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fix: 阴影不可见的真正根因——深度重映射矩阵公式错误

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诊断方法：日志打印 lightVP/lightProj/lightView 矩阵分解定位。
修复前 lightVP 在原点处 z=-14.70（应 ∈[-1,1]）——深度全部越界被裁。

根因：remap 公式把偏移量 0.5 错加进了 z 缩放系数：
  错：M[2][2] = M[2][2]*0.5 + 0.5   （0.5 混入 z 系数）
  对：M[2][2] *= 0.5                （z' = 0.5z + 0.5w，偏移属于 w 列）
      M[3][2] = M[3][2]*0.5 + 0.5
正交投影 w=1，错误的 0.5*z 项使深度随距离线性发散，shadow map
内所有深度越界，采样对比永不成立。透视投影同错（被 w 除法稀释
成近似常数偏移，此前一直"看起来正常"）。修复 Camera + lightProj。

同批修复：
- 深度 bias 1.25 → 0.0025/0.003（NDC 空间，1.25 会饱和全部深度）
- 光源位置 lightDir*30 → -lightDir*30（原方向反了：从地下往上照）
- lookAt 垂直光 up 退化（叉积为零 → NaN 矩阵）
- 地面改纯色纹理（Texture::CreateSolidColor，1x1 程序化生成）

矩阵诊断验证：lightVP 原点深度 -14.70 → 0.30，物体(0.30) < 地面(0.32)
遮挡关系正确。validation 零错误零警告。
This commit is contained in:
atdunbg
2026-09-22 15:35:52 +08:00
parent b86ca460de
commit 3907868417
9 changed files with 86 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files
App/main.cpp
+2 -2
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@@ -42,8 +42,8 @@ protected:
// 模型资产（AssetManager 负责加载/缓存/生命周期，返回句柄）
auto backpack = GetAssets().LoadModel("assets/models/backpack/backpack.obj");
// 地面：接收阴影
auto ground = GetAssets().CreatePlane(30.0f, "assets/textures/default.tga");
// 地面：接收阴影（中性灰纯色，衬托影子）
auto ground = GetAssets().CreatePlane(30.0f, {140, 140, 145});
auto groundEntity = scene.CreateEntity("Ground");
groundEntity.AddComponent<TransformComponent>().world =
glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, -2.0f, 0.0f));
Engine/include/Engine/Assets/AssetManager.h
+2 -2
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@@ -153,8 +153,8 @@ namespace Engine {
Model* GetModel(ModelHandle h) const { return m_Models.Get(h); }
void UnloadModel(ModelHandle h) { m_Models.Unload(h); }
// 程序化平面（地面等），同一 (size, texture) 只创建一次
ModelHandle CreatePlane(f32 size, const std::string& texturePath);
// 程序化平面（地面等），纯色贴图，同一 (size, color) 只创建一次
ModelHandle CreatePlane(f32 size, std::array<u8, 3> color);
AssetCache<Model>& Models() { return m_Models; }
Engine/include/Engine/Renderer/Model.h
+2 -2
View File
@@ -32,11 +32,11 @@ namespace Engine
DescriptorManager& descriptorManager,
vk::DescriptorSetLayout textureLayout,
const std::string& path);
// 程序化构造：单 quad 平面（XZ 平面朝上），不经过 assimp
// 程序化构造：单 quad 平面（XZ 平面朝上），纯色贴图，不经过 assimp
static Scope<Model> CreatePlane(Device& device, MemoryAllocator& allocator,
DescriptorManager& descriptorManager,
vk::DescriptorSetLayout textureLayout,
f32 size, const std::string& texturePath);
f32 size, std::array<u8, 3> color);
~Model();
Engine/include/Engine/Vulkan/Texture.h
+15
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@@ -9,6 +9,7 @@
#include <Engine/Core/Types.h>
#include <vulkan/vulkan.hpp>
#include <array>
#include <string>
#include "MemoryAllocator.h"
@@ -21,6 +22,12 @@ namespace Engine {
class Texture {
public:
Texture(Device& device, MemoryAllocator& allocator, const std::string& path);
// 程序化纯色纹理（不经过磁盘），width/height = 1 时即单色
static Scope<Texture> CreateSolidColor(Device& device, MemoryAllocator& allocator,
u32 width, u32 height,
