Make chunks check adjacent chunks when generating mesh

Makefile

@@ -1,11 +1,11 @@
 CXX = g++
-CXXFLAGS = -g -Isrc
+CXXFLAGS = -O3 -Isrc
 LD = ld
 
 LINKFLAGS = -lGL -lglfw
 
 CC = gcc
-CCFLAGS = -g -Isrc
+CCFLAGS = -O3 -Isrc
 
 XNOECRAFT_CPP_SRCS = $(shell find src/ -name '*.cpp')
 XNOECRAFT_C_SRCS = $(shell find src/ -name '*.c')

src/chunk.cpp

@@ -31,12 +31,37 @@ void Chunk::set_block(int x, int y, int z, int block) {
 }
 
 int Chunk::get_block(int x, int y, int z) {
-  if (x < 0 || x >= Chunk::horiz_size)
-    return 0;
-  if (z < 0 || z >= Chunk::horiz_size)
-    return 0;
   if (y < 0 || y >= Chunk::vert_size)
     return 0;
+
+  if (x < 0) {
+    Chunk* c;
+    if (c = World::get_chunk(this->x-1, this->z))
+      return c->get_block(Chunk::horiz_size-1, y, z);
+    else
+      return 0;
+  } else if (x >= Chunk::horiz_size) {
+    Chunk* c;
+    if (c = World::get_chunk(this->x+1, this->z))
+      return c->get_block(0, y, z);
+    else
+      return 0;
+  }
+
+  if (z < 0) {
+    Chunk* c;
+    if (c = World::get_chunk(this->x, this->z-1))
+      return c->get_block(x, y, Chunk::horiz_size-1);
+    else
+      return 0;
+  } else if (z >= Chunk::horiz_size) {
+    Chunk* c;
+    if (c = World::get_chunk(this->x, this->z+1))
+      return c->get_block(x, y, 0);
+    else
+      return 0;
+  }
+
   return this->blocks[y * Chunk::horiz_size * Chunk::horiz_size + z * Chunk::horiz_size + x];
 }
 
@@ -77,7 +102,6 @@ Chunk::~Chunk() {
 
 void Chunk::generate() {
   std::chrono::high_resolution_clock clock;
-  if (mesh_version < current_version) {
   auto t1 = clock.now();
   mesh_version++;
 
@@ -170,7 +194,6 @@ void Chunk::generate() {
   std::chrono::duration<double> d = (t2 - t1);
 
   std::cerr << "Generated chunk in " << d.count() << " seconds.\n";
-  }
 }
 
 bool Chunk::outdated() {

src/world.cpp

@@ -6,10 +6,11 @@ FastNoise World::noise;
 World::World() {
   World::noise = FastNoise();
   World::noise.SetNoiseType(FastNoise::Perlin);
+  World::world = this;
 }
 
 void World::generate_around(int x, int z) {
-  int world_size_half = this->world_size / 2;
+  int world_size_half = this->world_size;
 
   this->world_center = glm::vec2(x, z);
 
@@ -23,8 +24,6 @@ void World::generate_around(int x, int z) {
 
   for (Chunk* c : this->chunks)
     c->generate();
-  
-  World::world = this;
 }
 
 void World::process(int x, int z) {
@@ -34,12 +33,13 @@ void World::process(int x, int z) {
     return;
 
   std::vector<Chunk*> new_chunks;
+  std::vector<Chunk*> to_generate;
   
   // Player has moved from the world center.
 
   // Determine world bounds.
 
-  int world_size_half = this->world_size / 2;
+  int world_size_half = this->world_size;
 
   int x_low = x - world_size_half;
   int x_high = x + world_size_half;
@@ -68,20 +68,36 @@ void World::process(int x, int z) {
 
       Chunk* c = new Chunk(x + rel_x, z + rel_z);
       new_chunks.push_back(c);
+      to_generate.push_back(c);
       this->location_map[std::tuple<int, int>(x + rel_x, z + rel_z)] = c;
 
       // Remove and delete it.
       this->location_map.erase(std::tuple<int, int>(chunk->x, chunk->z));
       delete chunk;
     } else {
-      // If it's in bounds, keep it.
+      // If it's in bounds, keep it
       new_chunks.push_back(chunk);
+
+      // Determine if its mesh needs regeneration
+      if (x < this->world_center[0]) {
+        if (chunk->x == x_low+2 || chunk->x == x_high)
+          to_generate.push_back(chunk);
+      } else if (x > this->world_center[0]) {
+        if (chunk->x == x_low || chunk->x == x_high-2)
+          to_generate.push_back(chunk);
+      }
+      if (z < this->world_center[1]) {
+        if (chunk->z == z_low+2 || chunk->z == z_high)
+          to_generate.push_back(chunk);
+      } else if (z > this->world_center[1]) {
+        if (chunk->z == z_low || chunk->z == z_high-2)
+          to_generate.push_back(chunk);
+      }
     }
   }
 
   // Go through all the chunks and regenerate them if they are outdated
-  for (Chunk* chunk : new_chunks)
-    if (chunk->outdated())
+  for (Chunk* chunk : to_generate)
     chunk->generate();
 
   //new_chunks.swap(this->chunks);
@@ -95,8 +111,8 @@ float World::get_height_at(int x, int z) {
 }
 
 Chunk* World::get_chunk(int x, int z) {
-  auto search = this->location_map.find(std::tuple<int, int>(x, z));
-  if (search == this->location_map.end())
+  auto search = World::world->location_map.find(std::tuple<int, int>(x, z));
+  if (search == World::world->location_map.end())
     return 0;
   return std::get<1>(*search);
 }

src/world.h

@@ -30,7 +30,7 @@ private:
 
   glm::ivec2 world_center;
 
-  int world_size = 32;
+  int world_size = 16;
 
   static World* world;
 
@@ -41,7 +41,7 @@ public:
   void process(int x, int z);
 
   static float get_height_at(int x, int z);
-  Chunk* get_chunk(int x, int z);
+  static Chunk* get_chunk(int x, int z);
 
   void render(Camera* c, Shader* s);
 };