// Hyperbolic Rogue // Copyright (C) 2011-2012 Zeno Rogue, see 'hyper.cpp' for details enum eGeometry {gNormal, gEuclid, gSphere, gElliptic, gQuotient, gQuotient2, gTorus, gGUARD}; eGeometry geometry, targetgeometry = gEuclid; #define euclid (geometry == gEuclid || geometry == gTorus) #define sphere (geometry == gSphere || geometry == gElliptic) #define elliptic (geometry == gElliptic) #define quotient (geometry == gQuotient ? 1 : geometry == gQuotient2 ? 2 : 0) #define torus (geometry == gTorus) #define doall (quotient || torus) #define smallbounded (sphere || quotient == 1 || torus) // for the pure heptagonal grid bool purehepta = false; // hyperbolic points and matrices // basic functions and types //=========================== #ifdef SINHCOSH // ld sinh(ld alpha) { return (exp(alpha) - exp(-alpha)) / 2; } // ld cosh(ld alpha) { return (exp(alpha) + exp(-alpha)) / 2; } /* ld inverse_sinh(ld z) { return log(z+sqrt(1+z*z)); } double inverse_cos(double c) { double s = sqrt(1-c*c); double r = atan(s/c); if(r < 0) r = -r; return r; } // ld tanh(ld x) { return sinh(x) / cosh(x); } ld inverse_tanh(ld x) { return log((1+x)/(1-x)) / 2; } */ #endif #ifndef M_PI #define M_PI 3.14159265358979 #endif ld squar(ld x) { return x*x; } int sig(int z) { return (sphere || z<2)?1:-1; } // hyperbolic point: //=================== // we represent the points on the hyperbolic plane // by points in 3D space (Minkowski space) such that x^2+y^2-z^2 == -1, z > 0 // (this is analogous to representing a sphere with points such that x^2+y^2+z^2 == 1) struct hyperpoint { ld tab[3]; ld& operator [] (int i) { return tab[i]; } const ld& operator [] (int i) const { return tab[i]; } }; hyperpoint hpxyz(ld x, ld y, ld z) { // EUCLIDEAN hyperpoint r; r[0] = x; r[1] = y; r[2] = z; return r; } hyperpoint hpxy(ld x, ld y) { // EUCLIDEAN return hpxyz(x,y, euclid ? 1 : sphere ? sqrt(1-x*x-y*y) : sqrt(1+x*x+y*y)); } // center of the pseudosphere const hyperpoint Hypc = { {0,0,0} }; // origin of the hyperbolic plane const hyperpoint C0 = { {0,0,1} }; // a point (I hope this number needs no comments ;) ) const hyperpoint Cx1 = { {1,0,1.41421356237} }; // this function returns approximate square of distance between two points // (in the spherical analogy, this would be the distance in the 3D space, // through the interior, not on the surface) // also used to verify whether a point h1 is on the hyperbolic plane by using Hypc for h2 ld intval(const hyperpoint &h1, const hyperpoint &h2) { if(elliptic) { double d1 = squar(h1[0]-h2[0]) + squar(h1[1]-h2[1]) + squar(h1[2]-h2[2]); double d2 = squar(h1[0]+h2[0]) + squar(h1[1]+h2[1]) + squar(h1[2]+h2[2]); return min(d1, d2); } return squar(h1[0]-h2[0]) + squar(h1[1]-h2[1]) + (sphere?1:euclid?0:-1) * squar(h1[2]-h2[2]); } ld intvalxy(const hyperpoint &h1, const hyperpoint &h2) { return squar(h1[0]-h2[0]) + squar(h1[1]-h2[1]); } ld zlevel(const hyperpoint &h) { if(euclid) return h[2]; else