Merge pull request #76323 from aaronfranke/3.x-t2d-basis-det

[3.x] Expose `determinant` in Transform2D, rename internal method

core/math/transform_2d.cpp

@@ -44,7 +44,7 @@ Transform2D Transform2D::inverse() const {
 }
 
 void Transform2D::affine_invert() {
-	real_t det = basis_determinant();
+	real_t det = determinant();
 #ifdef MATH_CHECKS
 	ERR_FAIL_COND(det == 0);
 #endif
@@ -93,7 +93,7 @@ Transform2D::Transform2D(real_t p_rot, const Vector2 &p_pos) {
 }
 
 Size2 Transform2D::get_scale() const {
-	real_t det_sign = SGN(basis_determinant());
+	real_t det_sign = SGN(determinant());
 	return Size2(elements[0].length(), det_sign * elements[1].length());
 }
 
@@ -217,7 +217,7 @@ Transform2D Transform2D::rotated(real_t p_angle) const {
 	return copy;
 }
 
-real_t Transform2D::basis_determinant() const {
+real_t Transform2D::determinant() const {
 	return elements[0].x * elements[1].y - elements[0].y * elements[1].x;
 }
 

core/math/transform_2d.h

@@ -79,7 +79,7 @@ struct _NO_DISCARD_CLASS_ Transform2D {
 	void translate(real_t p_tx, real_t p_ty);
 	void translate(const Vector2 &p_translation);
 
-	real_t basis_determinant() const;
+	real_t determinant() const;
 
 	Size2 get_scale() const;
 	void set_scale(const Size2 &p_scale);

core/variant_call.cpp

@@ -886,6 +886,7 @@ struct _VariantCall {
 	VCALL_PTR1R(Transform2D, translated);
 	VCALL_PTR2R(Transform2D, interpolate_with);
 	VCALL_PTR1R(Transform2D, is_equal_approx);
+	VCALL_PTR0R(Transform2D, determinant);
 
 	static void _call_Transform2D_xform(Variant &r_ret, Variant &p_self, const Variant **p_args) {
 		switch (p_args[0]->type) {
@@ -2151,6 +2152,7 @@ void register_variant_methods() {
 	ADDFUNC1R(TRANSFORM2D, TRANSFORM2D, Transform2D, translated, VECTOR2, "offset", varray());
 	ADDFUNC1R(TRANSFORM2D, NIL, Transform2D, xform, NIL, "v", varray());
 	ADDFUNC1R(TRANSFORM2D, NIL, Transform2D, xform_inv, NIL, "v", varray());
+	ADDFUNC0R(TRANSFORM2D, REAL, Transform2D, determinant, varray());
 	ADDFUNC1R(TRANSFORM2D, VECTOR2, Transform2D, basis_xform, VECTOR2, "v", varray());
 	ADDFUNC1R(TRANSFORM2D, VECTOR2, Transform2D, basis_xform_inv, VECTOR2, "v", varray());
 	ADDFUNC2R(TRANSFORM2D, TRANSFORM2D, Transform2D, interpolate_with, TRANSFORM2D, "transform", REAL, "weight", varray());

doc/classes/Transform2D.xml

@@ -60,6 +60,13 @@
 				This method does not account for translation (the origin vector).
 			</description>
 		</method>
+		<method name="determinant">
+			<return type="float" />
+			<description>
+				Returns the determinant of the basis matrix. If the basis is uniformly scaled, then its determinant equals the square of the scale factor.
+				A negative determinant means the basis was flipped, so one part of the scale is negative. A zero determinant means the basis isn't invertible, and is usually considered invalid.
+			</description>
+		</method>
 		<method name="get_origin">
 			<return type="Vector2" />
 			<description>

drivers/gles2/rasterizer_canvas_base_gles2.cpp

@@ -837,7 +837,7 @@ void RasterizerCanvasBaseGLES2::canvas_light_shadow_buffer_update(RID p_buffer,
 			VS::CanvasOccluderPolygonCullMode transformed_cull_cache = instance->cull_cache;
 
