src/world/world.cpp

   1 #include "Body.hpp"
   2 #include "Orbit.hpp"
   3 #include "Planet.hpp"
   4 #include "Simulation.hpp"
   5 #include "Sun.hpp"
   6 #include "Tile.hpp"
   7 #include "TileSet.hpp"
   8 #include "TileType.hpp"
   9
  10 #include "Creature.hpp"
  11 #include "../const.hpp"
  12 #include "../app/Assets.hpp"
  13 #include "../graphics/Viewport.hpp"
  14 #include "../rand/OctaveNoise.hpp"
  15 #include "../rand/SimplexNoise.hpp"
  16
  17 #include <algorithm>
  18 #include <cmath>
  19 #include <iostream>
  20 #include <glm/gtc/matrix_transform.hpp>
  21 #include <glm/gtx/euler_angles.hpp>
  22 #include <glm/gtx/io.hpp>
  23 #include <glm/gtx/transform.hpp>
  24
  25 using blobs::G;
  26 using blobs::PI_2p0;
  27
  28 using std::sin;
  29 using std::cos;
  30 using std::pow;
  31 using std::sqrt;
  32
  33
  34 namespace blobs {
  35 namespace world {
  36
  37 Body::Body()
  38 : sim(nullptr)
  39 , parent(nullptr)
  40 , children()
  41 , mass(1.0)
  42 , radius(1.0)
  43 , orbit()
  44 , surface_tilt(0.0, 0.0)
  45 , axis_tilt(0.0, 0.0)
  46 , rotation(0.0)
  47 , angular(0.0)
  48 , orbital(1.0)
  49 , inverse_orbital(1.0)
  50 , local(1.0)
  51 , inverse_local(1.0)
  52 , creatures() {
  53 }
  54
  55 Body::~Body() {
  56         for (Creature *c : creatures) {
  57                 delete c;
  58         }
  59 }
  60
  61 void Body::SetSimulation(Simulation &s) noexcept {
  62         sim = &s;
  63         for (auto child : children) {
  64                 child->SetSimulation(s);
  65         }
  66 }
  67
  68 void Body::SetParent(Body &p) {
  69         if (HasParent()) {
  70                 UnsetParent();
  71         }
  72         parent = &p;
  73         parent->AddChild(*this);
  74 }
  75
  76 void Body::UnsetParent() {
  77         if (!HasParent()) return;
  78         parent->RemoveChild(*this);
  79         parent = nullptr;
  80 }
  81
  82 void Body::AddChild(Body &c) {
  83         children.push_back(&c);
  84         c.SetSimulation(*sim);
  85 }
  86
  87 void Body::RemoveChild(Body &c) {
  88         auto entry = std::find(children.begin(), children.end(), &c);
  89         if (entry != children.end()) {
  90                 children.erase(entry);
  91         }
  92 }
  93
  94 double Body::Inertia() const noexcept {
  95         // assume solid sphere for now
  96         return (2.0/5.0) * Mass() * pow(Radius(), 2);
  97 }
  98
  99 double Body::GravitationalParameter() const noexcept {
 100         return G * Mass();
 101 }
 102
 103 double Body::OrbitalPeriod() const noexcept {
 104         if (parent) {
 105                 return PI_2p0 * sqrt(pow(orbit.SemiMajorAxis(), 3) / (G * (parent->Mass() + Mass())));
 106         } else {
 107                 return 0.0;
 108         }
 109 }
 110
 111 double Body::RotationalPeriod() const noexcept {
 112         if (std::abs(angular) < std::numeric_limits<double>::epsilon()) {
 113                 return std::numeric_limits<double>::infinity();
 114         } else {
 115                 return PI_2p0 * Inertia() / angular;
 116         }
 117 }
 118
 119 glm::dmat4 Body::ToUniverse() const noexcept {
 120         glm::dmat4 m(1.0);
 121         const Body *b = this;
 122         while (b->HasParent()) {
 123                 m = b->ToParent() * m;
 124                 b = &b->Parent();
 125         }
 126         return m;
 127 }
 128
 129 glm::dmat4 Body::FromUniverse() const noexcept {
 130         glm::dmat4 m(1.0);
 131         const Body *b = this;
 132         while (b->HasParent()) {
 133                 m *= b->FromParent();
 134                 b = &b->Parent();
 135         }
 136         return m;
 137 }
 138
 139 void Body::Cache() noexcept {
 140         if (parent) {
 141                 orbital =
 142                         orbit.Matrix(PI_2p0 * (GetSimulation().Time() / OrbitalPeriod()))
 143                         * glm::eulerAngleXY(axis_tilt.x, axis_tilt.y);
 144                 inverse_orbital =
 145                         glm::eulerAngleYX(-axis_tilt.y, -axis_tilt.x)
 146                         * orbit.InverseMatrix(PI_2p0 * (GetSimulation().Time() / OrbitalPeriod()));
 147         } else {
