/ 
OpenHMD-0.001
River stage zero No dependents
/ OpenHMD::Backend::Inline

NAME

OpenHMD::Backend::Inline - Binding for the OpenHMD C library, using Inline::C

SYNOPSIS

This synopsis is available as eg/openhmd-backend-inline.pl

use OpenHMD::Backend::Inline qw(:all);

my $context = ohmd_ctx_create() or die 'Failed to create context';

my $count = ohmd_ctx_probe($context);
die sprintf 'Failed to probe devices: %s', ohmd_ctx_get_error($context)
    if $count < 0;
printf "Devices: %i\n\n", $count;

my $print_gets = sub {
    my ($title, $index, $type) = @_;
    my $value = ohmd_list_gets($context, $index, $type);

    printf "    %-8s:   %s\n", $title, $value;
};

foreach my $index (0 .. $count - 1) {
    printf "Device %i\n", $index;
    $print_gets->('Vendor', $index, $OHMD_VENDOR);
    $print_gets->('Product', $index, $OHMD_PRODUCT);
    $print_gets->('Path', $index, $OHMD_PATH);
    print "\n";
}

my $device = ohmd_list_open_device($context, 0);
die sprintf 'Failed to open device: %s', ohmd_ctx_get_error($context)
    if !$device;

my $geti = sub {
    my $type = shift;
    my $buffer = pack 'i';
    my $status = ohmd_device_geti($device, $type, $buffer);
    die 'Failed to get integer: %s', ohmd_ctx_get_error($context)
        if $status != $OHMD_S_OK;
    return unpack 'i', $buffer;
};

my @resolution = (
    $geti->($OHMD_SCREEN_HORIZONTAL_RESOLUTION),
    $geti->($OHMD_SCREEN_VERTICAL_RESOLUTION),
);
printf "%-20s:   %i x %i\n", 'Resolution', @resolution;

my $print_getf = sub {
    my ($title, $size, $type) = @_;
    my $buffer = pack sprintf 'f%i', $size;
    my $status = ohmd_device_getf($device, $type, $buffer);
    die 'Failed to get float: %s', ohmd_ctx_get_error($context)
        if $status != $OHMD_S_OK;

    printf "%-20s:   %s\n", (
        $title,
        join ' ', map { sprintf '% 6f', $_ } unpack 'f*', $buffer,
    );
};

$print_getf->('Horizontal Size',  1, $OHMD_SCREEN_HORIZONTAL_SIZE);
$print_getf->('Vertical Size',    1, $OHMD_SCREEN_VERTICAL_SIZE);
$print_getf->('Lens Separation',  1, $OHMD_LENS_HORIZONTAL_SEPARATION);
$print_getf->('Lens Position',    1, $OHMD_LENS_VERTICAL_POSITION);
$print_getf->('Left Eye FoV',     1, $OHMD_LEFT_EYE_FOV);
$print_getf->('Right Eye FoV',    1, $OHMD_RIGHT_EYE_FOV);
$print_getf->('Left Eye Aspect',  1, $OHMD_LEFT_EYE_ASPECT_RATIO);
$print_getf->('Right Eye Aspect', 1, $OHMD_RIGHT_EYE_ASPECT_RATIO);
$print_getf->('Distortion K',     6, $OHMD_DISTORTION_K);
print "\n";

$print_getf->('Default IPD', 1, $OHMD_EYE_IPD);
my $buffer = pack 'f', 0.55;
my $status = ohmd_device_setf($device, $OHMD_EYE_IPD, $buffer);
die sprintf 'Failed to set value: %s', ohmd_ctx_get_error($context)
    if $status != $OHMD_S_OK;
$print_getf->('Set IPD', 1, $OHMD_EYE_IPD);
print "\n";

foreach my $tick (0 .. 10) {
    ohmd_ctx_update($context);
    $print_getf->('Rotation Quaternion', 4, $OHMD_ROTATION_QUAT);
    select undef, undef, undef, 0.1;
}

$status = ohmd_close_device($device);
die sprintf 'Failed to close device: %s', ohmd_ctx_get_error($context)
    if $status != $OHMD_S_OK;

ohmd_ctx_destroy($context);

DESCRIPTION

OpenHMD::Backend::Inline is a thin wrapper for the OpenHMD C library, using Inline::C.

