To get a feeling for the programming model and experiment with the API, take a look at our interactive River Trail shell. The shell runs in any current version of Firefox, Chrome and Safari. If you are using Firefox and have installed the River Trail extension (see below on how to), your code will be executed in parallel. If you are using other browsers or have not installed the extension for Firefox, the shell will use a sequential library implementation and you won't see any speedup.
You need to install our Firefox extension to use our prototype compiler that enables execution of River Trail on parallel hardware. You can download a prebuilt version for Firefox 25.x running on Windows and MacOS (older versions for older browsers can be found here). We no longer provide a prebuilt Linux version. However, you can easily build it yourself. We have written a README that explains the process. If you are running Firefox on Windows or Linux, you additionally need to install Intel's OpenCL SDK (Please note the SDK's hardware requirements.).
Note that Firefox has deprecated the Components object in content code. However, we make heavy use of the Components.interfaces hierarchy in the compiler implementation. To still use River Trail, you have to set the dom.omit_components_in_content key in about:config to false. Detailed instructions on changing configuration variables are available in Mozilla's knowledge base.
If even after setting the above configuration flag you still cannot use River Trail, make sure that your OpenCL SDK is properly installed and supported by River Trail. Furthermore, not all device kinds on all platforms are supported. Take a look at the device selection settings to check whether your configuration is supported.
Once you have the extension installed and working, take a look at our demos:
For a first impression, you can watch this video, as well, or head over to InfoQ for an introductory talk recorded at TheStrangeLoop. For a interesting discussion of various problems we are trying to solve you can view this interview which discusses our approach and objectives.
A smaller example that gives a look behind the scenes and serves as an easy comparison of our programming model with WebCL is our
A word of caution: River Trail is a prototype and the extension is not yet meant for use on the public web. Please uninstall or disable the extension when surfing the web and use it only for web pages you trust.
Last edited by Stephan Herhut,