feat(shape): add RotateCW() and RotateCCW()

game/shape.go

@@ -56,3 +56,29 @@ func (s Shape) Coordinates() [4]core.Vec2i8 {
 		s.coordinates[2],
 	}
 }
+
+func (s Shape) RotateCW() Shape {
+	rotated := [3]core.Vec2i8{}
+
+	for i, block := range s.coordinates {
+		block.X, block.Y = -1*block.Y, block.X
+		rotated[i] = block
+	}
+	return Shape{
+		typ:         s.typ,
+		coordinates: rotated,
+	}
+}
+
+func (s Shape) RotateCCW() Shape {
+	rotated := [3]core.Vec2i8{}
+
+	for i, block := range s.coordinates {
+		block.X, block.Y = block.Y, -1*block.X
+		rotated[i] = block
+	}
+	return Shape{
+		typ:         s.typ,
+		coordinates: rotated,
+	}
+}