nunchuk.c

/*
 *	wiiuse
 *
 *	Written By:
 *		Michael Laforest	< para >
 *		Email: < thepara (--AT--) g m a i l [--DOT--] com >
 *
 *	Copyright 2006-2007
 *
 *	This file is part of wiiuse.
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 3 of the License, or
 *	(at your option) any later version.
 *
 *	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.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *	$Header$
 *
 */

/**
 *	@file
 *	@brief Nunchuk expansion device.
 */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#include "definitions.h"
#include "wiiuse_internal.h"
#include "dynamics.h"
#include "events.h"
#include "nunchuk.h"

static void nunchuk_pressed_buttons(struct nunchuk_t* nc, byte now);

/**
 *	@brief Handle the handshake data from the nunchuk.
 *
 *	@param nc		A pointer to a nunchuk_t structure.
 *	@param data		The data read in from the device.
 *	@param len		The length of the data block, in bytes.
 *
 *	@return	Returns 1 if handshake was successful, 0 if not.
 */
int nunchuk_handshake(struct wiimote_t* wm, struct nunchuk_t* nc, byte* data, unsigned short len) {
	int i;
	int offset = 0;

	nc->btns = 0;
	nc->btns_held = 0;
	nc->btns_released = 0;

	/* set the smoothing to the same as the wiimote */
	nc->flags = &wm->flags;
	nc->accel_calib.st_alpha = wm->accel_calib.st_alpha;

	/* decrypt data */
	for (i = 0; i < len; ++i)
		data[i] = (data[i] ^ 0x17) + 0x17;

	if (data[offset] == 0xFF) {
		/*
		 *	Sometimes the data returned here is not correct.
		 *	This might happen because the wiimote is lagging
		 *	behind our initialization sequence.
		 *	To fix this just request the handshake again.
		 *
		 *	Other times it's just the first 16 bytes are 0xFF,
		 *	but since the next 16 bytes are the same, just use
		 *	those.
		 */
		if (data[offset + 16] == 0xFF) {
			/* get the calibration data */
			byte* handshake_buf = malloc(EXP_HANDSHAKE_LEN * sizeof(byte));

			WIIUSE_DEBUG("Nunchuk handshake appears invalid, trying again.");
			wiiuse_read_data_cb(wm, handshake_expansion, handshake_buf, WM_EXP_MEM_CALIBR, EXP_HANDSHAKE_LEN);

			return 0;
		} else
			offset += 16;
	}

	nc->accel_calib.cal_zero.x = data[offset + 0];
	nc->accel_calib.cal_zero.y = data[offset + 1];
	nc->accel_calib.cal_zero.z = data[offset + 2];
	nc->accel_calib.cal_g.x = data[offset + 4];
	nc->accel_calib.cal_g.y = data[offset + 5];
	nc->accel_calib.cal_g.z = data[offset + 6];
	nc->js.max.x = data[offset + 8];
	nc->js.min.x = data[offset + 9];
	nc->js.center.x = data[offset + 10];
	nc->js.max.y = data[offset + 11];
	nc->js.min.y = data[offset + 12];
	nc->js.center.y = data[offset + 13];

	/* default the thresholds to the same as the wiimote */
	nc->orient_threshold = wm->orient_threshold;
	nc->accel_threshold = wm->accel_threshold;

	/* handshake done */
	wm->exp.type = EXP_NUNCHUK;

	#ifdef WIN32
	wm->timeout = WIIMOTE_DEFAULT_TIMEOUT;
	#endif

	return 1;
}


/**
 *	@brief The nunchuk disconnected.
 *
 *	@param nc		A pointer to a nunchuk_t structure.
 */
void nunchuk_disconnected(struct nunchuk_t* nc) {
	memset(nc, 0, sizeof(struct nunchuk_t));
}



/**
 *	@brief Handle nunchuk event.
 *
 *	@param nc		A pointer to a nunchuk_t structure.
 *	@param msg		The message specified in the event packet.
 */
void nunchuk_event(struct nunchuk_t* nc, byte* msg) {
	int i;

	/* decrypt data */
	for (i = 0; i < 6; ++i)
		msg[i] = (msg[i] ^ 0x17) + 0x17;

	/* get button states */
	nunchuk_pressed_buttons(nc, msg[5]);

	/* calculate joystick state */
	calc_joystick_state(&nc->js, msg[0], msg[1]);

	/* calculate orientation */
	nc->accel.x = msg[2];
	nc->accel.y = msg[3];
	nc->accel.z = msg[4];

	calculate_orientation(&nc->accel_calib, &nc->accel, &nc->orient, NUNCHUK_IS_FLAG_SET(nc, WIIUSE_SMOOTHING));
	calculate_gforce(&nc->accel_calib, &nc->accel, &nc->gforce);
}


/**
 *	@brief Find what buttons are pressed.
 *
 *	@param nc		Pointer to a nunchuk_t structure.
 *	@param msg		The message byte specified in the event packet.
 */
static void nunchuk_pressed_buttons(struct nunchuk_t* nc, byte now) {
	/* message is inverted (0 is active, 1 is inactive) */
	now = ~now & NUNCHUK_BUTTON_ALL;

	/* pressed now & were pressed, then held */
	nc->btns_held = (now & nc->btns);

	/* were pressed or were held & not pressed now, then released */
	nc->btns_released = ((nc->btns | nc->btns_held) & ~now);

	/* buttons pressed now */
	nc->btns = now;
}


/**
 *	@brief	Set the orientation event threshold for the nunchuk.
 *
 *	@param wm			Pointer to a wiimote_t structure with a nunchuk attached.
 *	@param threshold	The decimal place that should be considered a significant change.
 *
 *	See wiiuse_set_orient_threshold() for details.
 */
void wiiuse_set_nunchuk_orient_threshold(struct wiimote_t* wm, float threshold) {
	if (!wm)	return;

	wm->exp.nunchuk.orient_threshold = threshold;
}


/**
 *	@brief	Set the accelerometer event threshold for the nunchuk.
 *
 *	@param wm			Pointer to a wiimote_t structure with a nunchuk attached.
 *	@param threshold	The decimal place that should be considered a significant change.
 *
 *	See wiiuse_set_orient_threshold() for details.
 */
void wiiuse_set_nunchuk_accel_threshold(struct wiimote_t* wm, int threshold) {
	if (!wm)	return;

	wm->exp.nunchuk.accel_threshold = threshold;
}