Rules for Claiming a Conformant WebGL Implementation ==================================================== The WebGL API is a web standard, and many web browser implementers deliver their browser on multiple operating systems (OSs). WebGL implementations also typically rely on the presence of an OpenGL or OpenGL ES implementation on the OS. It can be appreciated that a WebGL implementation therefore has many dependencies. This document attempts to clarify to potential implementers the rules the Khronos Group uses to judge whether a particular WebGL implementation is conformant. There are two primary reasons to submit conformance results: A) A web browser implementer desires to certify their WebGL implementation as conformant. B) A GPU manufacturer delivering an embedded system including web browser with WebGL support desires to certify their WebGL implementation as conformant. Each of these situations carries different constraints, so the conformance rules are phrased differently for each. Typically, a web browser implementer aims to certify that the WebGL "layer" is correct. A GPU vendor typically aims to certify that a given device is physically capable of passing the tests. A newly-developed WebGL implementation should not support the "webgl" HTML Canvas context type by default in a shipping version of the product until reaching conformance. It is acceptable to give end users an option to turn on WebGL support in a non-conformant implementation as long as the documentation for that option clearly indicates that the implementation is not yet conformant and may have compatibility issues. It is suggested that the Canvas context type "experimental-webgl" may be supported by default in such implementations. A WebGL implementation might reach conformance, but a subsequent graphics driver release on a particular OS might introduce a regression causing failures of one or more of the WebGL conformance tests. In this situation it is not required to revoke support for the "webgl" HTML Canvas context type. The WebGL implementer should work with the GPU vendor to ensure the driver regression is fixed. A situation like this would, however, prevent the WebGL implementer from conforming to a subsequent version of the test suite. (A) Conformance Rules for a Web Browser Implementer =================================================== 1. Conformance on a particular operating system On a given OS, a WebGL implementation will be considered to conform to a particular version of the conformance suite if the suite passes with no test failures on at least two GPUs, each from a different vendor. If the OS only supports a GPU from one vendor, the two-GPU requirement is dropped. 2. Conformance across multiple operating systems A WebGL implementation will be considered to conform to a particular version of the conformance suite if it passes rule (1) on all of the OSs on which the WebGL implementation is intended to be supported. 3. Conformance as the web browser is upgraded WebGL conformance results submitted for an earlier version of the browser carry forward to later versions of the browser, unless the WebGL implementation changes substantially enough that it is expected that conformance may have been affected. In that case, the browser implementer should submit new conformance results. 4. Conformance as the operating system is upgraded If a new version is released of one of the OSs on which a WebGL implementation is intended to run, then WebGL conformance results submitted for earlier versions of that OS carry forward. Future conformance results must be submitted against the new version of the OS. If it is anticipated that the older OS version will be supported for some time, then future conformance results must be submitted separately for both the old and new versions of the OS. (B) Conformance Rules for a GPU Vendor ====================================== A GPU vendor submitting conformance results for a WebGL implementation typically does so because the device containing the GPU includes a built-in web browser. In this case the following rules apply: 1. Conformance results must be submitted for each GPU and operating system combination to be certified. It is not required to submit results for different devices containing the same GPU and running the same operating system. 2. Conformance results may be submitted up to three months in advance of the product reaching initial shipment. 3. Conformance results carry forward for a given GPU as the operating system and graphics driver are upgraded, unless there is an expectation that conformance may have been affected. In that case, the GPU vendor should submit new conformance results. Discussion ========== A WebGL implementation intended to ship on three OSs may reach conformance on two of them, but due to graphics driver bugs, may be unable to reach conformance on the third. In this situation the implementation is not yet considered to be conformant. An existing WebGL implementation which conformed to an earlier version of the test suite is not required to remove support for the "webgl" HTML Canvas context type while in the process of conforming to a later version of the test suite. However, the implementer must not advertise conformance to the later version until it has been reached. It is acceptable for the implementer to advertise details of their conformance, for example number or percentage of passing or failing tests, or names of passing or failing tests. A GPU vendor might submit conformance results in order to use the WebGL logo in a marketing campaign. In this situation, results may be submitted in advance of the product becoming available through sales channels, per the rules above. The WebGL API has strict security requirements. Even one failing test may indicate a serious security issue in the WebGL implementation. For this reason, no exceptions for failing conformance tests will be granted. The Khronos Group determines whether a particular WebGL implementation is conformant based on the implementer's conformance suite submissions, on multiple OSs and on multiple GPUs as necessary, using the rules above. An implementer shall not judge their own implementation conformant simply by applying the above rules.