WebGL parameters return the JavaScript types the specification assigns them
Check id webgl-param-value-types
What an ordinary browser yields
Each probed parameter comes back as the type the specification assigns it — typed arrays as typed arrays, not plain arrays.
What a detector infers
getParameter does not return loose values: the WebGL specification fixes the JavaScript TYPE of each one. MAX_VIEWPORT_DIMS and SCISSOR_BOX come back as Int32Array, ALIASED_LINE_WIDTH_RANGE and COLOR_CLEAR_VALUE as Float32Array, VERSION as a string, DEPTH_WRITEMASK as a boolean, COLOR_WRITEMASK as a plain array of four booleans. Those types are produced by the implementation, and a page that rewrites the parameter table in JavaScript almost never reproduces them — an override table naturally holds array literals and numbers, so a spoofed MAX_VIEWPORT_DIMS arrives as Array where every real driver on earth gives Int32Array. The check is entirely independent of the values: the numbers may be whatever the persona wants, and the constructor still gives the lie away. It is also why this sits beside the parameter-table row rather than inside it — that one asks whether the table is complete and hashes it, this one asks whether the table was built by an implementation.
How to resolve it
Override WebGL parameters at the engine level, where the return value is constructed by the implementation itself. A JavaScript wrapper around getParameter is visible from the constructor name alone, whatever the numbers say.
Read in the wild by
FakeBrowser (collector)
Stores every getParameter result as {type: value.constructor.name, value} across ~200 numeric enums — recording the constructor separately from the value, which is only necessary if the type has to be reproduced faithfully on replay.
dumpWebGLCore(), result.params[glEnum].type — script/dumpDD.js
kkoooqq/fakebrowser script/dumpDD.js
Every attribution traces to a published artifact. See the sources and their limits.
Nearby checks in Render & GPU
- WebGL renderer (software vs hardware)
webgl-not-softwareThe audit reads UNMASKED_RENDERER through the WEBGL_debug_renderer_info extension and matches it against SwiftShader, llvmpipe and Software. - WebGPU vendor coheres with WebGL vendor
webgl-webgpu-vendorTwo independent graphics stacks in the same browser are backed by the same physical adapter: this check lowercases the WebGL UNMASKED_VENDOR… - WebGL exposes a full parameter table + UNMASKED vendor/renderer
webgl-param-tableBeyond the two headline strings, a WebGL context answers getParameter for dozens of driver-specific limits. - WebGL vendor/renderer identical in a Worker
webgl-worker-vs-mainThe audit reads UNMASKED_VENDOR and UNMASKED_RENDERER on the main thread, then spawns a dedicated Worker that builds its own WebGL context… - masked WebGL VENDOR matches the engine
webgl-engine-vendorThis check reads the plain gl.getParameter(gl.VENDOR) — the masked value, not the debug extension's unmasked GPU string. - WebGL1 and WebGL2 report the same UNMASKED GPU
webgl1-webgl2-coherenceThe check creates a WebGL1 context and a WebGL2 context and reads UNMASKED_VENDOR_WEBGL / UNMASKED_RENDERER_WEBGL from each through the… - canvas readback is not noise-injected (1×1 probe)
canvas-tamperThe probe fills a single pixel with pure black on a 1x1 canvas and reads it straight back with getImageData. - one flat fill reads back as exactly one colour
canvas-flat-fill-uniformThis is the area form of the 1×1 canvas probe, and it exists because that probe is easy to pass by accident.
Clearcote is a browser built for fingerprint coherence
It is a Chromium fork, maintained by the same people who wrote this reference. It ships as a compiled browser rather than as a stealth script injected into someone else's — which is a description of how it is built, and is not an argument about how it behaves on this check.
This audit takes no position on how Clearcote scores on Render & GPU checks, on this one, or anywhere else. It has no baseline corpus of other people's fingerprints to rank you against and no vendor scoreboard — nearly every check is self-referential, asking one browser the same question through two independent APIs and reporting whether both answers can be true at once. It runs identically on any browser, including ours. Run it on yours and read the result yourself.
See the other checks in Render & GPU — the family webgl-param-value-types belongs to.