Discern between virtual and abstract class bindings

* Previous "virtual" classes (which can't be instantiated) are not corretly named "abstract".
* Added a new "virtual" category for classes, they can't be instantiated from the editor, but can be inherited from script and extensions.
* Converted a large amount of classes from "abstract" to "virtual" where it makes sense.

Most classes that make sense have been converted. Missing:

* Physics servers
* VideoStream
* Script* classes.

which will go in a separate PR due to the complexity involved.

28 files changed, 12 insertions, 77 deletions

diff --git a/scene/3d/cpu_particles_3d.cpp b/scene/3d/cpu_particles_3d.cpp
index a02b5f48a1..ab28a83806 100644
--- a/scene/3d/cpu_particles_3d.cpp
+++ b/scene/3d/cpu_particles_3d.cpp
@@ -39,10 +39,6 @@ AABB CPUParticles3D::get_aabb() const {
 	return AABB();
 }
 
-Vector<Face3> CPUParticles3D::get_faces(uint32_t p_usage_particle_flags) const {
-	return Vector<Face3>();
-}
-
 void CPUParticles3D::set_emitting(bool p_emitting) {
 	if (emitting == p_emitting) {
 		return;
diff --git a/scene/3d/cpu_particles_3d.h b/scene/3d/cpu_particles_3d.h
index bd736bdf24..5eeb5e75d3 100644
--- a/scene/3d/cpu_particles_3d.h
+++ b/scene/3d/cpu_particles_3d.h
@@ -201,7 +201,6 @@ protected:
 
 public:
 	AABB get_aabb() const override;
-	Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
 
 	void set_emitting(bool p_emitting);
 	void set_amount(int p_amount);
diff --git a/scene/3d/decal.cpp b/scene/3d/decal.cpp
index dfac9055f5..8d0edfd1f3 100644
--- a/scene/3d/decal.cpp
+++ b/scene/3d/decal.cpp
@@ -152,10 +152,6 @@ AABB Decal::get_aabb() const {
 	return aabb;
 }
 
-Vector<Face3> Decal::get_faces(uint32_t p_usage_flags) const {
-	return Vector<Face3>();
-}
-
 void Decal::_validate_property(PropertyInfo &property) const {
 	if (!distance_fade_enabled && (property.name == "distance_fade_begin" || property.name == "distance_fade_length")) {
 		property.usage = PROPERTY_USAGE_NO_EDITOR;
diff --git a/scene/3d/decal.h b/scene/3d/decal.h
index 740dd2c407..d5990272c6 100644
--- a/scene/3d/decal.h
+++ b/scene/3d/decal.h
@@ -104,7 +104,6 @@ public:
 	uint32_t get_cull_mask() const;
 
 	virtual AABB get_aabb() const override;
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
 
 	Decal();
 	~Decal();
diff --git a/scene/3d/fog_volume.h b/scene/3d/fog_volume.h
index 68d5c58169..556a92ad3f 100644
--- a/scene/3d/fog_volume.h
+++ b/scene/3d/fog_volume.h
@@ -62,7 +62,6 @@ public:
 	Ref<Material> get_material() const;
 
 	virtual AABB get_aabb() const override;
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override { return Vector<Face3>(); }
 	TypedArray<String> get_configuration_warnings() const override;
 
 	FogVolume();
diff --git a/scene/3d/gpu_particles_3d.cpp b/scene/3d/gpu_particles_3d.cpp
index 4e35f37291..9fe2210de6 100644
--- a/scene/3d/gpu_particles_3d.cpp
+++ b/scene/3d/gpu_particles_3d.cpp
@@ -36,10 +36,6 @@ AABB GPUParticles3D::get_aabb() const {
 	return AABB();
 }
 
-Vector<Face3> GPUParticles3D::get_faces(uint32_t p_usage_flags) const {
-	return Vector<Face3>();
-}
-
 void GPUParticles3D::set_emitting(bool p_emitting) {
 	RS::get_singleton()->particles_set_emitting(particles, p_emitting);
 
diff --git a/scene/3d/gpu_particles_3d.h b/scene/3d/gpu_particles_3d.h
index 54ae84628a..f3eb52d124 100644
--- a/scene/3d/gpu_particles_3d.h
+++ b/scene/3d/gpu_particles_3d.h
@@ -98,7 +98,6 @@ protected:
 
 public:
 	AABB get_aabb() const override;
-	Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
 
 	void set_emitting(bool p_emitting);
 	void set_amount(int p_amount);
diff --git a/scene/3d/gpu_particles_collision_3d.h b/scene/3d/gpu_particles_collision_3d.h
index b6de1d83fc..fdd2fa4b18 100644
--- a/scene/3d/gpu_particles_collision_3d.h
+++ b/scene/3d/gpu_particles_collision_3d.h
@@ -50,8 +50,6 @@ public:
 	void set_cull_mask(uint32_t p_cull_mask);
 	uint32_t get_cull_mask() const;
 