 			if (transformed_cull_cache != VS::CANVAS_OCCLUDER_POLYGON_CULL_DISABLED &&
-					(p_light_xform.basis_determinant() * instance->xform_cache.basis_determinant()) < 0) {
+					(p_light_xform.determinant() * instance->xform_cache.determinant()) < 0) {
 				transformed_cull_cache = (transformed_cull_cache == VS::CANVAS_OCCLUDER_POLYGON_CULL_CLOCKWISE)
 						? VS::CANVAS_OCCLUDER_POLYGON_CULL_COUNTER_CLOCKWISE
 						: VS::CANVAS_OCCLUDER_POLYGON_CULL_CLOCKWISE;

drivers/gles3/rasterizer_canvas_base_gles3.cpp

@@ -895,7 +895,7 @@ void RasterizerCanvasBaseGLES3::canvas_light_shadow_buffer_update(RID p_buffer,
 			VS::CanvasOccluderPolygonCullMode transformed_cull_cache = instance->cull_cache;
 
 			if (transformed_cull_cache != VS::CANVAS_OCCLUDER_POLYGON_CULL_DISABLED &&
-					(p_light_xform.basis_determinant() * instance->xform_cache.basis_determinant()) < 0) {
+					(p_light_xform.determinant() * instance->xform_cache.determinant()) < 0) {
 				transformed_cull_cache = (transformed_cull_cache == VS::CANVAS_OCCLUDER_POLYGON_CULL_CLOCKWISE)
 						? VS::CANVAS_OCCLUDER_POLYGON_CULL_COUNTER_CLOCKWISE
 						: VS::CANVAS_OCCLUDER_POLYGON_CULL_CLOCKWISE;

editor/plugins/canvas_item_editor_plugin.cpp

@@ -1623,7 +1623,7 @@ void CanvasItemEditor::_solve_IK(Node2D *leaf_node, Point2 target_position) {
 				Point2 current = (joints_list[node_id - 1]->get_global_position() - joints_list[node_id]->get_global_position()).normalized();
 				Point2 target = (joints_pos[node_id - 1] - joints_list[node_id]->get_global_position()).normalized();
 				float rot = current.angle_to(target);
-				if (joints_list[node_id]->get_global_transform().basis_determinant() < 0) {
+				if (joints_list[node_id]->get_global_transform().determinant() < 0) {
 					rot = -rot;
 				}
 				joints_list[node_id]->rotate(rot);

modules/gdnative/gdnative/transform2d.cpp

@@ -93,6 +93,11 @@ godot_vector2 GDAPI godot_transform2d_get_scale(const godot_transform2d *p_self)
 	return dest;
 }
 
+godot_real GDAPI godot_transform2d_determinant(const godot_transform2d *p_self) {
+	const Transform2D *self = (const Transform2D *)p_self;
+	return self->determinant();
+}
+
 godot_transform2d GDAPI godot_transform2d_orthonormalized(const godot_transform2d *p_self) {
 	godot_transform2d dest;
 	const Transform2D *self = (const Transform2D *)p_self;

modules/gdnative/gdnative_api.json

@@ -4431,6 +4431,13 @@
           ["const godot_transform2d *", "p_self"]
         ]
       },
+      {
+        "name": "godot_transform2d_determinant",
+        "return_type": "godot_real",
+        "arguments": [
+          ["const godot_transform2d *", "p_self"]
+        ]
+      },
       {
         "name": "godot_transform2d_orthonormalized",
         "return_type": "godot_transform2d",

modules/gdnative/include/gdnative/transform2d.h

@@ -74,6 +74,8 @@ godot_vector2 GDAPI godot_transform2d_get_origin(const godot_transform2d *p_self
 
 godot_vector2 GDAPI godot_transform2d_get_scale(const godot_transform2d *p_self);
 
+godot_real GDAPI godot_transform2d_determinant(const godot_transform2d *p_self);
+
 godot_transform2d GDAPI godot_transform2d_orthonormalized(const godot_transform2d *p_self);
 
 godot_transform2d GDAPI godot_transform2d_rotated(const godot_transform2d *p_self, const godot_real p_phi);

scene/main/viewport.cpp

@@ -1786,8 +1786,8 @@ Control *Viewport::_gui_find_control_at_pos(CanvasItem *p_node, const Point2 &p_
 	}
 
 	Transform2D matrix = p_xform * p_node->get_transform();
-	// matrix.basis_determinant() == 0.0f implies that node does not exist on scene
-	if (matrix.basis_determinant() == 0.0f) {
+	// matrix.determinant() == 0.0f implies that node does not exist on scene
+	if (matrix.determinant() == 0.0f) {
 		return nullptr;
 	}