include/SDL_haptic.h
author Edgar Simo <bobbens@gmail.com>
Tue, 15 Jul 2008 15:53:48 +0000
branchgsoc2008_force_feedback
changeset 2519 af9df9662807
parent 2517 37c13c12c878
child 2523 366d84fdf8d1
permissions -rw-r--r--
More explicit with iterations and length.
Added spherical coordinates (not available on linux).
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 2008 Edgar Simo
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Lesser General Public
     7     License as published by the Free Software Foundation; either
     8     version 2.1 of the License, or (at your option) any later version.
     9 
    10     This library is distributed in the hope that it will be useful,
    11     but WITHOUT ANY WARRANTY; without even the implied warranty of
    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13     Lesser General Public License for more details.
    14 
    15     You should have received a copy of the GNU Lesser General Public
    16     License along with this library; if not, write to the Free Software
    17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 
    23 /**
    24  * \file SDL_haptic.h
    25  *
    26  * \brief The SDL Haptic subsystem allows you to control haptic (force feedback)
    27  *  devices.
    28  *
    29  * The basic usage is as follows:
    30  *   - Initialize the Subsystem (SDL_INIT_HAPTIC).
    31  *   - Open a Haptic Device.
    32  *     - SDL_HapticOpen(...) to open from index.
    33  *     - SDL_HapticOpenFromJoystick(...) to open from an existing joystick.
    34  *   - Create an effect (SDL_HapticEffect).
    35  *   - Upload the effect with SDL_HapticNewEffect(...).
    36  *   - Run the effect with SDL_HapticRunEffect(...).
    37  *   - (optional) Free the effect with SDL_HapticDestroyEffect(...).
    38  *   - Close the haptic device with SDL_HapticClose(...).
    39  *
    40  * Example:
    41  *
    42  * \code
    43  * int test_haptic( SDL_Joystick * joystick ) {
    44  *    SDL_Haptic *haptic;
    45  *    SDL_HapticEffect effect;
    46  *    int effect_id;
    47  *
    48  *    // Open the device
    49  *    haptic = SDL_HapticOpenFromJoystick( joystick );
    50  *    if (haptic == NULL) return -1; // Most likely joystick isn't haptic
    51  *
    52  *    // See if it can do sine waves
    53  *    if ((SDL_HapticQuery(haptic) & SDL_HAPTIC_SINE)==0) {
    54  *       SDL_HapticClose(haptic); // No sine effect
    55  *       return -1;
    56  *    }
    57  *
    58  *    // Create the effect
    59  *    memset( &effect, 0, sizeof(SDL_HapticEffect) ); // 0 is safe default
    60  *    effect.type = SDL_HAPTIC_SINE;
    61  *    effect.periodic.direction.type = SDL_HAPTIC_POLAR; // Polar coordinates
    62  *    effect.periodic.direction.dir[0] = 18000; // Force comes from south
    63  *    effect.periodic.period = 1000; // 1000 ms
    64  *    effect.periodic.magnitude = 20000; // 20000/32767 strength
    65  *    effect.periodic.length = 5000; // 5 seconds long
    66  *    effect.periodic.attack_length = 1000; // Takes 1 second to get max strength
    67  *    effect.periodic.fade_length = 1000; // Takes 1 second to fade away
    68  *
    69  *    // Upload the effect
    70  *    effect_id = SDL_HapticNewEffect( haptic, &effect );
    71  *
    72  *    // Test the effect
    73  *    SDL_HapticRunEffect( haptic, effect_id, 1 );
    74  *    SDL_Delay( 5000); // Wait for the effect to finish
    75  *
    76  *    // We destroy the effect, although closing the device also does this
    77  *    SDL_HapticDestroyEffect( haptic, effect_id );
    78  *
    79  *    // Close the device
    80  *    SDL_HapticClose(haptic);
    81  *
    82  *    return 0; // Success
    83  * }
    84  * \endcode
    85  *
    86  * \author Edgar Simo Serra
    87  */
    88 
    89 #ifndef _SDL_haptic_h
    90 #define _SDL_haptic_h
    91 
    92 #include "SDL_stdinc.h"
    93 #include "SDL_error.h"
    94 #include "SDL_joystick.h"
    95 
    96 #include "begin_code.h"
    97 /* Set up for C function definitions, even when using C++ */
    98 #ifdef __cplusplus
    99 /* *INDENT-OFF* */
   100 extern "C" {
   101    /* *INDENT-ON* */                                                         
   102 #endif /* __cplusplus */
   103 
   104 /**
   105  * \typedef SDL_Haptic
   106  *
   107  * \brief The haptic structure used to identify an SDL haptic.
   108  *
   109  * \sa SDL_HapticOpen
   110  * \sa SDL_HapticOpenFromJoystick
   111  * \sa SDL_HapticClose
   112  */
   113 struct _SDL_Haptic;                                                     
   114 typedef struct _SDL_Haptic SDL_Haptic;
   115 
   116 
   117 /*
   118  * Different haptic features a device can have.
   119  */
   120 /**
   121  * \def SDL_HAPTIC_CONSTANT
   122  *
   123  * \brief Constant haptic effect.
