WebGLRenderingContext: compressedTexImage2D() method

The compressedTexImage2D() method of the WebGLRenderingContext interface of the WebGL API specifies a two-dimensional texture image in a compressed format.

Compressed image formats are only available via the WebGL2RenderingContext or some WebGL extension.

Syntax

// WebGL 1:
compressedTexImage2D(target, level, internalformat, width, height, border, srcData)

// Additionally available in WebGL 2:
compressedTexImage2D(target, level, internalformat, width, height, border, srcData, srcOffset)
compressedTexImage2D(target, level, internalformat, width, height, border, srcData, srcOffset, srcLengthOverride)
compressedTexImage2D(target, level, internalformat, width, height, border, imageSize, offset)

Parameters

target

A GLenum specifying the binding point (target) of the active compressed texture. Possible values:

• gl.TEXTURE_2D: A two-dimensional texture.
• gl.TEXTURE_CUBE_MAP_POSITIVE_X: Positive X face for a cube-mapped texture.
• gl.TEXTURE_CUBE_MAP_NEGATIVE_X: Negative X face for a cube-mapped texture.
• gl.TEXTURE_CUBE_MAP_POSITIVE_Y: Positive Y face for a cube-mapped texture.
• gl.TEXTURE_CUBE_MAP_NEGATIVE_Y: Negative Y face for a cube-mapped texture.
• gl.TEXTURE_CUBE_MAP_POSITIVE_Z: Positive Z face for a cube-mapped texture.
• gl.TEXTURE_CUBE_MAP_NEGATIVE_Z: Negative Z face for a cube-mapped texture.

level

A GLint specifying the level of detail. Level 0 is the base image level and level n is the n-th mipmap reduction level.

internalformat

A GLenum specifying the compressed image format. Compressed image formats are only available via the WebGL2RenderingContext or some WebGL extension. Possible values:

• When using WebGL2RenderingContext:

  • gl.GL_COMPRESSED_R11_EAC
  • gl.GL_COMPRESSED_SIGNED_R11_EAC
  • gl.GL_COMPRESSED_RG11_EAC
  • gl.GL_COMPRESSED_SIGNED_RG11_EAC
  • gl.GL_COMPRESSED_RGB8_ETC2
  • gl.GL_COMPRESSED_SRGB8_ETC2
  • gl.GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2
  • gl.GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2
  • gl.GL_COMPRESSED_RGBA8_ETC2_EAC
  • gl.GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC

• When using the WEBGL_compressed_texture_s3tc extension:

  • ext.COMPRESSED_RGB_S3TC_DXT1_EXT
  • ext.COMPRESSED_RGBA_S3TC_DXT1_EXT
  • ext.COMPRESSED_RGBA_S3TC_DXT3_EXT
  • ext.COMPRESSED_RGBA_S3TC_DXT5_EXT

• When using the WEBGL_compressed_texture_s3tc_srgb extension:

  • ext.COMPRESSED_SRGB_S3TC_DXT1_EXT
  • ext.COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT
  • ext.COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT
  • ext.COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT

• When using the WEBGL_compressed_texture_etc extension:

  • ext.COMPRESSED_R11_EAC
  • ext.COMPRESSED_SIGNED_R11_EAC
  • ext.COMPRESSED_RG11_EAC
  • ext.COMPRESSED_SIGNED_RG11_EAC
  • ext.COMPRESSED_RGB8_ETC2
  • ext.COMPRESSED_RGBA8_ETC2_EAC
  • ext.COMPRESSED_SRGB8_ETC2
  • ext.COMPRESSED_SRGB8_ALPHA8_ETC2_EAC
  • ext.COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2
  • ext.COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2

• When using the WEBGL_compressed_texture_pvrtc extension:

  • ext.COMPRESSED_RGB_PVRTC_4BPPV1_IMG
  • ext.COMPRESSED_RGBA_PVRTC_4BPPV1_IMG
  • ext.COMPRESSED_RGB_PVRTC_2BPPV1_IMG
  • ext.COMPRESSED_RGBA_PVRTC_2BPPV1_IMG

• When using the WEBGL_compressed_texture_etc1 extension:

