From 3bf42c6ff3805a0d42bbc661794a95ff31bedc26 Mon Sep 17 00:00:00 2001
From: untodesu <kirill@untode.su>
Date: Sat, 15 Mar 2025 16:22:09 +0500
Subject: Add whatever I was working on for the last month

---
 game/client/chunk_visibility.cc | 134 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 game/client/chunk_visibility.cc

(limited to 'game/client/chunk_visibility.cc')

diff --git a/game/client/chunk_visibility.cc b/game/client/chunk_visibility.cc
new file mode 100644
index 0000000..df0148c
--- /dev/null
+++ b/game/client/chunk_visibility.cc
@@ -0,0 +1,134 @@
+#include "client/pch.hh"
+#include "client/chunk_visibility.hh"
+
+#include "core/config.hh"
+
+#include "shared/chunk.hh"
+#include "shared/dimension.hh"
+#include "shared/protocol.hh"
+
+#include "client/camera.hh"
+#include "client/globals.hh"
+#include "client/session.hh"
+
+static chunk_pos cached_cpos;
+static unsigned int cached_dist;
+static std::vector<chunk_pos> requests;
+
+static void request_chunk(const chunk_pos &cpos)
+{
+    protocol::RequestChunk packet;
+    packet.cpos = cpos;
+    protocol::send(session::peer, protocol::encode(packet));
+}
+
+// Go through the list of chunk positions that should
+// be visible client-side but seem to not exist yet
+static void request_new_chunks(void)
+{
+    auto cmin = cached_cpos - static_cast<chunk_pos::value_type>(cached_dist);
+    auto cmax = cached_cpos + static_cast<chunk_pos::value_type>(cached_dist);
+
+    requests.clear();
+
+    for(auto cx = cmin.x; cx <= cmax.x; ++cx)
+    for(auto cy = cmin.y; cy <= cmax.y; ++cy)
+    for(auto cz = cmin.z; cz <= cmax.z; ++cz) {
+        if(globals::dimension->find_chunk({cx, cy, cz})) {
+            // The chunk already exists, we don't need
+            // to request it from the server anymore
+            continue;
+        }
+
+        requests.push_back(chunk_pos(cx, cy, cz));
+    }
+
+    std::sort(requests.begin(), requests.end(), [](const chunk_pos &ca, const chunk_pos &cb) {
+        auto dir_a = ca - cached_cpos;
+        auto dir_b = cb - cached_cpos;
+
+        const auto da = dir_a[0] * dir_a[0] + dir_a[1] * dir_a[1] + dir_a[2] * dir_a[2];
+        const auto db = dir_b[0] * dir_b[0] + dir_b[1] * dir_b[1] + dir_b[2] * dir_b[2];
+
+        return da > db;
+    });
+}
+
+static bool is_chunk_visible(const chunk_pos &cpos)
+{
+    const auto dx = cxpr::abs(cpos.x - cached_cpos.x);
+    const auto dy = cxpr::abs(cpos.z - cached_cpos.z);
+
+    if((dx <= cached_dist) && (dy <= cached_dist))
+        return true;
+    return false;
+}
+
+void chunk_visibility::update_chunk(entt::entity entity)
+{
+    if(auto component = globals::dimension->chunks.try_get<ChunkComponent>(entity)) {
+        if(is_chunk_visible(component->cpos))
+            globals::dimension->chunks.emplace_or_replace<ChunkVisibleComponent>(entity);
+        else globals::dimension->chunks.remove<ChunkVisibleComponent>(entity);
+    }
+}
+
+void chunk_visibility::update_chunk(const chunk_pos &cpos)
+{
+    if(auto chunk = globals::dimension->find_chunk(cpos)) {
+        const auto &component = globals::dimension->chunks.get<ChunkComponent>(chunk->get_entity());
+        if(is_chunk_visible(component.cpos))
+            globals::dimension->chunks.emplace_or_replace<ChunkVisibleComponent>(chunk->get_entity());
+        else globals::dimension->chunks.remove<ChunkVisibleComponent>(chunk->get_entity());
+    }
+}
+
+void chunk_visibility::update_chunks(void)
+{
+    const auto view = globals::dimension->chunks.view<ChunkComponent>();
+    
+    for(const auto [entity, chunk] : view.each()) {
+        if(is_chunk_visible(chunk.cpos))
+            globals::dimension->chunks.emplace_or_replace<ChunkVisibleComponent>(entity);
+        else globals::dimension->chunks.remove<ChunkVisibleComponent>(entity);
+    }
+
+    request_new_chunks();
+}
+
+void chunk_visibility::cleanup(void)
+{
+    cached_cpos = camera::position_chunk + 1;
+    cached_dist = camera::view_distance.get_value() + 1;
+    requests.clear();
+}
+
+void chunk_visibility::update(void)
+{
+    if(session::is_ingame()) {
+        if((cached_cpos != camera::position_chunk) || (cached_dist != camera::view_distance.get_value())) {
+            cached_cpos = camera::position_chunk;
+            cached_dist = camera::view_distance.get_value();
+            chunk_visibility::update_chunks();
+            return;
+        }
+
+        for(int i = 0; i < 16; ++i) {
+            if(requests.empty()) {
+                // Done sending requests
+                break;
+            }
+
+            request_chunk(requests.back());
+
+            requests.pop_back();
+        }
+        
+        cached_cpos = camera::position_chunk;
+        cached_dist = camera::view_distance.get_value();
+        return;
+    }
+    
+    cached_cpos = camera::position_chunk + 1;
+    cached_dist = camera::view_distance.get_value() + 1;
+}
-- 
cgit