Fix finding AnimationPlayer in scene import

The scene importer always assumed that the AnimationPlayer is called
"AnimationPlayer".

This is not always true: for example the GLTF importer just creates an
AnimationPlayer with the default name, which may be "animation_player",
depending on the project settings.

This fix instead chooses the first node that is an AnimationPlayer, and
warns if there is more than one.

editor/import/resource_importer_scene.cpp

@@ -629,15 +629,12 @@ Node *ResourceImporterScene::_fix_node(Node *p_node, Node *p_root, Map<Ref<Mesh>
 }
 
 void ResourceImporterScene::_create_clips(Node *scene, const Array &p_clips, bool p_bake_all) {
-	if (!scene->has_node(String("AnimationPlayer"))) {
+	AnimationPlayer *anim = _find_animation_player(scene);
+	if (!anim) {
+		WARN_PRINT("Creating clips is enabled, but no animation player was found.");
 		return;
 	}
 
-	Node *n = scene->get_node(String("AnimationPlayer"));
-	ERR_FAIL_COND(!n);
-	AnimationPlayer *anim = Object::cast_to<AnimationPlayer>(n);
-	ERR_FAIL_COND(!anim);
-
 	if (!anim->has_animation("default")) {
 		ERR_FAIL_COND_MSG(p_clips.size() > 0, "To create clips, animations must be named \"default\".");
 		return;
@@ -757,13 +754,10 @@ void ResourceImporterScene::_filter_anim_tracks(Ref<Animation> anim, Set<String>
 }
 
 void ResourceImporterScene::_filter_tracks(Node *scene, const String &p_text) {
-	if (!scene->has_node(String("AnimationPlayer"))) {
+	AnimationPlayer *anim = _find_animation_player(scene);
+	if (!anim) {
 		return;
 	}
-	Node *n = scene->get_node(String("AnimationPlayer"));
-	ERR_FAIL_COND(!n);
-	AnimationPlayer *anim = Object::cast_to<AnimationPlayer>(n);
-	ERR_FAIL_COND(!anim);
 
 	Vector<String> strings = p_text.split("\n");
 	for (int i = 0; i < strings.size(); i++) {
@@ -864,13 +858,10 @@ void ResourceImporterScene::_filter_tracks(Node *scene, const String &p_text) {
 }
 
 void ResourceImporterScene::_optimize_animations(Node *scene, float p_max_lin_error, float p_max_ang_error, float p_max_angle) {
-	if (!scene->has_node(String("AnimationPlayer"))) {
+	AnimationPlayer *anim = _find_animation_player(scene);
+	if (!anim) {
 		return;
 	}
-	Node *n = scene->get_node(String("AnimationPlayer"));
-	ERR_FAIL_COND(!n);
-	AnimationPlayer *anim = Object::cast_to<AnimationPlayer>(n);
-	ERR_FAIL_COND(!anim);
 
 	List<StringName> anim_names;
 	anim->get_animation_list(&anim_names);
@@ -895,6 +886,24 @@ static String _make_extname(const String &p_str) {
 	return ext_name;
 }
 
+AnimationPlayer *ResourceImporterScene::_find_animation_player(Node *p_node) {
+	// Find a direct child that is an AnimationPlayer.
+	AnimationPlayer *ret = nullptr;
+
+	for (int i = 0; i < p_node->get_child_count(); i++) {
+		AnimationPlayer *child = Object::cast_to<AnimationPlayer>(p_node->get_child(i));
+		if (child) {
+			if (ret == nullptr) {
+				ret = child;
+			} else {
+				WARN_PRINT("More than one animation player: \"" + ret->get_name() + "\" and \"" + child->get_name() + "\".");
+			}
+		}
+	}
+
+	return ret;
+}
+
 void ResourceImporterScene::_find_meshes(Node *p_node, Map<Ref<ArrayMesh>, Transform> &meshes) {
 	MeshInstance *mi = Object::cast_to<MeshInstance>(p_node);
 

editor/import/resource_importer_scene.h

@@ -32,6 +32,7 @@
 #define RESOURCE_IMPORTER_SCENE_H
 
 #include "core/io/resource_importer.h"
+#include "scene/animation/animation_player.h"
 #include "scene/resources/animation.h"
 #include "scene/resources/mesh.h"
 #include "scene/resources/shape.h"
@@ -144,6 +145,7 @@ public:
 	virtual int get_import_order() const { return ResourceImporter::IMPORT_ORDER_SCENE; }
 
 	void _find_meshes(Node *p_node, Map<Ref<ArrayMesh>, Transform> &meshes);
+	AnimationPlayer *_find_animation_player(Node *p_node);
 
 	void _make_external_resources(Node *p_node, const String &p_base_path, bool p_make_animations, bool p_animations_as_text, bool p_keep_animations, bool p_make_materials, bool p_materials_as_text, bool p_keep_materials, bool p_make_meshes, bool p_meshes_as_text, Map<Ref<Animation>, Ref<Animation>> &p_animations, Map<Ref<Material>, Ref<Material>> &p_materials, Map<Ref<ArrayMesh>, Ref<ArrayMesh>> &p_meshes);