   124  *
   125  * \sa SDL_HapticCondition
   126  */
   127 #define SDL_HAPTIC_CONSTANT   (1<<0) /* Constant effect supported */
   128 /**
   129  * \def SDL_HAPTIC_SINE
   130  *
   131  * \brief Periodic haptic effect that simulates sine waves.
   132  *
   133  * \sa SDL_HapticPeriodic
   134  */
   135 #define SDL_HAPTIC_SINE       (1<<1) /* Sine wave effect supported */
   136 /**
   137  * \def SDL_HAPTIC_SQUARE
   138  *
   139  * \brief Periodic haptic effect that simulates square waves.
   140  * 
   141  * \sa SDL_HapticPeriodic
   142  */
   143 #define SDL_HAPTIC_SQUARE     (1<<2) /* Square wave effect supported */
   144 /**
   145  * \def SDL_HAPTIC_TRIANGLE
   146  *
   147  * \brief Periodic haptic effect that simulates triangular waves.
   148  *
   149  * \sa SDL_HapticPeriodic
   150  */
   151 #define SDL_HAPTIC_TRIANGLE   (1<<3) /* Triangle wave effect supported */
   152 /**
   153  * \def SDL_HAPTIC_SAWTOOTHUP
   154  *
   155  * \brief Periodic haptic effect that simulates saw tooth up waves.
   156  *
   157  * \sa SDL_HapticPeriodic
   158  */
   159 #define SDL_HAPTIC_SAWTOOTHUP (1<<4) /* Sawtoothup wave effect supported */
   160 /**
   161  * \def SDL_HAPTIC_SAWTOOTHDOWN
   162  *
   163  * \brief Periodic haptic effect that simulates saw tooth down waves.
   164  *
   165  * \sa SDL_HapticPeriodic
   166  */
   167 #define SDL_HAPTIC_SAWTOOTHDOWN (1<<5) /* Sawtoothdown wave effect supported */
   168 /**
   169  * \def SDL_HAPTIC_RAMP
   170  *
   171  * \brief Ramp haptic effect.
   172  *
   173  * \sa SDL_HapticRamp
   174  */
   175 #define SDL_HAPTIC_RAMP       (1<<6) /* Ramp effect supported */
   176 /**
   177  * \def SDL_HAPTIC_SPRING
   178  *
   179  * \brief Condition haptic effect that simulates a spring.  Effect is based on the
   180  * axes position.
   181  *
   182  * \sa SDL_HapticCondition
   183  */
   184 #define SDL_HAPTIC_SPRING     (1<<7) /* Spring effect supported - uses axes position */
   185 /**
   186  * \def SDL_HAPTIC_DAMPER
   187  *
   188  * \brief Condition haptic effect that simulates dampening.  Effect is based on the
   189  * axes velocity.
   190  *
   191  * \sa SDL_HapticCondition
   192  */
   193 #define SDL_HAPTIC_DAMPER     (1<<8) /* Damper effect supported - uses axes velocity */
   194 /**
   195  * \def SDL_HAPTIC_INERTIA
   196  *
   197  * \brief Condition haptic effect that simulates inertia.  Effect is based on the axes
   198  * acceleration.
   199  *
   200  * \sa SDL_HapticCondition
   201  */
   202 #define SDL_HAPTIC_INERTIA    (1<<9) /* Inertia effect supported - uses axes acceleration */
   203 /**
   204  * \def SDL_HAPTIC_FRICTION
   205  *
   206  * \brief Condition haptic effect that simulates friction.  Effect is based on the axes
   207  * movement.
   208  *
   209  * \sa SDL_HapticCondition
   210  */
   211 #define SDL_HAPTIC_FRICTION   (1<<10) /* Friction effect supported - uses axes movement */
   212 /**
   213  * \def SDL_HAPTIC_CUSTOM
   214  *
   215  * \brief User defined custom haptic effect. @todo.
   216  */
   217 #define SDL_HAPTIC_CUSTOM     (1<<11) /* Custom effect is supported */
   218 /* These last two are features the device has, not effects */
   219 /**
   220  * \def SDL_HAPTIC_GAIN
   221  *
   222  * \brief Device supports setting the global gain.
   223  *
   224  * \sa SDL_HapticSetGain
   225  */
   226 #define SDL_HAPTIC_GAIN       (1<<12) /* Device can set global gain */
   227 /**
   228  * \def SDL_HAPTIC_AUTOCENTER
   229  *
   230  * \brief Device supports setting autocenter.
   231  *
   232  * \sa SDL_HapticSetAutocenter
   233  */
   234 #define SDL_HAPTIC_AUTOCENTER (1<<13) /* Device can set autocenter */
   235 /**
   236  * \def SDL_HAPTIC_STATUS
   237  *
   238  * \brief Device can be queried for effect status.
   239  *
   240  * \sa SDL_HapticGetEffectStatus
   241  */
   242 #define SDL_HAPTIC_STATUS     (1<<14) /* Device can be queried for effect status */
   243 
   244 
   245 /*
   246  * Direction encodings
   247  */
   248 /**
   249  * \def SDL_HAPTIC_POLAR
   250  *
   251  * \brief Uses polar coordinates for the direction.
   252  *
   253  * \sa SDL_HapticDirection
   254  */
   255 #define SDL_HAPTIC_POLAR      0
   256 /**
   257  * \def SDL_HAPTIC_CARTESIAN
   258  *
   259  * \brief Uses cartesian coordinates for the direction.
