Renamed EditorResourcePreviewGenerator.should_generate_small_preview() to generate_small_preview_automatically()

Added can_generate_small_preview() so the generator uses generate() or generate_from_path() if it returns true
Added can_generate_small_preview() and generate_small_preview_automatically() to the scripting languages

doc/classes/EditorResourcePreviewGenerator.xml

@@ -9,6 +9,14 @@
 	<tutorials>
 	</tutorials>
 	<methods>
+		<method name="can_generate_small_preview" qualifiers="virtual">
+			<return type="bool">
+			</return>
+			<description>
+				If this function returns true the generator will call [method generate] or [method generate_from_path] for small previews too.
+				By default it returns false.
+			</description>
+		</method>
 		<method name="generate" qualifiers="virtual">
 			<return type="Texture">
 			</return>
@@ -35,6 +43,14 @@
 				Care must be taken because this function is always called from a thread (not the main thread).
 			</description>
 		</method>
+		<method name="generate_small_preview_automatically" qualifiers="virtual">
+			<return type="bool">
+			</return>
+			<description>
+				If this function returns true the generator will automatically generate the small previews from the normal preview texture generated by the methods [method generate] or [method generate_from_path].
+				By default it returns false.
+			</description>
+		</method>
 		<method name="handles" qualifiers="virtual">
 			<return type="bool">
 			</return>

editor/editor_resource_preview.cpp

@@ -71,7 +71,21 @@ Ref<Texture> EditorResourcePreviewGenerator::generate_from_path(const String &p_
 	return generate(res, p_size);
 }
 
-bool EditorResourcePreviewGenerator::should_generate_small_preview() const {
+bool EditorResourcePreviewGenerator::generate_small_preview_automatically() const {
+
+	if (get_script_instance() && get_script_instance()->has_method("generate_small_preview_automatically")) {
+		return get_script_instance()->call("generate_small_preview_automatically");
+	}
+
+	return false;
+}
+
+bool EditorResourcePreviewGenerator::can_generate_small_preview() const {
+
+	if (get_script_instance() && get_script_instance()->has_method("can_generate_small_preview")) {
+		return get_script_instance()->call("can_generate_small_preview");
+	}
+
 	return false;
 }
 
@@ -80,6 +94,8 @@ void EditorResourcePreviewGenerator::_bind_methods() {
 	ClassDB::add_virtual_method(get_class_static(), MethodInfo(Variant::BOOL, "handles", PropertyInfo(Variant::STRING, "type")));
 	ClassDB::add_virtual_method(get_class_static(), MethodInfo(CLASS_INFO(Texture), "generate", PropertyInfo(Variant::OBJECT, "from", PROPERTY_HINT_RESOURCE_TYPE, "Resource"), PropertyInfo(Variant::VECTOR2, "size")));
 	ClassDB::add_virtual_method(get_class_static(), MethodInfo(CLASS_INFO(Texture), "generate_from_path", PropertyInfo(Variant::STRING, "path", PROPERTY_HINT_FILE), PropertyInfo(Variant::VECTOR2, "size")));
+	ClassDB::add_virtual_method(get_class_static(), MethodInfo(Variant::BOOL, "generate_small_preview_automatically"));
+	ClassDB::add_virtual_method(get_class_static(), MethodInfo(Variant::BOOL, "can_generate_small_preview"));
 }
 
 EditorResourcePreviewGenerator::EditorResourcePreviewGenerator() {
@@ -154,16 +170,27 @@ void EditorResourcePreview::_generate_preview(Ref<ImageTexture> &r_texture, Ref<
 		}
 		r_texture = generated;
 
-		if (r_texture.is_valid() && preview_generators[i]->should_generate_small_preview()) {
-			int small_thumbnail_size = EditorNode::get_singleton()->get_theme_base()->get_icon("Object", "EditorIcons")->get_width(); // Kind of a workaround to retrieve the default icon size
-			small_thumbnail_size *= EDSCALE;
+		int small_thumbnail_size = EditorNode::get_singleton()->get_theme_base()->get_icon("Object", "EditorIcons")->get_width(); // Kind of a workaround to retrieve the default icon size
+		small_thumbnail_size *= EDSCALE;
 
