211 lines
4.6 KiB
C
211 lines
4.6 KiB
C
/* $Id: points.c,v 1.6 2004-08-28 23:17:45 schaffner Exp $ */
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/*
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THE COMPUTER CODE CONTAINED HEREIN IS THE SOLE PROPERTY OF PARALLAX
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SOFTWARE CORPORATION ("PARALLAX"). PARALLAX, IN DISTRIBUTING THE CODE TO
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END-USERS, AND SUBJECT TO ALL OF THE TERMS AND CONDITIONS HEREIN, GRANTS A
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ROYALTY-FREE, PERPETUAL LICENSE TO SUCH END-USERS FOR USE BY SUCH END-USERS
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IN USING, DISPLAYING, AND CREATING DERIVATIVE WORKS THEREOF, SO LONG AS
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SUCH USE, DISPLAY OR CREATION IS FOR NON-COMMERCIAL, ROYALTY OR REVENUE
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FREE PURPOSES. IN NO EVENT SHALL THE END-USER USE THE COMPUTER CODE
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CONTAINED HEREIN FOR REVENUE-BEARING PURPOSES. THE END-USER UNDERSTANDS
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AND AGREES TO THE TERMS HEREIN AND ACCEPTS THE SAME BY USE OF THIS FILE.
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COPYRIGHT 1993-1998 PARALLAX SOFTWARE CORPORATION. ALL RIGHTS RESERVED.
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*/
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/*
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*
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* Routines for point definition, rotation, etc.
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include <conf.h>
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#endif
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#ifdef RCS
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static char rcsid[] = "$Id: points.c,v 1.6 2004-08-28 23:17:45 schaffner Exp $";
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#endif
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#include "3d.h"
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#include "globvars.h"
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//code a point. fills in the p3_codes field of the point, and returns the codes
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ubyte g3_code_point(g3s_point *p)
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{
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ubyte cc=0;
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if (p->p3_x > p->p3_z)
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cc |= CC_OFF_RIGHT;
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if (p->p3_y > p->p3_z)
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cc |= CC_OFF_TOP;
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if (p->p3_x < -p->p3_z)
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cc |= CC_OFF_LEFT;
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if (p->p3_y < -p->p3_z)
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cc |= CC_OFF_BOT;
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if (p->p3_z < 0)
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cc |= CC_BEHIND;
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return p->p3_codes = cc;
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}
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//rotates a point. returns codes. does not check if already rotated
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ubyte g3_rotate_point(g3s_point *dest,vms_vector *src)
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{
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vms_vector tempv;
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#ifdef D1XD3D
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dest->p3_orig = *src;
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#endif
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vm_vec_sub(&tempv,src,&View_position);
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vm_vec_rotate(&dest->p3_vec,&tempv,&View_matrix);
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dest->p3_flags = 0; //no projected
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return g3_code_point(dest);
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}
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//checks for overflow & divides if ok, fillig in r
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//returns true if div is ok, else false
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int checkmuldiv(fix *r,fix a,fix b,fix c)
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{
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quadint q,qt;
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q.low=q.high=0;
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fixmulaccum(&q,a,b);
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qt = q;
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if (qt.high < 0)
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fixquadnegate(&qt);
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qt.high *= 2;
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if (qt.low > 0x7fff)
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qt.high++;
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if (qt.high >= c)
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return 0;
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else {
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*r = fixdivquadlong(q.low,q.high,c);
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return 1;
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}
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}
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//projects a point
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void g3_project_point(g3s_point *p)
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{
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#ifndef __powerc
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fix tx,ty;
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if (p->p3_flags & PF_PROJECTED || p->p3_codes & CC_BEHIND)
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return;
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if (checkmuldiv(&tx,p->p3_x,Canv_w2,p->p3_z) && checkmuldiv(&ty,p->p3_y,Canv_h2,p->p3_z)) {
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p->p3_sx = Canv_w2 + tx;
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p->p3_sy = Canv_h2 - ty;
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p->p3_flags |= PF_PROJECTED;
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}
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else
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p->p3_flags |= PF_OVERFLOW;
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#else
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double fz;
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if ((p->p3_flags & PF_PROJECTED) || (p->p3_codes & CC_BEHIND))
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return;
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if ( p->p3_z <= 0 ) {
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p->p3_flags |= PF_OVERFLOW;
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return;
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}
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fz = f2fl(p->p3_z);
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p->p3_sx = fl2f(fCanv_w2 + (f2fl(p->p3_x)*fCanv_w2 / fz));
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p->p3_sy = fl2f(fCanv_h2 - (f2fl(p->p3_y)*fCanv_h2 / fz));
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p->p3_flags |= PF_PROJECTED;
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#endif
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}
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//from a 2d point, compute the vector through that point
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void g3_point_2_vec(vms_vector *v,short sx,short sy)
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{
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vms_vector tempv;
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vms_matrix tempm;
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tempv.x = fixmuldiv(fixdiv((sx<<16) - Canv_w2,Canv_w2),Matrix_scale.z,Matrix_scale.x);
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tempv.y = -fixmuldiv(fixdiv((sy<<16) - Canv_h2,Canv_h2),Matrix_scale.z,Matrix_scale.y);
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tempv.z = f1_0;
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vm_vec_normalize(&tempv);
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vm_copy_transpose_matrix(&tempm,&Unscaled_matrix);
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vm_vec_rotate(v,&tempv,&tempm);
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}
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//delta rotation functions
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vms_vector *g3_rotate_delta_x(vms_vector *dest,fix dx)
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{
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dest->x = fixmul(View_matrix.rvec.x,dx);
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dest->y = fixmul(View_matrix.uvec.x,dx);
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dest->z = fixmul(View_matrix.fvec.x,dx);
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return dest;
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}
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vms_vector *g3_rotate_delta_y(vms_vector *dest,fix dy)
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{
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dest->x = fixmul(View_matrix.rvec.y,dy);
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dest->y = fixmul(View_matrix.uvec.y,dy);
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dest->z = fixmul(View_matrix.fvec.y,dy);
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return dest;
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}
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vms_vector *g3_rotate_delta_z(vms_vector *dest,fix dz)
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{
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dest->x = fixmul(View_matrix.rvec.z,dz);
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dest->y = fixmul(View_matrix.uvec.z,dz);
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dest->z = fixmul(View_matrix.fvec.z,dz);
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return dest;
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}
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vms_vector *g3_rotate_delta_vec(vms_vector *dest,vms_vector *src)
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{
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return vm_vec_rotate(dest,src,&View_matrix);
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}
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ubyte g3_add_delta_vec(g3s_point *dest,g3s_point *src,vms_vector *deltav)
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{
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vm_vec_add(&dest->p3_vec,&src->p3_vec,deltav);
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dest->p3_flags = 0; //not projected
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return g3_code_point(dest);
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}
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//calculate the depth of a point - returns the z coord of the rotated point
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fix g3_calc_point_depth(vms_vector *pnt)
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{
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quadint q;
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q.low=q.high=0;
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fixmulaccum(&q,(pnt->x - View_position.x),View_matrix.fvec.x);
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fixmulaccum(&q,(pnt->y - View_position.y),View_matrix.fvec.y);
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fixmulaccum(&q,(pnt->z - View_position.z),View_matrix.fvec.z);
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return fixquadadjust(&q);
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}
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