From 6e107ac2ba204a092260a702d5a00386152434bd Mon Sep 17 00:00:00 2001
From: atdunbg <atdunbg@qq.com>
Date: Wed, 23 Sep 2026 19:07:53 +0800
Subject: [PATCH] =?UTF-8?q?fix:=20IBL=20=E6=A8=A1=E5=9E=8B=E5=85=A8?=
 =?UTF-8?q?=E9=BB=91=E2=80=94=E2=80=94prefilter=20mip=20=E6=8B=B7=E8=B4=9D?=
 =?UTF-8?q?=E5=81=8F=E7=A7=BB=E9=94=99=E4=BD=8D=20+=20=E9=87=87=E6=A0=B7?=
 =?UTF-8?q?=E5=99=A8=20maxLod=20=E9=94=99=E8=AF=AF?=
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- UploadCube 的 mip buffer 偏移误用当前 mip 尺寸×序号（mip 面递减，
  正确应为累积偏移）→ 各 mip 拷到 staging 错位数据，含未初始化 fp16
  NaN → 污染 ambient 输出整屏黑
- prefilter/irradiance 绑定改用环境采样器（maxLod=mipCount-1）：
  shadowSampler maxLod=0 会把 textureLod 显式 lod clamp 到 0，
  pre-filter 永远停在最锐 mip
---
 Engine/src/Renderer/Cubemap.cpp         | 10 ++++++++--
 Engine/src/Renderer/Passes/SceneGpu.cpp |  9 ++++++---
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/Engine/src/Renderer/Cubemap.cpp b/Engine/src/Renderer/Cubemap.cpp
index 6a3f3cc..2f59982 100644
--- a/Engine/src/Renderer/Cubemap.cpp
+++ b/Engine/src/Renderer/Cubemap.cpp
@@ -328,13 +328,17 @@ namespace Engine
             cmd.pipelineBarrier2(
                 vk::DependencyInfo{}.setImageMemoryBarriers(toTransfer));
 
+            // 逐 mip 逐面拷贝；buffer 偏移必须按 mips[0..mip) 字节数累积
+            //（mip 面尺寸递减，用当前 dim 乘 mip 序号会错位 → 读到
+            // staging 未初始化数据 → fp16 NaN 污染整屏）
+            vk::DeviceSize offset = 0;
             for (u32 mip = 0; mip < mipCount; ++mip) {
                 const u32 dim = mips[mip].faceSize;
                 for (u32 f = 0; f < kFaceCount; ++f) {
                     vk::BufferImageCopy region;
                     region.setBufferOffset(
-                               (static_cast<vk::DeviceSize>(dim) * dim * 8 *
-                                kFaceCount) * mip)
+                               offset + static_cast<vk::DeviceSize>(dim) *
+                                        dim * 8 * f)
                           .setBufferRowLength(0)
                           .setBufferImageHeight(0)
                           .setImageSubresource({vk::ImageAspectFlagBits::eColor,
@@ -345,6 +349,8 @@ namespace Engine
                                           vk::ImageLayout::eTransferDstOptimal,
                                           region);
                 }
+                offset += static_cast<vk::DeviceSize>(dim) * dim * 8 *
+                          kFaceCount;
             }
 
             vk::ImageMemoryBarrier2 toShader;
diff --git a/Engine/src/Renderer/Passes/SceneGpu.cpp b/Engine/src/Renderer/Passes/SceneGpu.cpp
index 44b35a5..2be4183 100644
--- a/Engine/src/Renderer/Passes/SceneGpu.cpp
+++ b/Engine/src/Renderer/Passes/SceneGpu.cpp
@@ -166,11 +166,14 @@ namespace Engine::Passes
 
     void SceneGpu::BindEnvironment(const Cubemap& env)
     {
-        // IBL 资源 view 全程稳定（不随 RG 重编译变化），绑一次即可
+        // IBL 资源 view 全程稳定（不随 RG 重编译变化），绑一次即可。
+        // cube 资源必须用带 mip 的环境采样器（textureLod 显式 lod 会被
+        // clamp 到 maxLod；shadowSampler maxLod=0 会让 pre-filter 永远
+        // 停在最锐的 mip）
         for (u32 slot = 0; slot < kMaxFramesInFlight; ++slot) {
-            m_Descriptors.UpdateTexture(shadowSets[slot], 3, shadowSampler,
+            m_Descriptors.UpdateTexture(shadowSets[slot], 3, env.GetSampler(),
                                         env.GetIrradianceView());
-            m_Descriptors.UpdateTexture(shadowSets[slot], 4, shadowSampler,
+            m_Descriptors.UpdateTexture(shadowSets[slot], 4, env.GetSampler(),
                                         env.GetPrefilteredView());
             m_Descriptors.UpdateTexture(shadowSets[slot], 5,
                                         env.GetBrdfLutSampler(),