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web api instance method

WebGLRenderingContext: pixelStorei() method

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Available in workers

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

Syntax

pixelStorei(pname, param)

Parameters

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

Return value

None (undefined).

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`](/firefox/mdn/api/webgl_api/types/) 4 1, 2, 4, 8 OpenGL ES 2.0
gl.UNPACK_ALIGNMENT Unpacking of pixel data from memory. [`GLint`](/firefox/mdn/api/webgl_api/types/) 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`](/firefox/mdn/api/webgl_api/types/) false true, false WebGL
gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL Multiplies the alpha channel into the other color channels [`GLboolean`](/firefox/mdn/api/webgl_api/types/) false true, false WebGL
gl.UNPACK_COLORSPACE_CONVERSION_WEBGL Default color space conversion or no color space conversion. [`GLenum`](/firefox/mdn/api/webgl_api/types/) 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`](/firefox/mdn/api/webgl_api/types/) 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`](/firefox/mdn/api/webgl_api/types/) 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`](/firefox/mdn/api/webgl_api/types/) 0 0 to Infinity OpenGL ES 3.0
gl.UNPACK_ROW_LENGTH Number of pixels in a row. [`GLint`](/firefox/mdn/api/webgl_api/types/) 0 0 to Infinity OpenGL ES 3.0
gl.UNPACK_IMAGE_HEIGHT Image height used for reading pixel data from memory [`GLint`](/firefox/mdn/api/webgl_api/types/) 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`](/firefox/mdn/api/webgl_api/types/) 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`](/firefox/mdn/api/webgl_api/types/) 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`](/firefox/mdn/api/webgl_api/types/) 0 0 to Infinity OpenGL ES 3.0

Examples

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

const 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 getParameter().

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

Specifications

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also