   260  *
   261  * \sa SDL_HapticDirection
   262  */
   263 #define SDL_HAPTIC_CARTESIAN  1
   264 /**
   265  * \def SDL_HAPTIC_SHPERICAL
   266  *
   267  * \brief Uses spherical coordinates for the direction.
   268  *
   269  * \sa SDL_HapticDirection
   270  */
   271 #define SDL_HAPTIC_SPHERICAL  2
   272 
   273 
   274 /*
   275  * Misc defines.
   276  */
   277 /**
   278  * \def SDL_HAPTIC_INFINITY
   279  *
   280  * \brief Used to play a device an infinite number of times.
   281  *
   282  * \sa SDL_HapticRunEffect
   283  */
   284 #define SDL_HAPTIC_INFINITY   4294967295U
   285 
   286 
   287 /**
   288  * \struct SDL_HapticDirection
   289  *
   290  * \brief Structure that represents a haptic direction.
   291  *
   292  * Directions can be specified by:
   293  *   - SDL_HAPTIC_POLAR : Specified by polar coordinates.
   294  *   - SDL_HAPTIC_CARTESIAN : Specified by cartesian coordinates.
   295  *
   296  * Cardinal directions of the haptic device are relative to the positioning
   297  *  of the device.  North is considered to be away from the user.
   298  *
   299  * The following diagram represents the cardinal directions:
   300  * \code
   301  *            .--.
   302  *            |__| .-------.
   303  *            |=.| |.-----.|
   304  *            |--| ||     ||
   305  *            |  | |'-----'|
   306  *            |__|~')_____('
   307  *              [ COMPUTER ]
   308  *
   309  *
   310  *                  North (-1)
   311  *                    ^
   312  *                    |
   313  *                    |
   314  * (1)  West <----[ HAPTIC ]----> East (-1)
   315  *                    |
   316  *                    |
   317  *                    v
   318  *                  South (1)
   319  *
   320  *
   321  *                 [ USER ]
   322  *                   \|||/
   323  *                   (o o)
   324  *             ---ooO-(_)-Ooo---
   325  * \endcode
   326  *
   327  * If type is SDL_HAPTIC_POLAR, direction is encoded by hundredths of a 
   328  *  degree starting north and turning clockwise.  SDL_HAPTIC_POLAR only uses
   329  *  the first dir parameter.  The cardinal directions would be:
   330  *   - North: 0 (0 degrees)
   331  *   - East: 9000 (90 degrees)
   332  *   - South: 18000 (180 degrees)
   333  *   - West: 27000 (270 degrees)
   334  *
   335  * If type is SDL_HAPTIC_CARTESIAN, direction is encoded by two positions
   336  *  (X axis and Y axis).  SDL_HAPTIC_CARTESIAN uses the first two dir 
   337  *  parameters.  The cardinal directions would be:
   338  *   - North:  0,-1
   339  *   - East:  -1, 0
   340  *   - South:  0, 1
   341  *   - West:   1, 0
   342  *
   343  * If type is SDL_HAPTIC_SPHERICAL, direction is encoded by three rotations.
   344  *  All three dir parameters are used.  The dir parameters are as follows
   345  *  (all values are in hundredths of degrees):
   346  *    1) Degrees from (1, 0) rotated towards (0, 1).
   347  *    2) Degrees towards (0, 0, 1) (device needs at least 3 axes).
   348  *    3) Degrees tworads (0, 0, 0, 1) (device needs at least 4 axes).
   349  *
   350  *
   351  * Example:
   352  * \code
   353  * SDL_HapticDirection direction;
   354  *
   355  * direction.type = SDL_HAPTIC_POLAR; // We'll be using polar direction encoding.
   356  * direction.dir = 18000; // Force comes from the south meaning the user will
   357  *                         // have to pull the stick to counteract.
   358  * \endcode
   359  *
   360  * \sa SDL_HAPTIC_POLAR
   361  * \sa SDL_HAPTIC_CARTESIAN
   362  * \sa SDL_HAPTIC_SHPERICAL
   363  * \sa SDL_HapticEffect
   364  */
   365 typedef struct SDL_HapticDirection {
   366    Uint8 type; /**< The type of encoding. */
   367    Uint16 dir[3]; /**< The encoded direction. */
   368 } SDL_HapticDirection;
   369 
   370 
   371 /**
   372  * \struct SDL_HapticConstant
   373  *
   374  * \brief A structure containing a template for a Constant effect.
   375  *
   376  * The struct is exclusive to the SDL_HAPTIC_CONSTANT effect.
   377  *
   378  * A constant effect applies a constant force in the specified direction
   379  *  to the joystick.
