NetNews Usenet Archive 1992 #27/NN_1992_27.iso/spool/alt/sources/2608/control.c

C/C++ Source or Header | 1992-11-23 | 4.8 KB | 243 lines

#ifndef lint
static    char    sccsid[] = "@(#)control.c 1.1 92/05/28 SMI" ;
    /* from control.c 1.3 90/05/02 SMI */
#endif

/*
 * Copyright (c) 1986 by Sun Microsystems, Inc.
 */

/*
 * this file contains generic control stuff:
 *
 * adjust_vector(object)
 *    re-calculate objects "Pointing" vector from its "Delta"
 *
 * adjust_vectors(object)
 *    updates an object's orientation according to its control inputs
 *
 * control_enemies()
 *    goes through object list and updates everything according to
 *    their last known control inputs
 *
 */




#include <stdio.h>
#include <math.h>
#include "dstar.h"
#include "object_types.h"



extern    int    debug_level ;


/****
 *
 * apply a delta to a vector
 *
 ****/


adjust_vector(object, delta)
register Object    *object ;
register Pt3d    *delta ;
{
    float   magnitude ;

/* transform Delta from ship coords to universal coords
 * matrix to go from ship coords to universe coords is:
 *
 * |  Right  |
 * |   Up    |
 * | Forward |
 *
 * (z-component of Delta is 1.0)
 */

    /* apply to forward vector */

    object->Pointing.x = delta->x*object->Right.x +
                 delta->y*object->Up.x +
                 object->Forward.x ;
    object->Pointing.y = delta->x*object->Right.y +
                 delta->y*object->Up.y +
                 object->Forward.y ;
    object->Pointing.z = delta->x*object->Right.z +
                 delta->y*object->Up.z +
                 object->Forward.z ;

    /* normalize the resulting vector */

    magnitude = object->Pointing.x*object->Pointing.x +
            object->Pointing.y*object->Pointing.y +
            object->Pointing.z*object->Pointing.z ;
    if(magnitude != 1.0)
    {
      magnitude = 1.0 / sqrt(magnitude) ;
      object->Pointing.x *= magnitude ;
      object->Pointing.y *= magnitude ;
      object->Pointing.z *= magnitude ;
    }
}



/****
 *
 * update object's position/velocity/"up" vectors
 *
 ****/


adjust_vectors(object)
register Object    *object ;
{
    Pt3d    delta1, delta2, Forward2, Up2, Right2 ;
    float    a ;
    float    x,y ;


    delta1 = object->Delta ;

    delta1.x *= Dtime ;
    delta1.y *= Dtime ;
    delta1.z *= Dtime ;


    /* transform Delta from ship coords to universal coords */
    /* matrix to go from ship coords to universe coords is:
     *
     * |  Right  |
     * |   Up    |
     * | Forward |
     */


    /* (z-component of Delta is zero) */

    delta2.x = delta1.x*object->Right.x + delta1.y*object->Up.x ;
    delta2.y = delta1.x*object->Right.y + delta1.y*object->Up.y ;
    delta2.z = delta1.x*object->Right.z + delta1.y*object->Up.z ;


    /* apply to forward vector */

    Forward2.x = object->Forward.x + delta2.x ;
    Forward2.y = object->Forward.y + delta2.y ;
    Forward2.z = object->Forward.z + delta2.z ;

    a = Forward2.x*Forward2.x +
        Forward2.y*Forward2.y +
        Forward2.z*Forward2.z ;

    if(a != 1.0)
    {
      a = 1.0 / sqrt(a) ;
      Forward2.x *= a ;
      Forward2.y *= a ;
      Forward2.z *= a ;
    }


    /* transform Roll from ship coords to universal coords */
    /* (y,z components are zero */

    delta2.x = delta1.z * object->Right.x ;
    delta2.y = delta1.z * object->Right.y ;
    delta2.z = delta1.z * object->Right.z ;

    Up2.x = object->Up.x + delta2.x ;
    Up2.y = object->Up.y + delta2.y ;
    Up2.z = object->Up.z + delta2.z ;



    /* calculate new Right vector and normalize */

    Right2.x = Forward2.z*Up2.y - Forward2.y*Up2.z ;
    Right2.y = Forward2.x*Up2.z - Forward2.z*Up2.x ;
    Right2.z = Forward2.y*Up2.x - Forward2.x*Up2.y ;

    a = Right2.x*Right2.x + Right2.y*Right2.y + Right2.z*Right2.z ;

    if(a != 1.0)
    {
      a = 1.0 / sqrt(a) ;
      Right2.x *= a ;
      Right2.y *= a ;
      Right2.z *= a ;
    }


    /* go back and recalculate Up vector */

    Up2.x = Right2.z*Forward2.y - Right2.y*Forward2.z ;
    Up2.y = Right2.x*Forward2.z - Right2.z*Forward2.x ;
    Up2.z = Right2.y*Forward2.x - Right2.x*Forward2.y ;

    a = Up2.x*Up2.x + Up2.y*Up2.y + Up2.z*Up2.z ;
    if(a > 1.00001  ||  a < .9999)
      printf("whadda fuck? a=%f\n",a) ;




    /* update position */

    object->Posn.x += object->Speed*Dtime*Forward2.x ;
    object->Posn.y += object->Speed*Dtime*Forward2.y ;
    object->Posn.z += object->Speed*Dtime*Forward2.z ;

    object->Forward = Forward2 ;
    object->Up = Up2 ;
    object->Right = Right2 ;
}





control_object(object)
    Object    *object ;
{
    adjust_vector(object,&object->Delta) ;
    adjust_vectors(object) ;
}





control_enemies()
{
register int    i ;
register Object    *object = &objects[0] ;

    /* adjust all active or dead, non-empty objects except
       for myself and my missiles (which are adjusted elsewhere).
       Do not adjust objects for which we've had a recent report. */


    for(i=MAX_PLAYERS; --i >= 0;)
    {
      if(object->class != OBJ_EMPTY  &&

        (object->status == OBJ_ACTIVE || object->status == OBJ_DEAD)  &&

         object != Me  &&
         !(object->class == OBJ_MISSILE  &&  object->team == Me->id)  &&

        (object->last_rep.tv_sec < Last_Time.tv_sec  ||
         (object->last_rep.tv_sec == Last_Time.tv_sec  &&
          object->last_rep.tv_usec < Last_Time.tv_usec)) )
      {
        (*object->f_vector[F_CONTROL])(object) ;
      }
      ++object ;
    }
}