3d/instance.c

   1 /* $Id: instance.c,v 1.5 2004-08-28 23:17:45 schaffner 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  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include <conf.h>
  22 #endif
  23
  24 #include <stdlib.h>
  25 #include "error.h"
  26
  27 #include "3d.h"
  28 #include "globvars.h"
  29
  30 #define MAX_INSTANCE_DEPTH      5
  31
  32 struct instance_context {
  33         vms_matrix m;
  34         vms_vector p;
  35 } instance_stack[MAX_INSTANCE_DEPTH];
  36
  37 int instance_depth = 0;
  38
  39 //instance at specified point with specified orientation
  40 //if matrix==NULL, don't modify matrix.  This will be like doing an offset
  41 void g3_start_instance_matrix(vms_vector *pos,vms_matrix *orient)
  42 {
  43         vms_vector tempv;
  44         vms_matrix tempm,tempm2;
  45
  46 #ifdef D1XD3D
  47         Win32_start_instance_matrix (pos, orient);
  48 #endif
  49
  50         Assert(instance_depth<MAX_INSTANCE_DEPTH);
  51
  52         instance_stack[instance_depth].m = View_matrix;
  53         instance_stack[instance_depth].p = View_position;
  54         instance_depth++;
  55
  56         //step 1: subtract object position from view position
  57
  58         vm_vec_sub(&tempv,&View_position,pos);
  59
  60
  61         if (orient) {
  62
  63                 //step 2: rotate view vector through object matrix
  64
  65                 vm_vec_rotate(&View_position,&tempv,orient);
  66
  67                 //step 3: rotate object matrix through view_matrix (vm = ob * vm)
  68
  69                 vm_copy_transpose_matrix(&tempm2,orient);
  70
  71                 vm_matrix_x_matrix(&tempm,&tempm2,&View_matrix);
  72                 View_matrix = tempm;
  73         }
  74 }
  75
  76
  77 //instance at specified point with specified orientation
  78 //if angles==NULL, don't modify matrix.  This will be like doing an offset
  79 void g3_start_instance_angles(vms_vector *pos,vms_angvec *angles)
  80 {
  81         vms_matrix tm;
  82
  83         if (angles==NULL) {
  84                 g3_start_instance_matrix(pos,NULL);
  85                 return;
  86         }
  87
  88         vm_angles_2_matrix(&tm,angles);
  89
  90         g3_start_instance_matrix(pos,&tm);
  91
  92 }
  93
  94
  95 //pops the old context
  96 void g3_done_instance()
  97 {
  98 #ifdef D1XD3D
  99         Win32_done_instance ();
 100 #endif
 101
 102         instance_depth--;
 103
 104         Assert(instance_depth >= 0);
 105
 106         View_position = instance_stack[instance_depth].p;
 107         View_matrix = instance_stack[instance_depth].m;
 108 }
 109
 110