if(sphere) return sqrt(intval(h, Hypc)); else return sqrt(-intval(h, Hypc)); } // display a hyperbolic point char *display(const hyperpoint& H) { static char buf[100]; sprintf(buf, "%8.4f:%8.4f:%8.4f", double(H[0]), double(H[1]), double(H[2])); return buf; } // get the center of the line segment from H1 to H2 hyperpoint mid(const hyperpoint& H1, const hyperpoint& H2) { hyperpoint H3; H3[0] = H1[0] + H2[0]; H3[1] = H1[1] + H2[1]; H3[2] = H1[2] + H2[2]; ld Z = 2; if(sphere) Z = sqrt(intval(H3, Hypc)); else if(!euclid) { Z = intval(H3, Hypc); Z = sqrt(-Z); } for(int c=0; c<3; c++) H3[c] /= Z; return H3; } // like mid, but take 3D into account hyperpoint midz(const hyperpoint& H1, const hyperpoint& H2) { hyperpoint H3; H3[0] = H1[0] + H2[0]; H3[1] = H1[1] + H2[1]; H3[2] = H1[2] + H2[2]; ld Z = 2; if(sphere || !euclid) Z = zlevel(H3) * 2 / (zlevel(H1) + zlevel(H2)); for(int c=0; c<3; c++) H3[c] /= Z; return H3; } // matrices //========== // matrices represent isometries of the hyperbolic plane // (just like isometries of the sphere are represented by rotation matrices) struct transmatrix { ld tab[3][3]; ld * operator [] (int i) { return tab[i]; } const ld * operator [] (int i) const { return tab[i]; } }; // identity matrix const transmatrix Id = {{{1,0,0}, {0,1,0}, {0,0,1}}}; // mirror image const transmatrix Mirror = {{{1,0,0}, {0,-1,0}, {0,0,1}}}; // mirror image const transmatrix MirrorX = {{{-1,0,0}, {0,1,0}, {0,0,1}}}; // rotate by PI const transmatrix pispin = {{{-1,0,0}, {0,-1,0}, {0,0,1}}}; hyperpoint operator * (const transmatrix& T, const hyperpoint& H) { hyperpoint z; for(int i=0; i<3; i++) { z[i] = 0; for(int j=0; j<3; j++) z[i] += T[i][j] * H[j]; } return z; } // T * C0, optimized inline hyperpoint tC0(const transmatrix &T) { hyperpoint z; z[0] = T[0][2]; z[1] = T[1][2]; z[2] = T[2][2]; return z; } inline transmatrix operator * (const transmatrix& T, const transmatrix& U) { transmatrix R; // for(int i=0; i<3; i++) for(int j=0; j<3; j++) R[i][j] = 0; for(int i=0; i<3; i++) for(int j=0; j<3; j++) // for(int k=0; k<3; k++) R[i][j] = T[i][0] * U[0][j] + T[i][1] * U[1][j] + T[i][2] * U[2][j]; return R; } // rotate by alpha degrees transmatrix spin(ld alpha) { transmatrix T = Id; T[0][0] = +cos(alpha); T[0][1] = +sin(alpha); T[1][0] = -sin(alpha); T[1][1] = +cos(alpha); T[2][2] = 1; return T; } transmatrix eupush(ld x, ld y) { transmatrix T = Id; T[0][2] = x; T[1][2] = y; return T; } // push alpha units to the right transmatrix xpush(ld alpha) { if(euclid) return eupush(alpha, 0); transmatrix T = Id; if(sphere) { T[0][0] = +cos(alpha); T[0][2] = +sin(alpha); T[2][0] = -sin(alpha); T[2][2] = +cos(alpha); } else { T[0][0] = +cosh(alpha); T[0][2] = +sinh(alpha); T[2][0] = +sinh(alpha); T[2][2] = +cosh(alpha); } return T; } inline hyperpoint xpush0(ld x) { hyperpoint h; if(euclid) return hpxy(x, 0); else if(sphere) h[0] = sin(x), h[1] = 0, h[2] = cos(x); else h[0] = sinh(x), h[1] = 0, h[2] = cosh(x); return