viewport 视口变换

.gitignore

@@ -44,3 +44,4 @@ compile_commands.json
 Thumbs.db
 SDL2-2.32.10-win32-x64.zip
 SDL2-devel-2.32.10-VC.zip
+/.dotnet-home

AGENTS.md

@@ -0,0 +1,30 @@
+# Repository Guidelines
+
+## Project Structure & Module Organization
+The repository is a single Visual Studio C++ project under `CPU-Software-Renderer/`. `main.cpp` is the current executable entry point and demo loop. Core renderer pieces live in `Core/` (`FrameBuffer`, `DepthBuffer`, `Renderer`), math types in `Math/`, rasterization logic in `Rasterizer/`, scene data in `Scene/`, asset loading in `Asset/`, and shader code in `Shading/`. SDL2 is vendored in `CPU-Software-Renderer/libs/SDL2/`. Planning notes live in `CPU-Software-Renderer/TODO.md`. Build outputs appear in `Debug/`, `Release/`, and `x64/`; do not commit those artifacts.
+
+## Build, Test, and Development Commands
+Use Visual Studio 2022 or MSBuild, not `dotnet build`, because the project depends on Visual C++ targets.
+
+```powershell
+MSBuild.exe CPU-Software-Renderer\CPU-Software-Renderer.vcxproj /p:Configuration=Debug /p:Platform=x64
+```
+
+Builds the debug x64 executable at `CPU-Software-Renderer/x64/Debug/CPU-Software-Renderer.exe`.
+
+```powershell
+MSBuild.exe CPU-Software-Renderer\CPU-Software-Renderer.vcxproj /p:Configuration=Release /p:Platform=x64
+```
+
+Builds the optimized release binary. In Visual Studio, open `CPU-Software-Renderer.slnx` or the `.vcxproj`, then run the selected `Debug|x64` or `Release|x64` target.
+
+## Coding Style & Naming Conventions
+Follow the existing C++20/MSVC style: tabs for indentation, braces on the next line for functions and control blocks, and include headers with quoted local paths such as `"FrameBuffer.h"`. Types and namespaces use `PascalCase` (`FrameBuffer`, `Math::Vector3`), methods use `snake_case` (`set_pixel`, `set_position`), and local variables use descriptive lowercase names. Keep modules narrow: math stays in `Math/`, render-domain structs in `RenderData/`, and behavior in `Core/` or `Rasterizer/`.
+
+## Testing Guidelines
+There is no automated test project yet. Validate changes by building `Debug|x64`, running the executable, and checking the rendered output or interaction path you changed. When adding nontrivial math or rasterization behavior, prefer small, isolated helper functions so a future test target can cover them easily.
+
+## Commit & Pull Request Guidelines
+Recent history uses short, imperative commit subjects, sometimes in English and sometimes in Chinese, for example `add TODO.md` and `完善 SDL 主循环并收紧三角形光栅化边界处理`. Keep the subject concise and focused on one change. Pull requests should describe the rendering behavior changed, list the build configuration used for verification, and include a screenshot or short note when the visual output changes.
+
+Use UTF-8 encoding when reading and writing.

CPU-Software-Renderer/CPU-Software-Renderer.vcxproj

@@ -58,24 +58,16 @@
   <ImportGroup Label="Shared">
   </ImportGroup>
   <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props"
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-      Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')"
-      Label="LocalAppDataPlatform" />
   </ImportGroup>
   <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props"
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-      Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')"
-      Label="LocalAppDataPlatform" />
   </ImportGroup>
   <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props"
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-      Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')"
-      Label="LocalAppDataPlatform" />
   </ImportGroup>
   <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props"
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-      Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')"
-      Label="LocalAppDataPlatform" />
   </ImportGroup>
   <PropertyGroup Label="UserMacros" />
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
@@ -123,6 +115,7 @@
       <LanguageStandard>stdcpp20</LanguageStandard>
       <AdditionalIncludeDirectories>
         $(ProjectDir)Asset;$(ProjectDir)Core;$(ProjectDir)Math;$(ProjectDir)Rasterizer;$(ProjectDir)RenderData;$(ProjectDir)Scene;$(ProjectDir)Shading;$(ProjectDir)libs\SDL2\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalOptions>/utf-8 %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>

CPU-Software-Renderer/CPU-Software-Renderer.vcxproj.filters

@@ -72,11 +72,15 @@
     <ClCompile Include="Rasterizer\TriangleRasterizer.cpp">
       <Filter>源文件\Rasterizer</Filter>
     </ClCompile>
+    <ClCompile Include="Scene\Camera.cpp">
+      <Filter>源文件</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <None Include="TODO.md">
       <Filter>资源文件</Filter>
     </None>
+    <None Include="..\README.md" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Core\DepthBuffer.h">

