src/joystick/iphoneos/SDLUIAccelerationDelegate.m
author David Ludwig <dludwig@pobox.com>
Tue, 24 Dec 2013 21:28:31 -0500
changeset 8552 abd934eac415
parent 7191 75360622e65f
child 8149 681eb46b8ac4
permissions -rw-r--r--
WinRT: moved ill-performing XInput device-detection calls to a separate thread
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
     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 
    22 #import "SDLUIAccelerationDelegate.h"
    23 /* needed for SDL_IPHONE_MAX_GFORCE macro */
    24 #import "../../../include/SDL_config_iphoneos.h"
    25 
    26 static SDLUIAccelerationDelegate *sharedDelegate=nil;
    27 
    28 @implementation SDLUIAccelerationDelegate
    29 
    30 /*
    31     Returns a shared instance of the SDLUIAccelerationDelegate, creating the shared delegate if it doesn't exist yet.
    32 */
    33 +(SDLUIAccelerationDelegate *)sharedDelegate {
    34     if (sharedDelegate == nil) {
    35         sharedDelegate = [[SDLUIAccelerationDelegate alloc] init];
    36     }
    37     return sharedDelegate;
    38 }
    39 /*
    40     UIAccelerometerDelegate delegate method.  Invoked by the UIAccelerometer instance when it has new data for us.
    41     We just take the data and mark that we have new data available so that the joystick system will pump it to the
    42     events system when SDL_SYS_JoystickUpdate is called.
    43 */
    44 -(void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {
    45 
    46     x = acceleration.x;
    47     y = acceleration.y;
    48     z = acceleration.z;
    49 
    50     hasNewData = YES;
    51 }
    52 /*
    53     getLastOrientation -- put last obtained accelerometer data into Sint16 array
    54 
    55     Called from the joystick system when it needs the accelerometer data.
    56     Function grabs the last data sent to the accelerometer and converts it
    57     from floating point to Sint16, which is what the joystick system expects.
    58 
    59     To do the conversion, the data is first clamped onto the interval
    60     [-SDL_IPHONE_MAX_G_FORCE, SDL_IPHONE_MAX_G_FORCE], then the data is multiplied
    61     by MAX_SINT16 so that it is mapped to the full range of an Sint16.
    62 
    63     You can customize the clamped range of this function by modifying the
    64     SDL_IPHONE_MAX_GFORCE macro in SDL_config_iphoneos.h.
    65 
    66     Once converted to Sint16, the accelerometer data no longer has coherent units.
    67     You can convert the data back to units of g-force by multiplying it
    68     in your application's code by SDL_IPHONE_MAX_GFORCE / 0x7FFF.
    69  */
    70 -(void)getLastOrientation:(Sint16 *)data {
    71 
    72     #define MAX_SINT16 0x7FFF
    73 
    74     /* clamp the data */
    75     if (x > SDL_IPHONE_MAX_GFORCE) x = SDL_IPHONE_MAX_GFORCE;
    76     else if (x < -SDL_IPHONE_MAX_GFORCE) x = -SDL_IPHONE_MAX_GFORCE;
    77     if (y > SDL_IPHONE_MAX_GFORCE) y = SDL_IPHONE_MAX_GFORCE;
    78     else if (y < -SDL_IPHONE_MAX_GFORCE) y = -SDL_IPHONE_MAX_GFORCE;
    79     if (z > SDL_IPHONE_MAX_GFORCE) z = SDL_IPHONE_MAX_GFORCE;
    80     else if (z < -SDL_IPHONE_MAX_GFORCE) z = -SDL_IPHONE_MAX_GFORCE;
    81 
    82     /* pass in data mapped to range of SInt16 */
    83     data[0] = (x / SDL_IPHONE_MAX_GFORCE) * MAX_SINT16;
    84     data[1] = (y / SDL_IPHONE_MAX_GFORCE) * MAX_SINT16;
    85     data[2] = (z / SDL_IPHONE_MAX_GFORCE) * MAX_SINT16;
    86 
    87 }
    88 
    89 /*
    90     Initialize SDLUIAccelerationDelegate.  Since we don't have any data yet,
    91     just set our last received data to zero, and indicate we don't have any;
    92 */
    93 -(id)init {
    94     self = [super init];
    95     x = y = z = 0.0;
    96     hasNewData = NO;
    97     return self;
    98 }
    99 
   100 -(void)dealloc {
   101     sharedDelegate = nil;
   102     [self shutdown];
   103     [super dealloc];
   104 }
   105 
   106 /*
   107     Lets our delegate start receiving accelerometer updates.
   108 */
   109 -(void)startup {
   110     [UIAccelerometer sharedAccelerometer].delegate = self;
   111     isRunning = YES;
   112 }
   113 /*
   114     Stops our delegate from receiving accelerometer updates.
   115 */
   116 -(void)shutdown {
   117     if ([UIAccelerometer sharedAccelerometer].delegate == self) {
   118         [UIAccelerometer sharedAccelerometer].delegate = nil;
   119     }
   120     isRunning = NO;
   121 }
   122 /*
   123     Our we currently receiving accelerometer updates?
   124 */
   125 -(BOOL)isRunning {
   126     return isRunning;
   127 }
   128 /*
   129     Do we have any data that hasn't been pumped into SDL's event system?
   130 */
   131 -(BOOL)hasNewData {
   132     return hasNewData;
   133 }
   134 /*
   135     When the joystick system grabs the new data, it sets this to NO.
   136 */
   137 -(void)setHasNewData:(BOOL)value {
   138     hasNewData = value;
   139 }
   140 
   141 @end