 148                 orbital = glm::eulerAngleXY(axis_tilt.x, axis_tilt.y);
 149                 inverse_orbital = glm::eulerAngleYX(-axis_tilt.y, -axis_tilt.x);
 150         }
 151         local =
 152                 glm::eulerAngleY(rotation)
 153                 * glm::eulerAngleXY(surface_tilt.x, surface_tilt.y);
 154         inverse_local =
 155                 glm::eulerAngleYX(-surface_tilt.y, -surface_tilt.x)
 156                 * glm::eulerAngleY(-rotation);
 157 }
 158
 159 void Body::AddCreature(Creature *c) {
 160         c->SetBody(*this);
 161         creatures.push_back(c);
 162 }
 163
 164
 165 Orbit::Orbit()
 166 : sma(1.0)
 167 , ecc(0.0)
 168 , inc(0.0)
 169 , asc(0.0)
 170 , arg(0.0)
 171 , mna(0.0) {
 172 }
 173
 174 Orbit::~Orbit() {
 175 }
 176
 177 double Orbit::SemiMajorAxis() const noexcept {
 178         return sma;
 179 }
 180
 181 Orbit &Orbit::SemiMajorAxis(double s) noexcept {
 182         sma = s;
 183         return *this;
 184 }
 185
 186 double Orbit::Eccentricity() const noexcept {
 187         return ecc;
 188 }
 189
 190 Orbit &Orbit::Eccentricity(double e) noexcept {
 191         ecc = e;
 192         return *this;
 193 }
 194
 195 double Orbit::Inclination() const noexcept {
 196         return inc;
 197 }
 198
 199 Orbit &Orbit::Inclination(double i) noexcept {
 200         inc = i;
 201         return *this;
 202 }
 203
 204 double Orbit::LongitudeAscending() const noexcept {
 205         return asc;
 206 }
 207
 208 Orbit &Orbit::LongitudeAscending(double l) noexcept {
 209         asc = l;
 210         return *this;
 211 }
 212
 213 double Orbit::ArgumentPeriapsis() const noexcept {
 214         return arg;
 215 }
 216
 217 Orbit &Orbit::ArgumentPeriapsis(double a) noexcept {
 218         arg = a;
 219         return *this;
 220 }
 221
 222 double Orbit::MeanAnomaly() const noexcept {
 223         return mna;
 224 }
 225
 226 Orbit &Orbit::MeanAnomaly(double m) noexcept {
 227         mna = m;
 228         return *this;
 229 }
 230
 231 namespace {
 232
 233 double mean2eccentric(double M, double e) {
 234         double E = M; // eccentric anomaly, solve M = E - e sin E
 235         // limit to 100 steps to prevent deadlocks in impossible situations
 236         for (int i = 0; i < 100; ++i) {
 237                 double dE = (E - e * sin(E) - M) / (1 - e * cos(E));
 238                 E -= dE;
 239                 if (abs(dE) < 1.0e-6) break;
 240         }
 241         return E;
 242 }
 243
 244 }
 245
 246 glm::dmat4 Orbit::Matrix(double t) const noexcept {
 247         double M = mna + t;
 248         double E = mean2eccentric(M, ecc);
 249
 250         // coordinates in orbital plane, P=x, Q=-z
 251         double P = sma * (cos(E) - ecc);
 252         double Q = sma * sin(E) * sqrt(1 - (ecc * ecc));
 253
 254         return glm::yawPitchRoll(asc, inc, arg) * glm::translate(glm::dvec3(P, 0.0, -Q));
 255 }
 256
 257 glm::dmat4 Orbit::InverseMatrix(double t) const noexcept {
 258         double M = mna + t;
 259         double E = mean2eccentric(M, ecc);
 260         double P = sma * (cos(E) - ecc);
 261         double Q = sma * sin(E) * sqrt(1 - (ecc * ecc));
 262         return glm::translate(glm::dvec3(-P, 0.0, Q)) * glm::transpose(glm::yawPitchRoll(asc, inc, arg));
 263 }
 264
 265
 266 Planet::Planet(int sidelength)
 267 : Body()
 268 , sidelength(sidelength)
 269 , tiles(TilesTotal())
 270 , vao() {
 271         Radius(double(sidelength) / 2.0);
 272 }
 273
 274 Planet::~Planet() {
 275 }
 276
 277 glm::dvec3 Planet::TileCenter(int surface, int x, int y) const noexcept {
 278         glm::dvec3 center(0.0f);
 279         center[(surface + 0) % 3] = x + 0.5 - Radius();
 280         center[(surface + 1) % 3] = y + 0.5 - Radius();
 281         center[(surface + 2) % 3] = surface < 3 ? Radius() : -Radius();
 282         return center;
 283 }
 284
 285 void Planet::BuildVAO(const TileSet &ts) {
 286         vao.Bind();
 287         vao.BindAttributes();
 288         vao.EnableAttribute(0);
 289         vao.EnableAttribute(1);
 290         vao.AttributePointer<glm::vec3>(0, false, offsetof(Attributes, position));
 291         vao.AttributePointer<glm::vec3>(1, false, offsetof(Attributes, tex_coord));
