broken-neees/ppu/VideoRegisters.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 _InMemoryRegister = _interopRequireDefault(require("../lib/InMemoryRegister"));
var _byte = _interopRequireDefault(require("../lib/byte"));
function _interopRequireDefault(e) { return e && e.__esModule ? e : { default: e }; }
class PPUCtrl extends _InMemoryRegister.default.PPU {
  onLoad() {
    this.addField("vramAddressIncrement32", 2).addField("sprite8x8PatternTableId", 3).addField("backgroundPatternTableId", 4).addField("spriteSize", 5).addField("generateNMIOnVBlank", 7);
  }
  onWrite(value) {
    this.setValue(value);
    this.ppu.loopy.onPPUCtrlWrite(value);
  }
}
class PPUMask extends _InMemoryRegister.default.PPU {
  onLoad() {
    this.addField("grayscale", 0).addField("showBackgroundInFirst8Pixels", 1).addField("showSpritesInFirst8Pixels", 2).addField("showBackground", 3).addField("showSprites", 4).addField("emphasizeRed", 5).addField("emphasizeGreen", 6).addField("emphasizeBlue", 7);
  }
  isRenderingEnabled() {
    return this.showBackground || this.showSprites;
  }
  transform(color) {
    let r = color >> 0 & 0xff;
    let g = color >> 8 & 0xff;
    let b = color >> 16 & 0xff;
    if (this.grayscale) {
      r = g = b = Math.floor((r + g + b) / 3);
    }
    if (this.emphasizeRed || this.emphasizeGreen || this.emphasizeBlue) {
      const all = this.emphasizeRed && this.emphasizeGreen && this.emphasizeBlue;
      if (!this.emphasizeRed || all) r = Math.floor(r * 0.75);
      if (!this.emphasizeGreen || all) g = Math.floor(g * 0.75);
      if (!this.emphasizeBlue || all) b = Math.floor(b * 0.75);
    }
    return 0xff000000 | r << 0 | g << 8 | b << 16;
  }
  onWrite(value) {
    this.setValue(value);
  }
}
class PPUStatus extends _InMemoryRegister.default.PPU {
  onLoad() {
    this.addWritableField("spriteOverflow", 5).addWritableField("sprite0Hit", 6).addWritableField("isInVBlankInterval", 7);
    this.setValue(0b10000000);
  }
  onRead() {
    if (this.ppu.isDebugging) return this.value;
    const value = this.value;
    this.isInVBlankInterval = 0;
    this.ppu.loopy.onPPUStatusRead();
    return value;
  }
}
class OAMAddr extends _InMemoryRegister.default.PPU {
  onWrite(value) {
    this.setValue(value);
  }
}
class OAMData extends _InMemoryRegister.default.PPU {
  onRead() {
    const oamAddress = this.ppu.registers.oamAddr;
    return this.ppu.memory.oamRam[oamAddress.value];
  }
  onWrite(value) {
    const oamAddress = this.ppu.registers.oamAddr;
    this.ppu.memory.oamRam[oamAddress.value] = value;
    this._incrementAddress();
  }
  _incrementAddress() {
    const oamAddress = this.ppu.registers.oamAddr;
    oamAddress.setValue(oamAddress.value + 1);
  }
}
class PPUScroll extends _InMemoryRegister.default.PPU {
  onWrite(value) {
    this.ppu.loopy.onPPUScrollWrite(value);
  }
}
class PPUAddr extends _InMemoryRegister.default.PPU {
  onWrite(value) {
    this.ppu.loopy.onPPUAddrWrite(value);
  }
}
class PPUData extends _InMemoryRegister.default.PPU {
  onLoad() {
    this.buffer = 0;
  }
  onRead() {
    if (this.ppu.isDebugging) return this.buffer;
    let data = this.buffer;
    const ppuAddress = this.ppu.loopy.vAddress.getValue();
    this.buffer = this.ppu.memory.read(ppuAddress);
    if (ppuAddress >= 0x3f00) data = this.buffer;
    this._incrementAddress();
    return data;
  }
  onWrite(value) {
    const ppuAddress = this.ppu.loopy.vAddress.getValue();
    this.ppu.memory.write(ppuAddress, value);
    this._incrementAddress();
  }
  _incrementAddress() {
    const {
      ppuCtrl
    } = this.ppu.registers;
    const ppuAddress = this.ppu.loopy.vAddress.getValue();
    this.ppu.loopy.vAddress.setValue(_byte.default.toU16(ppuAddress + (ppuCtrl.vramAddressIncrement32 ? 32 : 1)));
  }
}
class OAMDMA extends _InMemoryRegister.default.PPU {
  onWrite(value) {
    for (let i = 0; i < 256; i++) {
      const address = _byte.default.buildU16(value, i);
      const data = this.ppu.cpu.memory.read(address);
      this.ppu.memory.oamRam[i] = data;
    }
    this.ppu.cpu.extraCycles += 513;
  }
}
class VideoRegisters {
  constructor(ppu) {
    this.ppuCtrl = new PPUCtrl(ppu); //     $2000
    this.ppuMask = new PPUMask(ppu); //     $2001
    this.ppuStatus = new PPUStatus(ppu); // $2002
    this.oamAddr = new OAMAddr(ppu); //     $2003
    this.oamData = new OAMData(ppu); //     $2004
    this.ppuScroll = new PPUScroll(ppu); // $2005
    this.ppuAddr = new PPUAddr(ppu); //     $2006
    this.ppuData = new PPUData(ppu); //     $2007
    this.oamDma = new OAMDMA(ppu); //       $4014
  }
  read(address) {
    var _this$_getRegister;
    return (_this$_getRegister = this._getRegister(address)) === null || _this$_getRegister === void 0 ? void 0 : _this$_getRegister.onRead();
  }
  write(address, value) {
    var _this$_getRegister2;
    (_this$_getRegister2 = this._getRegister(address)) === null || _this$_getRegister2 === void 0 || _this$_getRegister2.onWrite(value);
  }
  _getRegister(address) {
    switch (address) {
      case 0x2000:
        return this.ppuCtrl;
      case 0x2001:
        return this.ppuMask;
      case 0x2002:
        return this.ppuStatus;
      case 0x2003:
        return this.oamAddr;
      case 0x2004:
        return this.oamData;
      case 0x2005:
        return this.ppuScroll;
      case 0x2006:
        return this.ppuAddr;
      case 0x2007:
        return this.ppuData;
      case 0x4014:
        return this.oamDma;
      default:
    }
  }
}
exports.default = VideoRegisters;