perf: keep block resolution off the heap

block/bounce.go

@@ -14,12 +14,13 @@ func (slime) Matches(b world.Block, name string) bool {
 	return name == "minecraft:slime"
 }
 
-func (slime) Apply(s *resolution) {
+func (slime) Apply(s resolution) resolution {
 	if !s.groundFrictionSet {
 		s.GroundFriction = 0.8
 		s.groundFrictionSet = true
 	}
 	s.Bounce = BounceSlime
+	return s
 }
 
 type bed struct{}
@@ -31,6 +32,7 @@ func (bed) Matches(b world.Block, name string) bool {
 	return name == "minecraft:bed"
 }
 
-func (bed) Apply(s *resolution) {
+func (bed) Apply(s resolution) resolution {
 	s.Bounce = BounceBed
+	return s
 }

block/climbable.go

@@ -21,6 +21,7 @@ func (climbableBlock) Matches(b world.Block, name string) bool {
 	}
 }
 
-func (climbableBlock) Apply(s *resolution) {
+func (climbableBlock) Apply(s resolution) resolution {
 	s.Climbable = true
+	return s
 }

block/contact.go

@@ -8,6 +8,7 @@ func (cobweb) Matches(_ world.Block, name string) bool {
 	return name == "minecraft:web"
 }
 
-func (cobweb) Apply(s *resolution) {
+func (cobweb) Apply(s resolution) resolution {
 	s.Cobweb = true
+	return s
 }

block/environment.go

@@ -13,8 +13,9 @@ func (r environmentRule) Matches(_ world.Block, name string) bool {
 	return name == r.name
 }
 
-func (r environmentRule) Apply(s *resolution) {
+func (r environmentRule) Apply(s resolution) resolution {
 	s.InsideMovement = r.inside
 	s.Traversal = r.traversal
 	s.Honey = r.honey
+	return s
 }

block/friction.go

@@ -11,9 +11,10 @@ func (b frictionBlock) Matches(_ world.Block, name string) bool {
 	return name == b.name
 }
 
-func (b frictionBlock) Apply(s *resolution) {
+func (b frictionBlock) Apply(s resolution) resolution {
 	if !s.groundFrictionSet {
 		s.GroundFriction = b.friction
 		s.groundFrictionSet = true
 	}
+	return s
 }

block/ground.go

@@ -14,7 +14,8 @@ func (soulSand) Matches(b world.Block, name string) bool {
 	return name == "minecraft:soul_sand"
 }
 
-func (soulSand) Apply(s *resolution) {
+func (soulSand) Apply(s resolution) resolution {
 	s.GroundAccelerationFrictionMultiplier *= SoulSandAccelerationFrictionMultiplier
 	s.SoulSpeedNeutralizesAccelerationFriction = true
+	return s
 }

block/semantics.go

@@ -56,7 +56,7 @@ type MovementSemantics struct {
 // rule contributes movement behavior for a block family.
 type rule interface {
 	Matches(world.Block, string) bool
-	Apply(*resolution)
+	Apply(resolution) resolution
 }
 
 type resolution struct {
@@ -92,7 +92,7 @@ func Resolve(b world.Block, name string) MovementSemantics {
 	}
 	for _, rule := range rules {
 		if rule.Matches(b, name) {
-			rule.Apply(&result)
+			result = rule.Apply(result)
 		}
 	}
 	if !result.groundFrictionSet {

block/semantics_test.go

@@ -15,9 +15,10 @@ func (r *countingRule) Matches(world.Block, string) bool {
 	return true
 }
 
-func (*countingRule) Apply(s *resolution) {
+func (*countingRule) Apply(s resolution) resolution {
 	s.GroundFriction = 0.7
 	s.groundFrictionSet = true
+	return s
 }
 
 func TestResolveVisitsEachRuleOnce(t *testing.T) {