Transform2D

include/J3ML/LinearAlgebra/Transform2D.hpp

@@ -12,11 +12,31 @@ namespace J3ML::LinearAlgebra {
         const static Transform2D FlipX;
         const static Transform2D FlipY;
 
+        /// Default constructor initializes to an Identity tansformation.
+        Transform2D()
+        {
+            transformation.Row(0) = {1, 0, 0};
+            transformation.Row(1) = {0, 1, 0};
+            transformation.Row(2) = {0, 0, 1};
+        }
+
         Transform2D(float rotation, const Vector2& pos);
         Transform2D(float px, float py, float sx, float sy, float ox, float oy, float kx, float ky, float rotation)
         {
             transformation = Matrix3x3(px, py, rotation, sx, sy, ox, oy, kx, ky);
         }
+
+        static Transform2D FromScale(float sx, float sy)
+        {
+            Transform2D s;
+            s.transformation[0][0] = sx;
+            s.transformation[1][1] = sy;
+            return s;
+        }
+        static Transform2D FromScale(const Vector2& scale)
+        {
+            return FromScale(scale.x, scale.y);
+        }
         Transform2D(const Vector2& pos, const Vector2& scale, const Vector2& origin, const Vector2& skew, float rotation);
         Transform2D(const Matrix3x3& transform);
         Transform2D Translate(const Vector2& offset) const;
@@ -25,7 +45,13 @@ namespace J3ML::LinearAlgebra {
         Transform2D Scale(float x, float y);      // Perform Nonunform Scale
         Transform2D Scale(const Vector2& scales); // Perform Nonuniform Scale
         Transform2D Rotate();
-        Vector2 Transform(const Vector2& input) const;
+        Vector2 Transform(const Vector2& point) const
+        {
+            Vector2 result;
+            result.x = transformation.At(0,0) * point.x + transformation.At(0,1) * point.y + transformation.At(0,2);
+            result.y = transformation.At(1,0) * point.x + transformation.At(1,1) * point.y + transformation.At(1,2);
+            return result;
+        }
         Transform2D Inverse() const;
         Transform2D AffineInverse() const;
         float Determinant() const;