amd64 fixes
[btb/d2x.git] / 3d / instance.c
1 /* $Id: instance.c,v 1.6 2005-08-02 06:14:48 chris 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         Assert(instance_depth<MAX_INSTANCE_DEPTH);
47
48         instance_stack[instance_depth].m = View_matrix;
49         instance_stack[instance_depth].p = View_position;
50         instance_depth++;
51
52         //step 1: subtract object position from view position
53
54         vm_vec_sub(&tempv,&View_position,pos);
55
56
57         if (orient) {
58
59                 //step 2: rotate view vector through object matrix
60
61                 vm_vec_rotate(&View_position,&tempv,orient);
62
63                 //step 3: rotate object matrix through view_matrix (vm = ob * vm)
64
65                 vm_copy_transpose_matrix(&tempm2,orient);
66
67                 vm_matrix_x_matrix(&tempm,&tempm2,&View_matrix);
68                 View_matrix = tempm;
69         }
70 }
71
72
73 //instance at specified point with specified orientation
74 //if angles==NULL, don't modify matrix.  This will be like doing an offset
75 void g3_start_instance_angles(vms_vector *pos,vms_angvec *angles)
76 {
77         vms_matrix tm;
78
79         if (angles==NULL) {
80                 g3_start_instance_matrix(pos,NULL);
81                 return;
82         }
83
84         vm_angles_2_matrix(&tm,angles);
85
86         g3_start_instance_matrix(pos,&tm);
87
88 }
89
90
91 //pops the old context
92 void g3_done_instance()
93 {
94         instance_depth--;
95
96         Assert(instance_depth >= 0);
97
98         View_position = instance_stack[instance_depth].p;
99         View_matrix = instance_stack[instance_depth].m;
100 }
101
102