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8 FREE PURPOSES. IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
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14 * $Source: /cvs/cvsroot/d2x/3d/points.c,v $
17 * $Date: 2001-01-31 15:17:48 $
19 * Routines for point definition, rotation, etc.
21 * $Log: not supported by cvs2svn $
22 * Revision 1.1.1.1 2001/01/19 03:29:58 bradleyb
25 * Revision 1.1.1.1 1999/06/14 21:57:49 donut
26 * Import of d1x 1.37 source.
28 * Revision 1.3 1995/09/21 17:29:40 allender
29 * changed project_point to overflow if z <= 0
31 * Revision 1.2 1995/09/13 11:31:28 allender
32 * removed checkmuldiv from g3_project_point
34 * Revision 1.1 1995/05/05 08:52:35 allender
37 * Revision 1.1 1995/04/17 04:32:25 matt
48 static char rcsid[] = "$Id: points.c,v 1.2 2001-01-31 15:17:48 bradleyb Exp $";
58 //code a point. fills in the p3_codes field of the point, and returns the codes
59 ubyte g3_code_point(g3s_point *p)
63 if (p->p3_x > p->p3_z)
66 if (p->p3_y > p->p3_z)
69 if (p->p3_x < -p->p3_z)
72 if (p->p3_y < -p->p3_z)
78 return p->p3_codes = cc;
82 //rotates a point. returns codes. does not check if already rotated
83 ubyte g3_rotate_point(g3s_point *dest,vms_vector *src)
91 vm_vec_sub(&tempv,src,&View_position);
93 vm_vec_rotate(&dest->p3_vec,&tempv,&View_matrix);
95 dest->p3_flags = 0; //no projected
97 return g3_code_point(dest);
101 //checks for overflow & divides if ok, fillig in r
102 //returns true if div is ok, else false
103 int checkmuldiv(fix *r,fix a,fix b,fix c)
121 *r = fixdivquadlong(q.low,q.high,c);
127 void g3_project_point(g3s_point *p)
132 if (p->p3_flags & PF_PROJECTED || p->p3_codes & CC_BEHIND)
135 if (checkmuldiv(&tx,p->p3_x,Canv_w2,p->p3_z) && checkmuldiv(&ty,p->p3_y,Canv_h2,p->p3_z)) {
136 p->p3_sx = Canv_w2 + tx;
137 p->p3_sy = Canv_h2 - ty;
138 p->p3_flags |= PF_PROJECTED;
141 p->p3_flags |= PF_OVERFLOW;
145 if ((p->p3_flags & PF_PROJECTED) || (p->p3_codes & CC_BEHIND))
148 if ( p->p3_z <= 0 ) {
149 p->p3_flags |= PF_OVERFLOW;
154 p->p3_sx = fl2f(fCanv_w2 + (f2fl(p->p3_x)*fCanv_w2 / fz));
155 p->p3_sy = fl2f(fCanv_h2 - (f2fl(p->p3_y)*fCanv_h2 / fz));
157 p->p3_flags |= PF_PROJECTED;
161 //from a 2d point, compute the vector through that point
162 void g3_point_2_vec(vms_vector *v,short sx,short sy)
167 tempv.x = fixmuldiv(fixdiv((sx<<16) - Canv_w2,Canv_w2),Matrix_scale.z,Matrix_scale.x);
168 tempv.y = -fixmuldiv(fixdiv((sy<<16) - Canv_h2,Canv_h2),Matrix_scale.z,Matrix_scale.y);
171 vm_vec_normalize(&tempv);
173 vm_copy_transpose_matrix(&tempm,&Unscaled_matrix);
175 vm_vec_rotate(v,&tempv,&tempm);
179 //delta rotation functions
180 vms_vector *g3_rotate_delta_x(vms_vector *dest,fix dx)
182 dest->x = fixmul(View_matrix.rvec.x,dx);
183 dest->y = fixmul(View_matrix.uvec.x,dx);
184 dest->z = fixmul(View_matrix.fvec.x,dx);
189 vms_vector *g3_rotate_delta_y(vms_vector *dest,fix dy)
191 dest->x = fixmul(View_matrix.rvec.y,dy);
192 dest->y = fixmul(View_matrix.uvec.y,dy);
193 dest->z = fixmul(View_matrix.fvec.y,dy);
198 vms_vector *g3_rotate_delta_z(vms_vector *dest,fix dz)
200 dest->x = fixmul(View_matrix.rvec.z,dz);
201 dest->y = fixmul(View_matrix.uvec.z,dz);
202 dest->z = fixmul(View_matrix.fvec.z,dz);
208 vms_vector *g3_rotate_delta_vec(vms_vector *dest,vms_vector *src)
210 return vm_vec_rotate(dest,src,&View_matrix);
213 ubyte g3_add_delta_vec(g3s_point *dest,g3s_point *src,vms_vector *deltav)
215 vm_vec_add(&dest->p3_vec,&src->p3_vec,deltav);
217 dest->p3_flags = 0; //not projected
219 return g3_code_point(dest);
222 //calculate the depth of a point - returns the z coord of the rotated point
223 fix g3_calc_point_depth(vms_vector *pnt)
228 fixmulaccum(&q,(pnt->x - View_position.x),View_matrix.fvec.x);
229 fixmulaccum(&q,(pnt->y - View_position.y),View_matrix.fvec.y);
230 fixmulaccum(&q,(pnt->z - View_position.z),View_matrix.fvec.z);
232 return fixquadadjust(&q);