h; } inline hyperpoint xspinpush0(ld alpha, ld x) { // return spin(alpha)*xpush0(x); ld s; hyperpoint h; if(euclid) return hpxy(x*cos(alpha), -x*sin(alpha)); else if(sphere) s=sin(x), h[0] = s*cos(alpha), h[1] = -s*sin(alpha), h[2] = cos(x); else s=sinh(x), h[0] = s*cos(alpha), h[1] = -s*sin(alpha), h[2] = cosh(x); return h; } // push alpha units vertically transmatrix ypush(ld alpha) { if(euclid) return eupush(0, alpha); transmatrix T = Id; if(sphere) { T[1][1] = +cos(alpha); T[1][2] = +sin(alpha); T[2][1] = -sin(alpha); T[2][2] = +cos(alpha); } else { T[1][1] = +cosh(alpha); T[1][2] = +sinh(alpha); T[2][1] = +sinh(alpha); T[2][2] = +cosh(alpha); } return T; } // rotate the hyperplane around C0 such that H[1] == 0 and H[0] >= 0 transmatrix spintox(const hyperpoint& H) { transmatrix T = Id; ld R = sqrt(H[0] * H[0] + H[1] * H[1]); if(R >= 1e-12) { T[0][0] = +H[0]/R; T[0][1] = +H[1]/R; T[1][0] = -H[1]/R; T[1][1] = +H[0]/R; } return T; } // reverse of spintox(H) transmatrix rspintox(const hyperpoint& H) { transmatrix T = Id; ld R = sqrt(H[0] * H[0] + H[1] * H[1]); if(R >= 1e-12) { T[0][0] = +H[0]/R; T[0][1] = -H[1]/R; T[1][0] = +H[1]/R; T[1][1] = +H[0]/R; } return T; } // for H such that H[1] == 0, this matrix pushes H to C0 transmatrix pushxto0(const hyperpoint& H) { if(euclid) return eupush(-H[0], -H[1]); transmatrix T = Id; if(sphere) { T[0][0] = +H[2]; T[0][2] = -H[0]; T[2][0] = +H[0]; T[2][2] = +H[2]; } else { T[0][0] = +H[2]; T[0][2] = -H[0]; T[2][0] = -H[0]; T[2][2] = +H[2]; } return T; } // reverse of pushxto0(H) transmatrix rpushxto0(const hyperpoint& H) { if(euclid) return eupush(H[0], H[1]); transmatrix T = Id; if(sphere) { T[0][0] = +H[2]; T[0][2] = +H[0]; T[2][0] = -H[0]; T[2][2] = +H[2]; } else { T[0][0] = +H[2]; T[0][2] = +H[0]; T[2][0] = +H[0]; T[2][2] = +H[2]; } return T; } // generalization: H[1] can be non-zero transmatrix gpushxto0(const hyperpoint& H) { hyperpoint H2 = spintox(H) * H; return rspintox(H) * pushxto0(H2) * spintox(H); } transmatrix rgpushxto0(const hyperpoint& H) { hyperpoint H2 = spintox(H) * H; return rspintox(H) * rpushxto0(H2) * spintox(H); } // fix the matrix T so that it is indeed an isometry // (without using this, imprecision could accumulate) void display(const transmatrix& T); void fixmatrix(transmatrix& T) { if(euclid) { for(int x=0; x<2; x++) for(int y=0; y<=x; y++) { ld dp = 0; for(int z=0; z<2; z++) dp += T[z][x] * T[z][y]; if(y == x) dp = 1 - sqrt(1/dp); for(int z=0; z<2; z++) T[z][x] -= dp * T[z][y]; } for(int x=0; x<2; x++) T[2][x] = 0; T[2][2] = 1; } else for(int x=0; x<3; x++) for(int y=0; y<=x; y++) { ld dp = 0; for(int z=0; z<3; z++) dp += T[z][x] * T[z][y] * sig(z); if(y == x) dp = 1 - sqrt(sig(x)/dp); for(int z=0; z<3; z++) T[z][x] -= dp * T[z][y]; } } // show the matrix on screen void display(const transmatrix& T) { for(int y=0; y<3; y++) { for(int x=0; x<3; x++) printf("%10.7f", double(T[y][x])); printf(" -> %10.7f\n", double(squar(T[y][0]) + squar(T[y][1]) + sig(2) * squar(T[y][2]))); // printf("\n"); } for(int