 
 extern float AMotionEvent_getAxisValue(const AInputEvent* motion_event,
       int32_t axis, size_t pointer_index);
@@ -1991,7 +1991,10 @@ static int16_t android_input_state(void *data, const struct retro_keybind **bind
       case RETRO_DEVICE_SENSOR_ACCELEROMETER:
          switch (id)
          {
-            /* FIXME - these are float values - might need a separate input state function */
+            // FIXME: These are float values.
+            // If they have a fixed range, e.g. (-1, 1), they can
+            // be converted to fixed point easily. If they have unbound range, this should be
+            // queried from a function in retro_sensor_interface.
             case RETRO_DEVICE_ID_SENSOR_ACCELEROMETER_X:
                return android->accelerometer_state.x;
             case RETRO_DEVICE_ID_SENSOR_ACCELEROMETER_Y:
@@ -2041,7 +2044,7 @@ static void android_input_enable_sensor_manager(void *data)
          android_app->looper, LOOPER_ID_USER, NULL, NULL);
 }
 
-static void android_input_set_sensor_state(void *data, unsigned port, unsigned action, unsigned event_rate)
+static bool android_input_set_sensor_state(void *data, unsigned port, enum retro_sensor_action action, unsigned event_rate)
 {
    android_input_t *android = (android_input_t*)data;
 
@@ -2053,7 +2056,7 @@ static void android_input_set_sensor_state(void *data, unsigned port, unsigned a
       case RETRO_SENSOR_ACCELEROMETER_ENABLE:
          if (android->sensor_state_mask &
                (1ULL << RETRO_SENSOR_ACCELEROMETER_ENABLE))
-            return;
+            return true;
 
          if (android->accelerometerSensor == NULL)
             android_input_enable_sensor_manager(android);
@@ -2067,18 +2070,22 @@ static void android_input_set_sensor_state(void *data, unsigned port, unsigned a
 
          android->sensor_state_mask &= ~(1ULL << RETRO_SENSOR_ACCELEROMETER_DISABLE);
          android->sensor_state_mask |= (1ULL  << RETRO_SENSOR_ACCELEROMETER_ENABLE);
-         break;
+         return true;
+
       case RETRO_SENSOR_ACCELEROMETER_DISABLE:
          if (android->sensor_state_mask &
                (1ULL << RETRO_SENSOR_ACCELEROMETER_DISABLE))
-            return;
+            return true;
 
          ASensorEventQueue_disableSensor(android->sensorEventQueue,
                android->accelerometerSensor);
          
          android->sensor_state_mask &= ~(1ULL << RETRO_SENSOR_ACCELEROMETER_ENABLE);
          android->sensor_state_mask |= (1ULL  << RETRO_SENSOR_ACCELEROMETER_DISABLE);
-         break;
+         return true;
+
+      default:
+         return false;
    }
 }
 

driver.c

@@ -409,6 +409,14 @@ bool driver_set_rumble_state(unsigned port, enum retro_rumble_effect effect, uin
       return false;
 }
 
+bool driver_set_sensor_state(unsigned port, enum retro_sensor_action action, unsigned rate)
+{
+   if (driver.input && driver.input_data && driver.input->set_sensor_state)
+      return driver.input->set_sensor_state(driver.input_data, port, action, rate);
+   else
+      return false;
+}
+
 uintptr_t driver_get_current_framebuffer(void)
 {
 #ifdef HAVE_FBO

driver.h

@@ -322,7 +322,7 @@ typedef struct input_driver
    bool (*key_pressed)(void *data, int key);
    void (*free)(void *data);
    void (*set_keybinds)(void *data, unsigned device, unsigned port, unsigned id, unsigned keybind_action);
-   void (*set_sensor_state)(void *data, unsigned port, unsigned action, unsigned event_rate);
+   bool (*set_sensor_state)(void *data, unsigned port, enum retro_sensor_action action, unsigned rate);
    uint64_t (*get_capabilities)(void *data);
    const char *ident;
 
@@ -504,6 +504,8 @@ retro_proc_address_t driver_get_proc_address(const char *sym);
 
 // Used by RETRO_ENVIRONMENT_GET_RUMBLE_INTERFACE
 bool driver_set_rumble_state(unsigned port, enum retro_rumble_effect effect, uint16_t strength);
+// Used by RETRO_ENVIRONMENT_GET_SENSOR_INTERFACE
+bool driver_set_sensor_state(unsigned port, enum retro_sensor_action action, unsigned rate);
 
 extern driver_t driver;
 

dynamic.c

@@ -775,6 +775,14 @@ bool rarch_environment_cb(unsigned cmd, void *data)
          break;
       }
 
+      case RETRO_ENVIRONMENT_GET_SENSOR_INTERFACE:
+      {
+         RARCH_LOG("Environ GET_SENSOR_INTERFACE.\n");
+         struct retro_sensor_interface *iface = (struct retro_sensor_interface*)data;
+         iface->set_sensor_state = driver_set_sensor_state;
+         break;
+      }
+
       // Private extensions for internal use, not part of libretro API.
       case RETRO_ENVIRONMENT_SET_LIBRETRO_PATH:
          RARCH_LOG("Environ (Private) SET_LIBRETRO_PATH.\n");

libretro.h

@@ -94,6 +94,7 @@ extern "C" {
 // Eventually _PRESSED will return false for an index. No further presses are registered at this point.
 #define RETRO_DEVICE_POINTER      6
 
+// FIXME: Document this.
 #define RETRO_DEVICE_SENSOR_ACCELEROMETER 7
 
 // These device types are specializations of the base types above.
@@ -533,7 +534,30 @@ enum retro_mod
                                            // Devices which are not handled or recognized always return 0 in retro_input_state_t.
                                            // Example bitmask: caps = (1 << RETRO_DEVICE_JOYPAD) | (1 << RETRO_DEVICE_ANALOG).
                                            // Should only be called in retro_run().
+                                           //
+#define RETRO_ENVIRONMENT_GET_SENSOR_INTERFACE (25 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+                                           // struct retro_sensor_interface * --
+                                           // Gets access to the sensor interface.
+                                           // The purpose of this interface is to allow
+                                           // setting state related to sensors such as polling rate, enabling/disable it entirely, etc.
+                                           // Reading sensor state is done via the normal input_state_callback API.
 
+// FIXME: Document the sensor API and work out behavior.
+// It will be marked as experimental until then.
+enum retro_sensor_action
+{
+   RETRO_SENSOR_ACCELEROMETER_ENABLE = 0,
+   RETRO_SENSOR_ACCELEROMETER_DISABLE,
+
+   RETRO_SENSOR_DUMMY = INT_MAX
+};
+
+typedef bool (*retro_set_sensor_state_t)(unsigned port, enum retro_sensor_action action, unsigned rate);
+struct retro_sensor_interface
+{
+   retro_set_sensor_state_t set_sensor_state;
+};
+////
 
 enum retro_rumble_effect
 {
@@ -543,14 +567,6 @@ enum retro_rumble_effect
    RETRO_RUMBLE_DUMMY = INT_MAX
 };
 
-enum retro_sensor_action
-{
-   RETRO_SENSOR_ACCELEROMETER_ENABLE = 0,
-   RETRO_SENSOR_ACCELEROMETER_DISABLE,
-};
-
-typedef bool (*retro_set_sensor_state_t)(unsigned port, enum retro_sensor_action action, unsigned event_rate);
-
 // Sets rumble state for joypad plugged in port 'port'. Rumble effects are controlled independently,
 // and setting e.g. strong rumble does not override weak rumble.
 // Strength has a range of [0, 0xffff].