From 223b8ecf70f9a1e1c1f30715baf36c2c8eadea28 Mon Sep 17 00:00:00 2001
From: gaozheng <gaozheng.cn@gmail.com>
Date: Wed, 17 Jun 2026 17:58:43 +0800
Subject: [PATCH] =?UTF-8?q?perf(vtk):=20=E7=93=A6=E7=89=87=E5=B0=B1?=
 =?UTF-8?q?=E8=BF=91=E4=BC=98=E5=85=88=E5=8A=A0=E8=BD=BD(=E7=A6=BB?=
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 =?UTF-8?q?=E7=94=A8=E6=88=B7=E6=AD=A3=E7=9C=8B=E5=8C=BA=E5=9F=9F=E6=9C=80?=
 =?UTF-8?q?=E5=85=88=E5=87=BA)+=E5=B9=B6=E5=8F=918->12?=
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---
 src/app/TileBasemap.cpp | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/src/app/TileBasemap.cpp b/src/app/TileBasemap.cpp
index 4cde51d..e403a52 100644
--- a/src/app/TileBasemap.cpp
+++ b/src/app/TileBasemap.cpp
@@ -4,6 +4,7 @@
 #include <cmath>
 #include <cstring>
 #include <utility>
+#include <vector>
 
 #include <QDebug>
 #include <QImage>
@@ -47,7 +48,7 @@ constexpr int kMaxLeaves = 200;       // 一次覆盖的叶瓦片上限(安全
 constexpr double kRangeFactor = 10.0;
 constexpr double kRangeFloor = 2000.0;    // 至少 2km(小剖面也有足够地理背景)
 constexpr double kRangeCeil = 30000.0;    // 最多 30km(防远裁剪面失控)
-constexpr int kMaxConcurrent = 8;     // 瓦片请求最大并发(防暴发饱和单域名连接)
+constexpr int kMaxConcurrent = 12;    // 瓦片请求最大并发(天地图 8 子域+Mapbox，适度提高吞吐)
 constexpr int kMinZoom = 3;
 constexpr int kMaxZoom = 18;
 constexpr double kGroundZ = 0.0;      // 底图置于 z=0 地面参考（剖面深度向下为负，落其下）
@@ -287,12 +288,23 @@ void TileBasemap::refresh() {
         for (int dx = -1; dx <= 1; ++dx)
             refineTile(kRootZoom, root.x + dx, root.y + dy, desired_, count);
 
-    // 拉取缺失瓦片（旧层暂不删，落地后由 purgeStale 清理）。
+    // 拉取缺失瓦片：按离相机距离排序，最近的先拉 → 用户正看的区域最先出现(而非粗/远块先出)。
+    std::vector<std::pair<double, long long>> todo;
     for (long long key : desired_) {
         if (placed_.count(key) || inFlight_.count(key)) continue;
         int z, x, y;
         unpackKey(key, z, x, y);
-        fetchTile(z, x, y, key);
+        const geopro::render::LonLatBox b = geopro::render::tileBounds(z, x, y);
+        const auto sw = frame_->toLocal(b.south, b.west);
+        const auto ne = frame_->toLocal(b.north, b.east);
+        const double cx = (sw.x + ne.x) * 0.5 - camX_, cy = (sw.y + ne.y) * 0.5 - camY_;
+        todo.push_back({cx * cx + cy * cy, key});
+    }
+    std::sort(todo.begin(), todo.end());
+    for (const auto& t : todo) {
+        int z, x, y;
+        unpackKey(t.second, z, x, y);
+        fetchTile(z, x, y, t.second);
     }
 
     purgeStale();