+		if (preview_generators[i]->can_generate_small_preview()) {
+			Ref<Texture> generated_small;
+			if (p_item.resource.is_valid()) {
+				generated_small = preview_generators[i]->generate(p_item.resource, Vector2(small_thumbnail_size, small_thumbnail_size));
+			} else {
+				generated_small = preview_generators[i]->generate_from_path(p_item.path, Vector2(small_thumbnail_size, small_thumbnail_size));
+			}
+			r_small_texture = generated_small;
+		}
+
+		if (!r_small_texture.is_valid() && r_texture.is_valid() && preview_generators[i]->generate_small_preview_automatically()) {
 			Ref<Image> small_image = r_texture->get_data();
 			small_image = small_image->duplicate();
 			small_image->resize(small_thumbnail_size, small_thumbnail_size, Image::INTERPOLATE_CUBIC);
 			r_small_texture.instance();
 			r_small_texture->create_from_image(small_image);
 		}
+
 		break;
 	}
 

editor/editor_resource_preview.h

@@ -48,7 +48,8 @@ public:
 	virtual Ref<Texture> generate(const RES &p_from, const Size2 p_size) const;
 	virtual Ref<Texture> generate_from_path(const String &p_path, const Size2 p_size) const;
 
-	virtual bool should_generate_small_preview() const;
+	virtual bool generate_small_preview_automatically() const;
+	virtual bool can_generate_small_preview() const;
 
 	EditorResourcePreviewGenerator();
 };

editor/plugins/editor_preview_plugins.cpp

@@ -78,7 +78,7 @@ bool EditorTexturePreviewPlugin::handles(const String &p_type) const {
 	return ClassDB::is_parent_class(p_type, "Texture");
 }
 
-bool EditorTexturePreviewPlugin::should_generate_small_preview() const {
+bool EditorTexturePreviewPlugin::generate_small_preview_automatically() const {
 	return true;
 }
 
@@ -186,7 +186,7 @@ Ref<Texture> EditorImagePreviewPlugin::generate(const RES &p_from, const Size2 p
 EditorImagePreviewPlugin::EditorImagePreviewPlugin() {
 }
 
-bool EditorImagePreviewPlugin::should_generate_small_preview() const {
+bool EditorImagePreviewPlugin::generate_small_preview_automatically() const {
 	return true;
 }
 ////////////////////////////////////////////////////////////////////////////
@@ -250,7 +250,7 @@ Ref<Texture> EditorBitmapPreviewPlugin::generate(const RES &p_from, const Size2
 	return ptex;
 }
 
-bool EditorBitmapPreviewPlugin::should_generate_small_preview() const {
+bool EditorBitmapPreviewPlugin::generate_small_preview_automatically() const {
 	return true;
 }
 
@@ -317,7 +317,7 @@ bool EditorMaterialPreviewPlugin::handles(const String &p_type) const {
 	return ClassDB::is_parent_class(p_type, "Material"); //any material
 }
 
-bool EditorMaterialPreviewPlugin::should_generate_small_preview() const {
+bool EditorMaterialPreviewPlugin::generate_small_preview_automatically() const {
 	return true;
 }
 

editor/plugins/editor_preview_plugins.h

@@ -39,7 +39,7 @@ class EditorTexturePreviewPlugin : public EditorResourcePreviewGenerator {
 	GDCLASS(EditorTexturePreviewPlugin, EditorResourcePreviewGenerator)
 public:
 	virtual bool handles(const String &p_type) const;
-	virtual bool should_generate_small_preview() const;
+	virtual bool generate_small_preview_automatically() const;
 	virtual Ref<Texture> generate(const RES &p_from, const Size2 p_size) const;
 
 	EditorTexturePreviewPlugin();
@@ -49,7 +49,7 @@ class EditorImagePreviewPlugin : public EditorResourcePreviewGenerator {
 	GDCLASS(EditorImagePreviewPlugin, EditorResourcePreviewGenerator)
 public:
 	virtual bool handles(const String &p_type) const;
-	virtual bool should_generate_small_preview() const;
+	virtual bool generate_small_preview_automatically() const;
 	virtual Ref<Texture> generate(const RES &p_from, const Size2 p_size) const;
 
 	EditorImagePreviewPlugin();
@@ -59,7 +59,7 @@ class EditorBitmapPreviewPlugin : public EditorResourcePreviewGenerator {
 	GDCLASS(EditorBitmapPreviewPlugin, EditorResourcePreviewGenerator)
 public:
 	virtual bool handles(const String &p_type) const;
-	virtual bool should_generate_small_preview() const;
+	virtual bool generate_small_preview_automatically() const;
 	virtual Ref<Texture> generate(const RES &p_from, const Size2 p_size) const;
 
 	EditorBitmapPreviewPlugin();
@@ -98,7 +98,7 @@ protected:
 
 public:
 	virtual bool handles(const String &p_type) const;
-	virtual bool should_generate_small_preview() const;
+	virtual bool generate_small_preview_automatically() const;
 	virtual Ref<Texture> generate(const RES &p_from, const Size2 p_size) const;
 
 	EditorMaterialPreviewPlugin();