 292         vao.ReserveAttributes(TilesTotal() * 4, GL_STATIC_DRAW);
 293         {
 294                 auto attrib = vao.MapAttributes(GL_WRITE_ONLY);
 295                 float offset = Radius();
 296
 297                 // srf  0  1  2  3  4  5
 298                 //  up +Z +X +Y -Z -X -Y
 299
 300                 for (int index = 0, surface = 0; surface < 6; ++surface) {
 301                         for (int y = 0; y < sidelength; ++y) {
 302                                 for (int x = 0; x < sidelength; ++x, ++index) {
 303                                         float tex = ts[TileAt(surface, x, y).type].texture;
 304                                         const float tex_u_begin = surface < 3 ? 1.0f : 0.0f;
 305                                         const float tex_u_end = surface < 3 ? 0.0f : 1.0f;
 306                                         attrib[4 * index + 0].position[(surface + 0) % 3] = x + 0 - offset;
 307                                         attrib[4 * index + 0].position[(surface + 1) % 3] = y + 0 - offset;
 308                                         attrib[4 * index + 0].position[(surface + 2) % 3] = surface < 3 ? offset : -offset;
 309                                         attrib[4 * index + 0].tex_coord[0] = tex_u_begin;
 310                                         attrib[4 * index + 0].tex_coord[1] = 1.0f;
 311                                         attrib[4 * index + 0].tex_coord[2] = tex;
 312
 313                                         attrib[4 * index + 1].position[(surface + 0) % 3] = x + 0 - offset;
 314                                         attrib[4 * index + 1].position[(surface + 1) % 3] = y + 1 - offset;
 315                                         attrib[4 * index + 1].position[(surface + 2) % 3] = surface < 3 ? offset : -offset;
 316                                         attrib[4 * index + 1].tex_coord[0] = tex_u_end;
 317                                         attrib[4 * index + 1].tex_coord[1] = 1.0f;
 318                                         attrib[4 * index + 1].tex_coord[2] = tex;
 319
 320                                         attrib[4 * index + 2].position[(surface + 0) % 3] = x + 1 - offset;
 321                                         attrib[4 * index + 2].position[(surface + 1) % 3] = y + 0 - offset;
 322                                         attrib[4 * index + 2].position[(surface + 2) % 3] = surface < 3 ? offset : -offset;
 323                                         attrib[4 * index + 2].tex_coord[0] = tex_u_begin;
 324                                         attrib[4 * index + 2].tex_coord[1] = 0.0f;
 325                                         attrib[4 * index + 2].tex_coord[2] = tex;
 326
 327                                         attrib[4 * index + 3].position[(surface + 0) % 3] = x + 1 - offset;
 328                                         attrib[4 * index + 3].position[(surface + 1) % 3] = y + 1 - offset;
 329                                         attrib[4 * index + 3].position[(surface + 2) % 3] = surface < 3 ? offset : -offset;
 330                                         attrib[4 * index + 3].tex_coord[0] = tex_u_end;
 331                                         attrib[4 * index + 3].tex_coord[1] = 0.0f;
 332                                         attrib[4 * index + 3].tex_coord[2] = tex;
 333                                 }
 334                         }
 335                 }
 336         }
 337         vao.BindElements();
 338         vao.ReserveElements(TilesTotal() * 6, GL_STATIC_DRAW);
 339         {
 340                 auto element = vao.MapElements(GL_WRITE_ONLY);
 341                 int index = 0;
 342                 for (int surface = 0; surface < 3; ++surface) {
 343                         for (int y = 0; y < sidelength; ++y) {
 344                                 for (int x = 0; x < sidelength; ++x, ++index) {
 345                                         element[6 * index + 0] = 4 * index + 0;
 346                                         element[6 * index + 1] = 4 * index + 2;
 347                                         element[6 * index + 2] = 4 * index + 1;
 348                                         element[6 * index + 3] = 4 * index + 1;
