Merge pull request #38394 from reduz/implement-skew

Implement Skew in Node2D

2 files changed, 23 insertions, 0 deletions

diff --git a/core/math/transform_2d.cpp b/core/math/transform_2d.cpp
index 97a9216a5a..ed95baa233 100644
--- a/core/math/transform_2d.cpp
+++ b/core/math/transform_2d.cpp
@@ -70,6 +70,18 @@ void Transform2D::rotate(real_t p_phi) {
 	*this = Transform2D(p_phi, Vector2()) * (*this);
 }
 
+real_t Transform2D::get_skew() const {
+
+	real_t det = basis_determinant();
+	return Math::acos(elements[0].normalized().dot(SGN(det) * elements[1].normalized())) - Math_PI * 0.5;
+}
+
+void Transform2D::set_skew(float p_angle) {
+
+	real_t det = basis_determinant();
+	elements[1] = SGN(det) * elements[0].rotated((Math_PI * 0.5 + p_angle)).normalized() * elements[1].length();
+}
+
 real_t Transform2D::get_rotation() const {
 	real_t det = basis_determinant();
 	Transform2D m = orthonormalized();
diff --git a/core/math/transform_2d.h b/core/math/transform_2d.h
index fa43762aa4..459ceed7a9 100644
--- a/core/math/transform_2d.h
+++ b/core/math/transform_2d.h
@@ -70,7 +70,10 @@ struct Transform2D {
 
 	void set_rotation(real_t p_rot);
 	real_t get_rotation() const;
+	real_t get_skew() const;
+	void set_skew(float p_angle);
 	_FORCE_INLINE_ void set_rotation_and_scale(real_t p_rot, const Size2 &p_scale);
+	_FORCE_INLINE_ void set_rotation_scale_and_skew(real_t p_rot, const Size2 &p_scale, float p_skew);
 	void rotate(real_t p_phi);
 
 	void scale(const Size2 &p_scale);
@@ -184,6 +187,14 @@ void Transform2D::set_rotation_and_scale(real_t p_rot, const Size2 &p_scale) {
 	elements[0][1] = Math::sin(p_rot) * p_scale.x;
 }
 
+void Transform2D::set_rotation_scale_and_skew(real_t p_rot, const Size2 &p_scale, float p_skew) {
+
+	elements[0][0] = Math::cos(p_rot) * p_scale.x;
+	elements[1][1] = Math::cos(p_rot + p_skew) * p_scale.y;
+	elements[1][0] = -Math::sin(p_rot + p_skew) * p_scale.y;
+	elements[0][1] = Math::sin(p_rot) * p_scale.x;
+}
+
 Rect2 Transform2D::xform_inv(const Rect2 &p_rect) const {
 
 	Vector2 ends[4] = {