feat: add game/block.go

This type represents a single block in a grid.

game/block.go

@@ -0,0 +1,30 @@
+package game
+
+import (
+	"tetris/assets"
+	"tetris/engine/graphics"
+)
+
+type Block byte
+
+const (
+	BLOCK_EMPTY Block = iota
+	BLOCK_RED
+	BLOCK_GREEN
+	BLOCK_BLUE
+	BLOCK_YELLOW
+	BLOCK_ORANGE
+	BLOCK_MAGENTA
+	BLOCK_TEAL
+)
+
+func (c Block) Tile() graphics.Tile {
+	if c >= 8 {
+		c = BLOCK_EMPTY
+	}
+	return graphics.Tile{
+		Size: assets.BLOCK_TILE_SIZE,
+		X:    byte(c),
+		Y:    byte(0),
+	}
+}