std::array<u8, 4> rgba);
~Texture();
Texture(const Texture&) = delete;
@@ -49,6 +56,14 @@ namespace Engine {
MemoryAllocator::Allocation m_ImageAllocation;
MemoryAllocator& m_Allocator;
// 公共上传路径：staging → device local image → view/sampler
// （文件加载与程序化创建共用）
void InitFromPixels(const void* pixels, u32 width, u32 height,
const std::string& debugName);
struct UploadTag {};
Texture(UploadTag, Device& device, MemoryAllocator& allocator);
};
} // namespace Engine
Engine/src/Assets/AssetManager.cpp
+6 -3
View File
@@ -28,13 +28,16 @@ namespace Engine::Assets {
});
}
ModelHandle AssetManager::CreatePlane(f32 size, const std::string& texturePath)
ModelHandle AssetManager::CreatePlane(f32 size, std::array<u8, 3> color)
{
const std::string key = "procedural://plane/" +
std::to_string(size) + "/" + texturePath;
std::to_string(size) + "/" +
std::to_string(color[0]) + "/" +
std::to_string(color[1]) + "/" +
std::to_string(color[2]);
return m_Models.Load(key, [&](const std::string&) -> Scope<Model> {
return Model::CreatePlane(m_Device, m_Allocator, m_Descriptors,
m_TextureLayout, size, texturePath);
m_TextureLayout, size, color);
});
}
Engine/src/Renderer/Camera.cpp
+6
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@@ -58,6 +58,12 @@ namespace Engine {
{
auto proj = glm::perspective(glm::radians(45.0f), aspect, nearZ, farZ);
proj[1][1] *= -1.0f; // Vulkan Y 翻转
// 深度重映射 z' = 0.5z + 0.5w（Vulkan clip volume [0,1]）：
// 缩放作用于 z 系数 [2][2]，偏移作用于 w 列系数 [3][2]。
// 没有这一步：近半段视锥被裁掉、深度精度减半。
proj[2][2] *= 0.5f;
proj[3][2] = proj[3][2] * 0.5f + 0.5f;
return proj;
}
Engine/src/Renderer/Model.cpp
+6 -3
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@@ -49,14 +49,17 @@ Model::Model(ProceduralTag, Device& device, MemoryAllocator& allocator,
Scope<Model> Model::CreatePlane(Device& device, MemoryAllocator& allocator,
DescriptorManager& descriptorManager,
vk::DescriptorSetLayout textureLayout,
f32 size, const std::string& texturePath)
f32 size, std::array<u8, 3> color)
{
auto model = Scope<Model>(new Model(ProceduralTag{}, device, allocator,
descriptorManager, textureLayout));
auto* texture = model->GetOrLoadTexture(texturePath);
// 纯色纹理（1x1）：不依赖磁盘资产
auto texture = Texture::CreateSolidColor(device, allocator, 1, 1,
{color[0], color[1], color[2], 255});
auto material = CreateScope<Material>(device, descriptorManager,
textureLayout, texture);
textureLayout, texture.get());
model->m_TextureCache["__solid_color"] = std::move(texture);
const f32 h = size * 0.5f;
std::vector<Vertex> vertices = {
Engine/src/Renderer/Renderer.cpp
+9 -3
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@@ -292,9 +292,12 @@ namespace Engine
cmd.setDepthBoundsTestEnable(VK_FALSE);
cmd.setStencilTestEnable(VK_FALSE);
// 深度偏移：缓解 shadow acne（斜率缩放）
// 深度偏移：缓解 shadow acne。
// 注意：bias 作用在 NDC 深度 [0,1] 上！正交阴影图的合理量级
// 是 0.001~0.005——写 1.25 会把全部深度饱和成 1.0，
// shadow map 变成纯白，采样对比永远不成立（无影子）。
cmd.setDepthBiasEnable(VK_TRUE);
cmd.setDepthBias(1.25f, 0.0f, 1.75f);
cmd.setDepthBias(0.0025f, 0.0f, 0.003f);
cmd.setPolygonModeEXT(vk::PolygonMode::eFill);
cmd.setCullMode(vk::CullModeFlagBits::eNone);
