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improvements in the two-point model on the sphere

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Zeno Rogue
2018-04-21 12:18:33 +02:00
parent abbf536466
commit 323893094f
4 changed files with 104 additions and 39 deletions
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96
polygons.cpp
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@@ -469,6 +469,10 @@ unsigned char& part(int& col, int i) {
bool in_twopoint = false;
ld glhypot2(glvertex a, glvertex b) {
return (a[0]-b[0]) * (a[0]-b[0]) + (a[1]-b[1]) * (a[1]-b[1]) + (a[2]-b[2]) * (a[2]-b[2]);
}
void drawpolyline(polytodraw& p) {
auto& pp = p.u.poly;
@@ -485,43 +489,79 @@ void drawpolyline(polytodraw& p) {
}
if(sphere && pmodel == mdTwoPoint && !in_twopoint) {
static vector<glvertex> v0, v1;
v0.clear(); v1.clear();
for(int i=0; i<pp.cnt; i++) {
glvertex h = glhr::pointtogl(pp.V * glhr::gltopoint((*pp.tab)[pp.offset+i]));
if(h[2] >= 0)
v0.push_back(h), v1.push_back(h);
else if(h[1] < 0)
v0.push_back(h);
else if(h[1] > 0)
v1.push_back(h);
#define MAX_PHASE 4
vector<glvertex> phases[MAX_PHASE];
extern int twopoint_sphere_flips;
extern bool twopoint_do_flips;
int pha;
if(twopoint_do_flips) {
for(int i=0; i<pp.cnt; i++) {
hyperpoint h1 = pp.V * glhr::gltopoint((*pp.tab)[pp.offset+i]);
for(int j=0; j<MAX_PHASE; j++) {
twopoint_sphere_flips = j;
hyperpoint h2; applymodel(h1, h2);
using namespace hyperpoint_vec;
glvertex h = glhr::pointtogl(h2 * vid.radius);
if(i == 0)
phases[j].push_back(h);
else {
int best = -1;
ld bhypot = 1e60;
for(int j0=0; j0<MAX_PHASE; j0++)
if(size(phases[j0]) == i) {
ld chypot = glhypot2(phases[j0].back(), h);
if(chypot < bhypot || best == -1) bhypot = chypot, best = j0;
}
phases[best].push_back(h);
}
}
}
twopoint_sphere_flips = 0;
pha = MAX_PHASE-1;
}
else {
pha = 1;
if(true) {
// a
// b
// lin(a,b) is of form (x, 0, z)
int cpha = 0;
for(int i=0; i<pp.cnt; i++) {
using namespace hyperpoint_vec;
hyperpoint h1 = pp.V * glhr::gltopoint((*pp.tab)[pp.offset+i]);
hyperpoint mh1; applymodel(h1, mh1);
phases[cpha].push_back(glhr::pointtogl(mh1 * vid.radius));
// check if the i-th edge intersects the boundary of the ellipse
// (which corresponds to the segment between the antipodes of foci)
// if yes, switch cpha to the opposite
hyperpoint h2 = pp.V * glhr::gltopoint((*pp.tab)[pp.offset+(i+1)%pp.cnt]);
if(h1[1] * h2[1] > 0) continue;
ld c1 = h1[1], c2 = -h2[1];
if(c1 < 0) c1 = -c1, c2 = -c2;
hyperpoint h = h1 * c1 + h2 * c2;
h /= hypot3(h);
if(h[2] < 0 && abs(h[0]) < sin(vid.twopoint_param)) cpha = 1-cpha, pha = 2;
}
if(cpha == 1) pha = 0;
}
}
auto tV = pp.V;
auto toffset = pp.offset;
auto ttab = pp.tab;
auto tcnt = pp.cnt;
vector<glvertex> tv;
if(pp.tinf) {
for(int i=0; i<pp.cnt; i++)
tv.push_back(pp.tinf->tvertices[pp.offset+i]);
swap(pp.tinf->tvertices, tv);
}
pp.V = Id; pp.offset = 0;
in_twopoint = true;
if(size(v0) == pp.cnt) {
pp.tab = &v0;
drawpolyline(p);
}
else if(size(v1) == pp.cnt) {
pp.tab = &v1;
dynamicval<eModel> d1(pmodel, mdUnchanged);
dynamicval<transmatrix> d2(pp.V, Id);
dynamicval<int> d3(pp.offset, 0);
dynamicval<decltype(pp.tab)> d4(pp.tab, pp.tab);
for(int j=0; j<pha; j++) {
dynamicval<int> d5(pp.cnt, size(phases[j]));
pp.tab = &phases[j];
drawpolyline(p);
}
else {
if(size(v0) >= 3) { pp.tab = &v0; pp.cnt = size(v0); drawpolyline(p); }
if(size(v1) >= 3) { pp.tab = &v1; pp.cnt = size(v1); drawpolyline(p); }
}
in_twopoint = false;
pp.V = tV; pp.offset = toffset; pp.tab = ttab; pp.cnt = tcnt;
if(pp.tinf) swap(pp.tinf->tvertices, tv);
return;
}