goog.provide('ol.webgl.TileLayerRenderer');

goog.require('goog.asserts');
goog.require('goog.events.EventType');
goog.require('goog.webgl');
goog.require('ol.TileLayer');
goog.require('ol.webgl.LayerRenderer');



/**
 * @constructor
 * @extends {ol.webgl.LayerRenderer}
 * @param {ol.webgl.Map} map Map.
 * @param {ol.TileLayer} tileLayer Tile layer.
 */
ol.webgl.TileLayerRenderer = function(map, tileLayer) {

  goog.base(this, map, tileLayer);

  /**
   * @private
   * @type {goog.math.Size}
   */
  this.size_ = null;

  /**
   * @private
   * @type {WebGLTexture}
   */
  this.texture_ = null;

  /**
   * @private
   * @type {WebGLRenderbuffer}
   */
  this.renderbuffer_ = null;

  /**
   * @private
   * @type {WebGLFramebuffer}
   */
  this.framebuffer_ = null;

  /**
   * @private
   * @type {goog.math.Size}
   */
  this.framebufferSize_ = null;

  /**
   * @private
   * @type {Object.<number, number>}
   */
  this.tileChangeListenerKeys_ = {};

};
goog.inherits(ol.webgl.TileLayerRenderer, ol.webgl.LayerRenderer);


/**
 * @inheritDoc
 */
ol.webgl.TileLayerRenderer.prototype.getTexture = function() {
  return this.texture_;
};


/**
 * @protected
 */
ol.webgl.TileLayerRenderer.prototype.dispatchChangeEvent = function() {
  this.dispatchEvent(goog.events.EventType.CHANGE);
};


/**
 * @protected
 */
ol.webgl.TileLayerRenderer.prototype.disposeInternal = function() {
  var gl = this.getGL();
  if (!gl.isContextLost()) {
    gl.deleteFramebuffer(this.framebuffer_);
    gl.deleteRenderbuffer(this.renderbuffer_);
    gl.deleteTexture(this.texture_);
  }
  goog.base(this, 'disposeInternal');
};


/**
 */
ol.webgl.TileLayerRenderer.prototype.handleWebGLContextLost = function() {
  this.texture_ = null;
  this.renderbuffer_ = null;
  this.framebuffer_ = null;
  this.framebufferSize_ = null;
};


/**
 * @protected
 */
ol.webgl.TileLayerRenderer.prototype.handleTileChange = function() {
  this.dispatchChangeEvent();
};


/**
 * @inheritDoc
 */
ol.webgl.TileLayerRenderer.prototype.redraw = function() {

  var gl = this.getGL();

  var map = this.getMap();
  var extent = map.getExtent();
  var resolution = map.getResolution();
  if (!goog.isDef(extent) || !goog.isDef(resolution)) {
    return;
  }

  var tileLayer = /** @type {ol.TileLayer} */ (this.getLayer());
  var tileStore = tileLayer.getStore();
  var tileGrid = tileStore.getTileGrid();
  var z = tileGrid.getZForResolution(resolution);
  var tileBounds = tileGrid.getExtentTileBounds(z, extent);
  var tileSize = tileGrid.getTileSize();

  var framebufferSize = new goog.math.Size(
      tileSize.width * (tileBounds.maxX - tileBounds.minX + 1),
      tileSize.height * (tileBounds.maxY - tileBounds.minY + 1));

  if (goog.isNull(this.framebufferSize_) ||
      !goog.math.Size.equals(this.framebufferSize_, framebufferSize)) {

    gl.deleteFramebuffer(this.framebuffer_);
    gl.deleteRenderbuffer(this.renderbuffer_);
    gl.deleteTexture(this.texture_);

    var texture = gl.createTexture();
    gl.bindTexture(goog.webgl.TEXTURE_2D, texture);
    gl.texImage2D(goog.webgl.TEXTURE_2D, 0, gl.RGBA, framebufferSize.width,
        framebufferSize.height, 0, goog.webgl.RGBA, goog.webgl.UNSIGNED_BYTE,
        null);
    gl.texParameteri(goog.webgl.TEXTURE_2D, goog.webgl.TEXTURE_MAG_FILTER,
        goog.webgl.NEAREST);
    gl.texParameteri(goog.webgl.TEXTURE_2D, goog.webgl.TEXTURE_MIN_FILTER,
        goog.webgl.NEAREST);
    gl.texParameteri(goog.webgl.TEXTURE_2D, goog.webgl.TEXTURE_WRAP_S,
        goog.webgl.REPEAT);
    gl.texParameteri(goog.webgl.TEXTURE_2D, goog.webgl.TEXTURE_WRAP_T,
        goog.webgl.REPEAT);

    var renderbuffer = gl.createRenderbuffer();
    gl.bindRenderbuffer(goog.webgl.RENDERBUFFER, renderbuffer);
    gl.renderbufferStorage(goog.webgl.RENDERBUFFER,
        goog.webgl.DEPTH_COMPONENT16, framebufferSize.width,
        framebufferSize.height);

    var framebuffer = gl.createFramebuffer();
    gl.bindFramebuffer(goog.webgl.FRAMEBUFFER, framebuffer);
    gl.framebufferTexture2D(goog.webgl.FRAMEBUFFER,
        goog.webgl.COLOR_ATTACHMENT0, goog.webgl.TEXTURE_2D, texture, 0);
    gl.framebufferRenderbuffer(goog.webgl.FRAMEBUFFER,
        goog.webgl.DEPTH_ATTACHMENT, goog.webgl.RENDERBUFFER, renderbuffer);

    this.texture_ = texture;
    this.renderbuffer_ = renderbuffer;
    this.framebuffer_ = framebuffer;
    this.framebufferSize_ = framebufferSize;

  } else {
    gl.bindFramebuffer(goog.webgl.FRAMEBUFFER, this.framebuffer_);
  }

  tileBounds.forEachTileCoord(z, function(tileCoord) {
    var tile = tileStore.getTile(tileCoord);
    if (goog.isNull(tile)) {
    } else if (tile.isLoaded()) {
      var x = tileSize.width * (tileCoord.x - tileBounds.minX);
      var y = tileSize.height * (tileCoord.y - tileBounds.minY);
      gl.bindTexture(goog.webgl.TEXTURE_2D, map.getTexture(tile.getImage()));
    } else {
      var key = goog.getUid(tile);
      if (!(key in this.tileChangeListenerKeys_)) {
        tile.load();
        // FIXME will need to handle aborts as well
        this.tileChangeListenerKeys_[key] = goog.events.listen(tile,
            goog.events.EventType.CHANGE, this.handleTileChange, false, this);
      }
    }
    return false;
  }, this);

};


/**
 * @inheritDoc
 */
ol.webgl.TileLayerRenderer.prototype.handleLayerOpacityChange = function() {
  this.dispatchChangeEvent();
};


/**
 * @inheritDoc
 */
ol.webgl.TileLayerRenderer.prototype.handleLayerVisibleChange = function() {
  this.dispatchChangeEvent();
};