@@ -567,7 +570,10 @@ namespace Engine
glm::mat4 lightProj = glm::ortho(
-20.0f, 20.0f, -20.0f, 20.0f, 0.1f, 100.0f);
lightProj[2][2] = lightProj[2][2] * 0.5f + 0.5f;
// 深度重映射 z' = 0.5z + 0.5w：缩放作用于 z 系数 [2][2]，
// 偏移作用于 w 列系数 [3][2]！之前把 0.5 错加进 [2][2]，
// 正交投影（w=1）下深度随距离发散，全部超出裁剪范围。
lightProj[2][2] *= 0.5f;
lightProj[3][2] = lightProj[3][2] * 0.5f + 0.5f;
m_LightSpaceMatrix = lightProj * lightView;
Engine/src/Vulkan/Texture.cpp
+38 -8
View File
@@ -28,8 +28,40 @@ namespace Engine
return;
}
m_Width = static_cast<u32>(width);
m_Height = static_cast<u32>(height);
InitFromPixels(pixels, static_cast<u32>(width), static_cast<u32>(height), path);
stbi_image_free(pixels);
}
Texture::Texture(UploadTag, Device& device, MemoryAllocator& allocator)
: m_Device(device), m_Allocator(allocator)
{
}
Scope<Texture> Texture::CreateSolidColor(Device& device, MemoryAllocator& allocator,
u32 width, u32 height,
std::array<u8, 4> rgba)
{
auto tex = Scope<Texture>(new Texture(UploadTag{}, device, allocator));
const size_t pixelCount = static_cast<size_t>(width) * height;
std::vector<u8> pixels(pixelCount * 4, rgba[3]); // 全填 alpha，下面覆写 RGB
for (size_t i = 0; i < pixelCount; ++i) {
pixels[i * 4 + 0] = rgba[0];
pixels[i * 4 + 1] = rgba[1];
pixels[i * 4 + 2] = rgba[2];
pixels[i * 4 + 3] = rgba[3];
}
tex->InitFromPixels(pixels.data(), width, height, "solid_color");
return tex;
}
void Texture::InitFromPixels(const void* pixels, u32 width, u32 height,
const std::string& debugName)
{
m_Width = width;
m_Height = height;
vk::DeviceSize imageSize = static_cast<vk::DeviceSize>(width) *
static_cast<vk::DeviceSize>(height) * 4; // RGBA8
@@ -42,7 +74,7 @@ namespace Engine
vk::Buffer stagingBuffer = m_Device.GetDevice().createBuffer(stagingInfo);
auto stagingReqs = m_Device.GetDevice().getBufferMemoryRequirements(stagingBuffer);
auto stagingAlloc = allocator.Allocate(
auto stagingAlloc = m_Allocator.Allocate(
stagingReqs,
vk::MemoryPropertyFlagBits::eHostVisible |
vk::MemoryPropertyFlagBits::eHostCoherent);
@@ -52,8 +84,6 @@ namespace Engine
// 3. 拷贝像素到 Staging Buffer
std::memcpy(stagingAlloc.MappedPtr, pixels, static_cast<size_t>(imageSize));
stbi_image_free(pixels);
// 4. 创建 Device Local Image
vk::ImageCreateInfo imageInfo;
imageInfo.setImageType(vk::ImageType::e2D)
@@ -70,7 +100,7 @@ namespace Engine
m_Image = m_Device.GetDevice().createImage(imageInfo);
auto imageReqs = m_Device.GetDevice().getImageMemoryRequirements(m_Image);
auto imageAlloc = allocator.Allocate(imageReqs, vk::MemoryPropertyFlagBits::eDeviceLocal);
auto imageAlloc = m_Allocator.Allocate(imageReqs, vk::MemoryPropertyFlagBits::eDeviceLocal);
m_ImageAllocation = imageAlloc;
@@ -185,10 +215,10 @@ namespace Engine
m_Device.GetDevice().destroyFence(fence);
m_Device.GetDevice().destroyCommandPool(pool);
m_Device.GetDevice().destroyBuffer(stagingBuffer);
allocator.Free(stagingAlloc);
m_Allocator.Free(stagingAlloc);
// staging 内存由 MemoryAllocator 统一释放
ENGINE_INFO("Texture loaded: {} ({}x{})", path, m_Width, m_Height);
ENGINE_INFO("Texture uploaded: {} ({}x{})", debugName, m_Width, m_Height);
// 显存占用 = 宽 * 高 * 4 字节（RGBA8）