   380  *
   381  * \sa SDL_HAPTIC_CONSTANT
   382  * \sa SDL_HapticEffect
   383  */
   384 typedef struct SDL_HapticConstant {
   385    /* Header */
   386    Uint16 type; /**< SDL_HAPTIC_CONSTANT */
   387    SDL_HapticDirection direction; /**< Direction of the effect. */
   388 
   389    /* Replay */
   390    Uint32 length; /**< Duration of the effect. */
   391    Uint16 delay; /**< Delay before starting the effect. */
   392 
   393    /* Trigger */
   394    Uint16 button; /**< Button that triggers the effect. */
   395    Uint16 interval; /**< How soon it can be triggered again after button. */
   396 
   397    /* Constant */
   398    Sint16 level; /**< Strength of the constant effect. */
   399 
   400    /* Envelope */
   401    Uint16 attack_length; /**< Duration of the attack. */
   402    Uint16 attack_level; /**< Level at the start of the attack. */
   403    Uint16 fade_length; /**< Duration of the fade. */
   404    Uint16 fade_level; /**< Level at the end of the fade. */
   405 } SDL_HapticConstant;
   406 /**
   407  * \struct SDL_HapticPeriodic
   408  *
   409  * \brief A structure containing a template for a Periodic effect.
   410  *
   411  * The struct handles the following effects:
   412  *   - SDL_HAPTIC_SINE
   413  *   - SDL_HAPTIC_SQUARE
   414  *   - SDL_HAPTIC_TRIANGLE
   415  *   - SDL_HAPTIC_SAWTOOTHUP
   416  *   - SDL_HAPTIC_SAWTOOTHDOWN
   417  *
   418  * A periodic effect consists in a wave-shaped effect that repeats itself
   419  *  over time.  The type determines the shape of the wave and the parameters
   420  *  determine the dimensions of the wave.
   421  *
   422  * Examples:
   423  * \code
   424  * SDL_HAPTIC_SINE
   425  *   __      __      __      __
   426  *  /  \    /  \    /  \    /
   427  * /    \__/    \__/    \__/
   428  *
   429  * SDL_HAPTIC_SQUARE
   430  *  __    __    __    __    __
   431  * |  |  |  |  |  |  |  |  |  |
   432  * |  |__|  |__|  |__|  |__|  |
   433  *
   434  * SDL_HAPTIC_TRIANGLE
   435  *   /\    /\    /\    /\    /\
   436  *  /  \  /  \  /  \  /  \  /
   437  * /    \/    \/    \/    \/
   438  *
   439  * SDL_HAPTIC_SAWTOOTHUP
   440  *   /|  /|  /|  /|  /|  /|  /|
   441  *  / | / | / | / | / | / | / |
   442  * /  |/  |/  |/  |/  |/  |/  |
   443  *
   444  * SDL_HAPTIC_SAWTOOTHDOWN
   445  * \  |\  |\  |\  |\  |\  |\  |
   446  *  \ | \ | \ | \ | \ | \ | \ |
   447  *   \|  \|  \|  \|  \|  \|  \|
   448  * \endcode
   449  *
   450  * \sa SDL_HAPTIC_SINE
   451  * \sa SDL_HAPTIC_SQUARE
   452  * \sa SDL_HAPTIC_TRIANGLE
   453  * \sa SDL_HAPTIC_SAWTOOTHUP
   454  * \sa SDL_HAPTIC_SAWTOOTHDOWN
   455  * \sa SDL_HapticEffect
   456  */
   457 typedef struct SDL_HapticPeriodic {
   458    /* Header */
   459    Uint16 type; /**< SDL_HAPTIC_SINE, SDL_HAPTIC_SQUARE,
   460                      SDL_HAPTIC_TRIANGLE, SDL_HAPTIC_SAWTOOTHUP or
   461                      SDL_HAPTIC_SAWTOOTHDOWN */
   462    SDL_HapticDirection direction; /**< Direction of the effect. */
   463 
   464    /* Replay */
   465    Uint32 length; /**< Duration of the effect. */
   466    Uint16 delay; /**< Delay before starting the effect. */
   467 
   468    /* Trigger */
   469    Uint16 button; /**< Button that triggers the effect. */
   470    Uint16 interval; /**< How soon it can be triggered again after button. */
   471 
   472    /* Periodic */
   473    Uint16 period; /**< Period of the wave. */
   474    Sint16 magnitude; /**< Peak value. */
   475    Sint16 offset; /**< Mean value of the wave. */
   476    Uint16 phase; /**< Horizontal shift. */
   477 
   478    /* Envelope */
   479    Uint16 attack_length; /**< Duration of the attack. */
   480    Uint16 attack_level; /**< Level at the start of the attack. */
   481    Uint16 fade_length; /**< Duration of the fade. */
   482    Uint16 fade_level; /**< Level at the end of the fade. */
   483 } SDL_HapticPeriodic;
   484 /**
   485  * \struct SDL_HapticCondition
   486  *
   487  * \brief A structure containing a template for a Condition effect.
   488  *
   489  * The struct handles the following effects:
   490  *   - SDL_HAPTIC_SPRING: Effect based on axes position.
   491  *   - SDL_HAPTIC_DAMPER: Effect based on axes velocity.
   492  *   - SDL_HAPTIC_INERTIA: Effect based on axes acceleration.
   493  *   - SDL_HAPTIC_FRICTION: Effect based on axes movement.
   494  *
   495  * Direction is handled by condition internals instead of a direction member.
   496  *  The condition effect specific members have two parameters.  The first
   497  *  refers to the X axis, the second refers to the Y axis.  The right terms
   498  *  refer to the positive side of the axis and the left terms refer to the
   499  *  negative side of the axis.  Please refer to the SDL_HapticDirection 
   500  *  diagram for which side is positive and which is negative.
