Rules for Claiming a Conformant WebGL Implementation
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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.

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.

Discussion
==========

A WebGL implementation might reach conformance on a particular OS, but
a subsequent graphics driver release on that OS might introduce a
regression causing failures of one or more of the WebGL conformance
tests. In this situation it is not required that the browser revoke
support for the "webgl" HTML Canvas context type. The browser vendor
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 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.

A web browser author developing a new 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.

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.

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.