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override { return Vector<Face3>(); }
-
 	~GPUParticlesCollision3D();
 };
 
@@ -274,8 +272,6 @@ public:
 	void set_directionality(real_t p_directionality);
 	real_t get_directionality() const;
 
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override { return Vector<Face3>(); }
-
 	~GPUParticlesAttractor3D();
 };
 
diff --git a/scene/3d/light_3d.cpp b/scene/3d/light_3d.cpp
index f2021aa3d5..e7e164d7da 100644
--- a/scene/3d/light_3d.cpp
+++ b/scene/3d/light_3d.cpp
@@ -156,10 +156,6 @@ AABB Light3D::get_aabb() const {
 	return AABB();
 }
 
-Vector<Face3> Light3D::get_faces(uint32_t p_usage_flags) const {
-	return Vector<Face3>();
-}
-
 void Light3D::set_bake_mode(BakeMode p_mode) {
 	bake_mode = p_mode;
 	RS::get_singleton()->light_set_bake_mode(light, RS::LightBakeMode(p_mode));
diff --git a/scene/3d/light_3d.h b/scene/3d/light_3d.h
index 11a9fcfc55..ed9e0bdfff 100644
--- a/scene/3d/light_3d.h
+++ b/scene/3d/light_3d.h
@@ -138,7 +138,6 @@ public:
 	Ref<Texture2D> get_projector() const;
 
 	virtual AABB get_aabb() const override;
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
 
 	Light3D();
 	~Light3D();
diff --git a/scene/3d/lightmap_gi.cpp b/scene/3d/lightmap_gi.cpp
index 07f41c0bf9..c74654b4bd 100644
--- a/scene/3d/lightmap_gi.cpp
+++ b/scene/3d/lightmap_gi.cpp
@@ -1263,10 +1263,6 @@ AABB LightmapGI::get_aabb() const {
 	return AABB();
 }
 
-Vector<Face3> LightmapGI::get_faces(uint32_t p_usage_flags) const {
-	return Vector<Face3>();
-}
-
 void LightmapGI::set_use_denoiser(bool p_enable) {
 	use_denoiser = p_enable;
 }
diff --git a/scene/3d/lightmap_gi.h b/scene/3d/lightmap_gi.h
index 66acf4f487..d29d7a7c28 100644
--- a/scene/3d/lightmap_gi.h
+++ b/scene/3d/lightmap_gi.h
@@ -267,7 +267,6 @@ public:
 	GenerateProbes get_generate_probes() const;
 
 	AABB get_aabb() const override;
-	Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
 
 	BakeError bake(Node *p_from_node, String p_image_data_path = "", Lightmapper::BakeStepFunc p_bake_step = nullptr, void *p_bake_userdata = nullptr);
 	LightmapGI();
diff --git a/scene/3d/mesh_instance_3d.cpp b/scene/3d/mesh_instance_3d.cpp
index fddfa17dbb..31c33a6b61 100644
--- a/scene/3d/mesh_instance_3d.cpp
+++ b/scene/3d/mesh_instance_3d.cpp
@@ -219,18 +219,6 @@ AABB MeshInstance3D::get_aabb() const {
 	return AABB();
 }
 
-Vector<Face3> MeshInstance3D::get_faces(uint32_t p_usage_flags) const {
-	if (!(p_usage_flags & (FACES_SOLID | FACES_ENCLOSING))) {
-		return Vector<Face3>();
-	}
-
-	if (mesh.is_null()) {
-		return Vector<Face3>();
-	}
-
-	return mesh->get_faces();
-}
-
 Node *MeshInstance3D::create_trimesh_collision_node() {
 	if (mesh.is_null()) {
 		return nullptr;
diff --git a/scene/3d/mesh_instance_3d.h b/scene/3d/mesh_instance_3d.h
index 03ee3cd608..0bf5c32410 100644
--- a/scene/3d/mesh_instance_3d.h
+++ b/scene/3d/mesh_instance_3d.h
@@ -93,7 +93,6 @@ public:
 	void create_debug_tangents();
 
 	virtual AABB get_aabb() const override;
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
 
 	MeshInstance3D();
 	~MeshInstance3D();
diff --git a/scene/3d/multimesh_instance_3d.cpp b/scene/3d/multimesh_instance_3d.cpp
index 34b1e86435..d197388fad 100644
--- a/scene/3d/multimesh_instance_3d.cpp
+++ b/scene/3d/multimesh_instance_3d.cpp
@@ -49,10 +49,6 @@ Ref<MultiMesh> MultiMeshInstance3D::get_multimesh() const {
 	return multimesh;
 }
 
