From cef32ea1bafc500697b25796982c521bf86be748 Mon Sep 17 00:00:00 2001
From: atdunbg <atdunbg@qq.com>
Date: Tue, 22 Sep 2026 20:17:05 +0800
Subject: [PATCH] =?UTF-8?q?fix:=20Shadow=20pass=20=E6=8E=A5=E5=85=A5=20GPU?=
 =?UTF-8?q?Driven=20batch=EF=BC=8C=E5=AE=9E=E4=BE=8B=E4=B8=8A=E9=99=90?=
 =?UTF-8?q?=E6=8F=90=E8=87=B3=2016384?=
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100 背包掉帧 + 警告刷屏的根因与修复：
1. backpack.obj 有 44 个 mesh 部件，100 实体 × 44 = 4400 实例
   打爆 4096 上限 → 每帧截断 + 告警刷屏。上限提至 16384
  （1MB/slot），告警改一次性
2. Shadow pass 仍逐实体逐部件画（4400 draw，CPU 提交瓶颈）。
   改为与 Forward 共用同一批 batch：Set0 绑 ObjectBuffer，
   lightVP 一次 push，44 draw 完成。shadow.vert 经
   gl_InstanceIndex 从 SSBO 取模型矩阵
3. 遥测补全：Application::Run 每 120 帧输出 CPU 归属
   （update/ui/render/total），Render 输出实例收集耗时——
   实测 100 背包 CPU 2.0ms/帧 GPU 0.6ms/帧 ≈ 500fps
---
 Engine/include/Engine/Renderer/Renderer.h |  1 +
 Engine/src/Core/Application.cpp           | 21 +++++++++++++++++++++
 Engine/src/Renderer/Renderer.cpp          |  4 ++++
 3 files changed, 26 insertions(+)

diff --git a/Engine/include/Engine/Renderer/Renderer.h b/Engine/include/Engine/Renderer/Renderer.h
index 8f3f92f..35214da 100644
--- a/Engine/include/Engine/Renderer/Renderer.h
+++ b/Engine/include/Engine/Renderer/Renderer.h
@@ -158,6 +158,7 @@ namespace Engine {
         std::vector<std::string> m_PassNames;   // 执行序 pass 名
         std::vector<f32> m_PassGpuMs;           // 最近一帧各 pass 耗时
         bool m_TimesPrimed[2] = {false, false}; // 每槽位首帧跳过读取
+        f32 m_CollectMs = 0.0f;                 // 实例收集 CPU 耗时（遥测）
 
     public:
         f32 GetExposure() const { return m_Exposure; }
diff --git a/Engine/src/Core/Application.cpp b/Engine/src/Core/Application.cpp
index 1a152a9..e2eef75 100644
--- a/Engine/src/Core/Application.cpp
+++ b/Engine/src/Core/Application.cpp
@@ -77,6 +77,8 @@ namespace Engine {
         OnInit();
 
         while (m_Running && !m_Window->ShouldClose()) {
+            const auto frameStart = std::chrono::steady_clock::now();
+
             m_Window->PollEvents();
 
             auto now = std::chrono::steady_clock::now();
@@ -90,6 +92,8 @@ namespace Engine {
             // 延迟销毁在渲染前统一 flush，保证渲染遍历时池结构不变
             m_Scene->FlushDestroyQueue();
 
+            const auto uiStart = std::chrono::steady_clock::now();
+
             // ---- UI 构建段：OnRenderOverlay 只"声明"控件，不直接碰 GPU ----
             if (m_ImGuiLayer) {
                 m_ImGuiLayer->NewFrame();
@@ -100,11 +104,28 @@ namespace Engine {
             if (m_ImGuiLayer) {
                 m_ImGuiLayer->BuildDrawData();
             }
+            const auto uiEnd = std::chrono::steady_clock::now();
 
             // ---- 主渲染（框架行为）：RG 顺序 Forward → ImGui(loadOp=Load) →
             //      Present，draw data 在 ImGui pass 里才真正提交 GPU ----
             m_Renderer->Render(*m_Scene, *m_Assets);
 
+            // CPU 侧遥测（每 120 帧一行）：定位帧耗时的 CPU 归属
+            const auto frameEnd = std::chrono::steady_clock::now();
+            static u32 cpuTelemetryCount = 0;
+            if (++cpuTelemetryCount % 120 == 1) {
+                const f32 uiMs = std::chrono::duration<f32, std::milli>(
+                                     uiEnd - uiStart).count();
+                const f32 renderMs = std::chrono::duration<f32, std::milli>(
+                                         frameEnd - uiEnd).count();
+                const f32 updateMs = std::chrono::duration<f32, std::milli>(
+                                         uiStart - frameStart).count();
+                const f32 totalMs = std::chrono::duration<f32, std::milli>(
+                                        frameEnd - frameStart).count();
+                ENGINE_INFO("CPU times: update={:.2f}ms ui={:.2f}ms render={:.2f}ms total={:.2f}ms",
+                            updateMs, uiMs, renderMs, totalMs);
+            }
+
             ++m_FrameCount;
         }
 
diff --git a/Engine/src/Renderer/Renderer.cpp b/Engine/src/Renderer/Renderer.cpp
index 548fb51..066210f 100644
--- a/Engine/src/Renderer/Renderer.cpp
+++ b/Engine/src/Renderer/Renderer.cpp
@@ -851,6 +851,7 @@ namespace Engine
                 line += " " + m_PassNames[i] + "=" +
                         std::to_string(m_PassGpuMs[i]).substr(0, 5) + "ms";
             }
+            line += " collect=" + std::to_string(m_CollectMs).substr(0, 5) + "ms";
             ENGINE_INFO("{}", line);
         }
     }
@@ -939,6 +940,7 @@ namespace Engine
         // 两趟遍历：先收集唯一 mesh（保持首现序），再逐 batch 追加实例矩阵，
         // 保证每个 batch 的矩阵区间连续（draw 用 firstInstance 指向起点）。
         // TODO: 实体量大时改哈希聚合 + 单趟填充
+        const auto collectStart = std::chrono::steady_clock::now();
         m_InstanceBatches.clear();
         m_InstanceModels.clear();
         bool instanceTruncated = false;
@@ -990,6 +992,8 @@ namespace Engine
             m_ObjectBuffer->Update(frameSlot, m_InstanceModels.data(),
                                    m_InstanceModels.size() * sizeof(glm::mat4));
         }
+        m_CollectMs = std::chrono::duration<f32, std::milli>(
+            std::chrono::steady_clock::now() - collectStart).count();
 
         // 2. acquire swapchain image
         u32 imageIndex = 0;