Add unit tests for room gfx nametable and a serialiser 📡.

src/lib/parser/parseRooms.js

@@ -1,5 +1,6 @@
 import Parser from './parser.js';
 import parseRoomHeader from './room/parseRoomHeader.js';
+import parseRoomNametable from './room/parseRoomNametable.js';
 import parseRoomBoxes from './room/parseRoomBoxes.js';
 import parseRoomMatrix from './room/parseRoomMatrix.js';
 
@@ -63,50 +64,17 @@ const parseRooms = (arrayBuffer, i = 0, offset = 0, characters = {}) => {
   }
 
   // Parse gfx nametable.
-  const nametableParser = new Parser(arrayBuffer.slice(nametableOffs));
-
-  const tileset = nametableParser.getUint8();
-
-  const palette = [];
-  const nametableObj = Array(16);
-  for (let i = 0; i < 16; i++) {
-    palette[i] = nametableParser.getUint8();
-  }
-  for (let i = 0; i < 16; i++) {
-    nametableObj[i] = Array(64).fill(0);
-    nametableObj[i][0] = 0;
-    nametableObj[i][1] = 0;
-    let n = 0;
-    while (n < width) {
-      const loop = nametableParser.getUint8();
-      if (loop & 0x80) {
-        for (let j = 0; j < (loop & 0x7f); j++) {
-          nametableObj[i][2 + n++] = nametableParser.getUint8();
-        }
-      } else {
-        const data = nametableParser.getUint8();
-        for (let j = 0; j < (loop & 0x7f); j++) {
-          nametableObj[i][2 + n++] = data;
-        }
-      }
-    }
-  }
-
-  const nametable = {
-    tileset,
-    palette,
-    nametableObj,
-  };
+  const { nametable, nametableMap } = parseRoomNametable(
+    arrayBuffer.slice(nametableOffs, attrOffs),
+    nametableOffs,
+    width,
+  );
 
-  map.push({
-    type: 'nametable',
-    from: nametableOffs,
-    to: nametableOffs + nametableParser.pointer - 1,
-  });
+  map.push(nametableMap);
 
   assert(
-    nametableOffs + nametableParser.pointer === attrOffs,
-    'name table overlaps on attributes table.',
+    nametableMap.to + 1 === attrOffs,
+    'Gfx nametable overlaps on attributes table.',
   );
 
   // Parse gfx attrtable.

src/lib/parser/room/parseRoomNametable.js

@@ -0,0 +1,70 @@
+import Parser from '../parser.js';
+
+const assert = console.assert;
+
+const parseRoomNametable = (arrayBuffer, offset = 0, width = 0) => {
+  const parser = new Parser(arrayBuffer);
+  const tileset = parser.getUint8();
+
+  const palette = [];
+  for (let i = 0; i < 16; i++) {
+    palette[i] = parser.getUint8();
+  }
+
+  const nametableObj = Array(16);
+  for (let i = 0; i < 16; i++) {
+    nametableObj[i] = Array(64).fill(0);
+    nametableObj[i][0] = 0;
+    nametableObj[i][1] = 0;
+
+    assert(
+      nametableObj[i][0] === 0,
+      'Gfx nametable strip does not start with 0x00 0x00.',
+    );
+    assert(
+      nametableObj[i][1] === 0,
+      'Gfx nametable strip does not start with 0x00 0x00.',
+    );
+
+    let n = 0;
+    while (n < width) {
+      const loop = parser.getUint8();
+      if (loop & 0x80) {
+        for (let j = 0; j < (loop & 0x7f); j++) {
+          nametableObj[i][2 + n++] = parser.getUint8();
+        }
+      } else {
+        const data = parser.getUint8();
+        for (let j = 0; j < (loop & 0x7f); j++) {
+          nametableObj[i][2 + n++] = data;
+        }
+      }
+    }
+
+    assert(
+      nametableObj[i][62] === 0,
+      'Gfx nametable strip does not end with 0x00 0x00.',
+    );
+    assert(
+      nametableObj[i][63] === 0,
+      'Gfx nametable strip does not end with 0x00 0x00.',
+    );
+  }
+
+  const nametableMap = {
+    type: 'nametable',
+    from: offset,
+    to: offset + parser.pointer - 1,
+  };
+
+  return {
+    nametable: {
+      tileset,
+      palette,
+      nametableObj,
+    },
+    nametableMap,
+  };
+};
+
+export default parseRoomNametable;

