new Conformal Square projection (with transition and shader and Euclidean form)

This commit is contained in:
Zeno Rogue 2023-03-19 12:21:05 +01:00
parent 02f0b1e714
commit 1b7f4b869e
4 changed files with 206 additions and 10 deletions

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@ -1014,9 +1014,9 @@ enum eModel : int {
mdWerner, mdAitoff, mdHammer, mdLoximuthal, mdMiller, mdGallStereographic, mdWinkelTripel,
// 39..48
mdPoorMan, mdPanini, mdRetroCraig, mdRetroLittrow, mdRetroHammer, mdThreePoint, mdLiePerspective, mdLieOrthogonal, mdRelPerspective, mdRelOrthogonal,
// 49
mdHorocyclicEqa,
// 50..
// 49..50
mdHorocyclicEqa, mdConformalSquare,
// 51..
mdGUARD, mdPixel, mdHyperboloidFlat, mdPolynomial, mdManual
};
#endif
@ -1078,6 +1078,7 @@ EX vector<modelinfo> mdinf = {
{X3("relativistic perspective"), mf::euc_boring | mf::perspective},
{X3("relativistic orthogonal"), mf::euc_boring},
{X3("horocyclic equal-area"), mf::euc_boring | mf::equiarea | mf::orientation | mf::horocyclic},
{X3("conformal square"), mf::orientation | mf::broken | mf::transition},
{X3("guard"), mf::technical},
{X3("pixel"), mf::technical},
{X3("hypflat"), mf::technical},

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@ -1622,10 +1622,14 @@ EX namespace ods {
bool broken_projection(dqi_poly& p0) {
int broken_coord = models::get_broken_coord(pmodel);
static bool in_broken = false;
bool both_broken = pmodel == mdConformalSquare;
if(broken_coord && !in_broken) {
int zcoord = broken_coord;
int ycoord = 3 - zcoord;
int xcoord = 0;
zcoord = 2;
vector<hyperpoint> all;
for(int i=0; i<p0.cnt; i++)
@ -1634,9 +1638,17 @@ bool broken_projection(dqi_poly& p0) {
int last_fail;
for(auto& h: all) models::apply_orientation(h[0], h[1]);
auto break_in_xz = [&] (hyperpoint a, hyperpoint b, int xcoord, int zcoord) {
return a[xcoord] * b[xcoord] <= 0 && (a[xcoord] * b[zcoord] - b[xcoord] * a[zcoord]) * (a[xcoord] - b[xcoord]) < 0;
};
auto break_in = [&] (hyperpoint a, hyperpoint b) {
return a[0] * b[0] <= 0 && (a[0] * b[zcoord] - b[0] * a[zcoord]) * (a[0] - b[0]) < 0;
if(both_broken) {
for(int xc=0; xc<2; xc++) {if(break_in_xz(a, b, xc, zcoord)) { xcoord = xc; ycoord = 1-xc; return true; } }
return false;
}
return break_in_xz(a, b, xcoord, zcoord);
};
for(int i=0; i<p0.cnt-1; i++)
@ -1655,7 +1667,12 @@ bool broken_projection(dqi_poly& p0) {
if(fail) {
if(p0.tinf) return true;
dynamicval<bool> ib(in_broken, true);
ld part = ilerp(all[last_fail][0], all[last_fail+1][0], 0);
ld part = ilerp(all[last_fail][xcoord], all[last_fail+1][xcoord], 0);
if(both_broken && all[last_fail][ycoord] * all[last_fail+1][ycoord] < 0) {
ld part2 = ilerp(all[last_fail][ycoord], all[last_fail+1][ycoord], 0);
if(part2 > part) part = part2, swap(xcoord, ycoord);
