From d550baa11e6c5fbf84441e4dccac1a6dcc66a099 Mon Sep 17 00:00:00 2001
From: SepComet <2428390463@qq.com>
Date: Mon, 16 Mar 2026 14:30:57 +0800
Subject: [PATCH] view matrix + half projection matrix

---
 .gitattributes                         |  2 ++
 CPU-Software-Renderer/Math/MathUtil.h  |  5 ++++
 CPU-Software-Renderer/Scene/Camera.cpp | 35 ++++++++++++++++++++------
 CPU-Software-Renderer/Scene/Camera.h   |  4 ++-
 4 files changed, 38 insertions(+), 8 deletions(-)
 create mode 100644 .gitattributes

diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..f934725
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,2 @@
+# Disable line-ending normalization in this repository.
+* -text
diff --git a/CPU-Software-Renderer/Math/MathUtil.h b/CPU-Software-Renderer/Math/MathUtil.h
index 8d1208b..996267a 100644
--- a/CPU-Software-Renderer/Math/MathUtil.h
+++ b/CPU-Software-Renderer/Math/MathUtil.h
@@ -92,5 +92,10 @@ namespace Math
 				0, 0, 0, 1
 			);
 		}
+
+		static Vector3 cross(const Vector3& vec1, const Vector3& vec2)
+		{
+			return vec1.cross(vec2);
+		}
 	};
 }
\ No newline at end of file
diff --git a/CPU-Software-Renderer/Scene/Camera.cpp b/CPU-Software-Renderer/Scene/Camera.cpp
index d838be8..0879549 100644
--- a/CPU-Software-Renderer/Scene/Camera.cpp
+++ b/CPU-Software-Renderer/Scene/Camera.cpp
@@ -2,6 +2,7 @@
 #include "Matrix4x4.h"
 #include "Camera.h"
 #include <Vector3.h>
+#include "MathUtil.h"
 
 namespace Scene
 {
@@ -9,20 +10,20 @@ namespace Scene
 	{
 		using namespace Math;
 
-		Vector3 forward = (target - position).normalized();
-		Vector3 right = forward.cross(up).normalized();
-		if (right.magnitude() < 1e-5) right = forward.cross(Vector3(0, 1, 0));
-		Vector3 cameraUp = right.cross(forward);
+		Vector3 backward = (position - target).normalized();
+		Vector3 right = MathUtil::cross(up, backward).normalized();
+		if (right.magnitude() < 1e-5) right = MathUtil::cross(Vector3(0, 1, 0), backward);
+		Vector3 cameraUp = MathUtil::cross(backward, right);
 
 		return Matrix4x4(
 			right.x, right.y, right.z, -right.dot(position),
 			cameraUp.x, cameraUp.y, cameraUp.z, -cameraUp.dot(position),
-			-forward.x, -forward.y, -forward.z, forward.dot(position),
+			backward.x, backward.y, backward.z, -backward.dot(position),
 			0, 0, 0, 1
 		);
 	}
 
-	Math::Matrix4x4 Camera::get_projection_matrix(float aspectRatio) const
+	Math::Matrix4x4 Camera::get_orthographic_projection_matrix(float aspectRatio) const
 	{
 		using namespace Math;
 
@@ -30,4 +31,24 @@ namespace Scene
 
 		);
 	}
-}
+
+	Math::Matrix4x4 Camera::get_perspective_projection_matrix(float width, float height) const
+	{
+		using namespace Math;
+
+		const float l = -width * 0.5f;
+		const float r = width * 0.5f;
+		const float b = -height * 0.5f;
+		const float t = height * 0.5f;
+		const float n = nearPlane;
+		const float f = farPlane;
+		const float length = n - f;
+
+		return Matrix4x4(
+			2.0f / width, 0, 0, -(r + l) / (r - l) + 1,
+			0, 2.0f / height, 0, -(t + b) / (t - b) + 1,
+			0, 0, 2.0f / length, -(n + f) / (n - f) + 1,
+			0, 0, 0, 1
+		);
+	}
+}
\ No newline at end of file
diff --git a/CPU-Software-Renderer/Scene/Camera.h b/CPU-Software-Renderer/Scene/Camera.h
index 5643cc8..f61a089 100644
--- a/CPU-Software-Renderer/Scene/Camera.h
+++ b/CPU-Software-Renderer/Scene/Camera.h
@@ -38,6 +38,8 @@ namespace Scene
 
 		Math::Matrix4x4 get_view_matrix() const;
 
-		Math::Matrix4x4 get_projection_matrix(float aspectRatio) const;
+		Math::Matrix4x4 get_orthographic_projection_matrix(float aspectRatio) const;
+
+		Math::Matrix4x4 get_perspective_projection_matrix(float width, float height) const;
 	};
 }