SourceNode = function()

in seriously.js [3089:3262]
96 lines of code
42 McCabe index (conditional complexity)

		SourceNode = function (hook, source, options) {
			var opts = options || {},
				flip = opts.flip === undefined ? true : opts.flip,
				width = opts.width,
				height = opts.height,
				deferTexture = false,
				that = this,
				matchedType = false,
				key,
				plugin;

			function sourcePlugin(hook, source, options, force) {
				var p = seriousSources[hook];
				if (p.definition) {
					p = p.definition.call(that, source, options, force);
					if (p) {
						p = extend(extend({}, seriousSources[hook]), p);
					} else {
						return null;
					}
				}
				return p;
			}

			function compareSource(source) {
				return that.source === source;
			}

			Node.call(this);

			if (hook && typeof hook !== 'string' || !source && source !== 0) {
				if (!options || typeof options !== 'object') {
					options = source;
				}
				source = hook;
			}

			if (typeof source === 'string' && isNaN(source)) {
				source = getElement(source, ['canvas', 'img', 'video']);
			}

			// forced source type?
			if (typeof hook === 'string' && seriousSources[hook]) {
				plugin = sourcePlugin(hook, source, options, true);
				if (plugin) {
					this.hook = hook;
					matchedType = true;
					deferTexture = plugin.deferTexture;
					this.plugin = plugin;
					this.compare = plugin.compare;
					this.checkDirty = plugin.checkDirty;
					if (plugin.source) {
						source = plugin.source;
					}
				}
			}

			//todo: could probably stand to re-work and re-indent this whole block now that we have plugins
			if (!plugin && source instanceof HTMLElement) {
				if (source.tagName === 'CANVAS') {
					this.width = source.width;
					this.height = source.height;

					this.render = this.renderImageCanvas;
					matchedType = true;
					this.hook = 'canvas';
					this.compare = compareSource;
				} else if (source.tagName === 'IMG') {
					this.width = source.naturalWidth || 1;
					this.height = source.naturalHeight || 1;

					if (!source.complete || !source.naturalWidth) {
						deferTexture = true;
					}

					source.addEventListener('load', function () {
						if (!that.isDestroyed) {
							if (that.width !== source.naturalWidth || that.height !== source.naturalHeight) {
								that.width = source.naturalWidth;
								that.height = source.naturalHeight;
								that.resize();
							}

							that.setDirty();
							that.setReady();
						}
					}, true);

					this.render = this.renderImageCanvas;
					matchedType = true;
					this.hook = 'image';
					this.compare = compareSource;
				}
			} else if (!plugin && source instanceof WebGLTexture) {
				if (gl && !gl.isTexture(source)) {
					throw new Error('Not a valid WebGL texture.');
				}

				//different defaults
				if (!isNaN(width)) {
					if (isNaN(height)) {
						height = width;
					}
				} else if (!isNaN(height)) {
					width = height;
				}/* else {
					//todo: guess based on dimensions of target canvas
					//throw new Error('Must specify width and height when using a WebGL texture as a source');
				}*/

				this.width = width;
				this.height = height;

				if (opts.flip === undefined) {
					flip = false;
				}
				matchedType = true;

				this.texture = source;
				this.initialized = true;
				this.hook = 'texture';
				this.compare = compareSource;

				//todo: if WebGLTexture source is from a different context render it and copy it over
				this.render = function () {};
			}

			if (!matchedType && !plugin) {
				for (key in seriousSources) {
					if (seriousSources.hasOwnProperty(key) && seriousSources[key]) {
						plugin = sourcePlugin(key, source, options, false);
						if (plugin) {
							this.hook = key;
							matchedType = true;
							deferTexture = plugin.deferTexture;
							this.plugin = plugin;
							this.compare = plugin.compare;
							this.checkDirty = plugin.checkDirty;
							if (plugin.source) {
								source = plugin.source;
							}

							break;
						}
					}
				}
			}

			if (!matchedType) {
				throw new Error('Unknown source type');
			}

			this.source = source;
			if (this.flip === undefined) {
				this.flip = flip;
			}

			this.targets = [];

			if (!deferTexture) {
				that.setReady();
			}

			this.pub = new Source(this);

			nodes.push(this);
			nodesById[this.id] = this;
			sources.push(this);
			allSourcesByHook[this.hook].push(this);

			if (sources.length && !rafId) {
				renderDaemon();
			}
		};