}
hyperpoint initial = normalize(lerp(all[last_fail], all[last_fail+1], 1 - (1-part) * .99));
bool have_initial = true;
v.push_back(glhr::pointtogl(initial));
@ -1663,19 +1680,46 @@ bool broken_projection(dqi_poly& p0) {
int at = last_fail;
do {
v.push_back(glhr::pointtogl(all[at]));
if(at == p0.cnt-1 && all[at] != all[0]) {
if(at == p0.cnt-1 && sqhypot_d(2, all[at] - all[0]) > 1e-6) {
p.cnt = isize(v); p.draw(); v.clear(); at = 0;
have_initial = false;
}
int next = at+1;
if(next == p0.cnt) next = 0;
if(break_in(all[at], all[next])) {
ld part = ilerp(all[at][0], all[next][0], 0);
ld part = ilerp(all[at][xcoord], all[next][xcoord], 0);
if(both_broken && all[at][ycoord] * all[next][ycoord] < 0) {
ld part2 = ilerp(all[at][ycoord], all[next][ycoord], 0);
if(part2 < part) part = part2, swap(xcoord, ycoord);
}
hyperpoint final = normalize(lerp(all[at], all[next], part * .99));
v.push_back(glhr::pointtogl(final));
if(have_initial) {
int max = 4 << vid.linequality;
if(final[0] * initial[0] > 0) {
if(both_broken) {
auto square_close_corner = [] (hyperpoint h) {
hyperpoint end = -C0;
if(abs(h[0]) > abs(h[1]))
end[0] = 0.01 * signum(h[0]), end[1] = 0.001 * signum(h[1]);
else
end[1] = 0.01 * signum(h[1]), end[0] = 0.001 * signum(h[0]);
return normalize(end);
};
hyperpoint endf = square_close_corner(final);
hyperpoint endi = square_close_corner(initial);
if(endf != endi) {
for(int i=1; i<=max; i++)
v.push_back(glhr::pointtogl(lerp(final, endf, i * 1. / max)));
for(int i=0; i<=max; i++)
v.push_back(glhr::pointtogl(lerp(endi, initial, i * 1. / max)));
}
else {
for(int i=1; i<=max; i++)
v.push_back(glhr::pointtogl(lerp(final, initial, i * 1. / max)));
}
}
else if(final[xcoord] * initial[xcoord] > 0) {
for(int i=1; i<=max; i++)
v.push_back(glhr::pointtogl(lerp(final, initial, i * 1. / max)));
}

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@ -528,6 +528,81 @@ EX void make_axial(hyperpoint H, hyperpoint& ret, const hr::function<ld(hyperpoi
models::apply_orientation_yz(ret[2], ret[1]);
}
// according to https://github.com/cspersonal/peirce-quincuncial-projection/blob/master/peirceQuincuncialProjection.R
ld ellRF(ld x, ld y, ld z) {
ld delx = 1, dely = 1, delz = 1;
const ld eps = 0.0025;
ld mean;
while(abs(delx) > eps || abs(dely) > eps || abs(delz) > eps) {
ld sx = sqrt(x);
ld sy = sqrt(y);
ld sz = sqrt(z);
ld len = sx * (sy+sz) + sy * sz;
x = .25 * (x+len);
y = .25 * (y+len);
z = .25 * (z+len);
mean = (x+y+z)/3;
delx = (mean-x) / mean;
dely = (mean-y) / mean;
delz = (mean-z) / mean;
}
ld e2 = delx * dely - delz * delz;
ld e3 = delx * dely * delz;
return ((1.0 + (e2 / 24.0 - 0.1 - 3.0 * e3 / 44.0) * e2+ e3 / 14) / sqrt(mean));
}
ld ellFaux(ld cos_phi, ld sin_phi, ld k) {
