import Graph from './Graph';
import TexturePool from './TexturePool';
import FrameBuffer from '../FrameBuffer';

/**
 * Compositor provide graph based post processing
 *
 * @constructor clay.compositor.Compositor
 * @extends clay.compositor.Graph
 *
 */
var Compositor = Graph.extend(function() {
    return {
        // Output node
        _outputs: [],

        _texturePool: new TexturePool(),

        _frameBuffer: new FrameBuffer({
            depthBuffer: false
        })
    };
},
/** @lends clay.compositor.Compositor.prototype */
{
    addNode: function(node) {
        Graph.prototype.addNode.call(this, node);
        node._compositor = this;
    },
    /**
     * @param  {clay.Renderer} renderer
     */
    render: function(renderer, frameBuffer) {
        if (this._dirty) {
            this.update();
            this._dirty = false;

            this._outputs.length = 0;
            for (var i = 0; i < this.nodes.length; i++) {
                if (!this.nodes[i].outputs) {
                    this._outputs.push(this.nodes[i]);
                }
            }
        }

        for (var i = 0; i < this.nodes.length; i++) {
            // Update the reference number of each output texture
            this.nodes[i].beforeFrame();
        }

        for (var i = 0; i < this._outputs.length; i++) {
            this._outputs[i].updateReference();
        }

        for (var i = 0; i < this._outputs.length; i++) {
            this._outputs[i].render(renderer, frameBuffer);
        }

        for (var i = 0; i < this.nodes.length; i++) {
            // Clear up
            this.nodes[i].afterFrame();
        }
    },

    allocateTexture: function (parameters) {
        return this._texturePool.get(parameters);
    },

    releaseTexture: function (parameters) {
        this._texturePool.put(parameters);
    },

    getFrameBuffer: function () {
        return this._frameBuffer;
    },

    /**
     * Dispose compositor
     * @param {clay.Renderer} renderer
     */
    dispose: function (renderer) {
        this._texturePool.clear(renderer);
    }
});

export default Compositor;