   501  *
   502  * \sa SDL_HapticDirection
   503  * \sa SDL_HAPTIC_SPRING
   504  * \sa SDL_HAPTIC_DAMPER
   505  * \sa SDL_HAPTIC_INERTIA
   506  * \sa SDL_HAPTIC_FRICTION
   507  * \sa SDL_HapticEffect
   508  */
   509 typedef struct SDL_HapticCondition {
   510    /* Header */
   511    Uint16 type; /**< SDL_HAPTIC_SPRING, SDL_HAPTIC_DAMPER,
   512                      SDL_HAPTIC_INERTIA or SDL_HAPTIC_FRICTION */
   513 
   514    /* Replay */
   515    Uint32 length; /**< Duration of the effect. */
   516    Uint16 delay; /**< Delay before starting the effect. */
   517 
   518    /* Trigger */
   519    Uint16 button; /**< Button that triggers the effect. */
   520    Uint16 interval; /**< How soon it can be triggered again after button. */
   521 
   522    /* Condition */
   523    Uint16 right_sat[2]; /**< Level when joystick is to the positive side. */
   524    Uint16 left_sat[2]; /**< Level when joystick is to the negative side. */
   525    Sint16 right_coeff[2]; /**< How fast to increase the force towards the positive side. */
   526    Sint16 left_coeff[2]; /**< How fast to increase the force towards the negative side. */
   527    Uint16 deadband[2]; /**< Size of the dead zone. */
   528    Sint16 center[2]; /**< Position of the dead zone. */
   529 } SDL_HapticCondition;
   530 /**
   531  * \struct SDL_HapticRamp
   532  *
   533  * \brief A structure containing a template for a Ramp effect.
   534  *
   535  * This struct is exclusively for the SDL_HAPTIC_RAMP effect.
   536  *
   537  * The ramp effect starts at start strength and ends at end strength.
   538  *  It augments in linear fashion.  If you use attack and fade with a ramp
   539  *  they effects get added to the ramp effect making the effect become
   540  *  quadratic instead of linear.
   541  *
   542  * \sa SDL_HAPTIC_RAMP
   543  * \sa SDL_HapticEffect
   544  */
   545 typedef struct SDL_HapticRamp {
   546    /* Header */
   547    Uint16 type; /**< SDL_HAPTIC_RAMP */
   548    SDL_HapticDirection direction; /**< Direction of the effect. */
   549 
   550    /* Replay */
   551    Uint32 length; /**< Duration of the effect. */
   552    Uint16 delay; /**< Delay before starting the effect. */
   553 
   554    /* Trigger */
   555    Uint16 button; /**< Button that triggers the effect. */
   556    Uint16 interval; /**< How soon it can be triggered again after button. */
   557 
   558    /* Ramp */
   559    Sint16 start; /**< Beginning strength level. */
   560    Sint16 end; /**< Ending strength level. */
   561 
   562    /* Envelope */
   563    Uint16 attack_length; /**< Duration of the attack. */
   564    Uint16 attack_level; /**< Level at the start of the attack. */
   565    Uint16 fade_length; /**< Duration of the fade. */
   566    Uint16 fade_level; /**< Level at the end of the fade. */
   567 } SDL_HapticRamp;
   568 /**
   569  * \union SDL_HapticEffect
   570  *
   571  * \brief The generic template for any haptic effect.
   572  *
   573  * All values max at 32767 (0x7FFF).  Signed values also can be negative.
   574  *  Time values unless specified otherwise are in milliseconds.
   575  *
   576  * You can also pass SDL_HAPTIC_INFINITY to length instead of a 0-32767 value.
   577  *  Neither delay, interval, attack_length nor fade_length support 
   578  *  SDL_HAPTIC_INFINITY.
   579  *
   580  * Common parts:
   581  * \code
   582  * // Replay - All effects have this
   583  * Uint32 length;        // Duration of effect (ms).
   584  * Uint16 delay;         // Delay before starting effect.
   585  *
   586  * // Trigger - All effects have this
   587  * Uint16 button;        // Button that triggers effect.
   588  * Uint16 interval;      // How soon before effect can be triggered again.
   589  *
   590  * // Envelope - All effects except condition effects have this
   591  * Uint16 attack_length; // Duration of the attack (ms).
   592  * Uint16 attack_level;  // Level at the start of the attack.
   593  * Uint16 fade_length;   // Duration of the fade out (ms).
   594  * Uint16 fade_level;    // Level at the end of the fade.
   595  * \endcode
   596  *
   597  *
   598  * Here we have an example of a constant effect evolution in time:
   599  *
   600  * \code
   601  * Strength
   602  * ^
   603  * |
   604  * |    effect level -->  _________________
   605  * |                     /                 \
   606  * |                    /                   \
   607  * |                   /                     \
   608  * |                  /                       \ 
   609  * | attack_level --> |                        \
   610  * |                  |                        |  <---  fade_level
   611  * |
   612  * +--------------------------------------------------> Time
   613  *                    [--]                 [---]
   614  *                    attack_length        fade_length
   615  * 
   616  * [------------------][-----------------------]
   617  * delay               length
   618  * \endcode
   619  *
   620  * Note either the attack_level or the fade_level may be above the actual
   621  *  effect level.
