emulator/fc/source/tile.js

var Tile = function() {
  // Tile data:
  this.pix = new Array(64);

  this.fbIndex = null;
  this.tIndex = null;
  this.x = null;
  this.y = null;
  this.w = null;
  this.h = null;
  this.incX = null;
  this.incY = null;
  this.palIndex = null;
  this.tpri = null;
  this.c = null;
  this.initialized = false;
  this.opaque = new Array(8);
};

Tile.prototype = {
  setBuffer: function(scanline) {
    for (this.y = 0; this.y < 8; this.y++) {
      this.setScanline(this.y, scanline[this.y], scanline[this.y + 8]);
    }
  },

  setScanline: function(sline, b1, b2) {
    this.initialized = true;
    this.tIndex = sline << 3;
    for (this.x = 0; this.x < 8; this.x++) {
      this.pix[this.tIndex + this.x] =
        ((b1 >> (7 - this.x)) & 1) + (((b2 >> (7 - this.x)) & 1) << 1);
      if (this.pix[this.tIndex + this.x] === 0) {
        this.opaque[sline] = false;
      }
    }
  },

  render: function(
    buffer,
    srcx1,
    srcy1,
    srcx2,
    srcy2,
    dx,
    dy,
    palAdd,
    palette,
    flipHorizontal,
    flipVertical,
    pri,
    priTable
  ) {
    if (dx < -7 || dx >= 256 || dy < -7 || dy >= 240) {
      return;
    }

    this.w = srcx2 - srcx1;
    this.h = srcy2 - srcy1;

    if (dx < 0) {
      srcx1 -= dx;
    }
    if (dx + srcx2 >= 256) {
      srcx2 = 256 - dx;
    }

    if (dy < 0) {
      srcy1 -= dy;
    }
    if (dy + srcy2 >= 240) {
      srcy2 = 240 - dy;
    }

    if (!flipHorizontal && !flipVertical) {
      this.fbIndex = (dy << 8) + dx;
      this.tIndex = 0;
      for (this.y = 0; this.y < 8; this.y++) {
        for (this.x = 0; this.x < 8; this.x++) {
          if (
            this.x >= srcx1 &&
            this.x < srcx2 &&
            this.y >= srcy1 &&
            this.y < srcy2
          ) {
            this.palIndex = this.pix[this.tIndex];
            this.tpri = priTable[this.fbIndex];
            if (this.palIndex !== 0 && pri <= (this.tpri & 0xff)) {
              //console.log("Rendering upright tile to buffer");
              buffer[this.fbIndex] = palette[this.palIndex + palAdd];
              this.tpri = (this.tpri & 0xf00) | pri;
              priTable[this.fbIndex] = this.tpri;
            }
          }
          this.fbIndex++;
          this.tIndex++;
        }
        this.fbIndex -= 8;
        this.fbIndex += 256;
      }
    } else if (flipHorizontal && !flipVertical) {
      this.fbIndex = (dy << 8) + dx;
      this.tIndex = 7;
      for (this.y = 0; this.y < 8; this.y++) {
        for (this.x = 0; this.x < 8; this.x++) {
          if (
            this.x >= srcx1 &&
            this.x < srcx2 &&
            this.y >= srcy1 &&
            this.y < srcy2
          ) {
            this.palIndex = this.pix[this.tIndex];
            this.tpri = priTable[this.fbIndex];
            if (this.palIndex !== 0 && pri <= (this.tpri & 0xff)) {
              buffer[this.fbIndex] = palette[this.palIndex + palAdd];
              this.tpri = (this.tpri & 0xf00) | pri;
              priTable[this.fbIndex] = this.tpri;
            }
          }
          this.fbIndex++;
          this.tIndex--;
        }
        this.fbIndex -= 8;
        this.fbIndex += 256;
        this.tIndex += 16;
      }
    } else if (flipVertical && !flipHorizontal) {
      this.fbIndex = (dy << 8) + dx;
      this.tIndex = 56;
      for (this.y = 0; this.y < 8; this.y++) {
        for (this.x = 0; this.x < 8; this.x++) {
          if (
            this.x >= srcx1 &&
            this.x < srcx2 &&
            this.y >= srcy1 &&
            this.y < srcy2
          ) {
            this.palIndex = this.pix[this.tIndex];
            this.tpri = priTable[this.fbIndex];
            if (this.palIndex !== 0 && pri <= (this.tpri & 0xff)) {
              buffer[this.fbIndex] = palette[this.palIndex + palAdd];
              this.tpri = (this.tpri & 0xf00) | pri;
              priTable[this.fbIndex] = this.tpri;
            }
          }
          this.fbIndex++;
          this.tIndex++;
        }
        this.fbIndex -= 8;
        this.fbIndex += 256;
        this.tIndex -= 16;
      }
    } else {
      this.fbIndex = (dy << 8) + dx;
      this.tIndex = 63;
      for (this.y = 0; this.y < 8; this.y++) {
        for (this.x = 0; this.x < 8; this.x++) {
          if (
            this.x >= srcx1 &&
            this.x < srcx2 &&
            this.y >= srcy1 &&
            this.y < srcy2
          ) {
            this.palIndex = this.pix[this.tIndex];
            this.tpri = priTable[this.fbIndex];
            if (this.palIndex !== 0 && pri <= (this.tpri & 0xff)) {
              buffer[this.fbIndex] = palette[this.palIndex + palAdd];
              this.tpri = (this.tpri & 0xf00) | pri;
              priTable[this.fbIndex] = this.tpri;
            }
          }
          this.fbIndex++;
          this.tIndex--;
        }
        this.fbIndex -= 8;
        this.fbIndex += 256;
      }
    }
  },

  isTransparent: function(x, y) {
    return this.pix[(y << 3) + x] === 0;
  },

  toJSON: function() {
    return {
      opaque: this.opaque,
      pix: this.pix
    };
  },

  fromJSON: function(s) {
    this.opaque = s.opaque;
    this.pix = s.pix;
  }
};

module.exports = Tile;