function FrameBuffer()

in seriously.js [717:803]
71 lines of code
13 McCabe index (conditional complexity)

	function FrameBuffer(gl, width, height, options) {
		var frameBuffer,
			renderBuffer,
			tex,
			status,
			useFloat = options === true ? options : (options && options.useFloat);

		useFloat = false;//useFloat && !!gl.getExtension('OES_texture_float'); //useFloat is not ready!
		if (useFloat) {
			this.type = gl.FLOAT;
		} else {
			this.type = gl.UNSIGNED_BYTE;
		}

		frameBuffer = gl.createFramebuffer();
		gl.bindFramebuffer(gl.FRAMEBUFFER, frameBuffer);

		if (options && options.texture) {
			this.texture = options.texture;
			gl.bindTexture(gl.TEXTURE_2D, this.texture);
			this.ownTexture = false;
		} else {
			this.texture = gl.createTexture();
			gl.bindTexture(gl.TEXTURE_2D, this.texture);
			gl.pixelStorei(gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL, false);
			gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
			gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
			gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
			gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
			this.ownTexture = true;
		}

		try {
			if (this.type === gl.FLOAT) {
				tex = new Float32Array(width * height * 4);
				gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.FLOAT, tex);
			} else {
				gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
				this.type = gl.UNSIGNED_BYTE;
			}
		} catch (e) {
			// Null rejected
			this.type = gl.UNSIGNED_BYTE;
			tex = new Uint8Array(width * height * 4);
			gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, width, height, 0, gl.RGBA, gl.UNSIGNED_BYTE, tex);
		}

		renderBuffer = gl.createRenderbuffer();
		gl.bindRenderbuffer(gl.RENDERBUFFER, renderBuffer);
		gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, width, height);
		gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, renderBuffer);

		gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, this.texture, 0);

		status = gl.checkFramebufferStatus(gl.FRAMEBUFFER);

		if (status === gl.FRAMEBUFFER_INCOMPLETE_ATTACHMENT) {
			throw new Error('Incomplete framebuffer: FRAMEBUFFER_INCOMPLETE_ATTACHMENT');
		}

		if (status === gl.FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT) {
			throw new Error('Incomplete framebuffer: FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT');
		}

		if (status === gl.FRAMEBUFFER_INCOMPLETE_DIMENSIONS) {
			throw new Error('Incomplete framebuffer: FRAMEBUFFER_INCOMPLETE_DIMENSIONS');
		}

		if (status === gl.FRAMEBUFFER_UNSUPPORTED) {
			throw new Error('Incomplete framebuffer: FRAMEBUFFER_UNSUPPORTED');
		}

		if (status !== gl.FRAMEBUFFER_COMPLETE) {
			throw new Error('Incomplete framebuffer: ' + status);
		}

		//clean up
		gl.bindTexture(gl.TEXTURE_2D, null);
		gl.bindRenderbuffer(gl.RENDERBUFFER, null);
		gl.bindFramebuffer(gl.FRAMEBUFFER, null);

		this.gl = gl;
		this.frameBuffer = frameBuffer;
		this.renderBuffer = renderBuffer;
		this.width = width;
		this.height = height;
	}