COSC-3P98-Final-Project/include/world/chunk/world.h

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/*
* Created by Brett on 11/02/23.
* Licensed under GNU General Public License V3.0
* See LICENSE file for license detail
*/
#ifndef FINALPROJECT_WORLD_H
#define FINALPROJECT_WORLD_H
#include <world/chunk/storage.h>
#include <render/gl.h>
#include <unordered_map>
namespace fp {
namespace _static {
/**
* Converts from world coord to chunk-internal coords
* @param coord world space coordinate
* @return chunk internal coord
*/
static inline int world_to_internal(int coord) {
auto val = coord % CHUNK_SIZE;
return val < 0 ? CHUNK_SIZE + val : val;
}
static inline block_pos world_to_internal(const block_pos& coord) {
return {world_to_internal(coord.x), world_to_internal(coord.y), world_to_internal(coord.z)};
}
/**
* Converts from world coord to chunk pos coords
*
* consider: (int) (-31 / 32) which equals 0
* but a negative chunk would be stored at -1, not 0 (since that is taken by the positive coord chunk)
* an arithmetic right shift would produce the desired -1 (see Java, which performs a signed right bit shift)
* however in C++ shifting on a signed type is undefined behaviour. So we must emulate an arithmetic right shift.
*
* @param coord x,y, or z coordinate to convert
* @return a right arithmetic bit shift resulting in a signed division of the coordinate by CHUNK_SIZE
*/
static inline int world_to_chunk(int coord) {
auto ucoord = (unsigned int) coord;
ucoord >>= CHUNK_SHIFT;
if (coord < 0) {
// the mask only has to be generated once since it is never modified at runtime beyond assignment
static unsigned int mask = 0;
if (mask == 0) {
for (int i = 0; i < CHUNK_SHIFT; i++)
mask |= (1 << ((sizeof(int) * 8 - 1) - i));
}
ucoord |= mask;
}
return (int) (ucoord);
}
static inline chunk_pos world_to_chunk(const block_pos& pos){
return {world_to_chunk(pos.x), world_to_chunk(pos.y), world_to_chunk(pos.z)};
}
}
struct chunk {
public:
block_storage* storage;
mesh_storage* mesh = nullptr;
VAO* chunk_vao;
chunk_pos pos;
chunk_status dirtiness = OKAY;
unsigned long render_size = 0;
public:
explicit chunk(chunk_pos pos): pos(pos) {
storage = new block_storage();
chunk_vao = new VAO();
// using indices uses:
// 12 faces * 4 vertex * 3 float * 4 bytes + 12 faces * 6 indices * 4 bytes = 864 bytes for vertex + index
// using only vertices:
// 12 faces * 6 vertex * 3 floats * 4 bytes = 864 bytes.
// since they both use the same amount of memory we will only store the vertices and draw with drawArrays, since it is less complex.
// set up the VBOs which will be later updated when the mesh is generated.
chunk_vao->bindVBO(new VBO(ARRAY_BUFFER, nullptr, 0), 0, 3);
}
~chunk() {
delete storage;
delete chunk_vao;
delete mesh;
}
};
class world {
private:
std::unordered_map<chunk_pos, chunk*, _static::chunk_pos_hash, _static::chunk_pos_equality> chunk_storage;
protected:
void generateChunkMesh(chunk* chunk);
inline void insertChunk(chunk* chunk){
chunk_storage.insert({chunk->pos, chunk});
}
inline chunk* getChunk(const block_pos& pos) {
return chunk_storage.at(_static::world_to_chunk(pos));
}
public:
world() {
insertChunk(new chunk({0, 0, 0}));
insertChunk(new chunk({-1, 0, 0}));
insertChunk(new chunk({0, 0, -1}));
insertChunk(new chunk({-1, 0, -1}));
}
void update();
void render(fp::shader& shader);
inline void setBlock(const block_pos& pos, char blockID) {
auto c = getChunk(pos);
// mark the chunk for a mesh update
c->dirtiness = FULL_MESH;
c->storage->set(_static::world_to_internal(pos), blockID);
}
inline char getBlock(const block_pos& pos) {
auto c = getChunk(pos);
return c->storage->get(_static::world_to_internal(pos));
}
~world() {
for (auto& chunk : chunk_storage)
delete (chunk.second);
}
};
}
#endif //FINALPROJECT_WORLD_H