OES_standard_derivatives

The OES_standard_derivatives extension is part of the WebGL API and adds the GLSL derivative functions dFdx, dFdy, and fwidth to fragment shaders. These functions allow shaders to compute the rate of change of values across pixels, useful for procedural effects, anti-aliasing, and normal map calculations. The GL_OES_standard_derivatives directive must be enabled in shaders. Available in WebGL1 only; in WebGL2, these functions are available by default.

Modern anti-bot systems verify WebGL extensions to detect automated browsers. Mismatches between GPU hardware and available extensions are strong bot signals.

What Anti-Bot Systems Check:

• Extension availability: Does the reported GPU support these extensions?
• Extension combinations: Are the extensions typical for this GPU model?
• Consistency checks: Do reported extensions match other GPU signals?
• Missing extensions: Are expected extensions for this GPU absent?