#include "ZAMProtos.h"

#include <FixMath.h>

#define kNumDirectionAngles 32

static fixPt    gDirectionTable[kNumDirectionAngles];

#define kRadiansInCircle 6.283185307178

void InitDirectionTable(void)

/*

    this procedure builds a table of fixed point vectors.

    These vectors are indexed by the direction number from 0 to kNumDirectionAngles

    and are evenly spaced around the compass.

*/

{

    short i;

    double angle = 0;

    double angleIncrement = kRadiansInCircle / kNumDirectionAngles;

    for (i = 0; i < kNumDirectionAngles; i++) {

        gDirectionTable[i].h = Frac2Fix( FracSin( X2Fix(angle) ));

        gDirectionTable[i].v = Frac2Fix( -FracCos( X2Fix(angle) ));

        angle += angleIncrement;

    }

}

void DirectionToVelocity(short dir, fixPt *vel)

/*

    grab a vector from the table, indexed by the direction number

    this would be better as a Macro, but hey, it isn't.

*/

{

    *vel = gDirectionTable[dir];

}

short VelocityToDirection(fixPt *vel)

/*

    Get a direction number from a velocity.

    This is a pretty LAME thing to have to do, because it requires a search of the vector table

*/

{

    short   i;

    for(i = 0; i < kNumDirectionAngles; i++)

        if( (gDirectionTable[i].h == vel->h) && (gDirectionTable[i].v == vel->v))

            return i;

    return -1;

}