FUNCTIONS

OpenHMD::Backend::Inline implements the following functions, which can be imported individually or using the :functions tag.

ohmd_close_device

my $status = ohmd_close_device($device);

Closes a device.

ohmd_ctx_create

my $context = ohmd_ctx_create();

Create a new OpenHMD context.

ohmd_ctx_destroy

ohmd_ctx_destroy($context);

Destroy an OpenHMD context.

ohmd_ctx_get_error

my $error = ohmd_ctx_get_error($context);

Gets the latest human readable error message.

ohmd_ctx_probe

my $device_count = ohmd_ctx_probe($context);

Probes for supported devices and returns the count of found devices.

ohmd_ctx_update

ohmd_ctx_update($context);

Updates an OpenHMD context.

ohmd_device_getf

my $status = ohmd_device_getf($device, $type, $out);

Populate $out with the float values for $type as a packed string.

# Get the rotation quaternion
my $out = pack 'f4';
my $status = ohmd_device_getf($device, $OHMD_ROTATION_QUAT, $out);
my @quaternion = unpack 'f*', $out;

ohmd_device_geti

my $status = ohmd_device_geti($device, $type, $out);

Populate $out with the integer values for $type as a packed string.

# Get the horizontal resolution
my $out = pack 'i1';
my $status = ohmd_device_geti(
    $device,
    $OHMD_SCREEN_HORIZONTAL_RESOLUTION,
    $out,
);
my $horizontal = unpack 'i*', $out;

ohmd_device_setf

my $status = ohmd_device_setf($device, $type, $in);

Sets float values for $type.

# Set the IPD to 0.6
my $in = pack 'f1', 0.6;
my $status = ohmd_device_getf($device, $OHMD_EYE_IPD, $in);

ohmd_list_gets

my $string = ohmd_list_gets($context, $index, $type);

Gets the string value of $type for device at $index.

# Get vendor of device at index 1
my $vendor = ohmd_list_gets($context, 1, $OHMD_VENDOR);

ohmd_list_open_device

my $device = ohmd_list_open_device($context, $index);

Opens the device at $index.

# Open the default device
my $device = ohmd_list_open_device($context, 0);

CONSTANTS

OpenHMD::Backend::Inline provides the following constants, which can be imported individually or using the :constants tag.

Float

$OHMD_DISTORTION_K
$OHMD_EYE_IPD
$OHMD_LEFT_EYE_ASPECT_RATIO
$OHMD_LEFT_EYE_FOV
$OHMD_LEFT_EYE_GL_MODELVIEW_MATRIX
$OHMD_LEFT_EYE_GL_PROJECTION_MATRIX
$OHMD_LENS_HORIZONTAL_SEPARATION
$OHMD_LENS_VERTICAL_POSITION
$OHMD_POSITION_VECTOR
$OHMD_PROJECTION_ZFAR
$OHMD_PROJECTION_ZNEAR
$OHMD_RIGHT_EYE_ASPECT_RATIO
$OHMD_RIGHT_EYE_FOV
$OHMD_RIGHT_EYE_GL_MODELVIEW_MATRIX
$OHMD_RIGHT_EYE_GL_PROJECTION_MATRIX
$OHMD_ROTATION_QUAT
$OHMD_SCREEN_HORIZONTAL_SIZE
$OHMD_SCREEN_VERTICAL_SIZE

Integer

$OHMD_SCREEN_HORIZONTAL_RESOLUTION
$OHMD_SCREEN_VERTICAL_RESOLUTION

Status

$OHMD_S_INVALID_PARAMETER
$OHMD_S_OK
$OHMD_S_UNKNOWN_ERROR
$OHMD_S_USER_RESERVED

String

$OHMD_PATH
$OHMD_PRODUCT
$OHMD_VENDOR

SEE ALSO

openhmd.net

OpenHMD's website.

#openhmd @ freenode

Official IRC channel for OpenHMD

DEPENDENCIES

OpenHMD::Backend::Inline depends on the following modules.

Carp

Throwing errors from the callers perspective.

Const::Fast

Exportable, read-only constants.

Exporter

Exporting constants and functions.

Inline::C

Access to C functions from Perl.

ACKNOWLEDGEMENTS

Fredrick Hultin and Joey Ferwerda

For their help with the C aspect of this module, answering questions, implementing suggested functionality into OpenHMD and generally being very encouraging and supportive.

NefariousMoogle

Reviewed documentation.

AUTHOR

CandyAngel <candyangel@electricjungle.org>

LICENSE AND COPYRIGHT

Copyright (c) 2015 CandyAngel <candyangel@electricjungle.org>. All rights reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.