src/lib/serialiser/room/serialiseRoomNametable.js

@@ -0,0 +1,61 @@
+import Serialiser from '../serialiser.js';
+
+const serialiseRoomNametable = (nametable = {}) => {
+  const serialiser = new Serialiser();
+  const { tileset, palette, nametableObj } = nametable;
+
+  serialiser.setUint8(tileset);
+
+  for (let i = 0; i < 16; i++) {
+    serialiser.setUint8(palette[i]);
+  }
+
+  for (let i = 0; i < 16; i++) {
+    serialiseOneStrip(nametableObj[i].slice(2, 62), serialiser);
+  }
+
+  return serialiser.buffer;
+};
+
+// Serialise one strip using the compression algorithm.
+const serialiseOneStrip = (nametableObj, serialiser) => {
+  let n = 0;
+  while (n < 60) {
+    let initialTile = nametableObj[n];
+    let loop = 0;
+
+    // Look 2 tiles ahead.
+    if (
+      nametableObj[n] !== nametableObj[n + 1] ||
+      nametableObj[n] !== nametableObj[n + 2]
+    ) {
+      // The next 3 tiles are different. Count how many unique tiles there are.
+      // It stops once it encounters 3 identical tiles in a row.
+      const initialN = n;
+
+      do {
+        loop++;
+        initialTile = nametableObj[++n];
+      } while (
+        initialTile !== nametableObj[n + 1] ||
+        initialTile !== nametableObj[n + 2]
+      );
+
+      serialiser.setUint8(loop | 0x80); // Set the type of loop.
+      for (let i = initialN; i < n; i++) {
+        serialiser.setUint8(nametableObj[i]);
+      }
+    } else {
+      // The next 3 tiles are identical. Count how many of them in a row.
+      // It stops when it finds a different tile.
+      do {
+        loop++;
+      } while (initialTile === nametableObj[++n]);
+
+      serialiser.setUint8(loop);
+      serialiser.setUint8(initialTile);
+    }
+  }
+};
+
+export default serialiseRoomNametable;

