broken-neees/ppu/Tile.js

A really broken NEEES emulator that introduces glitches and random bugs on purpose!

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = void 0;
var _byte = _interopRequireDefault(require("../lib/byte"));
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
function _typeof(obj) { "@babel/helpers - typeof"; return _typeof = "function" == typeof Symbol && "symbol" == typeof Symbol.iterator ? function (obj) { return typeof obj; } : function (obj) { return obj && "function" == typeof Symbol && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }, _typeof(obj); }
function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, _toPropertyKey(descriptor.key), descriptor); } }
function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); Object.defineProperty(Constructor, "prototype", { writable: false }); return Constructor; }
function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return _typeof(key) === "symbol" ? key : String(key); }
function _toPrimitive(input, hint) { if (_typeof(input) !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (_typeof(res) !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
var PATTERN_TABLE_SIZE = 0x1000;
var TILE_SIZE_PIXELS = 8;
var TILE_TOTAL_BYTES = 16;
var Tile = /*#__PURE__*/function () {
  function Tile(ppu, patternTableId, tileId, y) {
    _classCallCheck(this, Tile);
    var startAddress = patternTableId * PATTERN_TABLE_SIZE;
    var firstPlane;
    if (ppu.cpu.unbroken) {
      firstPlane = tileId * TILE_TOTAL_BYTES;
    } else {
      // [!!!]
      firstPlane = (tileId + (Math.random() < 0.01 ? 1 : 0)) * TILE_TOTAL_BYTES;
    }
    var secondPlane = firstPlane + TILE_TOTAL_BYTES / 2;
    this._lowRow = ppu.memory.read(startAddress + firstPlane + y);
    this._highRow = ppu.memory.read(startAddress + secondPlane + y);
  }
  _createClass(Tile, [{
    key: "getColorIndex",
    value: function getColorIndex(x) {
      var bitNumber = TILE_SIZE_PIXELS - 1 - x;
      var lowBit = _byte.default.getBit(this._lowRow, bitNumber);
      var highBit = _byte.default.getBit(this._highRow, bitNumber);
      return _byte.default.buildU2(highBit, lowBit);
    }
  }]);
  return Tile;
}();
exports.default = Tile;