Add slime blocks

server/block/register.go

@@ -80,6 +80,7 @@ func init() {
 	world.RegisterBlock(Sand{})
 	world.RegisterBlock(SeaLantern{})
 	world.RegisterBlock(Shroomlight{})
+	world.RegisterBlock(SlimeBlock{})
 	world.RegisterBlock(Snow{})
 	world.RegisterBlock(SoulSand{})
 	world.RegisterBlock(SoulSoil{})

server/block/slime_block.go

@@ -0,0 +1,55 @@
+package block
+
+import (
+	"github.com/df-mc/dragonfly/server/block/cube"
+	"github.com/df-mc/dragonfly/server/world"
+	"github.com/go-gl/mathgl/mgl64"
+)
+
+// SlimeBlock is a block that slows down entities and bounces them up if they drop onto it.
+type SlimeBlock struct {
+	solid
+	transparent
+}
+
+// velocityEntity is an entity that has velocity.
+type velocityEntity interface {
+	// Velocity returns the current velocity of the entity. The values in the Vec3 returned represent the speed on
+	// that axis in blocks/tick.
+	Velocity() mgl64.Vec3
+	// SetVelocity sets the velocity of the entity. The values in the Vec3 passed represent the speed on
+	// that axis in blocks/tick.
+	SetVelocity(v mgl64.Vec3)
+}
+
+// EntityLand ...
+func (SlimeBlock) EntityLand(_ cube.Pos, _ *world.World, e world.Entity) {
+	if e, ok := e.(fallDistanceEntity); ok {
+		e.ResetFallDistance()
+	}
+	if e, ok := e.(velocityEntity); ok {
+		v := e.Velocity()
+		v[1] *= -1
+		e.SetVelocity(v)
+	}
+}
+
+// BreakInfo ...
+func (s SlimeBlock) BreakInfo() BreakInfo {
+	return newBreakInfo(0, alwaysHarvestable, nothingEffective, oneOf(s))
+}
+
+// Friction ...
+func (SlimeBlock) Friction() float64 {
+	return 0.8
+}
+
+// EncodeItem ...
+func (SlimeBlock) EncodeItem() (name string, meta int16) {
+	return "minecraft:slime", 0
+}
+
+// EncodeBlock ...
+func (SlimeBlock) EncodeBlock() (string, map[string]interface{}) {
+	return "minecraft:slime", nil
+}

server/entity/item.go

@@ -69,6 +69,12 @@ func (it *Item) SetPickupDelay(d time.Duration) {
 	it.pickupDelay = ticks
 }
 
+// entityLander represents a block that reacts to an entity landing on it after falling.
+type entityLander interface {
+	// EntityLand is called when an entity lands on the block.
+	EntityLand(pos cube.Pos, w *world.World, e world.Entity)
+}
+
 // Tick ticks the entity, performing movement.
 func (it *Item) Tick(w *world.World, current int64) {
 	it.mu.Lock()
@@ -78,6 +84,16 @@ func (it *Item) Tick(w *world.World, current int64) {
 
 	m.Send()
 
+	pos := cube.PosFromVec3(m.pos)
+	b := w.Block(pos)
+	if len(b.Model().BBox(pos, w)) == 0 {
+		pos = pos.Sub(cube.Pos{0, 1})
+		b = w.Block(pos)
+	}
+	if h, ok := b.(entityLander); ok {
+		h.EntityLand(pos, w, it)
+	}
+
 	if m.pos[1] < float64(w.Range()[0]) && current%10 == 0 {
 		_ = it.Close()
 		return