test/parseRoomNametable.test.js

@@ -0,0 +1,130 @@
+import { describe, it } from 'node:test';
+import assert from 'node:assert/strict';
+import parseRoomNametable from '../src/lib/parser/room/parseRoomNametable.js';
+import serialiseRoomNametable from '../src/lib/serialiser/room/serialiseRoomNametable.js';
+
+const roomNametableEmptyBuffer = (tileset) => {
+  const buffer = new ArrayBuffer(1 + 16 + 16 * 64);
+  const view = new DataView(buffer);
+  view.setUint8(0x00, tileset); // Set the value of tileset.
+  return buffer;
+};
+
+const roomNametableBuffer = () => {
+  const array = [
+    0x01, 0x0d, 0x07, 0x27, 0x3c, 0x0d, 0x17, 0x2a, 0x3a, 0x0d, 0x0d, 0x2a,
+    0x28, 0x0d, 0x0d, 0x37, 0x20, 0x87, 0x01, 0x01, 0x62, 0x01, 0x63, 0x01,
+    0x64, 0x03, 0x65, 0x82, 0x63, 0x64, 0x04, 0x65, 0x82, 0x63, 0x64, 0x09,
+    0x65, 0x81, 0x63, 0x05, 0x65, 0x82, 0x63, 0x64, 0x03, 0x65, 0x83, 0x01,
+    0x63, 0x74, 0x05, 0x01, 0x81, 0x62, 0x05, 0x01, 0x84, 0x74, 0x01, 0x01,
+    0x74, 0x04, 0x01, 0x93, 0x01, 0x62, 0x62, 0x01, 0x63, 0x01, 0x64, 0x66,
+    0x67, 0x68, 0x63, 0x66, 0x67, 0x68, 0x65, 0x66, 0x63, 0x68, 0x69, 0x06,
+    0x6a, 0x8f, 0x6b, 0x66, 0x63, 0x68, 0x65, 0x66, 0x67, 0x68, 0x63, 0x66,
+    0x67, 0x68, 0x65, 0x01, 0x63, 0x0c, 0x01, 0x88, 0x62, 0x01, 0x01, 0x62,
+    0x01, 0x01, 0x62, 0x74, 0x04, 0x01, 0xa4, 0x63, 0x01, 0x64, 0x6c, 0x01,
+    0x6d, 0x63, 0x6c, 0x01, 0x6d, 0x65, 0x6c, 0x63, 0x6d, 0x6e, 0x36, 0x39,
+    0x37, 0x36, 0x39, 0x37, 0x6f, 0x6c, 0x63, 0x6d, 0x65, 0x6c, 0x01, 0x6d,
+    0x63, 0x6c, 0x01, 0x6d, 0x65, 0x01, 0x63, 0x03, 0x01, 0x87, 0x74, 0x01,
+    0x01, 0x62, 0x01, 0x01, 0x74, 0x04, 0x01, 0x86, 0x74, 0x01, 0x01, 0x74,
+    0x01, 0x01, 0x81, 0x62, 0x03, 0x01, 0xa5, 0x63, 0x01, 0x64, 0x70, 0x71,
+    0x72, 0x63, 0x70, 0x71, 0x72, 0x65, 0x70, 0x63, 0x72, 0x6e, 0x3e, 0x73,
+    0x40, 0x3b, 0x73, 0x3c, 0x6f, 0x70, 0x63, 0xb4, 0x65, 0x70, 0xb5, 0xb4,
+    0x63, 0x70, 0xb5, 0xb4, 0x65, 0x01, 0x63, 0x62, 0x13, 0x01, 0xa8, 0x01,
+    0x62, 0x01, 0x74, 0x63, 0x01, 0x64, 0x6c, 0x01, 0x6d, 0x63, 0x6c, 0x01,
+    0x6d, 0x65, 0x6c, 0x63, 0x6d, 0x6e, 0x3b, 0x3d, 0x40, 0x3b, 0x3d, 0x40,
+    0x6f, 0x6c, 0x63, 0x6d, 0x65, 0x6c, 0x01, 0x6d, 0x63, 0x6c, 0x01, 0x6d,
+    0x65, 0x01, 0x63, 0x03, 0x01, 0x83, 0x62, 0x01, 0x74, 0x03, 0x01, 0x81,
+    0x62, 0x04, 0x01, 0x83, 0x62, 0x01, 0x74, 0x03, 0x01, 0x04, 0x01, 0xa4,
+    0x63, 0x01, 0x64, 0x75, 0x76, 0x77, 0x63, 0x75, 0x76, 0x77, 0x65, 0x75,
+    0x63, 0x77, 0x6e, 0x3b, 0x3d, 0x40, 0x3b, 0x3d, 0x40, 0x78, 0x75, 0x63,
+    0x77, 0x65, 0x75, 0x76, 0x77, 0x63, 0x75, 0x76, 0x77, 0x65, 0x01, 0x63,
+    0x0b, 0x01, 0x81, 0x74, 0x08, 0x01, 0x87, 0x62, 0x01, 0x01, 0x79, 0x7a,
+    0x7b, 0x7c, 0x03, 0x7d, 0x82, 0x7a, 0x7c, 0x04, 0x7d, 0x8c, 0x7a, 0x64,
+    0x6e, 0x3b, 0x3d, 0x49, 0x49, 0x3d, 0x40, 0x6f, 0x65, 0x7a, 0x05, 0x7d,
+    0x81, 0x7a, 0x04, 0x7d, 0x83, 0x7b, 0x7a, 0xb6, 0x03, 0x01, 0x82, 0x74,
+    0x62, 0x03, 0x01, 0x81, 0x62, 0x08, 0x01, 0x82, 0x62, 0x01, 0xab, 0x01,
+    0x74, 0x01, 0x7e, 0x63, 0x01, 0x7f, 0x64, 0x7f, 0x64, 0x7f, 0x64, 0x7f,
+    0x64, 0x7f, 0x64, 0x7f, 0x64, 0x6e, 0x3b, 0x3d, 0x40, 0x3b, 0x3d, 0x40,
+    0x6f, 0x65, 0x7f, 0x64, 0x7f, 0x64, 0x7f, 0x64, 0x7f, 0x64, 0x7f, 0x64,
+    0x7f, 0x01, 0x63, 0x7e, 0x01, 0x74, 0x03, 0x01, 0x84, 0x74, 0x01, 0xb7,
+    0x62, 0x0a, 0xb7, 0x03, 0x01, 0xb4, 0x80, 0x63, 0x01, 0x81, 0x64, 0x81,
+    0x64, 0x81, 0x64, 0x81, 0x64, 0x81, 0x64, 0x81, 0x64, 0x6e, 0x3e, 0x3d,