   622  *
   623  * \sa SDL_HapticConstant
   624  * \sa SDL_HapticPeriodic
   625  * \sa SDL_HapticCondition
   626  * \sa SDL_HapticRamp
   627  */
   628 typedef union SDL_HapticEffect {
   629    /* Common for all force feedback effects */
   630    Uint16 type; /**< Effect type. */
   631    SDL_HapticConstant constant; /**< Constant effect. */
   632    SDL_HapticPeriodic periodic; /**< Periodic effect. */
   633    SDL_HapticCondition condition; /**< Condition effect. */
   634    SDL_HapticRamp ramp; /**< Ramp effect. */
   635 } SDL_HapticEffect;
   636 
   637 
   638 /* Function prototypes */
   639 /**
   640  * \fn int SDL_NumHaptics(void)
   641  *
   642  * \brief Count the number of joysticks attached to the system.
   643  *
   644  *    \return Number of haptic devices detected on the system.
   645  */
   646 extern DECLSPEC int SDLCALL SDL_NumHaptics(void);
   647 
   648 /**
   649  * \fn const char * SDL_HapticName(int device_index)
   650  *
   651  * \brief Get the implementation dependent name of a Haptic device.
   652  * This can be called before any joysticks are opened.
   653  * If no name can be found, this function returns NULL.
   654  *
   655  *    \param device_index Index of the device to get it's name.
   656  *    \return Name of the device or NULL on error.
   657  *
   658  * \sa SDL_NumHaptics
   659  */
   660 extern DECLSPEC const char *SDLCALL SDL_HapticName(int device_index);
   661 
   662 /**
   663  * \fn SDL_Haptic * SDL_HapticOpen(int device_index)
   664  *
   665  * \brief Opens a Haptic device for usage - the index passed as an
   666  * argument refers to the N'th Haptic device on this system.
   667  *
   668  * When opening a haptic device, it's gain will be set to maximum and
   669  *  autocenter will be disabled.  To modify these values use
   670  *  SDL_HapticSetGain and SDL_HapticSetAutocenter
   671  *
   672  *    \param device_index Index of the device to open.
   673  *    \return Device identifier or NULL on error.
   674  *
   675  * \sa SDL_HapticIndex
   676  * \sa SDL_HapticOpenFromMouse
   677  * \sa SDL_HapticOpenFromJoystick
   678  * \sa SDL_HapticClose
   679  * \sa SDL_HapticSetGain
   680  * \sa SDL_HapticSetAutocenter
   681  */
   682 extern DECLSPEC SDL_Haptic * SDL_HapticOpen(int device_index);
   683 
   684 /**
   685  * \fn int SDL_HapticOpened(int device_index)
   686  *
   687  * \brief Checks if the haptic device at index has been opened.
   688  *
   689  *    \param device_index Index to check to see if it has been opened.
   690  *    \return 1 if it has been opened or 0 if it hasn't.
   691  * 
   692  * \sa SDL_HapticOpen
   693  * \sa SDL_HapticIndex
   694  */
   695 extern DECLSPEC int SDL_HapticOpened(int device_index);
   696 
   697 /**
   698  * \fn int SDL_HapticIndex(SDL_Haptic * haptic)
   699  *
   700  * \brief Gets the index of a haptic device.
   701  *
   702  *    \param haptic Haptic device to get the index of.
   703  *    \return The index of the haptic device or -1 on error.
   704  *
   705  * \sa SDL_HapticOpen
   706  * \sa SDL_HapticOpened
   707  */
   708 extern DECLSPEC int SDL_HapticIndex(SDL_Haptic * haptic);
   709 
   710 /**
   711  * \fn int SDL_MouseIsHaptic(void)
   712  *
   713  * \brief Gets whether or not the current mouse has haptic capabilities.
   714  *
   715  *    \return SDL_TRUE if the mouse is haptic, SDL_FALSE if it isn't.
   716  *
   717  * \sa SDL_HapticOpenFromMouse
   718  */
   719 extern DECLSPEC int SDL_MouseIsHaptic(void);
   720 
   721 /**
   722  * \fn SDL_Haptic * SDL_HapticOpenFromMouse(void)
   723  *
   724  * \brief Tries to open a haptic device from the current mouse.
   725  *
   726  *    \return The haptic device identifier or NULL on error.
   727  *
   728  * \sa SDL_MouseIsHaptic
   729  * \sa SDL_HapticOpen
   730  */
   731 extern DECLSPEC SDL_Haptic * SDL_HapticOpenFromMouse(void);
   732 
   733 /**
   734  * \fn int SDL_JoystickIsHaptic(SDL_Joystick * joystick)
   735  *
   736  * \brief Checks to see if a joystick has haptic features.
   737  *
   738  *    \param joystick Joystick to test for haptic capabilities.
   739  *    \return SDL_TRUE if the joystick is haptic, SDL_FALSE if it isn't
   740  *            or -1 if an error ocurred.
