Add hold boxv1.0.0

2 files changed, 25 insertions, 0 deletions

diff --git a/tris/core.go b/tris/core.go
index 6963294..089dca4 100644
--- a/tris/core.go
+++ b/tris/core.go
@@ -20,6 +20,7 @@ type Piece [4]uint16
 // A table that represents each piece from https://tetris.fandom.com/wiki/SRS
 // in binary starting with 1 top left going per row, here in hexadecimal shorthand.
 var (
+	EmptyPiece = Piece{}
 	IPiece = Piece{0x0F00, 0x4444, 0x00F0, 0x2222}
 	JPiece = Piece{0x1700, 0x6220, 0x0740, 0x2230}
 	LPiece = Piece{0x4700, 0x2260, 0x0710, 0x3220}
@@ -130,6 +131,7 @@ func (b Bag) Randomize() Bag {
 }
 
 func (b Bag) Pick() (Bag, Placement) {
+	Swapped = false
 	if len(b) == 0 {
 		b = NewBag()
 	}
diff --git a/tris/hold.go b/tris/hold.go
new file mode 100644
index 0000000..6a82f5b
--- /dev/null
+++ b/tris/hold.go
@@ -0,0 +1,23 @@
+package tris
+
+var HoldPiece Piece
+
+var HoldBox Field
+
+var Swapped bool
+
+func (b Bag) Swap(p Placement) (Bag, Placement) {
+	if Swapped {
+		return b, p
+	}
+	var tempp Placement
+	if HoldPiece == EmptyPiece {
+		b, tempp = b.Pick()
+		HoldPiece = tempp.piece
+	}
+	p.piece, HoldPiece = HoldPiece, p.piece
+	Swapped = true
+	HoldBox, _ = Placement{piece: HoldPiece, X: 0, Y:0}.Field(2,4)
+	p.Rot, p.X, p.Y = 0, 3, -2
+	return b, p
+}