From 09f850728a728b1fd211ec30153dc51bcc83725e Mon Sep 17 00:00:00 2001
From: Stephan Unverwerth <s.unverwerth@gmx.de>
Date: Sun, 18 Apr 2021 16:25:25 +0200
Subject: [PATCH] LibGfx: Add some missing operators to Vector3 Vector4 and
 Matrix4x4

---
 Userland/Libraries/LibGfx/Matrix4x4.h | 19 +++++++++++++++++++
 Userland/Libraries/LibGfx/Vector3.h   | 16 ++++++++++++++++
 Userland/Libraries/LibGfx/Vector4.h   | 18 ++++++++++++++++++
 3 files changed, 53 insertions(+)

diff --git a/Userland/Libraries/LibGfx/Matrix4x4.h b/Userland/Libraries/LibGfx/Matrix4x4.h
index 16f927d3ce..c1ebdfaaa5 100644
--- a/Userland/Libraries/LibGfx/Matrix4x4.h
+++ b/Userland/Libraries/LibGfx/Matrix4x4.h
@@ -8,6 +8,7 @@
 
 #include <LibGfx/Matrix.h>
 #include <LibGfx/Vector3.h>
+#include <LibGfx/Vector4.h>
 #include <math.h>
 
 namespace Gfx {
@@ -46,6 +47,15 @@ public:
         return product;
     }
 
+    Vector4<T> operator*(const Vector4<T>& v) const
+    {
+        return Vector4<T>(
+            v.x() * m_elements[0][0] + v.y() * m_elements[1][0] + v.z() * m_elements[2][0] + v.w() * m_elements[3][0],
+            v.x() * m_elements[0][1] + v.y() * m_elements[1][1] + v.z() * m_elements[2][1] + v.w() * m_elements[3][1],
+            v.x() * m_elements[0][2] + v.y() * m_elements[1][2] + v.z() * m_elements[2][2] + v.w() * m_elements[3][2],
+            v.x() * m_elements[0][3] + v.y() * m_elements[1][3] + v.z() * m_elements[2][3] + v.w() * m_elements[3][3]);
+    }
+    
     Vector3<T> transform_point(const Vector3<T>& p) const
     {
         return Vector3<T>(
@@ -54,6 +64,15 @@ public:
             p.x() * m_elements[0][2] + p.y() * m_elements[1][2] + p.z() * m_elements[2][2] + m_elements[3][2]);
     }
 
+    static Matrix4x4 identity()
+    {
+        return Matrix4x4(
+            1, 0, 0, 0,
+            0, 1, 0, 0,
+            0, 0, 1, 0,
+            0, 0, 0, 1);
+    }
+
     static Matrix4x4 translate(const Vector3<T>& p)
     {
         return Matrix4x4(
diff --git a/Userland/Libraries/LibGfx/Vector3.h b/Userland/Libraries/LibGfx/Vector3.h
index 49c8c05afc..2a3a143113 100644
--- a/Userland/Libraries/LibGfx/Vector3.h
+++ b/Userland/Libraries/LibGfx/Vector3.h
@@ -28,6 +28,22 @@ public:
     void set_y(T value) { m_y = value; }
     void set_z(T value) { m_z = value; }
 
+    Vector3& operator+=(const Vector3& other)
+    {
+        m_x += other.m_x;
+        m_y += other.m_y;
+        m_z += other.m_z;
+        return *this;
+    }
+
+    Vector3& operator-=(const Vector3& other)
+    {
+        m_x -= other.m_x;
+        m_y -= other.m_y;
+        m_z -= other.m_z;
+        return *this;
+    }
+
     Vector3 operator+(const Vector3& other) const
     {
         return Vector3(m_x + other.m_x, m_y + other.m_y, m_z + other.m_z);
diff --git a/Userland/Libraries/LibGfx/Vector4.h b/Userland/Libraries/LibGfx/Vector4.h
index c48d349565..3f735c3669 100644
--- a/Userland/Libraries/LibGfx/Vector4.h
+++ b/Userland/Libraries/LibGfx/Vector4.h
@@ -31,6 +31,24 @@ public:
     void set_z(T value) { m_z = value; }
     void set_w(T value) { m_w = value; }
 
+    Vector4& operator+=(const Vector4& other)
+    {
+        m_x += other.m_x;
+        m_y += other.m_y;
+        m_z += other.m_z;
+        m_w += other.m_w;
+        return *this;
+    }
+
+    Vector4& operator-=(const Vector4& other)
+    {
+        m_x -= other.m_x;
+        m_y -= other.m_y;
+        m_z -= other.m_z;
+        m_w -= other.m_w;
+        return *this;
+    }
+
     Vector4 operator+(const Vector4& other) const
     {
         return Vector4(m_x + other.m_x, m_y + other.m_y, m_z + other.m_z, m_w + other.m_w);