WebGLRenderingContext: pixelStorei() method

{{APIRef("WebGL")}} {{AvailableInWorkers}}

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

Syntax

pixelStorei(pname, param)

Parameters

pname
- : A {{domxref("WebGL_API/Types", "GLenum")}} specifying which parameter to set. See below for possible values.
param
- : A {{domxref("WebGL_API/Types", "GLint")}} specifying a value to set the pname parameter to. See below for possible values.

Return value

None ({{jsxref("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	`{{domxref("WebGL_API/Types", "GLint")}}`	4	1, 2, 4, 8	OpenGL ES 2.0
`gl.UNPACK_ALIGNMENT`	Unpacking of pixel data from memory.	`{{domxref("WebGL_API/Types", "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.	`{{domxref("WebGL_API/Types", "GLboolean")}}`	false	true, false	WebGL
`gl.UNPACK_PREMULTIPLY_ALPHA_WEBGL`	Multiplies the alpha channel into the other color channels	`{{domxref("WebGL_API/Types", "GLboolean")}}`	false	true, false	WebGL
`gl.UNPACK_COLORSPACE_CONVERSION_WEBGL`	Default color space conversion or no color space conversion.	`{{domxref("WebGL_API/Types", "GLenum")}}`	`gl.BROWSER_DEFAULT_WEBGL`	`gl.BROWSER_DEFAULT_WEBGL`, `gl.NONE`	WebGL

When using a {{domxref("WebGL2RenderingContext", "WebGL 2 context", "", 1)}} , the following values are available additionally:

Constant	Description	Type	Allowed values (for `param`)	Specified in
`gl.PACK_ROW_LENGTH`	Number of pixels in a row.	`{{domxref("WebGL_API/Types", "GLint")}}`	0 to `Infinity`	OpenGL ES 3.0
`gl.PACK_SKIP_PIXELS`	Number of pixel locations skipped before the first pixel is written into memory.	`{{domxref("WebGL_API/Types", "GLint")}}`	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	`{{domxref("WebGL_API/Types", "GLint")}}`	0 to `Infinity`	OpenGL ES 3.0
`gl.UNPACK_ROW_LENGTH`	Number of pixels in a row.	`{{domxref("WebGL_API/Types", "GLint")}}`	0 to `Infinity`	OpenGL ES 3.0
`gl.UNPACK_IMAGE_HEIGHT`	Image height used for reading pixel data from memory	`{{domxref("WebGL_API/Types", "GLint")}}`	0 to `Infinity`	OpenGL ES 3.0
`gl.UNPACK_SKIP_PIXELS`	Number of pixel images skipped before the first pixel is read from memory	`{{domxref("WebGL_API/Types", "GLint")}}`	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	`{{domxref("WebGL_API/Types", "GLint")}}`	0 to `Infinity`	OpenGL ES 3.0
`gl.UNPACK_SKIP_IMAGES`	Number of pixel images skipped before the first pixel is read from memory	`{{domxref("WebGL_API/Types", "GLint")}}`	0 to `Infinity`	OpenGL ES 3.0

Examples

Setting the pixel storage mode affects the {{domxref("WebGLRenderingContext.readPixels()")}} operations, as well as unpacking of textures with the {{domxref("WebGLRenderingContext.texImage2D()")}} and {{domxref("WebGLRenderingContext.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 {{domxref("WebGLRenderingContext.getParameter()")}} .

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

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

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