From 6dcadb5131805fdcf6a8149070539e0ddb9e1a72 Mon Sep 17 00:00:00 2001
From: NoriteSC <53096989+NoriteSC@users.noreply.github.com>
Date: Wed, 8 Nov 2023 18:34:17 +0100
Subject: [PATCH] Compacted UpdateTransform Matrix math

---
 Source/Engine/UI/GUI/Control.Bounds.cs | 53 +++++++++++++++++++-------
 1 file changed, 40 insertions(+), 13 deletions(-)

diff --git a/Source/Engine/UI/GUI/Control.Bounds.cs b/Source/Engine/UI/GUI/Control.Bounds.cs
index c6260b648..272b1c5f1 100644
--- a/Source/Engine/UI/GUI/Control.Bounds.cs
+++ b/Source/Engine/UI/GUI/Control.Bounds.cs
@@ -487,9 +487,12 @@ namespace FlaxEngine.GUI
         public void UpdateTransform()
         {
             // Actual pivot and negative pivot
-            Float2.Multiply(ref _pivot, ref _bounds.Size, out var v1);
-            Float2.Negate(ref v1, out var v2);
-            Float2.Add(ref v1, ref _bounds.Location, out v1);
+            //Float2.Multiply(ref _pivot, ref _bounds.Size, out var v1);
+            //Float2.Negate(ref v1, out var v2);
+            //Float2.Add(ref v1, ref _bounds.Location, out v1);
+            var v1 = _pivot * _bounds.Size;
+            var v2 = -v1;
+            v1 += _bounds.Location;
 
             // ------ Matrix3x3 based version:
 
@@ -518,18 +521,42 @@ namespace FlaxEngine.GUI
             // ------ Matrix2x2 based version:
 
             // 2D transformation
-            Matrix2x2.Scale(ref _scale, out Matrix2x2 m1);
-            Matrix2x2.Shear(ref _shear, out Matrix2x2 m2);
-            Matrix2x2.Multiply(ref m1, ref m2, out m1);
-            Matrix2x2.Rotation(Mathf.DegreesToRadians * _rotation, out m2);
-            Matrix2x2.Multiply(ref m1, ref m2, out m1);
+
+            //Matrix2x2.Scale(ref _scale, out Matrix2x2 m1);
+            //Matrix2x2.Shear(ref _shear, out Matrix2x2 m2);
+            //Matrix2x2.Multiply(ref m1, ref m2, out m1);
+
+            // Scale and Shear
+            Matrix3x3 m1 = new Matrix3x3
+                (
+                _scale.X,
+                _scale.X * (_shear.X == 0 ? 0 : (1.0f / Mathf.Tan(Mathf.DegreesToRadians * (90 - Mathf.Clamp(_shear.X, -89.0f, 89.0f))))),
+                0,
+                _scale.Y * (_shear.Y == 0 ? 0 : (1.0f / Mathf.Tan(Mathf.DegreesToRadians * (90 - Mathf.Clamp(_shear.Y, -89.0f, 89.0f))))),
+                _scale.Y,
+                0, 0, 0, 1
+                );
+
+            
+            //Matrix2x2.Rotation(Mathf.DegreesToRadians * _rotation, out m2);
+            float sin = Mathf.Sin(Mathf.DegreesToRadians * _rotation);
+            float cos = Mathf.Cos(Mathf.DegreesToRadians * _rotation);
+
+            //Matrix2x2.Multiply(ref m1, ref m2, out m1);
+            m1.M11 = (_scale.X * cos) + (m1.M12 * -sin);
+            m1.M12 = (_scale.X * sin) + (m1.M12 * cos);
+            m1.M21 = (m1.M21 * cos) + (_scale.Y * -sin);
+            m1.M22 = (m1.M21 * sin) + (_scale.Y * cos);
 
             // Mix all the stuff
-            Matrix3x3.Translation2D(ref v2, out Matrix3x3 m3);
-            Matrix3x3 m4 = (Matrix3x3)m1;
-            Matrix3x3.Multiply(ref m3, ref m4, out m3);
-            Matrix3x3.Translation2D(ref v1, out m4);
-            Matrix3x3.Multiply(ref m3, ref m4, out _cachedTransform);
+            //Matrix3x3.Translation2D(ref v2, out Matrix3x3 m3);
+            //Matrix3x3 m4 = (Matrix3x3)m1;
+            //Matrix3x3.Multiply(ref m3, ref m4, out m3);
+            //Matrix3x3.Translation2D(ref v1, out Matrix3x3 m4);
+            //Matrix3x3.Multiply(ref m3, ref m4, out _cachedTransform);
+            m1.M31 = (v2.X * m1.M11) + (v2.Y * m1.M21) + v1.X;
+            m1.M32 = (v2.X * m1.M12) + (v2.Y * m1.M22) + v1.Y;
+            _cachedTransform = m1;
 
             // Cache inverted transform
             Matrix3x3.Invert(ref _cachedTransform, out _cachedTransformInv);