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14 * $Source: /cvs/cvsroot/d2x/3d/points.c,v $
15 * $Revision: 1.1.1.1 $
17 * $Date: 2001-01-19 03:29:58 $
19 * Routines for point definition, rotation, etc.
21 * $Log: not supported by cvs2svn $
22 * Revision 1.1.1.1 1999/06/14 21:57:49 donut
23 * Import of d1x 1.37 source.
25 * Revision 1.3 1995/09/21 17:29:40 allender
26 * changed project_point to overflow if z <= 0
28 * Revision 1.2 1995/09/13 11:31:28 allender
29 * removed checkmuldiv from g3_project_point
31 * Revision 1.1 1995/05/05 08:52:35 allender
34 * Revision 1.1 1995/04/17 04:32:25 matt
41 static char rcsid[] = "$Id: points.c,v 1.1.1.1 2001-01-19 03:29:58 bradleyb Exp $";
53 //code a point. fills in the p3_codes field of the point, and returns the codes
54 ubyte g3_code_point(g3s_point *p)
58 if (p->p3_x > p->p3_z)
61 if (p->p3_y > p->p3_z)
64 if (p->p3_x < -p->p3_z)
67 if (p->p3_y < -p->p3_z)
73 return p->p3_codes = cc;
77 //rotates a point. returns codes. does not check if already rotated
78 ubyte g3_rotate_point(g3s_point *dest,vms_vector *src)
86 vm_vec_sub(&tempv,src,&View_position);
88 vm_vec_rotate(&dest->p3_vec,&tempv,&View_matrix);
90 dest->p3_flags = 0; //no projected
92 return g3_code_point(dest);
96 //checks for overflow & divides if ok, fillig in r
97 //returns true if div is ok, else false
98 int checkmuldiv(fix *r,fix a,fix b,fix c)
116 *r = fixdivquadlong(q.low,q.high,c);
122 void g3_project_point(g3s_point *p)
127 if (p->p3_flags & PF_PROJECTED || p->p3_codes & CC_BEHIND)
130 if (checkmuldiv(&tx,p->p3_x,Canv_w2,p->p3_z) && checkmuldiv(&ty,p->p3_y,Canv_h2,p->p3_z)) {
131 p->p3_sx = Canv_w2 + tx;
132 p->p3_sy = Canv_h2 - ty;
133 p->p3_flags |= PF_PROJECTED;
136 p->p3_flags |= PF_OVERFLOW;
140 if ((p->p3_flags & PF_PROJECTED) || (p->p3_codes & CC_BEHIND))
143 if ( p->p3_z <= 0 ) {
144 p->p3_flags |= PF_OVERFLOW;
149 p->p3_sx = fl2f(fCanv_w2 + (f2fl(p->p3_x)*fCanv_w2 / fz));
150 p->p3_sy = fl2f(fCanv_h2 - (f2fl(p->p3_y)*fCanv_h2 / fz));
152 p->p3_flags |= PF_PROJECTED;
156 //from a 2d point, compute the vector through that point
157 void g3_point_2_vec(vms_vector *v,short sx,short sy)
162 tempv.x = fixmuldiv(fixdiv((sx<<16) - Canv_w2,Canv_w2),Matrix_scale.z,Matrix_scale.x);
163 tempv.y = -fixmuldiv(fixdiv((sy<<16) - Canv_h2,Canv_h2),Matrix_scale.z,Matrix_scale.y);
166 vm_vec_normalize(&tempv);
168 vm_copy_transpose_matrix(&tempm,&Unscaled_matrix);
170 vm_vec_rotate(v,&tempv,&tempm);
174 //delta rotation functions
175 vms_vector *g3_rotate_delta_x(vms_vector *dest,fix dx)
177 dest->x = fixmul(View_matrix.rvec.x,dx);
178 dest->y = fixmul(View_matrix.uvec.x,dx);
179 dest->z = fixmul(View_matrix.fvec.x,dx);
184 vms_vector *g3_rotate_delta_y(vms_vector *dest,fix dy)
186 dest->x = fixmul(View_matrix.rvec.y,dy);
187 dest->y = fixmul(View_matrix.uvec.y,dy);
188 dest->z = fixmul(View_matrix.fvec.y,dy);
193 vms_vector *g3_rotate_delta_z(vms_vector *dest,fix dz)
195 dest->x = fixmul(View_matrix.rvec.z,dz);
196 dest->y = fixmul(View_matrix.uvec.z,dz);
197 dest->z = fixmul(View_matrix.fvec.z,dz);
203 vms_vector *g3_rotate_delta_vec(vms_vector *dest,vms_vector *src)
205 return vm_vec_rotate(dest,src,&View_matrix);
208 ubyte g3_add_delta_vec(g3s_point *dest,g3s_point *src,vms_vector *deltav)
210 vm_vec_add(&dest->p3_vec,&src->p3_vec,deltav);
212 dest->p3_flags = 0; //not projected
214 return g3_code_point(dest);
217 //calculate the depth of a point - returns the z coord of the rotated point
218 fix g3_calc_point_depth(vms_vector *pnt)
223 fixmulaccum(&q,(pnt->x - View_position.x),View_matrix.fvec.x);
224 fixmulaccum(&q,(pnt->y - View_position.y),View_matrix.fvec.y);
225 fixmulaccum(&q,(pnt->z - View_position.z),View_matrix.fvec.z);
227 return fixquadadjust(&q);