ld x = cos_phi * cos_phi;
ld y = 1 - k * k * sin_phi * sin_phi;
return sin_phi * ellRF(x, y, 1);
}
ld sqrt_clamp(ld x) { if(x<0) return 0; return sqrt(x); }
hyperpoint to_square(hyperpoint H) {
ld d = hypot_d(2, H);
ld x = d / (H[2] + 1);
x *= pconf.model_transition;
ld cos_phiosqrt2 = sqrt(2) / (x + 1/x);
ld cos_lambda = -H[1] / d;
ld sin_lambda = H[0] / d;
ld cos_a = cos_phiosqrt2 * (sin_lambda + cos_lambda);
ld cos_b = cos_phiosqrt2 * (sin_lambda - cos_lambda);
ld sin_a = sqrt(1 - cos_a * cos_a);
ld sin_b = sqrt(1 - cos_b * cos_b);
ld cos_a_cos_b = cos_a * cos_b;
ld sin_a_sin_b = sin_a * sin_b;
ld sin2_m = 1.0 + cos_a_cos_b - sin_a_sin_b;
ld sin2_n = 1.0 - cos_a_cos_b - sin_a_sin_b;
ld sin_m = sqrt_clamp(sin2_m);
ld cos_m = sqrt_clamp(1 - sin2_m);
if(sin_lambda < 0) sin_m = -sin_m;
ld sin_n = sqrt_clamp(sin2_n);
ld cos_n = sqrt_clamp(1.0 - sin2_n);
if(cos_lambda > 0.0) sin_n = -sin_n;
hyperpoint res;
ld divby = 0.53935260118837935472;
res[0] = ellFaux(cos_m,sin_m,sqrt(2)/2.) * divby;
res[1] = ellFaux(cos_n,sin_n,sqrt(2)/2.) * divby;
res[2] = 0; res[3] = 1;
if(x > 1) {
if(abs(res[0]) > abs(res[1])) {
if(res[0] > 0) res[0] = 2 - res[0]; else res[0] = -2 - res[0];
}
else {
if(res[1] > 0) res[1] = 2 - res[1]; else res[1] = -2 - res[1];
}
}
res /= pconf.model_transition;
return res;
}
EX void apply_other_model(shiftpoint H_orig, hyperpoint& ret, eModel md) {
hyperpoint H = H_orig.h;
@ -810,6 +885,16 @@ EX void apply_other_model(shiftpoint H_orig, hyperpoint& ret, eModel md) {
break;
}
case mdConformalSquare: {
find_zlev(H);
models::apply_orientation_yz(H[1], H[2]);
models::apply_orientation(H[0], H[1]);
ret = to_square(H);
models::apply_orientation(ret[1], ret[0]);
models::apply_orientation_yz(ret[2], ret[1]);
break;
}
case mdLieOrthogonal: {
ret = lie_log_correct(H_orig, H);

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@ -276,10 +276,15 @@ shared_ptr<glhr::GLprogram> write_shader(flagtype shader_flags) {
}
else if(pmodel == mdDisk && GDIM == 3 && !spherespecial && !nonisotropic && !gproduct) {
coordinator += "t /= (t[3] + uAlpha);\n";
vsh += "uniform mediump float uAlpha;";
vsh += "uniform mediump float uAlpha;\n";
shader_flags |= SF_DIRECT | SF_BOX | SF_ZFOG;
treset = true;
}
else if(pmodel == mdConformalSquare && pconf.model_transition == 1) {
shader_flags |= SF_ORIENT | SF_DIRECT;
coordinator += "t = uPP * t;", vsh += "uniform mediump mat4 uPP;";
coordinator += "t = to_square(t);";
}
else if(pmodel == mdBand && hyperbolic) {
shader_flags |= SF_BAND | SF_ORIENT | SF_BOX | SF_DIRECT;
coordinator += "t = uPP * t;", vsh += "uniform mediump mat4 uPP;";
@ -848,6 +853,67 @@ EX void add_if(string& shader, const string& seek, const string& function) {
EX void add_fixed_functions(string& shader) {
