fixedpoint.java

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                        int k;
                        n = -n;

                        if ((n & (FIX_UNIT>>1)) != 0)
                                k = (((n+FIX_UNIT)>>FIX_SHIFT)<<FIX_SHIFT);
                        else
                                k = (((n)>>FIX_SHIFT)<<FIX_SHIFT);

                        return -k;
                }// ~else
        }/// END FUNC

        /**
        * @name sin
        * @brief sine function value read from table
        * @param x fixed point value [0..2PI]
        * @return FixedPoint sine of x [0..1]
        * @author Stellars Henson
        */
        public static final int sin(int x)
        {
                x = (x<<8)/(2*FIXED_PI+1);
                return FIX_SIN[x & 0xff];
        }/// END FUNC

        /**
        * @name cos
        * @brief cosine function value read from table
        * @param x fixed point value [0..2PI]
        * @return FixedPoint cosine of x [0..1]
        * @author Stellars Henson
        */
        public static final int cos(int x)
        {
                x = (x<<8)/(2*FIXED_PI+1);
                return FIX_COS[x & 0xff];
        }/// END FUNC

        /**
         * routinge returns FixedPoint angle
         * for line binding the given point (x,y)
         * and the point (0,0). The angle of 0
         * is equal to x positive axis
         * @name angle
         * @brief calculates angle for given point
         * @version 1.4
         * @param x horizontal coord (FixedPoint)
         * @param y vertical coord (FixedPoint)
         * @author Stellars Henson
         * @return angle FixedPoint [0..2PI]
         */
        public static final int angle( int x, int y ) {
                /* prepare environment */
                int sampleX = 0;
                int sampleY = 0;
                int sampleAngle = 0;
                int xSign = 1;
                int ySign = 1;
                int angleSign = 1;
                int angleOffset = 0;
                boolean swapCoords = false;

                /* special situations */
                if( x == 0 && y == 0 )
                        return 0;

                /*
                 * calculate in which of
                 * eight fracts the point is.
                 * move counterclockwise
                 */
                /* first quarter, x>0, y>0 */
                if( x>=0 && y>=0 && x>=y ) {
                        swapCoords = false;
                        xSign = 1;
                        ySign = 1;
                        angleSign = 1;
                        angleOffset = 0;
                } else if( x>0 && y>0 && x<y ) {
                        swapCoords = true;
                        xSign = 1;
                        ySign = 1;
                        angleSign = -1;
                        angleOffset = FIXED_HALFPI;
                }// ~elseif
                /* second quarter, x<0, y>0 */
                else if( x<=0 && y>=0 && (-x)<=y ) {
                        swapCoords = true;
                        xSign = -1;
                        ySign = 1;
                        angleSign = 1;
                        angleOffset = FIXED_HALFPI;
                } else if( x<0 && y>0 && (-x)>y ) {
                        swapCoords = false;
                        xSign = -1;
                        ySign = 1;
                        angleSign = -1;
                        angleOffset = FIXED_PI;
                }// ~elseif
                /* third quarter, x<0, y<0 */
                else if( x<=0 && y<=0 && (-x)>=(-y) ) {
                        swapCoords = false;
                        xSign = -1;
                        ySign = -1;
                        angleSign = 1;
                        angleOffset = FIXED_PI;
                } else if( x<0 && y<0 && (-x)<(-y) ) {
                        swapCoords = true;
                        xSign = -1;
                        ySign = -1;
                        angleSign = -1;
                        angleOffset = 3 * FIXED_HALFPI;
                }// ~elseif
                /* fourth quarter, x>0, y<0 */
                else if( x>=0 && y<=0 && x<=(-y) ) {
                        swapCoords = true;
                        xSign = 1;
                        ySign = -1;
                        angleSign = 1;
                        angleOffset = 3 * FIXED_HALFPI;
                } else if( x>0 && y<0 && x>(-y) ) {
                        swapCoords = false;
                        xSign = 1;
                        ySign = -1;
                        angleSign = -1;
                        angleOffset = 4 * FIXED_HALFPI;
                }// ~elseif

                /* calculate sample coords */
                if( swapCoords == false ) {
                        sampleX = xSign * x;
                        sampleY = ySign * y;
                }// ~if
                else {
                        sampleX = ySign * y;
                        sampleY = xSign * x;
                }// ~else

                /* now, calculate the sample angle */
                sampleAngle = FIX_ATAN[ (( Div(sampleY,sampleX) )>>8) & 0xff ];

                /* and return the real angle */
                return ( angleOffset + angleSign * sampleAngle );
        }/// END FUNC

