up3

server/item/bow.go

@@ -0,0 +1,119 @@
+package item
+
+import (
+	"github.com/df-mc/dragonfly/server/item/potion"
+	"github.com/df-mc/dragonfly/server/world"
+	"github.com/df-mc/dragonfly/server/world/sound"
+	"math"
+	"time"
+)
+
+// Bow is a ranged weapon that fires arrows.
+type Bow struct{}
+
+// MaxCount always returns 1.
+func (Bow) MaxCount() int {
+	return 1
+}
+
+// DurabilityInfo ...
+func (Bow) DurabilityInfo() DurabilityInfo {
+	return DurabilityInfo{
+		MaxDurability: 385,
+		BrokenItem:    simpleItem(Stack{}),
+	}
+}
+
+// FuelInfo ...
+func (Bow) FuelInfo() FuelInfo {
+	return newFuelInfo(time.Second * 10)
+}
+
+// Release ...
+func (Bow) Release(releaser Releaser, tx *world.Tx, ctx *UseContext, duration time.Duration) {
+	creative := releaser.GameMode().CreativeInventory()
+	ticks := duration.Milliseconds() / 50
+	if ticks < 3 {
+		// The player must hold the bow for at least three ticks.
+		return
+	}
+
+	d := float64(ticks) / 20
+	force := math.Min((d*d+d*2)/3, 1)
+	if force < 0.1 {
+		// The force must be at least 0.1.
+		return
+	}
+
+	arrow, ok := ctx.FirstFunc(func(stack Stack) bool {
+		_, ok := stack.Item().(Arrow)
+		return ok
+	})
+	if !ok && !creative {
+		// No arrows in inventory and not in creative mode.
+		return
+	}
+
+	var tip potion.Potion
+	if !arrow.Empty() {
+		// Arrow is empty if not found in the creative inventory.
+		tip = arrow.Item().(Arrow).Tip
+	}
+
+	held, _ := releaser.HeldItems()
+	damage, punchLevel, burnDuration, consume := 2.0, 0, time.Duration(0), !creative
+	for _, enchant := range held.Enchantments() {
+		if f, ok := enchant.Type().(interface{ BurnDuration() time.Duration }); ok {
+			burnDuration = f.BurnDuration()
+		}
+		if _, ok := enchant.Type().(interface{ KnockBackMultiplier() float64 }); ok {
+			punchLevel = enchant.Level()
+		}
+		if p, ok := enchant.Type().(interface{ PowerDamage(int) float64 }); ok {
+			damage += p.PowerDamage(enchant.Level())
+		}
+		if i, ok := enchant.Type().(interface{ ConsumesArrows() bool }); ok && !i.ConsumesArrows() {
+			consume = false
+		}
+	}
+
+	create := tx.World().EntityRegistry().Config().Arrow
+	opts := world.EntitySpawnOpts{
+		Position: eyePosition(releaser),
+		Velocity: releaser.Rotation().Vec3().Mul(force * 5),
+		Rotation: releaser.Rotation().Neg(),
+	}
+	projectile := tx.AddEntity(create(opts, world.ArrowSpawnConfig{
+		Damage:              damage,
+		Owner:               releaser,
+		Critical:            force >= 1,
+		ObtainArrowOnPickup: !creative && consume,
+		PunchLevel:          punchLevel,
+		Tip:                 tip,
+	}))
+	if f, ok := projectile.(interface{ SetOnFire(duration time.Duration) }); ok {
+		f.SetOnFire(burnDuration)
+	}
+
+	ctx.DamageItem(1)
+	if consume {
+		ctx.Consume(arrow.Grow(-arrow.Count() + 1))
+	}
+
+	tx.PlaySound(releaser.Position(), sound.BowShoot{})
+}
+
+// EnchantmentValue ...
+func (Bow) EnchantmentValue() int {
+	return 1
+}
+
+// Requirements returns the required items to release this item.
+func (Bow) Requirements() []Stack {
+	return []Stack{NewStack(Arrow{}, 1)}
+}
+
+// EncodeItem ...
+func (Bow) EncodeItem() (name string, meta int16) {
+	return "minecraft:bow", 0
+}