new item type, "Dynamic Item"; working text terminal

Former-commit-id: 81e6d836f5f1e6490027d38146a32d404cf9ce3e
Former-commit-id: af6557340f9cd0ea0b67eb7a8825aeffe75f9d82

src/net/torvald/terrarum/gameworld/MapLayer.kt

@@ -0,0 +1,58 @@
+package net.torvald.terrarum.gameworld
+
+/**
+ * Created by minjaesong on 16-01-17.
+ */
+class MapLayer(var width: Int, var height: Int) : Iterable<Byte> {
+
+    internal var data: Array<ByteArray>
+
+    init {
+        data = Array(height) { ByteArray(width) }
+    }
+
+    /**
+     * Returns an iterator over elements of type `T`.
+
+     * @return an Iterator.
+     */
+    override fun iterator(): Iterator<Byte> {
+        return object : Iterator<Byte> {
+
+            private var iteratorCount = 0
+
+            override fun hasNext(): Boolean {
+                return iteratorCount < width * height
+            }
+
+            override fun next(): Byte {
+                val y = iteratorCount / width
+                val x = iteratorCount % width
+                // advance counter
+                iteratorCount += 1
+
+                return data[y][x]
+            }
+        }
+    }
+
+    internal fun getTile(x: Int, y: Int): Int? {
+        return if (x !in 0..width - 1 || y !in 0..height - 1)
+            null
+        else
+            data[y][x].toUint()
+    }
+
+    internal fun setTile(x: Int, y: Int, tile: Byte) {
+        data[y][x] = tile
+    }
+
+    fun isInBound(x: Int, y: Int) = (x >= 0 && y >= 0 && x < width && y < height)
+
+    companion object {
+        @Transient const val RANGE = 256
+        @Transient const val SIZEOF: Byte = 1 // 1 for 8-bit, 2 for 16-bit, ...
+    }
+}
+
+fun Byte.toUint() = java.lang.Byte.toUnsignedInt(this)