src/world/Generator.cpp

   1 #include "Generator.hpp"
   2
   3 #include "BlockType.hpp"
   4 #include "BlockTypeRegistry.hpp"
   5 #include "Chunk.hpp"
   6 #include "../graphics/glm.hpp"
   7 #include "../rand/OctaveNoise.hpp"
   8
   9
  10 namespace blank {
  11
  12 namespace {
  13
  14 struct Candidate {
  15         const BlockType *type;
  16         float threshold;
  17         Candidate(const BlockType *type, float threshold)
  18         : type(type), threshold(threshold) { }
  19 };
  20
  21 std::vector<Candidate> candidates;
  22
  23 }
  24
  25 Generator::Generator(const Config &config) noexcept
  26 : config(config)
  27 , types()
  28 , min_solidity(2.0f)
  29 , solidity_noise(config.seed ^ config.solidity.seed_mask)
  30 , humidity_noise(config.seed ^ config.humidity.seed_mask)
  31 , temperature_noise(config.seed ^ config.temperature.seed_mask)
  32 , richness_noise(config.seed ^ config.richness.seed_mask)
  33 , random_noise(config.seed ^ config.randomness.seed_mask) {
  34
  35 }
  36
  37 void Generator::LoadTypes(const BlockTypeRegistry &reg) {
  38         types.clear();
  39         min_solidity = 2.0f;
  40         for (const BlockType &type : reg) {
  41                 if (type.generate) {
  42                         types.push_back(&type);
  43                         if (type.solidity.Min() < min_solidity) {
  44                                 min_solidity = type.solidity.Min();
  45                         }
  46                 }
  47         }
  48         candidates.reserve(types.size());
  49 }
  50
  51 namespace {
  52
  53 struct Interpolation {
  54         /// sample points for interpolation
  55         /// given coordinates should be the absoloute position of the chunk's (0,0,0) block
  56         Interpolation(
  57                 const SimplexNoise &noise,
  58                 const glm::vec3 &base,
  59                 const Generator::Config::NoiseParam &conf
  60         ) noexcept {
  61                 for (int z = 0; z < 5; ++z) {
  62                         for (int y = 0; y < 5; ++y) {
  63                                 for (int x = 0; x < 5; ++x) {
  64                                         samples[z][y][x] = OctaveNoise(
  65                                                 noise,
  66                                                 base + (glm::vec3(x, y, z) * 4.0f),
  67                                                 conf.octaves,
  68                                                 conf.persistence,
  69                                                 conf.frequency,
  70                                                 conf.amplitude,
  71                                                 conf.growth
  72                                         );
  73                                 }
  74                         }
  75                 }
  76         }
  77         float samples[5][5][5];
  78 };
  79
  80 struct Parameters {
  81         glm::ivec3 a;
  82         glm::ivec3 b;
  83         glm::ivec3 d;
  84 };
  85
  86 struct Detail {
  87         float humidity;
  88         float temperature;
  89         float richness;
  90         float randomness;
  91 };
  92
  93 }
  94
  95 struct Generator::ValueField {
  96
  97         Interpolation solidity;
  98         Interpolation humidity;
  99         Interpolation temperature;
 100         Interpolation richness;
 101         Interpolation randomness;
 102
 103         static Parameters GetParams(const glm::ivec3 &pos) noexcept {
 104                 Parameters p;
 105                 p.a = pos / 4;
 106                 p.b = p.a + 1;
 107                 p.d = pos % 4;
 108                 return p;
 109         }
 110
 111         static float Interpolate(const Interpolation &i, const Parameters &p) noexcept {
 112                 constexpr float A[4] = { 1.0f, 0.75f, 0.5f, 0.25f };
 113                 constexpr float B[4] = { 0.0f, 0.25f, 0.5f, 0.75f };
 114                 const float l1[4] = {
 115                         i.samples[p.a.z][p.a.y][p.a.x] * A[p.d.x] + i.samples[p.a.z][p.a.y][p.b.x] * B[p.d.x],
