From a595ed8d9fbe6ff4a7a6f13c279b5412aeb41ab4 Mon Sep 17 00:00:00 2001
From: LawnCable <git@lawncable.net>
Date: Fri, 15 Apr 2022 08:37:05 +0200
Subject: layer tiles, draft for object parsing and more

---
 src/lowlevel/layer_tile.rs | 73 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 src/lowlevel/layer_tile.rs

(limited to 'src/lowlevel/layer_tile.rs')

diff --git a/src/lowlevel/layer_tile.rs b/src/lowlevel/layer_tile.rs
new file mode 100644
index 0000000..bca5daf
--- /dev/null
+++ b/src/lowlevel/layer_tile.rs
@@ -0,0 +1,73 @@
+// Bits on the far end of the 32-bit global tile ID are used for tile flags
+const FLIPPED_HORIZONTALLY_FLAG: u32 = 0x80000000;
+const FLIPPED_VERTICALLY_FLAG: u32 = 0x40000000;
+const FLIPPED_DIAGONALLY_FLAG: u32 = 0x20000000;
+
+#[derive(Debug, Default, PartialEq)]
+pub struct TileFlip {
+    // whether tile is flipped diagonally (should be the first operation)
+    pub diagonally: bool,
+    // whether tile is flipped horizontally (should be the second operation)
+    pub horizontally: bool,
+    // whether tile is flipped vertically (should be the third operation)
+    pub vertically: bool,
+}
+
+impl TileFlip {
+    fn new(diagonally: bool, horizontally: bool, vertically: bool) -> Self {
+        Self {
+            diagonally,
+            horizontally,
+            vertically,
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct LayerTile(u32);
+
+impl LayerTile {
+    /// Global Tile Id
+    pub fn gid(&self) -> u32 {
+        // Clear the flags
+        self.0 & !(FLIPPED_HORIZONTALLY_FLAG | FLIPPED_VERTICALLY_FLAG | FLIPPED_DIAGONALLY_FLAG)
+    }
+
+    pub fn get_flip(&self) -> TileFlip {
+        // Read out the flags
+        TileFlip {
+            diagonally: (self.0 & FLIPPED_DIAGONALLY_FLAG) > 0,
+            horizontally: (self.0 & FLIPPED_HORIZONTALLY_FLAG) > 0,
+            vertically: (self.0 & FLIPPED_VERTICALLY_FLAG) > 0,
+        }
+    }
+}
+
+#[cfg(test)]
+mod test_layer_tile {
+    use crate::lowlevel::{layer_tile::*};
+
+    #[test]
+    fn test_get_flip() {
+        assert_eq!(LayerTile(13).get_flip(), TileFlip::default());
+        assert_eq!(
+            LayerTile(3451 | FLIPPED_DIAGONALLY_FLAG).get_flip(),
+            TileFlip::new(true, false, false)
+        );
+    }
+
+    #[test]
+    fn test_gid() {
+        assert_eq!(LayerTile(5).gid(), 5);
+        assert_eq!(
+            LayerTile(
+                52 | (FLIPPED_HORIZONTALLY_FLAG
+                    | FLIPPED_VERTICALLY_FLAG
+                    | FLIPPED_DIAGONALLY_FLAG)
+            )
+            .gid(),
+            52
+        );
+        assert_eq!(LayerTile(798 | (FLIPPED_DIAGONALLY_FLAG)).gid(), 798);
+    }
+}
-- 
cgit v1.2.3-60-g2f50