        /**
         * @name toString
         * @brief translates fixedpoint value to String
         * @param f fixedpoint value
         * @return string reprezentation of fixedpoint
         */
        public static final String fpToStr(int f)
        {
                byte[] pow = gP;
                byte[] acc = gA;
                int digit, carry;
                boolean neg;
                StringBuffer sb = gB;
                digit = 0;
                do
                        pow[digit] = acc[digit] = 0;
                while (++digit < 21);

                pow[9] = 1;
                pow[10] = 5;
                pow[11] = 2;
                pow[12] = 5;
                pow[13] = 8;
                pow[14] = 7;
                pow[15] = 8;
                pow[16] = 9;
                pow[17] = 0;
                pow[18] = 6;
                pow[19] = 2;
                pow[20] = 5;
                if (neg = f < 0)
                        f = -f;
                while (f != 0) {
                        if ((f & 1) != 0) {
                                digit = 20;
                                carry = 0;
                                do {
                                        acc[digit] = (byte)(acc[digit] + pow[digit] + carry);
                                        if (acc[digit] > 9) {
                                                acc[digit] -= 10;
                                                carry = 1;
                                        }
                                        else
                                                carry = 0;
                                }
                                while (--digit >= 0);
                        }
                        digit = 20;
                        carry = 0;
                        do {
                                pow[digit] = (byte)(pow[digit] + pow[digit] + carry);
                                if (pow[digit] > 9) {
                                        pow[digit] -= 10;
                                        carry = 1;
                                }
                                else
                                        carry = 0;
                        }
                        while (--digit >= 0);
                        f >>>= 1;
                }// ~while
                sb.setLength(0);
                if (neg)
                        sb.append('-');
                for (f = 0; f < 21 && acc[f] == 0; f++)
                        ;
                if (f > 4)
                        sb.append('0');
                for (digit = f; digit < 5; digit++)
                        sb.append(acc[digit]);
                for (f = 20; f >= 0 && acc[f] == 0; f--)
                        ;
                if (f > 4)
                        sb.append('.');
                for (digit = 5; digit <= f; digit++)
                        sb.append(acc[digit]);
                return sb.toString();
        }/// END FUNC

        /////////////////////////////////////////////////////////
        /// Lookup tables                                     ///
        /////////////////////////////////////////////////////////

        /** Private */

                /* sine values table */
                private static final int[] FIX_SIN = {
                        (int)(0.000000*FIX_UNIT), (int)(0.024541*FIX_UNIT), (int)(0.049068*FIX_UNIT), (int)(0.073565*FIX_UNIT),
                        (int)(0.098017*FIX_UNIT), (int)(0.122411*FIX_UNIT), (int)(0.146730*FIX_UNIT), (int)(0.170962*FIX_UNIT),
                        (int)(0.195090*FIX_UNIT), (int)(0.219101*FIX_UNIT), (int)(0.242980*FIX_UNIT), (int)(0.266713*FIX_UNIT),
                        (int)(0.290285*FIX_UNIT), (int)(0.313682*FIX_UNIT), (int)(0.336890*FIX_UNIT), (int)(0.359895*FIX_UNIT),
                        (int)(0.382683*FIX_UNIT), (int)(0.405241*FIX_UNIT), (int)(0.427555*FIX_UNIT), (int)(0.449611*FIX_UNIT),
                        (int)(0.471397*FIX_UNIT), (int)(0.492898*FIX_UNIT), (int)(0.514103*FIX_UNIT), (int)(0.534998*FIX_UNIT),
                        (int)(0.555570*FIX_UNIT), (int)(0.575808*FIX_UNIT), (int)(0.595699*FIX_UNIT), (int)(0.615232*FIX_UNIT),
                        (int)(0.634393*FIX_UNIT), (int)(0.653173*FIX_UNIT), (int)(0.671559*FIX_UNIT), (int)(0.689541*FIX_UNIT),
                        (int)(0.707107*FIX_UNIT), (int)(0.724247*FIX_UNIT), (int)(0.740951*FIX_UNIT), (int)(0.757209*FIX_UNIT),
                        (int)(0.773010*FIX_UNIT), (int)(0.788346*FIX_UNIT), (int)(0.803208*FIX_UNIT), (int)(0.817585*FIX_UNIT),
                        (int)(0.831470*FIX_UNIT), (int)(0.844854*FIX_UNIT), (int)(0.857729*FIX_UNIT), (int)(0.870087*FIX_UNIT),
                        (int)(0.881921*FIX_UNIT), (int)(0.893224*FIX_UNIT), (int)(0.903989*FIX_UNIT), (int)(0.914210*FIX_UNIT),
                        (int)(0.923880*FIX_UNIT), (int)(0.932993*FIX_UNIT), (int)(0.941544*FIX_UNIT), (int)(0.949528*FIX_UNIT),
                        (int)(0.956940*FIX_UNIT), (int)(0.963776*FIX_UNIT), (int)(0.970031*FIX_UNIT), (int)(0.975702*FIX_UNIT),
                        (int)(0.980785*FIX_UNIT), (int)(0.985278*FIX_UNIT), (int)(0.989177*FIX_UNIT), (int)(0.992480*FIX_UNIT),
                        (int)(0.995185*FIX_UNIT), (int)(0.997290*FIX_UNIT), (int)(0.998795*FIX_UNIT), (int)(0.999699*FIX_UNIT),
                        (int)(1.000000*FIX_UNIT), (int)(0.999699*FIX_UNIT), (int)(0.998795*FIX_UNIT), (int)(0.997290*FIX_UNIT),
                        (int)(0.995185*FIX_UNIT), (int)(0.992480*FIX_UNIT), (int)(0.989177*FIX_UNIT), (int)(0.985278*FIX_UNIT),
                        (int)(0.980785*FIX_UNIT), (int)(0.975702*FIX_UNIT), (int)(0.970031*FIX_UNIT), (int)(0.963776*FIX_UNIT),