/*
* This file is part of the DXX-Rebirth project .
* It is copyright by its individual contributors, as recorded in the
* project's Git history. See COPYING.txt at the top level for license
* terms and a link to the Git history.
*/
#include "3d.h"
#include "globvars.h"
#include "clipper.h"
#include "dxxerror.h"
#include "compiler-exchange.h"
int free_point_num=0;
g3s_point temp_points[MAX_POINTS_IN_POLY];
g3s_point *free_points[MAX_POINTS_IN_POLY];
void init_free_points(void)
{
for (int i=0;ip3_flags & PF_TEMP_POINT);
free_points[--free_point_num] = p;
p->p3_flags &= ~PF_TEMP_POINT;
}
//clips an edge against one plane.
static g3s_point &clip_edge(int plane_flag,g3s_point *on_pnt,g3s_point *off_pnt)
{
fix psx_ratio;
fix a,b,kn,kd;
//compute clipping value k = (xs-zs) / (xs-xe-zs+ze)
//use x or y as appropriate, and negate x/y value as appropriate
if (plane_flag & (CC_OFF_RIGHT | CC_OFF_LEFT)) {
a = on_pnt->p3_x;
b = off_pnt->p3_x;
}
else {
a = on_pnt->p3_y;
b = off_pnt->p3_y;
}
if (plane_flag & (CC_OFF_LEFT | CC_OFF_BOT)) {
a = -a;
b = -b;
}
kn = a - on_pnt->p3_z; //xs-zs
kd = kn - b + off_pnt->p3_z; //xs-zs-xe+ze
auto &tmp = get_temp_point();
psx_ratio = fixdiv( kn, kd );
tmp.p3_x = on_pnt->p3_x + fixmul( (off_pnt->p3_x-on_pnt->p3_x), psx_ratio);
tmp.p3_y = on_pnt->p3_y + fixmul( (off_pnt->p3_y-on_pnt->p3_y), psx_ratio);
if (plane_flag & (CC_OFF_TOP|CC_OFF_BOT))
tmp.p3_z = tmp.p3_y;
else
tmp.p3_z = tmp.p3_x;
if (plane_flag & (CC_OFF_LEFT|CC_OFF_BOT))
tmp.p3_z = -tmp.p3_z;
if (on_pnt->p3_flags & PF_UVS) {
// PSX_HACK!!!!
// tmp.p3_u = on_pnt->p3_u + fixmuldiv(off_pnt->p3_u-on_pnt->p3_u,kn,kd);
// tmp.p3_v = on_pnt->p3_v + fixmuldiv(off_pnt->p3_v-on_pnt->p3_v,kn,kd);
tmp.p3_u = on_pnt->p3_u + fixmul((off_pnt->p3_u-on_pnt->p3_u), psx_ratio);
tmp.p3_v = on_pnt->p3_v + fixmul((off_pnt->p3_v-on_pnt->p3_v), psx_ratio);
tmp.p3_flags |= PF_UVS;
}
if (on_pnt->p3_flags & PF_LS) {
// PSX_HACK
// tmp.p3_r = on_pnt->p3_r + fixmuldiv(off_pnt->p3_r-on_pnt->p3_r,kn,kd);
// tmp.p3_g = on_pnt->p3_g + fixmuldiv(off_pnt->p3_g-on_pnt->p3_g,kn,kd);
// tmp.p3_b = on_pnt->p3_b + fixmuldiv(off_pnt->p3_b-on_pnt->p3_b,kn,kd);
tmp.p3_l = on_pnt->p3_l + fixmul((off_pnt->p3_l-on_pnt->p3_l), psx_ratio);
tmp.p3_flags |= PF_LS;
}
g3_code_point(tmp);
return tmp;
}
#ifndef OGL
//clips a line to the viewing pyramid.
void clip_line(g3s_point *&p0,g3s_point *&p1,ubyte codes_or)
{
//might have these left over
p0->p3_flags &= ~(PF_UVS|PF_LS);
p1->p3_flags &= ~(PF_UVS|PF_LS);
for (int plane_flag=1;plane_flag<16;plane_flag<<=1)
if (codes_or & plane_flag) {
if (p0->p3_codes & plane_flag)
std::swap(p0, p1);
const auto old_p1 = exchange(p1, &clip_edge(plane_flag,p0,p1));
if (old_p1->p3_flags & PF_TEMP_POINT)
free_temp_point(old_p1);
}
}
#endif
static int clip_plane(int plane_flag,polygon_clip_points &src,polygon_clip_points &dest,int *nv,g3s_codes *cc)
{
//copy first two verts to end
src[*nv] = src[0];
src[*nv+1] = src[1];
cc->uand = 0xff; cc->uor = 0;
uint_fast32_t j = 0;
for (int i=1;i<=*nv;i++) {
if (src[i]->p3_codes & plane_flag) { //cur point off?
if (! (src[i-1]->p3_codes & plane_flag)) { //prev not off?
dest[j] = &clip_edge(plane_flag,src[i-1],src[i]);
cc->uor |= dest[j]->p3_codes;
cc->uand &= dest[j]->p3_codes;
++j;
}
if (! (src[i+1]->p3_codes & plane_flag)) {
dest[j] = &clip_edge(plane_flag,src[i+1],src[i]);
cc->uor |= dest[j]->p3_codes;
cc->uand &= dest[j]->p3_codes;
++j;
}
//see if must free discarded point
if (src[i]->p3_flags & PF_TEMP_POINT)
free_temp_point(src[i]);
}
else { //cur not off, copy to dest buffer
dest[j++] = src[i];
cc->uor |= src[i]->p3_codes;
cc->uand &= src[i]->p3_codes;
}
}
return j;
}
const polygon_clip_points &clip_polygon(polygon_clip_points &rsrc,polygon_clip_points &rdest,int *nv,g3s_codes *cc)
{
polygon_clip_points *src = &rsrc, *dest = &rdest;
for (int plane_flag=1;plane_flag<16;plane_flag<<=1)
if (cc->uor & plane_flag) {
*nv = clip_plane(plane_flag,*src,*dest,nv,cc);
if (cc->uand) //clipped away
return *dest;
std::swap(src, dest);
}
return *src; //we swapped after we copied
}