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compressedTexSubImage2D method

Specifies a two-dimensional texture or cube Map sub-image from compressed image data. You must call getExtension("WEBGL_compressed_texture_s3tc") to enable compressed textures before calling this method.

IE11

 

Syntax

WebGLRenderingContext.compressedTexSubImage2D(target, level, xoffset, yoffset, width, height, format, data);

Parameters

target [in]

Type: Number

The target texture. One of the following:

ValueMeaning
gl.TEXTURE_2D

Uses a 2D image.

gl.TEXTURE_CUBE_MAP_POSITIVE_X

Image for the positive X face of the cube map.

gl.TEXTURE_CUBE_MAP_NEGATIVE_X

Image for the negative X face of the cube map.

gl.TEXTURE_CUBE_MAP_POSITIVE_Y

Image for the positive Y face of the cube map.

gl.TEXTURE_CUBE_MAP_NEGATIVE_Y

Image for the negative Y face of the cube map.

gl.TEXTURE_CUBE_MAP_POSITIVE_Z

Image for the positive Z face of the cube map.

gl.TEXTURE_CUBE_MAP_NEGATIVE_Z

Image for the negative Z face of the cube map.

 

level [in]

Type: Number

The level of detail. Level 0 equals the base image level. Only level 0 is supported in IE11.

xoffset [in]

Type: Number

The horizontal offset of the image in the texture array.

yoffset [in]

Type: Number

The vertical offset of the image in the texture array.

width [in]

Type: Number

The width of the subimage texture.

height [in]

Type: Number

The height of the subimage texture.

format [in]

Type: Number

The format or extension of the compressed image. This must be the same format specified previously by compressedTexImage2D. Possible values:

ValueMeaning
COMPRESSED_RGB_S3TC_DXT1_EXT

The byteLength of data (ArrayBufferView) in pixels that's passed must be match the equation floor((width + 3) / 4) * floor((height + 3) / 4) * 8

COMPRESSED_RGBA_S3TC_DXT1_EXT

The byteLength of data (ArrayBufferView) in pixels that's passed must be match the equation floor((width + 3) / 4) * floor((height + 3) / 4) * 8

COMPRESSED_RGBA_S3TC_DXT3_EXT

The byteLength of data (ArrayBufferView) in pixels that's passed must be match the equation floor((width + 3) / 4) * floor((height + 3) / 4) * 16

COMPRESSED_RGBA_S3TC_DXT5_EXT

The byteLength of data (ArrayBufferView) in pixels that's passed must be match the equation floor((width + 3) / 4) * floor((height + 3) / 4) * 16

 

data [in]

Type: ArrayBufferView

Object that contains the image data.

Return value

This method does not return a value.

Remarks

WebGL errorDescription
gl.INVALID_VALUEIf internalFormat does not equal one of the specified values.
gl.INVALID_OPERATIONIf width or height are not a multiple of 4.
gl.INVALID_OPERATIONIf xoffset or yoffset are not a multiple of 4, and width or height are not multiples of 4 or equal to the original width and height of level.

 

See also

WebGLRenderingContext
compressedTexImage2D

 

 

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