Joe 2009-11-23 21:31:10 PST
authorSam Lantinga <slouken@libsdl.org>
Fri, 27 Nov 2009 19:29:27 +0000
changeset 349678fc8ea578b2
parent 3495 1b22878e04d0
child 3497 74d2f44a85de
Joe 2009-11-23 21:31:10 PST

If type is ::SDL_HAPTIC_CARTESIAN, direction is encoded by three positions
367 * (X axis, Y axis and Z axis (with 3 axes)). ::SDL_HAPTIC_CARTESIAN
uses
368 * the first three \c dir parameters. The cardinal directions would
be:
369 * - North: 0,-1, 0
370 * - East: -1, 0, 0
371 * - South: 0, 1, 0
372 * - West: 1, 0, 0

typedef struct SDL_HapticDirection
{
Uint8 type; /**< The type of encoding. */
Uint16 dir[3]; /**< The encoded direction. */
} SDL_HapticDirection;

An unsigned int can't store negative values and I don't see an alternate way to
encode them in the docs or source. The best I have been able to come up with is
using a negative magnitude for the effect but this will only get me 2 of the 4
quadrants in the plane for 2d effects. I looked at the win32 and linux
implementations and I believe is is safe to use signed ints in the direction
struct. I am unfamiliar with the darwin haptics API so I don't know if it is
safe.
include/SDL_haptic.h
     1.1 --- a/include/SDL_haptic.h	Fri Nov 27 03:11:26 2009 +0000
     1.2 +++ b/include/SDL_haptic.h	Fri Nov 27 19:29:27 2009 +0000
     1.3 @@ -411,7 +411,7 @@
     1.4  typedef struct SDL_HapticDirection
     1.5  {
     1.6      Uint8 type;         /**< The type of encoding. */
     1.7 -    Uint16 dir[3];      /**< The encoded direction. */
     1.8 +    Sint32 dir[3];      /**< The encoded direction. */
     1.9  } SDL_HapticDirection;
    1.10  
    1.11