source: code/branches/wiimote/src/external/wiicpp/wiic/nunchuk.c @ 11398

/*
 *    nunchuck.c
 *
 *        This file is part of WiiC, written by:
 *              Gabriele Randelli
 *              Email: randelli@dis.uniroma1.it
 *
 *    Copyright 2010
 *              
 *        This file is based on Wiiuse, written By:
 *              Michael Laforest        < para >
 *              Email: < thepara (--AT--) g m a i l [--DOT--] com >
 *
 *        Copyright 2006-2007
 *
 *    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 "wiic_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));

                        WIIC_DEBUG("Nunchuk handshake appears invalid, trying again.");
                        wiic_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;

        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_gforce(&nc->accel_calib, &nc->accel, &nc->gforce, NUNCHUK_IS_FLAG_SET(nc, WIIC_SMOOTHING));
        calculate_orientation(&nc->gforce.vec, &nc->orient.angle);
}


/**
 *      @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 wiic_set_orient_threshold() for details.
 */
void wiic_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 wiic_set_orient_threshold() for details.
 */
void wiic_set_nunchuk_accel_threshold(struct wiimote_t* wm, int threshold) {
        if (!wm)        return;

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