WebGLRenderingContext.pixelStorei()

The WebGLRenderingContext.pixelStorei() method of the WebGL API specifies the pixel storage modes.

Syntax

void gl.pixelStorei(pname, param);

Parameters

pname
A Glenum specifying which parameter to set. See below for possible values.
param
GLint specifying a value to set the pname parameter to. See below for possible values.

Return value

None.

Pixel storage parameters

Parameter name (for pname) Description Type Default value Allowed values (for param) Specified in
gl.PACK_ALIGNMENT Packing of pixel data into memory GLint 4 1, 2, 4, 8 OpenGL ES 2.0
gl.UNPACK_ALIGNMENT Unpacking of pixel data from memory. GLint 4 1, 2, 4, 8 OpenGL ES 2.0
gl.UNPACK_FLIP_Y_WEBGL Flips the source data along its vertical axis if true. GLboolean false true, false WebGL
gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL Multiplies the alpha channel into the other color channels GLboolean false true, false WebGL
gl.UNPACK_COLORSPACE_CONVERSION_WEBGL Default color space conversion or no color space conversion. GLenum gl.BROWSER_DEFAULT_WEBGL gl.BROWSER_DEFAULT_WEBGL, gl.NONE WebGL

When using a WebGL 2 context, the following values are available additionally:

Constant Description Type Default value Allowed values (for param) Specified in
gl.PACK_ROW_LENGTH Number of pixels in a row. GLint 0 0 to Infinity OpenGL ES 3.0
gl.PACK_SKIP_PIXELS Number of pixel locations skipped before the first pixel is written into memory. GLint 0 0 to Infinity OpenGL ES 3.0
gl.PACK_SKIP_ROWS Number of rows of pixel locations skipped before the first pixel is written into memory GLint 0 0 to Infinity OpenGL ES 3.0
gl.UNPACK_ROW_LENGTH Number of pixels in a row. GLint 0 0 to Infinity OpenGL ES 3.0
gl.UNPACK_IMAGE_HEIGHT Image height used for reading pixel data from memory GLint 0 0 to Infinity OpenGL ES 3.0
gl.UNPACK_SKIP_PIXELS Number of pixel images skipped before the first pixel is read from memory GLint 0 0 to Infinity OpenGL ES 3.0
gl.UNPACK_SKIP_ROWS Number of rows of pixel locations skipped before the first pixel is read from memory GLint 0 0 to Infinity OpenGL ES 3.0
gl.UNPACK_SKIP_IMAGES Number of pixel images skipped before the first pixel is read from memory GLint 0 0 to Infinity OpenGL ES 3.0

Examples

Setting the pixel storage mode affects the WebGLRenderingContext.readPixels() operations, as well as unpacking of textures with the WebGLRenderingContext.texImage2D() and WebGLRenderingContext.texSubImage2D() methods.
 

var tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.pixelStorei(gl.PACK_ALIGNMENT, 4);

To check the values for packing and unpacking of pixel data, you can query the same pixel storage parameters with WebGLRenderingContext.getParameter().

gl.getParameter(gl.PACK_ALIGNMENT);
gl.getParameter(gl.UNPACK_ALIGNMENT);

Specifications

Specification Status Comment
WebGL 1.0
The definition of 'pixelStorei' in that specification.
Recommendation Initial definition for WebGL.
WebGL 1.0
The definition of 'Pixel Storage Parameters' in that specification.
Recommendation Additional pixel storage parameters that aren't specified in OpenGL.
OpenGL ES 2.0
The definition of 'glPixelStorei' in that specification.
Standard Man page of the OpenGL ES 2.0 API.
WebGL 2.0
The definition of 'pixelStorei' in that specification.
Editor's Draft Updated definition for WebGL 2.
OpenGL ES 3.0
The definition of 'glPixelStorei' in that specification.
Standard Man page of the OpenGL ES 3.0 API.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic supportChrome Full support 9Edge Full support 12Firefox Full support 4IE Full support 11Opera Full support 12Safari Full support 5.1WebView Android Full support YesChrome Android Full support 25Edge Mobile Full support YesFirefox Android Full support YesOpera Android Full support 12Safari iOS Full support 8.1Samsung Internet Android Full support Yes
WebGL2Chrome Full support 56Edge No support NoFirefox Full support 51IE No support NoOpera Full support 43Safari No support NoWebView Android Full support 58Chrome Android Full support 58Edge Mobile No support NoFirefox Android Full support 51Opera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 7.0

Legend

Full support  
Full support
No support  
No support

See also

Document Tags and Contributors

Contributors to this page: fscholz, teoli, player1537
Last updated by: fscholz,