/* from the most complex to the simplest */
add_if(shader, "to_square",
"mediump vec4 to_square(mediump vec4 h) {\n"
"float d = length(h.xy);\n"
"float x = d / (h.z + 1.);\n"
"float cos_phiosqrt2 = sqrt(2.) / (x + 1./x);\n"
"float cos_lambda = -h.y / d;\n"
"float sin_lambda = h.x / d;\n"
"float cos_a = cos_phiosqrt2 * (sin_lambda + cos_lambda);\n"
"float cos_b = cos_phiosqrt2 * (sin_lambda - cos_lambda);\n"
"float sin_a = sqrt(1. - cos_a * cos_a);\n"
"float sin_b = sqrt(1. - cos_b * cos_b);\n"
"float cos_a_cos_b = cos_a * cos_b;\n"
"float sin_a_sin_b = sin_a * sin_b;\n"
"float sin2_m = 1.0 + cos_a_cos_b - sin_a_sin_b;\n"
"float sin2_n = 1.0 - cos_a_cos_b - sin_a_sin_b;\n"
"float sin_m = sqrt_clamp(sin2_m);\n"
"float cos_m = sqrt_clamp(1. - sin2_m);\n"
"if(sin_lambda < 0.) sin_m = -sin_m;\n"
"float sin_n = sqrt_clamp(sin2_n);\n"
"float cos_n = sqrt_clamp(1.0 - sin2_n);\n"
"if(cos_lambda > 0.0) sin_n = -sin_n;\n"
"#define divby 0.53935260118837935472\n"
"vec4 res = vec4(ellFaux(cos_m,sin_m,sqrt(2.)/2.) * divby, ellFaux(cos_n,sin_n,sqrt(2.)/2.) * divby, 0, 1);\n"
"if(x > 1.) {\n"
" if(abs(res[0]) > abs(res[1])) {\n"
" if(res[0] > 0.) res[0] = 2. - res[0]; else res[0] = -2. - res[0];\n"
" }\n"
" else {\n"
" if(res[1] > 0.) res[1] = 2. - res[1]; else res[1] = -2. - res[1];\n"
" }\n"
" }\n"
"return res;\n"
"}\n");
add_if(shader, "sqrt_clamp", "mediump float sqrt_clamp(mediump float x) { return x >= 0. ? sqrt(x) : 0.; }\n");
add_if(shader, "ellFaux", "mediump float ellFaux(mediump float cos_phi, mediump float sin_phi, mediump float k) {\n"
"return sin_phi * ellRF(cos_phi * cos_phi, 1. - k * k * sin_phi * sin_phi, 1.);\n"
"}\n");
add_if(shader, "ellRF", "mediump float ellRF(mediump float x, mediump float y, mediump float z) {\n"
"float delx = 1., dely = 1., delz = 1.;\n"
"const float eps = 0.0025;\n"
"float mean;\n"
"while(abs(delx) > eps || abs(dely) > eps || abs(delz) > eps) {\n"
" float sx = sqrt(x);\n"
" float sy = sqrt(y);\n"
" float sz = sqrt(z);\n"
" float len = sx * (sy+sz) + sy * sz;\n"
" float x = .25 * (x+len);\n"
" float y = .25 * (y+len);\n"
" float z = .25 * (z+len);\n"
" mean = (x+y+z)/3.;\n"
" delx = (mean-x) / mean;\n"
" dely = (mean-y) / mean;\n"
" delz = (mean-z) / mean;\n"
" }\n"
"float e2 = delx * dely - delz * delz;\n"
"float e3 = delx * dely * delz;\n"
"return ((1.0 + (e2 / 24.0 - 0.1 - 3.0 * e3 / 44.0) * e2+ e3 / 14.) / sqrt(mean));\n"
"}\n");
add_if(shader, "tanh", "mediump float tanh(mediump float x) { return sinh(x) / cosh(x); }\n");
add_if(shader, "sinh", "mediump float sinh(mediump float x) { return (exp(x) - exp(-x)) / 2.0; }\n");
add_if(shader, "asin_clamp", "mediump float asin_clamp(mediump float x) { return x > 1. ? PI/2. : x < -1. ? -PI/2. : asin(x); }\n");