Implement hanging signs

cmd/blockhash/main.go

@@ -244,6 +244,9 @@ func (b *hashBuilder) ftype(structName, s string, expr ast.Expr, directives map[
 			return "uint64(" + s + ".FaceUint8())", 3
 		}
 		return "uint64(" + s + ".Uint8())", 5
+	case "HangingAttachment":
+		// Wall (0-3), Ceiling non-attached (4-7), Ceiling attached (8-23) = 24 values, 5 bits.
+		return "uint64(" + s + ".Uint8())", 5
 	case "GrindstoneAttachment":
 		return "uint64(" + s + ".Uint8())", 2
 	case "WoodType", "LeavesType", "FlowerType", "DoubleFlowerType", "Colour":

server/block/hanging_attachment.go

@@ -0,0 +1,48 @@
+package block
+
+import "github.com/df-mc/dragonfly/server/block/cube"
+
+// HangingAttachment describes how a hanging sign is attached. It may be mounted to the side of a block, hang
+// underneath a block by chains, or be attached underneath a block with the 16-direction ceiling variant.
+type HangingAttachment struct {
+	ceiling  bool
+	attached bool
+	facing   cube.Direction
+	o        cube.Orientation
+}
+
+// WallHangingAttachment returns a HangingAttachment for a hanging sign mounted to the side of a block.
+func WallHangingAttachment(facing cube.Direction) HangingAttachment {
+	return HangingAttachment{facing: facing}
+}
+
+// CeilingHangingAttachment returns a HangingAttachment for a hanging sign hanging underneath a block.
+func CeilingHangingAttachment(facing cube.Direction) HangingAttachment {
+	return HangingAttachment{ceiling: true, facing: facing}
+}
+
+// AttachedCeilingHangingAttachment returns a HangingAttachment for a hanging sign attached underneath a block using
+// the 16-direction ceiling variant.
+func AttachedCeilingHangingAttachment(o cube.Orientation) HangingAttachment {
+	return HangingAttachment{ceiling: true, attached: true, o: o}
+}
+
+// Uint8 returns the HangingAttachment as a uint8.
+// Wall: 0-3, Ceiling (non-attached): 4-7, Ceiling (attached): 8-23.
+func (a HangingAttachment) Uint8() uint8 {
+	if !a.ceiling {
+		return uint8(a.facing)
+	}
+	if !a.attached {
+		return 4 + uint8(a.facing)
+	}
+	return 8 + uint8(a.o)
+}
+
+// Rotation returns the rotation of the HangingAttachment.
+func (a HangingAttachment) Rotation() cube.Rotation {
+	if a.attached {
+		return cube.Rotation{a.o.Yaw()}
+	}
+	return WallAttachment(a.facing).Rotation()
+}