   741  *
   742  * \sa SDL_HapticOpenFromJoystick
   743  */
   744 extern DECLSPEC int SDL_JoystickIsHaptic(SDL_Joystick * joystick);
   745 
   746 /**
   747  * \fn SDL_Haptic * SDL_HapticOpenFromJoystick(SDL_Joystick * joystick)
   748  *
   749  * \brief Opens a Haptic device for usage from a Joystick device.  Still has
   750  * to be closed seperately to the joystick.
   751  *
   752  *    \param joystick Joystick to create a haptic device from.
   753  *    \return A valid haptic device identifier on success or NULL on error.
   754  *
   755  * \sa SDL_HapticOpen
   756  * \sa SDL_HapticClose
   757  */
   758 extern DECLSPEC SDL_Haptic * SDL_HapticOpenFromJoystick(SDL_Joystick * joystick);
   759 
   760 /**
   761  * \fn void SDL_HapticClose(SDL_Haptic * haptic)
   762  *
   763  * \brief Closes a Haptic device previously opened with SDL_HapticOpen.
   764  *
   765  *    \param haptic Haptic device to close.
   766  */
   767 extern DECLSPEC void SDL_HapticClose(SDL_Haptic * haptic);
   768 
   769 /**
   770  * \fn int SDL_HapticNumEffects(SDL_Haptic * haptic)
   771  *
   772  * \brief Returns the number of effects a haptic device can store.
   773  *
   774  *    \param haptic The haptic device to query effect max.
   775  *    \return The number of effects the haptic device can store or
   776  *            -1 on error.
   777  *
   778  * \sa SDL_HapticNumEffectsPlaying
   779  * \sa SDL_HapticQuery
   780  */
   781 extern DECLSPEC int SDL_HapticNumEffects(SDL_Haptic * haptic);
   782 
   783 /**
   784  * \fn int SDL_HapticNumEffectsPlaying(SDL_Haptic * haptic)
   785  *
   786  * \brief Returns the number of effects a haptic device can play at the same time.
   787  *
   788  *    \param haptic The haptic device to query maximum playing effect.s
   789  *    \return The number of effects the haptic device can play at the same time
   790  *            or -1 on error.
   791  *
   792  * \sa SDL_HapticNumEffects
   793  * \sa SDL_HapticQuery
   794  */
   795 extern DECLSPEC int SDL_HapticNumEffectsPlaying(SDL_Haptic * haptic);
   796 
   797 /**
   798  * \fn unsigned int SDL_HapticQuery(SDL_Haptic * haptic)
   799  *
   800  * \brief Gets the haptic devices supported features in bitwise matter.
   801  *
   802  * Example: 
   803  * \code
   804  * if (SDL_HapticQueryEffects(haptic) & SDL_HAPTIC_CONSTANT) {
   805  *    printf("We have constant haptic effect!");
   806  * }
   807  * \endcode
   808  *    
   809  *
   810  *    \param haptic The haptic device to query.
   811  *    \return Haptic features in bitwise manner (OR'd).
   812  *
   813  * \sa SDL_HapticNumEffects
   814  * \sa SDL_HapticEffectSupported
   815  */
   816 extern DECLSPEC unsigned int SDL_HapticQuery(SDL_Haptic * haptic);
   817 
   818 /**
   819  * \fn int SDL_HapticEffectSupported(SDL_Haptic * haptic, SDL_HapticEffect * effect)
   820  *
   821  * \brief Checks to see if effect is supported by haptic.
   822  *
   823  *    \param haptic Haptic device to check on.
   824  *    \param effect Effect to check to see if it is supported.
   825  *    \return SDL_TRUE if effect is supported, SDL_FALSE if it isn't or 
   826  *            -1 on error.
   827  * 
   828  * \sa SDL_HapticQuery
   829  * \sa SDL_HapticNewEffect
   830  */
   831 extern DECLSPEC int SDL_HapticEffectSupported(SDL_Haptic * haptic, SDL_HapticEffect * effect);
   832 
   833 /**
   834  * \fn int SDL_HapticNewEffect(SDL_Haptic * haptic, SDL_HapticEffect * effect)
   835  *
   836  * \brief Creates a new haptic effect on the device.
   837  *
   838  *    \param haptic Haptic device to create the effect on.
   839  *    \param effect Properties of the effect to create.
   840  *    \return The id of the effect on success or -1 on error.
   841  *
   842  * \sa SDL_HapticUpdateEffect
   843  * \sa SDL_HapticRunEffect
   844  * \sa SDL_HapticDestroyEffect
   845  */
   846 extern DECLSPEC int SDL_HapticNewEffect(SDL_Haptic * haptic, SDL_HapticEffect * effect);
   847 
   848 /**
   849  * \fn int SDL_HapticUpdateEffect(SDL_Haptic * haptic, int effect, SDL_HapticEffect * data)
   850  *
   851  * \brief Updates an effect.  Can be used dynamically, although behaviour when
   852  * dynamically changing direction may be strange.  Specifically the effect
   853  * may reupload itself and start playing from the start.  You cannot change
   854  * the type either when running UpdateEffect.
   855  *
   856  *    \param haptic Haptic device that has the effect.
   857  *    \param effect Effect to update.
   858  *    \param data New effect properties to use.
   859  *    \return The id of the effect on success or -1 on error.