-Vector<Face3> MultiMeshInstance3D::get_faces(uint32_t p_usage_flags) const {
-	return Vector<Face3>();
-}
-
 AABB MultiMeshInstance3D::get_aabb() const {
 	if (multimesh.is_null()) {
 		return AABB();
diff --git a/scene/3d/multimesh_instance_3d.h b/scene/3d/multimesh_instance_3d.h
index d03b24eb4e..111f1e9c09 100644
--- a/scene/3d/multimesh_instance_3d.h
+++ b/scene/3d/multimesh_instance_3d.h
@@ -44,8 +44,6 @@ protected:
 	// bind helpers
 
 public:
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
-
 	void set_multimesh(const Ref<MultiMesh> &p_multimesh);
 	Ref<MultiMesh> get_multimesh() const;
 
diff --git a/scene/3d/occluder_instance_3d.cpp b/scene/3d/occluder_instance_3d.cpp
index 855922c341..b82f05544b 100644
--- a/scene/3d/occluder_instance_3d.cpp
+++ b/scene/3d/occluder_instance_3d.cpp
@@ -433,10 +433,6 @@ AABB OccluderInstance3D::get_aabb() const {
 	return AABB();
 }
 
-Vector<Face3> OccluderInstance3D::get_faces(uint32_t p_usage_flags) const {
-	return Vector<Face3>();
-}
-
 void OccluderInstance3D::set_occluder(const Ref<Occluder3D> &p_occluder) {
 	if (occluder == p_occluder) {
 		return;
diff --git a/scene/3d/occluder_instance_3d.h b/scene/3d/occluder_instance_3d.h
index 669ddba775..ed6610074e 100644
--- a/scene/3d/occluder_instance_3d.h
+++ b/scene/3d/occluder_instance_3d.h
@@ -194,7 +194,6 @@ public:
 	Ref<Occluder3D> get_occluder() const;
 
 	virtual AABB get_aabb() const override;
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
 
 	void set_bake_mask(uint32_t p_mask);
 	uint32_t get_bake_mask() const;
diff --git a/scene/3d/reflection_probe.cpp b/scene/3d/reflection_probe.cpp
index be655e71db..1bebd8e335 100644
--- a/scene/3d/reflection_probe.cpp
+++ b/scene/3d/reflection_probe.cpp
@@ -178,10 +178,6 @@ AABB ReflectionProbe::get_aabb() const {
 	return aabb;
 }
 
-Vector<Face3> ReflectionProbe::get_faces(uint32_t p_usage_flags) const {
-	return Vector<Face3>();
-}
-
 void ReflectionProbe::_validate_property(PropertyInfo &property) const {
 	if (property.name == "interior/ambient_color" || property.name == "interior/ambient_color_energy") {
 		if (ambient_mode != AMBIENT_COLOR) {
diff --git a/scene/3d/reflection_probe.h b/scene/3d/reflection_probe.h
index d0643496a4..424976d895 100644
--- a/scene/3d/reflection_probe.h
+++ b/scene/3d/reflection_probe.h
@@ -113,7 +113,6 @@ public:
 	UpdateMode get_update_mode() const;
 
 	virtual AABB get_aabb() const override;
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
 
 	ReflectionProbe();
 	~ReflectionProbe();
diff --git a/scene/3d/sprite_3d.cpp b/scene/3d/sprite_3d.cpp
index ce281c79bc..514bd4aba0 100644
--- a/scene/3d/sprite_3d.cpp
+++ b/scene/3d/sprite_3d.cpp
@@ -177,10 +177,6 @@ AABB SpriteBase3D::get_aabb() const {
 	return aabb;
 }
 
-Vector<Face3> SpriteBase3D::get_faces(uint32_t p_usage_flags) const {
-	return Vector<Face3>();
-}
-
 Ref<TriangleMesh> SpriteBase3D::generate_triangle_mesh() const {
 	if (triangle_mesh.is_valid()) {
 		return triangle_mesh;
diff --git a/scene/3d/sprite_3d.h b/scene/3d/sprite_3d.h
index 985103e190..92dbef0855 100644
--- a/scene/3d/sprite_3d.h
+++ b/scene/3d/sprite_3d.h
@@ -137,7 +137,7 @@ public:
 	virtual Rect2 get_item_rect() const = 0;
 
 	virtual AABB get_aabb() const override;
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
+
 	Ref<TriangleMesh> generate_triangle_mesh() const;
 
