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.

1 files changed, 15 insertions, 3 deletions

diff --git a/servers/audio/audio_effect.h b/servers/audio/audio_effect.h
index 00a5d6c004..3a0578679d 100644
--- a/servers/audio/audio_effect.h
+++ b/servers/audio/audio_effect.h
@@ -33,20 +33,32 @@
 
 #include "core/io/resource.h"
 #include "core/math/audio_frame.h"
+#include "core/object/gdvirtual.gen.inc"
+#include "core/object/script_language.h"
+#include "core/variant/native_ptr.h"
 
 class AudioEffectInstance : public RefCounted {
 	GDCLASS(AudioEffectInstance, RefCounted);
 
+protected:
+	GDVIRTUAL3(_process, GDNativeConstPtr<AudioFrame>, GDNativePtr<AudioFrame>, int)
+	GDVIRTUAL0RC(bool, _process_silence)
+	static void _bind_methods();
+
 public:
-	virtual void process(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count) = 0;
-	virtual bool process_silence() const { return false; }
+	virtual void process(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count);
+	virtual bool process_silence() const;
 };
 
 class AudioEffect : public Resource {
 	GDCLASS(AudioEffect, Resource);
 
+protected:
+	GDVIRTUAL0R(Ref<AudioEffectInstance>, _instantiate)
+	static void _bind_methods();
+
 public:
-	virtual Ref<AudioEffectInstance> instantiate() = 0;
+	virtual Ref<AudioEffectInstance> instantiate();
 	AudioEffect();
 };