We're looking for a user researcher to understand the needs of developers and designers. Is this you or someone you know? Check out the post: https://mzl.la/2IGzdXS

Unsere Freiwilligen haben diesen Artikel noch nicht in Deutsch übersetzt. Machen Sie mit und helfen Sie, das zu erledigen!
Sie können den Artikel auch auf English (US) lesen.

The OES_standard_derivatives extension is part of the WebGL API and adds the GLSL derivative functions dFdx, dFdy, and fwidth.

WebGL extensions are available using the WebGLRenderingContext.getExtension() method. For more information, see also Using Extensions in the WebGL tutorial.

Availability: This extension is only available to WebGL1 contexts. In WebGL2, the functionality of this extension is available on the WebGL2 context by default. In WebGL 2, the constant is available as gl.FRAGMENT_SHADER_DERIVATIVE_HINT and it requires GLSL #version 300 es.

Constants

This extension exposes one new constant, which can be used in the hint() and getParameter() methods.

ext.FRAGMENT_SHADER_DERIVATIVE_HINT_OES
A Glenum indicating the accuracy of the derivative calculation for the GLSL built-in functions: dFdx, dFdy, and fwidth.

GLSL built-in functions

The following new functions can be used in GLSL shader code, if this extension is enabled:

genType dFdx(genType)
genType dFdy(genType)
genType fwidth(genType)

Examples

Enabling the extensions:

gl.getExtension('OES_standard_derivatives');
gl.getExtension('EXT_shader_texture_lod');

Shader code that avoids artifacts when wrapping texture coordinates:

<script type="x-shader/x-fragment">
#extension GL_EXT_shader_texture_lod : enable
#extension GL_OES_standard_derivatives : enable

uniform sampler2D myTexture;
varying vec2 texcoord;

void main(){
  gl_FragColor = texture2DGradEXT(myTexture, mod(texcoord, vec2(0.1, 0.5)), 
                                  dFdx(texcoord), dFdy(texcoord));
}
</script>

Specifications

Specification Status Comment
OES_standard_derivatives
The definition of 'OES_standard_derivatives' in that specification.
Recommendation Initial definition.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support ? Yes10 ? ? ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support ? ? Yes ? ? ? ?

See also

Schlagwörter des Dokuments und Mitwirkende

Schlagwörter: 
Mitwirkende an dieser Seite: fscholz, nmve, teoli
Zuletzt aktualisiert von: fscholz,