x=0; x<3; x++) printf("%10.7f", double(squar(T[0][x]) + squar(T[1][x]) + sig(2) * squar(T[2][x]))); printf("\n"); for(int x=0; x<3; x++) { int y = (x+1) % 3; printf("%10.7f", double(T[0][x]*T[0][y] + T[1][x]*T[1][y] + sig(2) * T[2][x]*T[2][y])); } printf("\n\n"); } ld det(const transmatrix& T) { ld det = 0; for(int i=0; i<3; i++) det += T[0][i] * T[1][(i+1)%3] * T[2][(i+2)%3]; for(int i=0; i<3; i++) det -= T[0][i] * T[1][(i+2)%3] * T[2][(i+1)%3]; return det; } transmatrix inverse(const transmatrix& T) { profile_start(7); ld d = det(T); transmatrix T2; if(d == 0) return T2; for(int i=0; i<3; i++) for(int j=0; j<3; j++) T2[j][i] = (T[(i+1)%3][(j+1)%3] * T[(i+2)%3][(j+2)%3] - T[(i+1)%3][(j+2)%3] * T[(i+2)%3][(j+1)%3]) / d; profile_stop(7); return T2; } // distance between mh and 0 double hdist0(const hyperpoint& mh) { if(sphere) { ld res = mh[2] >= 1 ? 0 : mh[2] <= -1 ? M_PI : acos(mh[2]); if(elliptic && res > M_PI/2) res = 2*M_PI-res; return res; } if(!euclid && mh[2] > 1.5) return acosh(mh[2]); ld d = sqrt(mh[0]*mh[0]+mh[1]*mh[1]); if(euclid) return d; return asinh(d); } // distance between two points double hdist(const hyperpoint& h1, const hyperpoint& h2) { return hdist0(gpushxto0(h1) * h2); } namespace hyperpoint_vec { hyperpoint operator * (double d, hyperpoint h) { return hpxyz(h[0]*d, h[1]*d, h[2]*d); } hyperpoint operator * (hyperpoint h, double d) { return hpxyz(h[0]*d, h[1]*d, h[2]*d); } hyperpoint operator / (hyperpoint h, double d) { return hpxyz(h[0]/d, h[1]/d, h[2]/d); } hyperpoint operator + (hyperpoint h, hyperpoint h2) { return hpxyz(h[0]+h2[0], h[1]+h2[1], h[2]+h2[2]); } hyperpoint operator - (hyperpoint h, hyperpoint h2) { return hpxyz(h[0]-h2[0], h[1]-h2[1], h[2]-h2[2]); } } hyperpoint mscale(const hyperpoint& t, double fac) { hyperpoint res; for(int i=0; i<3; i++) res[i] = t[i] * fac; return res; } transmatrix mscale(const transmatrix& t, double fac) { transmatrix res; for(int i=0; i<3; i++) for(int j=0; j<3; j++) res[i][j] = t[i][j] * fac; return res; } transmatrix xyscale(const transmatrix& t, double fac) { transmatrix res; for(int i=0; i<3; i++) for(int j=0; j<2; j++) res[i][j] = t[i][j] * fac; return res; } transmatrix xyzscale(const transmatrix& t, double fac, double facz) { transmatrix res; for(int i=0; i<3; i++) for(int j=0; j<2; j++) res[i][j] = t[i][j] * fac; for(int i=0; i<3; i++) res[i][2] = t[i][2] * facz; return res; } // double downspin_zivory; transmatrix mzscale(const transmatrix& t, double fac) { // take only the spin transmatrix tcentered = gpushxto0(tC0(t)) * t; // tcentered = tcentered * spin(downspin_zivory); fac -= 1; transmatrix res = t * inverse(tcentered) * ypush(-fac) * tcentered; fac *= .2; fac += 1; for(int i=0; i<3; i++) for(int j=0; j<3; j++) res[i][j] = res[i][j] * fac; return res; } transmatrix pushone() { return euclid ? eupush(1, 0) : xpush(sphere?.5 : 1); }