   860  *
   861  * \sa SDL_HapticNewEffect
   862  * \sa SDL_HapticRunEffect
   863  * \sa SDL_HapticDestroyEffect
   864  */
   865 extern DECLSPEC int SDL_HapticUpdateEffect(SDL_Haptic * haptic, int effect, SDL_HapticEffect * data);
   866 
   867 /**
   868  * \fn int SDL_HapticRunEffect(SDL_Haptic * haptic, int effect, int iterations)
   869  *
   870  * \brief Runs the haptic effect on it's assosciated haptic device.
   871  *
   872  *    \param haptic Haptic device to run the effect on.
   873  *    \param effect Identifier of the haptic effect to run.
   874  *    \param iterations Number of iterations to run the effect. Use
   875  *           SDL_HAPTIC_INFINITY for infinity.
   876  *    \return 0 on success or -1 on error.
   877  *
   878  * \sa SDL_HapticStopEffect
   879  * \sa SDL_HapticDestroyEffect
   880  * \sa SDL_HapticGetEffectStatus
   881  */
   882 extern DECLSPEC int SDL_HapticRunEffect(SDL_Haptic * haptic, int effect, Uint32 iterations);
   883 
   884 /**
   885  * \fn int SDL_HapticStopEffect(SDL_Haptic * haptic, int effect)
   886  *
   887  * \brief Stops the haptic effect on it's assosciated haptic device.
   888  *
   889  *    \param haptic Haptic device to stop the effect on.
   890  *    \param effect Identifier of the effect to stop.
   891  *    \return 0 on success or -1 on error.
   892  *
   893  * \sa SDL_HapticRunEffect
   894  * \sa SDL_HapticDestroyEffect
   895  */
   896 extern DECLSPEC int SDL_HapticStopEffect(SDL_Haptic * haptic, int effect);
   897 
   898 /**
   899  * \fn void SDL_HapticDestroyEffect(SDL_Haptic * haptic, int effect)
   900  *
   901  * \brief Destroys a haptic effect on the device.  This will stop the effect
   902  * if it's running.  Effects are automatically destroyed when the device is
   903  * closed.
   904  *
   905  *    \param haptic Device to destroy the effect on.
   906  *    \param effect Identifier of the effect to destroy.
   907  * 
   908  * \sa SDL_HapticNewEffect
   909  */
   910 extern DECLSPEC void SDL_HapticDestroyEffect(SDL_Haptic * haptic, int effect);
   911 
   912 /**
   913  * \fn int SDL_HapticGetEffectStatus(SDL_Haptic *haptic, int effect)
   914  *
   915  * \brief Gets the status of the current effect on the haptic device.
   916  *
   917  * Device must support the SDL_HAPTIC_STATUS feature.
   918  *
   919  *    \param haptic Haptic device to query the effect status on.
   920  *    \param effect Identifier of the effect to query it's status.
   921  *    \return 0 if it isn't playing, SDL_HAPTIC_PLAYING if it is playing
   922  *            or -1 on error.
   923  *
   924  * \sa SDL_HapticRunEffect
   925  * \sa SDL_HapticStopEffect
   926  */
   927 extern DECLSPEC int SDL_HapticGetEffectStatus(SDL_Haptic *haptic, int effect);
   928 
   929 /**
   930  * \fn int SDL_HapticSetGain(SDL_Haptic * haptic, int gain)
   931  *
   932  * \brief Sets the global gain of the device.  Gain should be between 0 and 100.
   933  *
   934  * Device must support the SDL_HAPTIC_GAIN feature.
   935  *
   936  * The user may specify the maxmimum gain by setting the environment variable
   937  *  SDL_HAPTIC_GAIN_MAX which should be between 0 and 100.  All calls to
   938  *  SDL_HapticSetGain will scale linearly using SDL_HAPTIC_GAIN_MAX as the
   939  *  maximum.
   940  *
   941  *    \param haptic Haptic device to set the gain on.
   942  *    \param gain Value to set the gain to, should be between 0 and 100.
   943  *    \return 0 on success or -1 on error.
   944  *
   945  * \sa SDL_HapticQuery
   946  */
   947 extern DECLSPEC int SDL_HapticSetGain(SDL_Haptic * haptic, int gain);
   948 
   949 /**
   950  * \fn int SDL_HapticSetAutocenter(SDL_Haptic * haptic, int autocenter)
   951  *
   952  * \brief Sets the global autocenter of the device.  Autocenter should be between
   953  * 0 and 100.  Setting it to 0 will disable autocentering.
   954  *
   955  * Device must support the SDL_HAPTIC_AUTOCENTER feature.
   956  *
   957  *    \param haptic Haptic device to set autocentering on.
   958  *    \param autocenter Value to set autocenter to, 0 disables autocentering.
   959  *    \return 0 on success or -1 on error.
   960  *
   961  * \sa SDL_HapticQuery
   962  */
   963 extern DECLSPEC int SDL_HapticSetAutocenter(SDL_Haptic * haptic, int autocenter);
   964 
   965 
   966 /* Ends C function definitions when using C++ */
   967 #ifdef __cplusplus
   968 /* *INDENT-OFF* */
   969 }
   970 /* *INDENT-ON* */
   971 #endif
   972 #include "close_code.h"
   973 
   974 #endif /* _SDL_haptic_h */
   975 
   976 /* vi: set ts=4 sw=4 expandtab: */
   977 
   978