 349                                         element[6 * index + 4] = 4 * index + 2;
 350                                         element[6 * index + 5] = 4 * index + 3;
 351                                 }
 352                         }
 353                 }
 354                 for (int surface = 3; surface < 6; ++surface) {
 355                         for (int y = 0; y < sidelength; ++y) {
 356                                 for (int x = 0; x < sidelength; ++x, ++index) {
 357                                         element[6 * index + 0] = 4 * index + 0;
 358                                         element[6 * index + 1] = 4 * index + 1;
 359                                         element[6 * index + 2] = 4 * index + 2;
 360                                         element[6 * index + 3] = 4 * index + 2;
 361                                         element[6 * index + 4] = 4 * index + 1;
 362                                         element[6 * index + 5] = 4 * index + 3;
 363                                 }
 364                         }
 365                 }
 366         }
 367         vao.Unbind();
 368 }
 369
 370 void Planet::Draw(app::Assets &assets, graphics::Viewport &viewport) {
 371         vao.Bind();
 372         const glm::mat4 &MV = assets.shaders.planet_surface.MV();
 373         assets.shaders.planet_surface.SetNormal(glm::vec3(MV * glm::vec4(0.0f, 0.0f, 1.0f, 0.0f)));
 374         vao.DrawTriangles(TilesPerSurface() * 6, TilesPerSurface() * 6 * 0);
 375         assets.shaders.planet_surface.SetNormal(glm::vec3(MV * glm::vec4(1.0f, 0.0f, 0.0f, 0.0f)));
 376         vao.DrawTriangles(TilesPerSurface() * 6, TilesPerSurface() * 6 * 1);
 377         assets.shaders.planet_surface.SetNormal(glm::vec3(MV * glm::vec4(0.0f, 1.0f, 0.0f, 0.0f)));
 378         vao.DrawTriangles(TilesPerSurface() * 6, TilesPerSurface() * 6 * 2);
 379         assets.shaders.planet_surface.SetNormal(glm::vec3(MV * glm::vec4(0.0f, 0.0f, -1.0f, 0.0f)));
 380         vao.DrawTriangles(TilesPerSurface() * 6, TilesPerSurface() * 6 * 3);
 381         assets.shaders.planet_surface.SetNormal(glm::vec3(MV * glm::vec4(-1.0f, 0.0f, 0.0f, 0.0f)));
 382         vao.DrawTriangles(TilesPerSurface() * 6, TilesPerSurface() * 6 * 4);
 383         assets.shaders.planet_surface.SetNormal(glm::vec3(MV * glm::vec4(0.0f, -1.0f, 0.0f, 0.0f)));
 384         vao.DrawTriangles(TilesPerSurface() * 6, TilesPerSurface() * 6 * 5);
 385 }
 386
 387
 388 void GenerateEarthlike(const TileSet &tiles, Planet &p) noexcept {
 389         rand::SimplexNoise elevation_gen(0);
 390
 391         const int ice = tiles["ice"].id;
 392         const int ocean = tiles["ocean"].id;
 393         const int water = tiles["water"].id;
 394         const int sand = tiles["sand"].id;
 395         const int grass = tiles["grass"].id;
 396         const int tundra = tiles["tundra"].id;
 397         const int desert = tiles["desert"].id;
 398         const int mntn = tiles["mountain"].id;
 399
 400         constexpr double ocean_thresh = -0.2;
 401         constexpr double water_thresh = 0.0;
 402         constexpr double beach_thresh = 0.1;
 403         constexpr double mountain_thresh = 0.5;
 404
 405         const glm::dvec3 axis(glm::dvec4(0.0, 1.0, 0.0, 0.0) * glm::eulerAngleXY(p.SurfaceTilt().x, p.SurfaceTilt().y));
 406         const double cap_thresh = std::abs(std::cos(p.AxialTilt().x));
 407         const double equ_thresh = 2.0 * (1.0 - cap_thresh);
 408         const double fzone_start = equ_thresh - (equ_thresh - cap_thresh) / 3.0;
 409         const double fzone_end = cap_thresh + (equ_thresh - cap_thresh) / 3.0;
 410
 411         for (int surface = 0; surface <= 5; ++surface) {
 412                 for (int y = 0; y < p.SideLength(); ++y) {
 413                         for (int x = 0; x < p.SideLength(); ++x) {
 414                                 glm::dvec3 to_tile = p.TileCenter(surface, x, y);
 415                                 double near_axis = std::abs(glm::dot(glm::normalize(to_tile), axis));
 416                                 if (near_axis > cap_thresh) {
 417                                         p.TileAt(surface, x, y).type = ice;
 418                                         continue;
