world/viewer: Add ViewEntityAnimation for resource-pack based animati…

…ons (#773)

server/session/world.go

@@ -912,6 +912,16 @@ func (s *Session) ViewEntityState(e world.Entity) {
 	})
 }
 
+// ViewEntityAnimation ...
+func (s *Session) ViewEntityAnimation(e world.Entity, animationName string) {
+	s.writePacket(&packet.AnimateEntity{
+		Animation: animationName,
+		EntityRuntimeIDs: []uint64{
+			s.entityRuntimeID(e),
+		},
+	})
+}
+
 // OpenBlockContainer ...
 func (s *Session) OpenBlockContainer(pos cube.Pos) {
 	if s.containerOpened.Load() && s.openedPos.Load() == pos {

server/world/viewer.go

@@ -47,6 +47,8 @@ type Viewer interface {
 	// ViewEntityState views the current state of an entity. It is called whenever an entity changes its
 	// physical appearance, for example when sprinting.
 	ViewEntityState(e Entity)
+	// ViewEntityAnimation starts viewing an animation performed by an entity. The animation has to be from a resource pack.
+	ViewEntityAnimation(e Entity, animationName string)
 	// ViewParticle views a particle spawned at a given position in the world. It is called when a particle,
 	// for example a block breaking particle, is spawned near the player.
 	ViewParticle(pos mgl64.Vec3, p Particle)
@@ -87,6 +89,7 @@ func (NopViewer) ViewEntityItems(Entity)                                     {}
 func (NopViewer) ViewEntityArmour(Entity)                                    {}
 func (NopViewer) ViewEntityAction(Entity, EntityAction)                      {}
 func (NopViewer) ViewEntityState(Entity)                                     {}
+func (NopViewer) ViewEntityAnimation(Entity, string)                         {}
 func (NopViewer) ViewParticle(mgl64.Vec3, Particle)                          {}
 func (NopViewer) ViewSound(mgl64.Vec3, Sound)                                {}
 func (NopViewer) ViewBlockUpdate(cube.Pos, Block, int)                       {}