VoxelEngine/src/world/generator/SurroundMap.cpp
2024-08-28 11:41:04 +03:00

118 lines
3.5 KiB
C++

#include "SurroundMap.hpp"
#include <queue>
#include <cstring>
#include <stdexcept>
void SurroundMap::resetMarks() {
for (auto& [_, entry] : entries) {
entry.marked = false;
}
}
bool SurroundMap::createEntry(const glm::ivec2& origin) {
auto& entry = entries[origin];
if (entry.confirmed) {
return false;
}
entry.confirmed = true;
// calculate initial number of surrounding entries (any level)
int bitOffset = 0;
for (int y = -1; y <= 1; y++) {
for (int x = -1; x <= 1; x++) {
if (x == y && x == 0) {
continue;
}
const auto& found = entries.find(origin + glm::ivec2(x, y));
if (found != entries.end()) {
entry.surrounding |= (1 << bitOffset);
if (found->second.level == 0) {
found->second.surrounding |= (1 << (7 - bitOffset));
}
}
bitOffset++;
}
}
return true;
}
std::vector<glm::ivec2> SurroundMap::upgrade() {
std::vector<glm::ivec2> expansion;
std::queue<glm::ivec2> expanding;
for (const auto& [pos, entry] : entries) {
if (entry.confirmed && entry.surrounding != 0xFF) {
expanding.push(pos);
}
}
while (!expanding.empty()) {
assert(expanding.size() < 64);
glm::ivec2 pos = expanding.front();
expanding.pop();
const auto& found = entries.find(pos);
assert(found != entries.end() && "concurrent modification");
auto& entry = found->second;
int uplevelSurrounding = 0;
int bitOffset = 0;
for (int y = -1; y <= 1; y++) {
for (int x = -1; x <= 1; x++) {
if (x == y && x == 0) {
continue;
}
glm::ivec2 npos = {pos.x+x, pos.y+y};
const auto& nfound = entries.find(npos);
if (entry.surrounding & (1 << bitOffset)) {
auto& nentry = nfound->second;
if (nentry.level > entry.level) {
uplevelSurrounding |= (1 << bitOffset);
}
bitOffset++;
continue;
}
if (entry.level == 0) {
// neighbour entry does not exist
createEntry(npos);
expansion.push_back(npos);
} else{
assert(nfound != entries.end() && "invalid map state");
if (nfound->second.level == entry.level + 1) {
nfound->second.surrounding |= (1 << (7 - bitOffset));
expanding.push(npos);
}
}
bitOffset++;
}
}
// level up
entry.surrounding = uplevelSurrounding;
entry.level++;
}
return expansion;
}
void SurroundMap::getLevels(unsigned char* out, int width, int height, int ox, int oy) const {
std::memset(out, 0, width * height);
for (const auto& [pos, entry] : entries) {
int x = pos.x - ox;
int y = pos.y - oy;
if (x < 0 || x >= width || y < 0 || y >= height) {
continue;
}
int surroundNum = 0;
for (int i = 0; i < 8; i++) {
if (entry.surrounding & (1 << i)) {
surroundNum++;
}
}
if (surroundNum) {
out[y * width + x] = surroundNum + 1;
}
out[y * width + x] = entry.level + 1;
}
}