3d/instance.c

   1 /* $Id: instance.c,v 1.4 2002-07-17 21:55:19 bradleyb Exp $ */
   2 /*
   3 THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
   4 SOFTWARE CORPORATION ("PARALLAX").  PARALLAX, IN DISTRIBUTING THE CODE TO
   5 END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
   6 ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
   7 IN USING, DISPLAYING,  AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
   8 SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
   9 FREE PURPOSES.  IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
  10 CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES.  THE END-USER UNDERSTANDS
  11 AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
  12 COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION.  ALL RIGHTS RESERVED.
  13 */
  14 /*
  15  *
  16  * Instancing routines
  17  *
  18  * Old Log:
  19  *
  20  * Revision 1.2  1995/06/12  12:36:57  allender
  21  * fixed bug where g3_start_instance_angles recursively called itself
  22  *
  23  * Revision 1.1  1995/05/05  08:51:27  allender
  24  * Initial revision
  25  *
  26  * Revision 1.1  1995/04/17  06:43:29  matt
  27  * Initial revision
  28  *
  29  *
  30  */
  31
  32 #ifdef HAVE_CONFIG_H
  33 #include <conf.h>
  34 #endif
  35
  36 #include <stdlib.h>
  37 #include "error.h"
  38
  39 #include "3d.h"
  40 #include "globvars.h"
  41
  42 #define MAX_INSTANCE_DEPTH      5
  43
  44 struct instance_context {
  45         vms_matrix m;
  46         vms_vector p;
  47 } instance_stack[MAX_INSTANCE_DEPTH];
  48
  49 int instance_depth = 0;
  50
  51 //instance at specified point with specified orientation
  52 //if matrix==NULL, don't modify matrix.  This will be like doing an offset
  53 void g3_start_instance_matrix(vms_vector *pos,vms_matrix *orient)
  54 {
  55         vms_vector tempv;
  56         vms_matrix tempm,tempm2;
  57
  58 #ifdef D1XD3D
  59         Win32_start_instance_matrix (pos, orient);
  60 #endif
  61
  62         Assert(instance_depth<MAX_INSTANCE_DEPTH);
  63
  64         instance_stack[instance_depth].m = View_matrix;
  65         instance_stack[instance_depth].p = View_position;
  66         instance_depth++;
  67
  68         //step 1: subtract object position from view position
  69
  70         vm_vec_sub(&tempv,&View_position,pos);
  71
  72
  73         if (orient) {
  74
  75                 //step 2: rotate view vector through object matrix
  76
  77                 vm_vec_rotate(&View_position,&tempv,orient);
  78
  79                 //step 3: rotate object matrix through view_matrix (vm = ob * vm)
  80
  81                 vm_copy_transpose_matrix(&tempm2,orient);
  82
  83                 vm_matrix_x_matrix(&tempm,&tempm2,&View_matrix);
  84                 View_matrix = tempm;
  85         }
  86 }
  87
  88
  89 //instance at specified point with specified orientation
  90 //if angles==NULL, don't modify matrix.  This will be like doing an offset
  91 void g3_start_instance_angles(vms_vector *pos,vms_angvec *angles)
  92 {
  93         vms_matrix tm;
  94
  95         if (angles==NULL) {
  96                 g3_start_instance_matrix(pos,NULL);
  97                 return;
  98         }
  99
 100         vm_angles_2_matrix(&tm,angles);
 101
 102         g3_start_instance_matrix(pos,&tm);
 103
 104 }
 105
 106
 107 //pops the old context
 108 void g3_done_instance()
 109 {
 110 #ifdef D1XD3D
 111         Win32_done_instance ();
 112 #endif
 113
 114         instance_depth--;
 115
 116         Assert(instance_depth >= 0);
 117
 118         View_position = instance_stack[instance_depth].p;
 119         View_matrix = instance_stack[instance_depth].m;
 120 }
 121
 122