 	SpriteBase3D();
diff --git a/scene/3d/visible_on_screen_notifier_3d.cpp b/scene/3d/visible_on_screen_notifier_3d.cpp
index 11367d7ca9..41cd604a4f 100644
--- a/scene/3d/visible_on_screen_notifier_3d.cpp
+++ b/scene/3d/visible_on_screen_notifier_3d.cpp
@@ -89,10 +89,6 @@ void VisibleOnScreenNotifier3D::_bind_methods() {
 	ADD_SIGNAL(MethodInfo("screen_exited"));
 }
 
-Vector<Face3> VisibleOnScreenNotifier3D::get_faces(uint32_t p_usage_flags) const {
-	return Vector<Face3>();
-}
-
 VisibleOnScreenNotifier3D::VisibleOnScreenNotifier3D() {
 	RID notifier = RS::get_singleton()->visibility_notifier_create();
 	RS::get_singleton()->visibility_notifier_set_aabb(notifier, aabb);
diff --git a/scene/3d/visible_on_screen_notifier_3d.h b/scene/3d/visible_on_screen_notifier_3d.h
index 852c7e2ed3..fe17f1e444 100644
--- a/scene/3d/visible_on_screen_notifier_3d.h
+++ b/scene/3d/visible_on_screen_notifier_3d.h
@@ -57,8 +57,6 @@ public:
 	virtual AABB get_aabb() const override;
 	bool is_on_screen() const;
 
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
-
 	VisibleOnScreenNotifier3D();
 	~VisibleOnScreenNotifier3D();
 };
diff --git a/scene/3d/visual_instance_3d.cpp b/scene/3d/visual_instance_3d.cpp
index d8dffe6c7d..b8a68cdca9 100644
--- a/scene/3d/visual_instance_3d.cpp
+++ b/scene/3d/visual_instance_3d.cpp
@@ -32,6 +32,14 @@
 
 #include "scene/scene_string_names.h"
 
+AABB VisualInstance3D::get_aabb() const {
+	AABB ret;
+	if (GDVIRTUAL_CALL(_get_aabb, ret)) {
+		return ret;
+	}
+	return AABB();
+}
+
 AABB VisualInstance3D::get_transformed_aabb() const {
 	return get_global_transform().xform(get_aabb());
 }
@@ -115,6 +123,7 @@ void VisualInstance3D::_bind_methods() {
 
 	ClassDB::bind_method(D_METHOD("get_transformed_aabb"), &VisualInstance3D::get_transformed_aabb);
 
+	GDVIRTUAL_BIND(_get_aabb);
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "layers", PROPERTY_HINT_LAYERS_3D_RENDER), "set_layer_mask", "get_layer_mask");
 }
 
diff --git a/scene/3d/visual_instance_3d.h b/scene/3d/visual_instance_3d.h
index 02f62b41e5..1c044ba681 100644
--- a/scene/3d/visual_instance_3d.h
+++ b/scene/3d/visual_instance_3d.h
@@ -49,6 +49,7 @@ protected:
 	void _notification(int p_what);
 	static void _bind_methods();
 
+	GDVIRTUAL0RC(AABB, _get_aabb)
 public:
 	enum GetFacesFlags {
 		FACES_SOLID = 1, // solid geometry
@@ -58,8 +59,7 @@ public:
 	};
 
 	RID get_instance() const;
-	virtual AABB get_aabb() const = 0;
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const = 0;
+	virtual AABB get_aabb() const;
 
 	virtual AABB get_transformed_aabb() const; // helper
 
diff --git a/scene/3d/voxel_gi.cpp b/scene/3d/voxel_gi.cpp
index bfe3c80a4f..6840d15f78 100644
--- a/scene/3d/voxel_gi.cpp
+++ b/scene/3d/voxel_gi.cpp
@@ -450,10 +450,6 @@ AABB VoxelGI::get_aabb() const {
 	return AABB(-extents, extents * 2);
 }
 
-Vector<Face3> VoxelGI::get_faces(uint32_t p_usage_flags) const {
-	return Vector<Face3>();
-}
-
 TypedArray<String> VoxelGI::get_configuration_warnings() const {
 	TypedArray<String> warnings = Node::get_configuration_warnings();
 
diff --git a/scene/3d/voxel_gi.h b/scene/3d/voxel_gi.h
index 3678bd4f3b..e1a38dd7a0 100644
--- a/scene/3d/voxel_gi.h
+++ b/scene/3d/voxel_gi.h
@@ -149,7 +149,6 @@ public:
 	void bake(Node *p_from_node = nullptr, bool p_create_visual_debug = false);
 
 	virtual AABB get_aabb() const override;
-	virtual Vector<Face3> get_faces(uint32_t p_usage_flags) const override;
 
 	TypedArray<String> get_configuration_warnings() const override;