Univerxel/src/contouring/surrounding.cpp

#include "surrounding.hpp"

#include "../world/Chunk.hpp"

namespace contouring::surrounding {
    bool load(chunks &out, const chunk_pos &chunkPos, const robin_hood::unordered_map<chunk_pos, std::shared_ptr<Chunk>> &chunks) {
        {
            const auto it = chunks.find(chunkPos);
            if (it == chunks.end())
                return false;

            out[CENTER] = it->second;
        }
        for (size_t i = 0; i < CENTER; i++) {
            const auto it = chunks.find(chunkPos + g_face_offsets[i]);
            if (it == chunks.end())
                return false;

            out[i] = it->second;
        }
        return true;
    }

    std::pair<ushort, ushort> getNeighborIdx(ushort idx, Face face) {
        switch (face) {
        case Face::Forward:
            if (idx % CHUNK_LENGTH >= CHUNK_LENGTH - 1)
                return {static_cast<int>(Face::Forward), idx - (CHUNK_LENGTH - 1)};
            return {CENTER, idx + 1};

        case Face::Backward:
            if (idx % CHUNK_LENGTH <= 0)
                return {static_cast<int>(Face::Backward), idx + (CHUNK_LENGTH - 1)};
            return {CENTER, idx - 1};

        case Face::Up:
            if ((idx / CHUNK_LENGTH) % CHUNK_LENGTH >= CHUNK_LENGTH - 1)
                return {static_cast<int>(Face::Up), idx - (CHUNK_LENGTH2 - CHUNK_LENGTH)};
            return {CENTER, idx + CHUNK_LENGTH};

        case Face::Down:
            if ((idx / CHUNK_LENGTH) % CHUNK_LENGTH <= 0)
                return {static_cast<int>(Face::Down), idx + (CHUNK_LENGTH2 - CHUNK_LENGTH)};
            return {CENTER, idx - CHUNK_LENGTH};

        case Face::Right:
            if (idx / CHUNK_LENGTH2 >= CHUNK_LENGTH - 1)
                return {static_cast<int>(Face::Right), idx - (CHUNK_SIZE - CHUNK_LENGTH2)};
            return {CENTER, idx + CHUNK_LENGTH2};

        case Face::Left:
            if (idx / CHUNK_LENGTH2 <= 0)
                return {static_cast<int>(Face::Left), idx + (CHUNK_SIZE - CHUNK_LENGTH2)};
            return {CENTER, idx - CHUNK_LENGTH2};

        default:
            return {CENTER, idx};
        }
    }
}