 419                                 }
 420                                 float elevation = rand::OctaveNoise(
 421                                         elevation_gen,
 422                                         to_tile / p.Radius(),
 423                                         3,   // octaves
 424                                         0.5, // persistence
 425                                         2 / p.Radius(), // frequency
 426                                         2,   // amplitude
 427                                         2    // growth
 428                                 );
 429                                 if (elevation < ocean_thresh) {
 430                                         p.TileAt(surface, x, y).type = ocean;
 431                                 } else if (elevation < water_thresh) {
 432                                         p.TileAt(surface, x, y).type = water;
 433                                 } else if (elevation < beach_thresh) {
 434                                         p.TileAt(surface, x, y).type = sand;
 435                                 } else if (elevation < mountain_thresh) {
 436                                         // TODO: perturb climate rings a little
 437                                         if (near_axis < equ_thresh) {
 438                                                 p.TileAt(surface, x, y).type = desert;
 439                                         } else if (near_axis < fzone_start) {
 440                                                 p.TileAt(surface, x, y).type = grass;
 441                                         } else if (near_axis < fzone_end) {
 442                                                 p.TileAt(surface, x, y).type = tundra;
 443                                         } else {
 444                                                 p.TileAt(surface, x, y).type = grass;
 445                                         }
 446                                 } else {
 447                                         p.TileAt(surface, x, y).type = mntn;
 448                                 }
 449                         }
 450                 }
 451         }
 452         p.BuildVAO(tiles);
 453 }
 454
 455 void GenerateTest(const TileSet &tiles, Planet &p) noexcept {
 456         for (int surface = 0; surface <= 5; ++surface) {
 457                 for (int y = 0; y < p.SideLength(); ++y) {
 458                         for (int x = 0; x < p.SideLength(); ++x) {
 459                                 if (x == p.SideLength() / 2 && y == p.SideLength() / 2) {
 460                                         p.TileAt(surface, x, y).type = surface;
 461                                 } else {
 462                                         p.TileAt(surface, x, y).type = (x == p.SideLength()/2) + (y == p.SideLength()/2) + 6;
 463                                 }
 464                         }
 465                 }
 466         }
 467         p.BuildVAO(tiles);
 468 }
 469
 470
 471 Sun::Sun()
 472 : Body() {
 473 }
 474
 475 Sun::~Sun() {
 476 }
 477
 478 TileSet::TileSet()
 479 : types()
 480 , names() {
 481 }
 482
 483 TileSet::~TileSet() {
 484 }
 485
 486 int TileSet::Add(const TileType &t) {
 487         int id = types.size();
 488         if (!names.emplace(t.name, id).second) {
 489                 throw std::runtime_error("duplicate tile type name " + t.name);
 490         }
 491         types.emplace_back(t);
 492         types.back().id = id;
 493         return id;
 494 }
 495
 496 TileType &TileSet::operator [](const std::string &name) {
 497         auto entry = names.find(name);
 498         if (entry != names.end()) {
 499                 return types[entry->second];
 500         } else {
 501                 throw std::runtime_error("unknown tile type " + name);
 502         }
 503 }
 504
 505 const TileType &TileSet::operator [](const std::string &name) const {
 506         auto entry = names.find(name);
 507         if (entry != names.end()) {
 508                 return types[entry->second];
 509         } else {
 510                 throw std::runtime_error("unknown tile type " + name);
 511         }
 512 }
 513
 514 }
 515 }