Import step interpolation for loc/rot/scale from GLTF as nearest

Currently all object transform animation tracks get imported and baked
as linear. For step interpolation mark the resulting animation track
with Nearest interpolation to make sure there are no in-betweens
generated. This is useful for camera cuts or similar.

modules/gltf/gltf_document.cpp

@@ -6288,6 +6288,9 @@ void GLTFDocument::_import_animation(Ref<GLTFState> p_state, AnimationPlayer *p_
 					animation->add_track(Animation::TYPE_POSITION_3D);
 					animation->track_set_path(position_idx, transform_node_path);
 					animation->track_set_imported(position_idx, true); //helps merging later
+					if (track.position_track.interpolation == GLTFAnimation::INTERP_STEP) {
+						animation->track_set_interpolation_type(position_idx, Animation::InterpolationType::INTERPOLATION_NEAREST);
+					}
 					base_idx++;
 				}
 			}
@@ -6310,6 +6313,9 @@ void GLTFDocument::_import_animation(Ref<GLTFState> p_state, AnimationPlayer *p_
 					animation->add_track(Animation::TYPE_ROTATION_3D);
 					animation->track_set_path(rotation_idx, transform_node_path);
 					animation->track_set_imported(rotation_idx, true); //helps merging later
+					if (track.rotation_track.interpolation == GLTFAnimation::INTERP_STEP) {
+						animation->track_set_interpolation_type(rotation_idx, Animation::InterpolationType::INTERPOLATION_NEAREST);
+					}
 					base_idx++;
 				}
 			}
@@ -6332,6 +6338,9 @@ void GLTFDocument::_import_animation(Ref<GLTFState> p_state, AnimationPlayer *p_
 					animation->add_track(Animation::TYPE_SCALE_3D);
 					animation->track_set_path(scale_idx, transform_node_path);
 					animation->track_set_imported(scale_idx, true); //helps merging later
+					if (track.scale_track.interpolation == GLTFAnimation::INTERP_STEP) {
+						animation->track_set_interpolation_type(scale_idx, Animation::InterpolationType::INTERPOLATION_NEAREST);
+					}
 					base_idx++;
 				}
 			}