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/*

This program (files math.c and math.h) is free software; you can redistribute it and/or modify

it under the terms of the GNU Lesser 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 and GNU Lesser General Public License for more details.

You should have received a copy of GNU General Public License (License_GPL.txt)  and

GNU Lesser General Public License (License_LGPL.txt) along with this program.

If not, see <http://www.gnu.org/licenses/>.

Please note: All the other files for the project "Mikrokopter" by H.Buss are under the license (license_buss.txt) published by www.mikrokopter.de

*/

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Peter Muehlenbrock

Winkelfunktionen sin, cos und arctan in

brute-force Art: Sehr Schnell, nicht sonderlich genau, aber ausreichend

get_dist Funktion fuer Entfernungsermittlung

Stand 12.10.2007

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

*/

#include "main.h"

// arctan Funktion: Eingabewert x,y Rueckgabe =arctan(x,y) in grad

int arctan_i( signed int x,  signed int y)

{

        short int change_xy = 0;

        signed int i;

        long signed int wert;

        int return_value;

        if ((abs(x)) > (abs(y)))  // x,y Werte vertauschen damit arctan <45 grad bleibt

        {      

                change_xy       = 1;

                i                       = x;

                x                       = y;

                y                       = i;

        }

        // Quadranten ermitteln

        // Wert durch lineare Interpolation ermitteln 

        if ((y == 0) && (x == 0))  wert =1; // Division durch 0 nicht erlaubt

        else wert= abs(((long)x*1000)/((long)y));

        if (wert <=268) //0...0.0,268  entsprechend 0..15 Grad

        {

                return_value = (signed int)((wert*100)/(268-0)*(15-0)/100) +0;

        }

        else if (wert <=578) //0,268...0.0,568  entsprechend 15..30 Grad

        {      

                return_value = (signed int)((((wert-268)*100)/(578-268)*(30-15))/100) +15;             

        }

        else //0,568...1  entsprechend 30..45 Grad

        {      

                return_value = (signed int)((((wert-578)*50)/(1000-578)*(45-30))/50) +30;              

        }

        if (change_xy == 0)  return_value = 90-return_value; //Quadrant 45..90 Grad

        if ((x >= 0) && (y <0)) return_value = - return_value;

        else if ((x < 0) && (y >= 0)) return_value = - return_value;

return return_value;

}

// cosinus Funktion: Eingabewert Winkel in Grad, Rueckgabe =cos(winkel)*1000

signed int cos_i(signed int winkel)

{

  winkel = sin_i(90-winkel);

  return winkel;

}

const unsigned int pgm_sinus[91] PROGMEM = {0,17,35,52,70,87,105,122,139,156,174,191,208,225,242,259,276,292,309,326,342,358,375,391,407,423,438,454,469,485,500,515,530,545,559,574,588,602,616,629,643,656,669,682,695,707,719,731,743,755,766,777,788,799,809,819,829,839,848,857,866,875,883,891,899,906,914,921,927,934,940,946,951,956,961,966,970,974,978,982,985,988,990,993,995,996,998,999,999,1000,1000};

//von Nick666, Stand 28.9.2007

// sinus Funktion: Eingabewert Winkel in Grad, Rueckgabe =sin(winkel)*1000

signed int sin_i(signed int winkel)

{

 short int m,n;

 if (abs(winkel) >=360) winkel = winkel % 360;

 if (winkel < 0)

 {

        m = -1;

        winkel = abs(winkel);

 }

 else m = +1;

 n =1;

 // Quadranten auswerten

 if ((winkel > 90 ) && (winkel <= 180)) winkel = 180 - winkel;

 else if ((winkel > 180 ) && (winkel <= 270))

 {

        winkel = winkel -180;

        n = -1;

 }

  else if ((winkel > 270) && (winkel <= 360))

 {

        winkel = 360 - winkel;

        n = -1;

 }

 // else //0 - 90 Grad

 winkel = pgm_read_word(&pgm_sinus[winkel]);

 return (winkel*m*n);

}

// Aus x,y und Winkel Distanz ermitteln

long get_dist(signed int x, signed int y, signed int phi)

{

        long dist;

        if (abs(x) > abs(y) )

        {

                dist = (long) x; //Groesseren Wert wegen besserer Genauigkeit nehmen

                dist = abs((dist *1000) / (long) sin_i(phi));

        }

        else

        {

                dist = (long) y;

                dist = abs((dist *1000) / (long) cos_i(phi));

        }

  return dist;

}