ardupilot/ArduCopter/commands.pde

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-

static void init_commands()
{
    g.command_index         = NO_COMMAND;
    command_nav_index       = NO_COMMAND;
    command_cond_index      = NO_COMMAND;
    prev_nav_index          = NO_COMMAND;
    command_cond_queue.id   = NO_COMMAND;
    command_nav_queue.id    = NO_COMMAND;
}

// Getters
// -------
static struct Location get_cmd_with_index(int i)
{
    struct Location temp;

    // Find out proper location in memory by using the start_byte position + the index
    // --------------------------------------------------------------------------------
    if (i >= g.command_total) {
        // we do not have a valid command to load
        // return a WP with a "Blank" id
        temp.id = CMD_BLANK;

        // no reason to carry on
        return temp;

    }else{
        // we can load a command, we don't process it yet
        // read WP position
        uint16_t mem = (WP_START_BYTE) + (i * WP_SIZE);

        temp.id = hal.storage->read_byte(mem);

        mem++;
        temp.options = hal.storage->read_byte(mem);

        mem++;
        temp.p1 = hal.storage->read_byte(mem);

        mem++;
        temp.alt = hal.storage->read_dword(mem);           // alt is stored in CM! Alt is stored relative!

        mem += 4;
        temp.lat = hal.storage->read_dword(mem);         // lat is stored in decimal * 10,000,000

        mem += 4;
        temp.lng = hal.storage->read_dword(mem);         // lon is stored in decimal * 10,000,000
    }

    // Add on home altitude if we are a nav command (or other command with altitude) and stored alt is relative
    //if((temp.id < MAV_CMD_NAV_LAST || temp.id == MAV_CMD_CONDITION_CHANGE_ALT) && (temp.options & MASK_OPTIONS_RELATIVE_ALT)){
    //temp.alt += home.alt;
    //}

    if(temp.options & WP_OPTION_RELATIVE) {
        // If were relative, just offset from home
        temp.lat        +=      home.lat;
        temp.lng        +=      home.lng;
    }

    return temp;
}

// Setters
// -------
static void set_cmd_with_index(struct Location temp, int i)
{

    i = constrain_int16(i, 0, g.command_total.get());

    // store home as 0 altitude!!!
    // Home is always a MAV_CMD_NAV_WAYPOINT (16)
    if (i == 0) {
        temp.alt = 0;
        temp.id = MAV_CMD_NAV_WAYPOINT;
    }

    uint16_t mem = WP_START_BYTE + (i * WP_SIZE);

    hal.storage->write_byte(mem, temp.id);

    mem++;
    hal.storage->write_byte(mem, temp.options);

    mem++;
    hal.storage->write_byte(mem, temp.p1);

    mem++;
    hal.storage->write_dword(mem, temp.alt);     // Alt is stored in CM!

    mem += 4;
    hal.storage->write_dword(mem, temp.lat);     // Lat is stored in decimal degrees * 10^7

    mem += 4;
    hal.storage->write_dword(mem, temp.lng);     // Long is stored in decimal degrees * 10^7

    // Make sure our WP_total
    if(g.command_total < (i+1))
        g.command_total.set_and_save(i+1);
}

static int32_t get_RTL_alt()
{
    if(g.rtl_altitude <= 0) {
		return min(current_loc.alt, RTL_ALT_MAX);
    }else if (g.rtl_altitude < current_loc.alt) {
		return min(current_loc.alt, RTL_ALT_MAX);
    }else{
        return g.rtl_altitude;
    }
}

// run this at setup on the ground
// -------------------------------
static void init_home()
{
    set_home_is_set(true);
    home.id         = MAV_CMD_NAV_WAYPOINT;
    home.lng        = g_gps->longitude;                                 // Lon * 10**7
    home.lat        = g_gps->latitude;                                  // Lat * 10**7
    home.alt        = 0;                                                        // Home is always 0

    // Save Home to EEPROM
    // -------------------
    // no need to save this to EPROM
    set_cmd_with_index(home, 0);

    // set inertial nav's home position
    inertial_nav.set_home_position(g_gps->longitude, g_gps->latitude);

    if (g.log_bitmask & MASK_LOG_CMD)
        Log_Write_Cmd(0, &home);

    // update navigation scalers.  used to offset the shrinking longitude as we go towards the poles
    scaleLongDown = longitude_scale(home);
    scaleLongUp   = 1.0f/scaleLongDown;
}