From c026038dc0067d0107ced18632b38a76a8145890 Mon Sep 17 00:00:00 2001
From: edo999 <edo999@gmail.com>
Date: Thu, 23 May 2024 11:03:56 +0100
Subject: [PATCH] =?UTF-8?q?Implement=20object=20attributes=20override=20?=
 =?UTF-8?q?=F0=9F=9B=9E.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/containers/ScreenCanvasContainer.js | 54 +++++++++++++++++++++----
 src/lib/parser/parseRooms.js            | 14 ++++++-
 2 files changed, 58 insertions(+), 10 deletions(-)

diff --git a/src/containers/ScreenCanvasContainer.js b/src/containers/ScreenCanvasContainer.js
index 594b882..7aba9df 100644
--- a/src/containers/ScreenCanvasContainer.js
+++ b/src/containers/ScreenCanvasContainer.js
@@ -51,17 +51,20 @@ const draw = (
   crop,
 ) => {
   const { width, height } = room.header;
-  const { nametableObj, palette } = room.nametable;
-  const attributes = room.attributes;
+  const { palette } = room.nametable;
   const baseTilesNum = baseTiles?.gfx?.length / 8 / 2;
-  const nametableObjCopy = nametableObj.map((arr) => arr.slice());
+  const nametableObj = structuredClone(room.nametable.nametableObj);
+  const attributes = structuredClone(room.attributes);
 
-  // Overwrite tiles with selected object.
+  // Overwrite tiles and palette with selected object.
   // Start with highest id as it is the way it is implemented with overlapping object images.
   for (let i = selectedObjects.length - 1; i >= 0; i--) {
+    const object = room?.objects[i];
     const objectImage = room?.objectImages[i];
-    const x = room?.objects[i]?.x; // Can be 0?
-    const y = room?.objects[i]?.y; // Can be 0?
+    const x = object?.x; // Can be 0?
+    const y = object?.y; // Can be 0?
+    const width = object?.width;
+    const height = object?.height;
 
     if (
       !selectedObjects[i] ||
@@ -75,15 +78,50 @@ const draw = (
 
     for (let j = 0; j < objectImage.tiles.length; j++) {
       for (let i = 0; i < objectImage.tiles[j].length; i++) {
-        nametableObjCopy[y + j][x + i + 2] = objectImage.tiles[j][i];
+        nametableObj[y + j][x + i + 2] = objectImage.tiles[j][i];
       }
     }
+
+    // Port of https://github.com/scummvm/scummvm/blob/master/engines/scumm/gfx.cpp#L3103-L3134
+    let j = height >> 1;
+    let ay = y;
+    let ptr = 0;
+    while (j) {
+      let ax = x + 2;
+      let i = 0;
+      let adata = 0;
+      while (i < width >> 1) {
+        if (!(i & 3)) {
+          adata = objectImage.attributes[ptr++];
+        }
+
+        let aand = 3;
+        let aor = adata & 3;
+        if (ay & 0x02) {
+          aand <<= 4;
+          aor <<= 4;
+        }
+        if (ax & 0x02) {
+          aand <<= 2;
+          aor <<= 2;
+        }
+        const attr = attributes[((ay << 2) & 0x30) | ((ax >> 2) & 0xf)];
+        attributes[((ay << 2) & 0x30) | ((ax >> 2) & 0xf)] =
+          (~aand & attr) | aor;
+
+        adata >>= 2;
+        ax += 2;
+        i++;
+      }
+      ay += 2;
+      j--;
+    }
   }
 
   // Now generate the image of the room.
   for (let sprY = 0; sprY < height; sprY++) {
     for (let sprX = 0; sprX < 62; sprX++) {
-      let tile = nametableObjCopy[sprY][sprX];
+      let tile = nametableObj[sprY][sprX];
 
       let gfx = baseTiles?.gfx;
       if (tile >= baseTilesNum) {
diff --git a/src/lib/parser/parseRooms.js b/src/lib/parser/parseRooms.js
index 5351835..333919f 100644
--- a/src/lib/parser/parseRooms.js
+++ b/src/lib/parser/parseRooms.js
@@ -293,9 +293,19 @@ const parseRooms = (arrayBuffer, i = 0, offset = 0, characters = {}) => {
       }
     }
 
-    // @todo Implement attribute changes and mask tables for object images.
+    // Parse object attrtable override.
+    const attributes = [];
+    if (tiles?.length) {
+      // Is that this length number of bytes to parse?
+      for (let i = 0; i < (objWidth >> 1) * (objHeight >> 1); i++) {
+        attributes.push(objectImagesParser.getUint8());
+      }
+    }
+
+    const objectImage = { tiles, attributes };
+    objectImages.push(objectImage);
 
-    objectImages.push({ tiles });
+    // @todo Implement mask tables for object images.
 
     // @fixme This does not account for object scripts.
     if (objectCodeMap.to < objectOffs + objectImagesParser.pointer) {