150 lines
3.2 KiB
C++
150 lines
3.2 KiB
C++
/*
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* This file is part of the DXX-Rebirth project <http://www.dxx-rebirth.com/>.
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* It is copyright by its individual contributors, as recorded in the
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* project's Git history. See COPYING.txt at the top level for license
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* terms and a link to the Git history.
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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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#include "3d.h"
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#include "globvars.h"
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namespace dcx {
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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,const vms_vector &src)
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{
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const auto tempv = vm_vec_sub(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.q = 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 = static_cast<int32_t>(q.q / static_cast<int64_t>(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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tempm = vm_transposed_matrix(Unscaled_matrix);
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vm_vec_rotate(v,tempv,tempm);
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}
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void g3_rotate_delta_vec(vms_vector &dest,const vms_vector &src)
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{
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vm_vec_rotate(dest,src,View_matrix);
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}
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ubyte g3_add_delta_vec(g3s_point &dest,const g3s_point &src,const 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(const vms_vector &pnt)
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{
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quadint q;
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q.q = 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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}
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