CPU-Software-Renderer/Core/FrameBuffer.cpp

@@ -18,6 +18,7 @@ namespace Core
 		{
 			return;
 		}
+		// Row-major layout with y = 0 on the first row, matching a top-left screen origin.
 		size_t index = static_cast<size_t>(y) * width + x;
 		buffer.at(index) = color;
 	}

CPU-Software-Renderer/Math/MathUtil.h

@@ -5,7 +5,7 @@
 
 namespace Math
 {
-	static class MathUtil
+	class MathUtil
 	{
 	public:
 		static Matrix4x4 get_translate_matrix(const float x, const float y, const float z) { return get_translate_matrix(Vector3(x, y, z)); }

CPU-Software-Renderer/Scene/Camera.cpp

@@ -3,6 +3,7 @@
 #include "Camera.h"
 #include <Vector3.h>
 #include "MathUtil.h"
+#include <cmath>
 
 namespace Scene
 {
@@ -56,4 +57,16 @@ namespace Scene
 			0, 0, -1, 0
 		);
 	}
+
+	Math::Matrix4x4 Camera::get_viewport_matrix(float width, float height) const
+	{
+		using namespace Math;
+
+		return Matrix4x4(
+			(width - 1) / 2, 0, 0, (width - 1) / 2,
+			0, -(height - 1) / 2, 0, (height - 1) / 2,
+			0, 0, 1, 0,
+			0, 0, 0, 1
+		);
+	}
 }

CPU-Software-Renderer/Scene/Camera.h

@@ -41,5 +41,7 @@ namespace Scene
 		Math::Matrix4x4 get_orthographic_projection_matrix(float width, float height) const;
 
 		Math::Matrix4x4 get_perspective_projection_matrix(float aspectRatio) const;
+
+		Math::Matrix4x4 get_viewport_matrix(float width, float height) const;
 	};
 }

CPU-Software-Renderer/main.cpp

@@ -17,6 +17,8 @@
 #include "Camera.h"
 #include "SDL_events.h"
 #include "SDL_keycode.h"
+#include "SDL_timer.h"
+#include <cstdlib>
 
 const uint32_t SDL_INIT_FLAGS = SDL_INIT_VIDEO;
 const int32_t width = 800;
@@ -128,8 +130,7 @@ struct CubeFace
 static ProjectedVertex ProjectToScreen(
 	const Math::Vector3& vertex,
 	const Math::Matrix4x4& mvp,
-	const int32_t screenWidth,
+	const Math::Matrix4x4& viewport)
-	const int32_t screenHeight)
 {
 	using namespace Math;
 
@@ -149,8 +150,9 @@ static ProjectedVertex ProjectToScreen(
 		return {};
 	}
 
-	const float screenX = (ndcX * 0.5f + 0.5f) * static_cast<float>(screenWidth - 1);
+	const Vector4 screen = viewport * Vector4(ndcX, ndcY, ndcZ, 1.0f);
-	const float screenY = (1.0f - (ndcY * 0.5f + 0.5f)) * static_cast<float>(screenHeight - 1);
+	const float screenX = screen.x;
+	const float screenY = screen.y;
 
 	return { Vector2(screenX, screenY).to_vector2Int(), true };
 }
@@ -247,6 +249,7 @@ int main(int argc, char* argv[])
 		const Math::Matrix4x4 view = camera.get_view_matrix();
 		const Math::Matrix4x4 modelView = view * model;
 		const Math::Matrix4x4 projection = camera.get_perspective_projection_matrix(aspectRatio);
+		const Math::Matrix4x4 viewport = camera.get_viewport_matrix(static_cast<float>(width), static_cast<float>(height));
 		const Math::Matrix4x4 mvp = projection * modelView;
 
 		std::array<Math::Vector3, 8> viewSpaceVertices;
@@ -254,7 +257,7 @@ int main(int argc, char* argv[])
 		for (size_t i = 0; i < cubeVertices.size(); ++i)
 		{
 			viewSpaceVertices[i] = (modelView * Math::Vector4::Point(cubeVertices[i])).to_vector3();
-			projectedVertices[i] = ProjectToScreen(cubeVertices[i], mvp, width, height);
+			projectedVertices[i] = ProjectToScreen(cubeVertices[i], mvp, viewport);
 		}
 
 		std::array<bool, 12> visibleEdges = {};