+    0x40, 0x3b, 0x3d, 0x3c, 0x6f, 0x65, 0x81, 0x64, 0x81, 0x64, 0x81, 0x64,
+    0x81, 0x64, 0x81, 0x64, 0x81, 0x01, 0x63, 0x80, 0x01, 0x62, 0x01, 0x01,
+    0x62, 0x01, 0x01, 0xb8, 0xb9, 0xb8, 0xb8, 0xba, 0xb8, 0xb8, 0x05, 0xba,
+    0xb7, 0x62, 0x01, 0x01, 0x82, 0x82, 0x83, 0x82, 0x84, 0x82, 0x84, 0x82,
+    0x84, 0x82, 0x84, 0x82, 0x84, 0x82, 0x64, 0x6e, 0x41, 0x43, 0x44, 0x41,
+    0x43, 0x44, 0x6f, 0x65, 0x82, 0x84, 0xbb, 0x84, 0xbb, 0x84, 0xbb, 0x84,
+    0xbb, 0x84, 0xbb, 0x83, 0xbb, 0xbb, 0x01, 0xc4, 0xc5, 0x01, 0xc4, 0xc5,
+    0x01, 0xc4, 0xc5, 0xbc, 0xbc, 0xbd, 0xbc, 0xbc, 0x05, 0xbd, 0x84, 0x85,
+    0x86, 0x87, 0x01, 0x0d, 0x88, 0x82, 0x89, 0x84, 0x06, 0x8a, 0x83, 0x84,
+    0x8b, 0x88, 0x0c, 0xbe, 0x8a, 0x01, 0x01, 0xc7, 0xc7, 0x01, 0xc7, 0xc7,
+    0x01, 0xc7, 0xc7, 0x04, 0xbd, 0x82, 0xbf, 0xc0, 0x04, 0xbd, 0x84, 0x8c,
+    0x8d, 0x8e, 0x01, 0x08, 0x8f, 0x04, 0x90, 0x82, 0x91, 0x92, 0x08, 0x93,
+    0x82, 0x94, 0x91, 0x04, 0xce, 0x08, 0x8f, 0x8b, 0x01, 0x62, 0xbf, 0xc0,
+    0x01, 0xbf, 0xc0, 0x01, 0xbf, 0xc0, 0xbc, 0x05, 0xbd, 0x81, 0xbc, 0x03,
+    0xbd, 0x84, 0x01, 0x95, 0x01, 0x01, 0x06, 0x8f, 0x88, 0x96, 0x96, 0x97,
+    0x98, 0x97, 0x98, 0x99, 0x9a, 0x08, 0x9b, 0x86, 0x9c, 0x9d, 0x97, 0xcf,
+    0x97, 0xcf, 0x08, 0x8f, 0x14, 0xc1, 0x84, 0x9e, 0x9f, 0x9e, 0x9e, 0x08,
+    0x90, 0x85, 0xa0, 0xa1, 0xa0, 0xa1, 0x82, 0x0a, 0x84, 0x85, 0x82, 0xa0,
+    0xd1, 0xa0, 0xd1, 0x08, 0xc2, 0x14, 0x3d, 0x88, 0x3d, 0xa2, 0x3d, 0x3d,
+    0xa3, 0xa4, 0xa4, 0xa5, 0x16, 0x3d, 0x81, 0xc6, 0x1d, 0x3d, 0x88, 0x3d,
+    0xa2, 0x3d, 0x3d, 0xa6, 0xa7, 0xa8, 0xa7, 0x34, 0x3d,
+  ];
+  const buffer = new ArrayBuffer(array.length);
+  const view = new DataView(buffer);
+  array.forEach((v, i) => view.setUint8(i, v));
+  return buffer;
+};
+
+describe('parseRoomNametable', () => {
+  it('should return a non empty object.', () => {
+    const { nametable } = parseRoomNametable(roomNametableEmptyBuffer(0));
+
+    assert.equal(typeof nametable, 'object');
+    assert.deepEqual(Object.keys(nametable), [
+      'tileset',
+      'palette',
+      'nametableObj',
+    ]);
+    assert.ok(Number.isInteger(nametable.tileset));
+    assert.ok(Array.isArray(nametable.palette));
+    assert.equal(nametable.palette.length, 16);
+    assert.ok(Array.isArray(nametable.nametableObj));
+    assert.equal(nametable.nametableObj.length, 16);
+    assert.ok(Array.isArray(nametable.nametableObj[0]));
+    assert.equal(nametable.nametableObj[0].length, 64);
+  });
+
+  it('should parse the tileset.', () => {
+    const { nametable } = parseRoomNametable(roomNametableEmptyBuffer(5));
+
+    assert.equal(nametable.tileset, 5);
+  });
+
+  it('should return a map object.', () => {
+    const { nametableMap } = parseRoomNametable(roomNametableEmptyBuffer(0));
+
+    assert.equal(typeof nametableMap, 'object');
+    assert.equal(nametableMap.from, 0);
+    assert.equal(nametableMap.to, 16);
+  });
+
+  it('should return a map object with a start offset.', () => {
+    const { nametableMap } = parseRoomNametable(
+      roomNametableEmptyBuffer(0),
+      0xabc,
+    );
+
+    assert.equal(nametableMap.from, 0xabc);
+    assert.equal(nametableMap.to, 0xacc);
+  });
+
+  it('should be the inverse of serialiseRoomNametable.', () => {
+    const initialBuffer = roomNametableBuffer();
+    const { nametable } = parseRoomNametable(initialBuffer, 0, 60);
+    const buffer = serialiseRoomNametable(nametable);
+
+    assert.deepEqual(initialBuffer, buffer);
+  });
+});