  • ext.COMPRESSED_RGB_ETC1_WEBGL

• When using the WEBGL_compressed_texture_astc extension:

  • ext.COMPRESSED_RGBA_ASTC_4x4_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR
  • ext.COMPRESSED_RGBA_ASTC_5x4_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR
  • ext.COMPRESSED_RGBA_ASTC_5x5_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR
  • ext.COMPRESSED_RGBA_ASTC_6x5_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR
  • ext.COMPRESSED_RGBA_ASTC_6x6_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR
  • ext.COMPRESSED_RGBA_ASTC_8x5_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR
  • ext.COMPRESSED_RGBA_ASTC_8x6_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR
  • ext.COMPRESSED_RGBA_ASTC_8x8_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR
  • ext.COMPRESSED_RGBA_ASTC_10x5_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x5_KHR
  • ext.COMPRESSED_RGBA_ASTC_10x6_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR
  • ext.COMPRESSED_RGBA_ASTC_10x6_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR
  • ext.COMPRESSED_RGBA_ASTC_10x10_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR
  • ext.COMPRESSED_RGBA_ASTC_12x10_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR
  • ext.COMPRESSED_RGBA_ASTC_12x12_KHR, ext.COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR

• When using the EXT_texture_compression_bptc extension:

  • ext.COMPRESSED_RGBA_BPTC_UNORM_EXT
  • ext.COMPRESSED_SRGB_ALPHA_BPTC_UNORM_EXT
  • ext.COMPRESSED_RGB_BPTC_SIGNED_FLOAT_EXT
  • ext.COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT_EXT

• When using the EXT_texture_compression_rgtc extension:

  • ext.COMPRESSED_RED_RGTC1_EXT
  • ext.COMPRESSED_SIGNED_RED_RGTC1_EXT
  • ext.COMPRESSED_RED_GREEN_RGTC2_EXT
  • ext.COMPRESSED_SIGNED_RED_GREEN_RGTC2_EXT

width

A GLsizei specifying the width of the texture in texels.

height

A GLsizei specifying the height of the texture in texels.

depth

A GLsizei specifying the depth of the texture/the number of textures in a TEXTURE_2D_ARRAY.

border

A GLint specifying the width of the border. Must be 0.

The texture source can be provided in one of two ways: from an ArrayBuffer (possibly shared) using srcData, srcOffset, and srcLengthOverride; or, in WebGL 2, from gl.PIXEL_UNPACK_BUFFER using imageSize and offset.

srcData

A TypedArray or DataView containing the compressed texture data.

srcOffset Optional

(WebGL 2 only) An integer specifying the index of srcData to start reading from. Defaults to 0.

srcLengthOverride Optional

(WebGL 2 only) An integer specifying the number of elements in srcData to read. Defaults to srcData.length - srcOffset.

imageSize

(WebGL 2 only) A GLsizei specifying the size of the image data in bytes.

offset

(WebGL 2 only) A GLintptr specifying the starting address in the buffer bound to gl.PIXEL_UNPACK_BUFFER.

Return value

None (undefined).

Examples

const ext =
  gl.getExtension("WEBGL_compressed_texture_s3tc") ||
  gl.getExtension("MOZ_WEBGL_compressed_texture_s3tc") ||
  gl.getExtension("WEBKIT_WEBGL_compressed_texture_s3tc");

const texture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.compressedTexImage2D(
  gl.TEXTURE_2D,
  0,
  ext.COMPRESSED_RGBA_S3TC_DXT5_EXT,
  512,
  512,
  0,
  textureData,
);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);

Specifications

Browser compatibility

See also

• Using WebGL extensions
• WebGLRenderingContext.getExtension()
• WebGLRenderingContext.compressedTexSubImage2D()
• WebGL2RenderingContext.compressedTexSubImage3D()
• WebGL2RenderingContext.compressedTexImage3D()
• WEBGL_compressed_texture_s3tc
• WEBGL_compressed_texture_s3tc_srgb
• WEBGL_compressed_texture_etc
• WEBGL_compressed_texture_pvrtc
• WEBGL_compressed_texture_etc1
• WEBGL_compressed_texture_astc
• EXT_texture_compression_bptc
• EXT_texture_compression_rgtc