1 files changed, 87 insertions, 0 deletions
diff --git a/src/game/client/chunk_visibility.cc b/src/game/client/chunk_visibility.cc
new file mode 100644
index 0000000..f832529
--- /dev/null
+++ b/src/game/client/chunk_visibility.cc
@@ -0,0 +1,87 @@
+#include "client/pch.hh"
+
+#include "client/chunk_visibility.hh"
+
+#include "core/config.hh"
+#include "core/vectors.hh"
+
+#include "shared/chunk.hh"
+#include "shared/chunk_aabb.hh"
+#include "shared/dimension.hh"
+#include "shared/protocol.hh"
+
+#include "client/camera.hh"
+#include "client/globals.hh"
+#include "client/session.hh"
+
+// Sending a somewhat large amount of network packets
+// can easily overwhelm both client, server and the network
+// channel created between the two. To prevent this from happening
+// we throttle the client's ever increasing itch for new chunks
+constexpr static unsigned int MAX_CHUNKS_REQUESTS_PER_FRAME = 16U;
+
+static ChunkAABB current_view_box;
+static ChunkAABB previous_view_box;
+static std::vector<chunk_pos> requests;
+
+static void update_requests(void)
+{
+    requests.clear();
+
+    for(auto cx = current_view_box.min.x; cx != current_view_box.max.x; cx += 1)
+        for(auto cy = current_view_box.min.y; cy != current_view_box.max.y; cy += 1)
+            for(auto cz = current_view_box.min.z; cz != current_view_box.max.z; cz += 1) {
+                auto cpos = chunk_pos(cx, cy, cz);
+
+                if(!globals::dimension->find_chunk(cpos)) {
+                    requests.push_back(cpos);
+                }
+            }
+
+    std::sort(requests.begin(), requests.end(), [](const chunk_pos& cpos_a, const chunk_pos& cpos_b) {
+        auto da = vx::distance2(cpos_a, camera::position_chunk);
+        auto db = vx::distance2(cpos_b, camera::position_chunk);
+        return da > db;
+    });
+}
+
+void chunk_visibility::update_late(void)
+{
+    current_view_box.min = camera::position_chunk - static_cast<chunk_pos::value_type>(camera::view_distance.get_value());
+    current_view_box.max = camera::position_chunk + static_cast<chunk_pos::value_type>(camera::view_distance.get_value());
+
+    if(!session::is_ingame()) {
+        // This makes sure the previous view box
+        // is always different from the current one
+        previous_view_box.min = chunk_pos(INT32_MIN, INT32_MIN, INT32_MIN);
+        previous_view_box.max = chunk_pos(INT32_MAX, INT32_MAX, INT32_MAX);
+        return;
+    }
+
+    if((current_view_box.min != previous_view_box.min) || (current_view_box.max != previous_view_box.max)) {
+        update_requests();
+    }
+
+    for(unsigned int i = 0U; i < MAX_CHUNKS_REQUESTS_PER_FRAME; ++i) {
+        if(requests.empty()) {
+            // Done sending requests
+            break;
+        }
+
+        protocol::RequestChunk packet;
+        packet.cpos = requests.back();
+        protocol::send(session::peer, protocol::encode(packet));
+
+        requests.pop_back();
+    }
+
+    auto view = globals::dimension->chunks.view<ChunkComponent>();
+
+    for(const auto [entity, chunk] : view.each()) {
+        if(!current_view_box.contains(chunk.cpos)) {
+            globals::dimension->remove_chunk(entity);
+        }
+    }
+
+    previous_view_box = current_view_box;
+}