NAME

SDL2::HapticDirection - Structure that represents a haptic direction

SYNOPSIS

    use SDL2 qw[:all];
    my $direction = SDL2::HapticDirection->new(
        {   type => SDL_HAPTIC_CARTESIAN,    # Using cartesian direction encoding
            dir  => [ 0, 1 ]                 # X and Y positions
			# Assuming the device has 2 axes, we don't need to specify third parameter
        }
    );

DESCRIPTION

This is the direction where the force comes from, instead of the direction in which the force is exerted.

Directions can be specified by:

SDL_HAPTIC_POLAR - Specified by polar coordinates

SDL_HAPTIC_CARTESIAN - Specified by cartesian coordinates

SDL_HAPTIC_SPHERICAL - Specified by spherical coordinates

Cardinal directions of the haptic device are relative to the positioning of the device. North is considered to be away from the user.

The following diagram represents the cardinal directions:

              .--.
              |__| .-------.
              |=.| |.-----.|
              |--| ||     ||
              |  | |'-----'|
              |__|~')_____('
                [ COMPUTER ]
                  North (0,-1)
                      ^
                      |
                      |
(-1,0)  West <----[ HAPTIC ]----> East (1,0)
                      |
                      |
                      v
                   South (0,1)
                   [ USER ]
                     \|||/
                     (o o)
               ---ooO-(_)-Ooo---

If type is SDL_HAPTIC_POLAR, direction is encoded by hundredths of a degree starting north and turning clockwise. SDL_HAPTIC_POLAR only uses dir parameter. The cardinal directions would be:

North - 0 (0 degrees)

East - 9000 (90 degrees)

South - 18000 (180 degrees)

West - 27000 (270 degrees)

If type is SDL_HAPTIC_CARTESIAN, direction is encoded by three positions (X axis, Y axis and Z axis (with 3 axes)). SDL_HAPTIC_CARTESIAN uses the first three dir parameters. The cardinal directions would be:

North - 0,-1, 0

East - 1, 0, 0

South - 0, 1, 0

West - -1, 0, 0

The Z axis represents the height of the effect if supported, otherwise it's unused. In cartesian encoding (1, 2) would be the same as (2, 4), you can use any multiple you want, only the direction matters.

If type is SDL_HAPTIC_SPHERICAL, direction is encoded by two rotations. The first two dir parameters are used. The dir parameters are as follows (all values are in hundredths of degrees):

Degrees from (1, 0) rotated towards (0, 1).

Degrees towards (0, 0, 1) (device needs at least 3 axes).

Example of force coming from the south with all encodings (force coming from the south means the user will have to pull the stick to counteract):

# Cartesian directions
my $direction = SDL2::HapticDirection->new(
    {   type => SDL_HAPTIC_CARTESIAN,    # Using cartesian direction encoding
        dir  => [ 0, 1 ]                 # X and Y positions
    }
);
# Assuming the device has 2 axes, we don't need to specify third parameter.

# Polar directions
$direction->type(SDL_HAPTIC_POLAR); # We'll be using polar direction encoding
$direction->dir->[0] = 18000;    # Polar only uses first parameter

# Spherical coordinates
$direction->type(SDL_HAPTIC_SPHERICAL);    # Spherical encoding
$direction->dir->[0] = 9000;    # Since we only have two axes we don't need more parameters

Fields

type - The type of encoding

dir - The encoded direction

LICENSE

Copyright (C) Sanko Robinson.

This library is free software; you can redistribute it and/or modify it under the terms found in the Artistic License 2. Other copyrights, terms, and conditions may apply to data transmitted through this module.

AUTHOR

Sanko Robinson <sanko@cpan.org>