 116                         i.samples[p.a.z][p.b.y][p.a.x] * A[p.d.x] + i.samples[p.a.z][p.b.y][p.b.x] * B[p.d.x],
 117                         i.samples[p.b.z][p.a.y][p.a.x] * A[p.d.x] + i.samples[p.b.z][p.a.y][p.b.x] * B[p.d.x],
 118                         i.samples[p.b.z][p.b.y][p.a.x] * A[p.d.x] + i.samples[p.b.z][p.b.y][p.b.x] * B[p.d.x],
 119                 };
 120                 const float l2[2] = {
 121                         l1[0] * A[p.d.y] + l1[1] * B[p.d.y],
 122                         l1[2] * A[p.d.y] + l1[3] * B[p.d.y],
 123                 };
 124                 return l2[0] * A[p.d.z] + l2[1] * B[p.d.z];
 125         }
 126
 127 };
 128
 129 void Generator::operator ()(Chunk &chunk) const noexcept {
 130         ExactLocation::Fine coords(chunk.Position() * ExactLocation::Extent());
 131         coords += 0.5f;
 132         ValueField field {
 133                 { solidity_noise, coords, config.solidity },
 134                 { humidity_noise, coords, config.humidity },
 135                 { temperature_noise, coords, config.temperature },
 136                 { richness_noise, coords, config.richness },
 137                 { random_noise, coords, config.randomness },
 138         };
 139         for (int z = 0; z < Chunk::side; ++z) {
 140                 for (int y = 0; y < Chunk::side; ++y) {
 141                         for (int x = 0; x < Chunk::side; ++x) {
 142                                 chunk.SetBlock(RoughLocation::Fine(x, y, z), Generate(field, RoughLocation::Fine(x, y, z)));
 143                         }
 144                 }
 145         }
 146         chunk.SetGenerated();
 147 }
 148
 149 Block Generator::Generate(const ValueField &field, const glm::ivec3 &pos) const noexcept {
 150         Parameters params(ValueField::GetParams(pos));
 151         float solidity = ValueField::Interpolate(field.solidity, params);
 152         if (solidity < min_solidity) {
 153                 return Block(0);
 154         }
 155         float humidity = ValueField::Interpolate(field.humidity, params);
 156         float temperature = ValueField::Interpolate(field.temperature, params);
 157         float richness = ValueField::Interpolate(field.richness, params);
 158
 159         candidates.clear();
 160         float total = 0.0f;
 161         for (const BlockType *type : types) {
 162                 if (!type->solidity.Valid(solidity)) continue;
 163                 if (!type->humidity.Valid(humidity)) continue;
 164                 if (!type->temperature.Valid(temperature)) continue;
 165                 if (!type->richness.Valid(richness)) continue;
 166                 float solidity_match = type->solidity.Map(solidity);
 167                 float humidity_match = type->humidity.Map(humidity);
 168                 float temperature_match = type->temperature.Map(temperature);
 169                 float richness_match = type->richness.Map(richness);
 170                 float chance = (solidity_match + humidity_match + temperature_match + richness_match) * type->commonness;
 171                 total += chance;
 172                 candidates.emplace_back(type, total);
 173         }
 174         if (candidates.empty()) {
 175                 return Block(0);
 176         }
 177         float random = ValueField::Interpolate(field.randomness, params);
 178         // as weird as it sounds, but this is faster tham glm::fract and generates a
 179         // better distribution than (transformed variants of) erf, erfc, atan, and smoothstep
 180         if (random < 0.0f) random += 1.0f;
 181         float value = random * total;
 182         // TODO: change to binary search
 183         for (const Candidate &cand : candidates) {
 184                 if (value < cand.threshold) {
 185                         return Block(cand.type->id);
 186                 }
 187         }
 188         // theoretically, this should never happen
 189         return Block(candidates.back().type->id);
 190 }
 191
 192 }