Introduce entity animations

server/entity/animation/animation.go

@@ -0,0 +1,61 @@
+package animation
+
+// Animation represents an animation & controller that may be attached to an entity.
+// Animations and controllers must be defined in a resource pack
+type Animation struct {
+	name, state, controller string
+	stopCondition           string
+}
+
+// New returns a new animation that can be attached to an entity. By default no controller or state is sent to the viewer.
+// To add a state and controller use WithController and WithState respectively.
+func New(animationName string) Animation {
+	return Animation{
+		name:          animationName,
+		state:         "",
+		controller:    "",
+		stopCondition: "",
+	}
+}
+
+// Name returns the name of the animation to be played
+func (a Animation) Name() string {
+	return a.name
+}
+
+// WithController sets the controller with the specified state.
+// The controller must be added in a resource pack
+func (a Animation) WithController(controller string) Animation {
+	a.controller = controller
+	return a
+}
+
+// Controller returns the name of the controller being used. Controller returns an empty string if
+// no controller was previously set
+func (a Animation) Controller() string {
+	return a.controller
+}
+
+// WithState sets the state to transition to as defined in the controller.
+func (a Animation) WithState(state string) Animation {
+	a.state = state
+	return a
+}
+
+// State returns the current state being played. State returns an empty string if
+// no controller was previously set
+func (a Animation) State() string {
+	return a.state
+}
+
+// WithStopCondition takes the molang expression and stops the animation if the query passes.
+func (a Animation) WithStopCondition(condition string) Animation {
+	a.stopCondition = condition
+	return a
+}
+
+// StopCondition returns the stop condition. StopCondition returns an empty string if
+// no molang expression was set
+func (a Animation) StopCondition() string {
+	return a.stopCondition
+}

server/session/world.go

@@ -1,12 +1,14 @@
 package session
 
 import (
-	"github.com/df-mc/dragonfly/server/entity/effect"
 	"image/color"
 	"math/rand"
 	"strings"
 	"time"
 
+	"github.com/df-mc/dragonfly/server/entity/animation"
+	"github.com/df-mc/dragonfly/server/entity/effect"
+
 	"github.com/df-mc/dragonfly/server/block"
 	"github.com/df-mc/dragonfly/server/block/cube"
 	"github.com/df-mc/dragonfly/server/entity"
@@ -915,9 +917,12 @@ func (s *Session) ViewEntityState(e world.Entity) {
 }
 
 // ViewEntityAnimation ...
-func (s *Session) ViewEntityAnimation(e world.Entity, animationName string) {
+func (s *Session) ViewEntityAnimation(e world.Entity, animation animation.Animation) {
 	s.writePacket(&packet.AnimateEntity{
-		Animation: animationName,
+		Animation:     animation.Name(),
+		NextState:     animation.State(),
+		StopCondition: animation.StopCondition(),
+		Controller:    animation.Controller(),
 		EntityRuntimeIDs: []uint64{
 			s.entityRuntimeID(e),
 		},

server/world/viewer.go

@@ -1,11 +1,13 @@
 package world
 
 import (
+	"time"
+
 	"github.com/df-mc/dragonfly/server/block/cube"
+	"github.com/df-mc/dragonfly/server/entity/animation"
 	"github.com/df-mc/dragonfly/server/world/chunk"
 	"github.com/go-gl/mathgl/mgl64"
 	"github.com/google/uuid"
-	"time"
 )
 
 // Viewer is a viewer in the world. It can view changes that are made in the world, such as the addition of
@@ -48,7 +50,7 @@ type Viewer interface {
 	// 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)
+	ViewEntityAnimation(e Entity, animation animation.Animation)
 	// 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)
@@ -89,7 +91,7 @@ func (NopViewer) ViewEntityItems(Entity)                                     {}
 func (NopViewer) ViewEntityArmour(Entity)                                    {}
 func (NopViewer) ViewEntityAction(Entity, EntityAction)                      {}
 func (NopViewer) ViewEntityState(Entity)                                     {}
-func (NopViewer) ViewEntityAnimation(Entity, string)                         {}
+func (NopViewer) ViewEntityAnimation(Entity, animation.Animation)            {}
 func (NopViewer) ViewParticle(mgl64.Vec3, Particle)                          {}
 func (NopViewer) ViewSound(mgl64.Vec3, Sound)                                {}
 func (NopViewer) ViewBlockUpdate(cube.Pos, Block, int)                       {}

server/world/world.go

@@ -2,13 +2,15 @@ package world
 
 import (
 	"errors"
-	"github.com/df-mc/goleveldb/leveldb"
 	"math/rand"
 	"sync"
 	"time"
 
+	"github.com/df-mc/goleveldb/leveldb"
+
 	"github.com/df-mc/atomic"
 	"github.com/df-mc/dragonfly/server/block/cube"
+	"github.com/df-mc/dragonfly/server/entity/animation"
 	"github.com/df-mc/dragonfly/server/event"
 	"github.com/df-mc/dragonfly/server/internal/sliceutil"
 	"github.com/df-mc/dragonfly/server/world/chunk"
@@ -643,6 +645,19 @@ func (w *World) AddParticle(pos mgl64.Vec3, p Particle) {
 	}
 }
 
+// AnimateEntity will start an animation for the specified entity. Viewers that are viewing the entity will be
+// played the animation.
+func (w *World) AnimateEntity(e Entity, animation animation.Animation) {
+	// Ignore if no animation name has been given
+	if animation.Name() == "" {
+		return
+	}
+
+	for _, v := range w.Viewers(e.Position()) {
+		v.ViewEntityAnimation(e, animation)
+	}
+}
+
 // PlaySound plays a sound at a specific position in the world. Viewers of that position will be able to hear
 // the sound if they're close enough.
 func (w *World) PlaySound(pos mgl64.Vec3, s Sound) {