From 34191ca98435c71ce88884b90adc0412c68ad06a Mon Sep 17 00:00:00 2001
From: DualFroz <me@dualfroz.com>
Date: Tue, 8 Sep 2026 18:09:23 +0200
Subject: [PATCH] feat: add chunkOf and squaredDistance

---
 core/src/NetSession.cpp | 160 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 160 insertions(+)
 create mode 100644 core/src/NetSession.cpp

diff --git a/core/src/NetSession.cpp b/core/src/NetSession.cpp
new file mode 100644
index 0000000..f146427
--- /dev/null
+++ b/core/src/NetSession.cpp
@@ -0,0 +1,160 @@
+#include "vf/NetSession.h"
+
+#include <algorithm>
+#include <cmath>
+
+namespace vf {
+
+namespace {
+
+Vec3i chunkOf(const Vec3& position) {
+    int gx = static_cast<int>(std::floor(position.x));
+    int gy = static_cast<int>(std::floor(position.y));
+    int gz = static_cast<int>(std::floor(position.z));
+    return Vec3i{floorDiv(gx, chunkSize), floorDiv(gy, chunkSize), floorDiv(gz, chunkSize)};
+}
+
+int64_t squaredDistance(const Vec3i& a, const Vec3i& b) {
+    int64_t dx = a.x - b.x;
+    int64_t dy = a.y - b.y;
+    int64_t dz = a.z - b.z;
+    return dx * dx + dy * dy + dz * dz;
+}
+
+}  // namespace
+
+ViewTracker::ViewTracker(int radius) : viewRadius(radius < 0 ? 0 : radius) {}
+
+void ViewTracker::setRadius(int radius) { viewRadius = radius < 0 ? 0 : radius; }
+
+void ViewTracker::clear() {
+    resident.clear();
+    centred = false;
+    centreChunk = Vec3i{0, 0, 0};
+}
+
+void ViewTracker::update(const Vec3i& newCentre, std::vector<Vec3i>& entered,
+                         std::vector<Vec3i>& left) {
+    entered.clear();
+    left.clear();
+
+    std::vector<Vec3i> wanted;
+    int64_t limit = static_cast<int64_t>(viewRadius) * static_cast<int64_t>(viewRadius);
+    for (int dy = -viewRadius; dy <= viewRadius; ++dy) {
+        for (int dz = -viewRadius; dz <= viewRadius; ++dz) {
+            for (int dx = -viewRadius; dx <= viewRadius; ++dx) {
+                Vec3i coord{newCentre.x + dx, newCentre.y + dy, newCentre.z + dz};
+                if (squaredDistance(coord, newCentre) > limit) continue;
+                wanted.push_back(coord);
+            }
+        }
+    }
+
+    std::stable_sort(wanted.begin(), wanted.end(),
+                     [&newCentre](const Vec3i& a, const Vec3i& b) {
+                         int64_t da = squaredDistance(a, newCentre);
+                         int64_t db = squaredDistance(b, newCentre);
+                         if (da != db) return da < db;
+                         if (a.y != b.y) return a.y < b.y;
+                         if (a.z != b.z) return a.z < b.z;
+                         return a.x < b.x;
+                     });
+
+    std::unordered_set<Vec3i, Vec3iHash> next;
+    next.reserve(wanted.size() * 2);
+    for (const Vec3i& coord : wanted) {
+        next.insert(coord);
+        if (resident.count(coord) == 0) entered.push_back(coord);
+    }
+    for (const Vec3i& coord : resident)
+        if (next.count(coord) == 0) left.push_back(coord);
+
+    std::stable_sort(left.begin(), left.end(), [](const Vec3i& a, const Vec3i& b) {
+        if (a.y != b.y) return a.y < b.y;
+        if (a.z != b.z) return a.z < b.z;
+        return a.x < b.x;
+    });
+
+    resident.swap(next);
+    centreChunk = newCentre;
+    centred = true;
+}
+
+void ClientView::queueChunk(const Vec3i& coord) {
+    if (!queued.insert(coord).second) return;
+    pending.push_back(coord);
+}
+
+bool ClientView::takeNextPending(Vec3i& out) {
+    while (!pending.empty()) {
+        Vec3i coord = pending.front();
+        pending.pop_front();
+        if (queued.erase(coord) == 0) continue;
+        out = coord;
+        return true;
+    }
+    return false;
+}
+
+void ClientView::forget(const Vec3i& coord) {
+    sent.erase(coord);
+    queued.erase(coord);
+}
+
+void ClientView::reset() {
+    tracker.clear();
+    pending.clear();
+    queued.clear();
+    sent.clear();
+    centreChunk = Vec3i{0, 0, 0};
+    position = Vec3{0.0f, 0.0f, 0.0f};
+}
+
+NetSession::NetSession(Transport& transport, Role role, SessionConfig config)
+    : transport(&transport), role(role), config(config), clientView(config.viewRadius) {}
+
+std::size_t NetSession::queuedByteCount() const {
+    std::size_t total = 0;
+    for (const QueuedPacket& packet : outbound) total += packet.frame.size();
+    return total;
+}
+
+void NetSession::disconnect(const std::string& why) {
+    if (currentPhase == SessionPhase::Disconnected) return;
+    currentPhase = SessionPhase::Disconnected;
+    reason = why;
+    outbound.clear();
+}
+
+void NetSession::enqueue(PacketId id, const PacketWriter& body, bool reliable) {
+    ByteWriter stream;
+    writeFramed(stream, id, body);
+    QueuedPacket packet;
+    packet.frame = stream.bytes();
+    packet.reliable = reliable;
+    statistics.bytesQueued += packet.frame.size();
+    outbound.push_back(std::move(packet));
+}
+
+void NetSession::beginHandshake(const std::string& playerName, uint64_t high, uint64_t low) {
+    name = playerName;
+    uuidHi = high;
+    uuidLo = low;
+
+    Handshake hello;
+    hello.protocolVersion = config.protocolVersion;
+    hello.serverAddress = "loopback";
+    hello.serverPort = 0;
+    hello.nextState = 2;
+    PacketWriter helloBody;
+    hello.encode(helloBody);
+    enqueue(PacketId::Handshake, helloBody, true);
+
+    LoginStart login;
+    login.name = playerName;
+    login.uuidHi = high;
+    login.uuidLo = low;
+    PacketWriter loginBody;
+    login.encode(loginBody);
+    enqueue(PacketId::LoginStart, loginBody, true);
+