WebGLRenderingContext.compressedTexImage[23]D()

下面这两个function:

 WebGLRenderingContext.compressedTexImage2D()  and WebGL2RenderingContext.compressedTexImage3D()WebGL API 中特指压缩二维或三维纹理图像的格式。

在使用这些方法之前,必须通过 WebGL extensions, 也就是 WebGL扩展启用压缩图像格式。

Syntax

// WebGL 1:
void gl.compressedTexImage2D(target, level, internalformat, width, height, border, ArrayBufferView? pixels);

// Additionally available in WebGL 2:
// read from buffer bound to gl.PIXEL_UNPACK_BUFFER
void gl.compressedTexImage2D(target, level, internalformat, width, height, border, GLsizei imageSize, GLintptr offset);
void gl.compressedTexImage2D(target, level, internalformat, width, height, border,
                             ArrayBufferView srcData, optional srcOffset, optional srcLengthOverride);

 // read from buffer bound to gl.PIXEL_UNPACK_BUFFER
void gl.compressedTexImage3D(target, level, internalformat, width, height, depth, border, GLsizei imageSize, GLintptr offset);
void gl.compressedTexImage3D(target, level, internalformat, width, height, depth, border,
                             ArrayBufferView srcData, optional srcOffset, optional srcLengthOverride);

Parameters

target
A GLenum (en-US) specifying the binding point (target) of the active texture. Possible values for compressedTexImage2D:
  • 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.
Possible values for compressedTexImage3D:
  • gl.TEXTURE_2D_ARRAY
  • gl.TEXTURE_3D
level
A GLint (en-US) specifying the level of detail. Level 0 is the base image level and level n is the nth mipmap reduction level.
internalformat
A GLenum (en-US) specifying the compressed image format. Compressed image formats must be enabled by WebGL extensions before using this method. All values are possible for compressedTexImage2D. See compressed texture formats for which are valid for compressedTexImage3D. Possible values:
  • When using the WEBGL_compressed_texture_s3tc (en-US) 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 (en-US) 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 (en-US) 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 (en-US) 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 (en-US) extension:
    • ext.COMPRESSED_RGB_ETC1_WEBGL
  • When using the WEBGL_compressed_texture_atc (en-US) extension:
    • ext.COMPRESSED_RGB_ATC_WEBGL
    • ext.COMPRESSED_RGBA_ATC_EXPLICIT_ALPHA_WEBGL
    • ext.COMPRESSED_RGBA_ATC_INTERPOLATED_ALPHA_WEBGL
  • When using the WEBGL_compressed_texture_astc (en-US) 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_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 (en-US) 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 (en-US) 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 (en-US) specifying the width of the texture.
height
A GLsizei (en-US) specifying the height of the texture.
depth
A GLsizei (en-US) specifying the depth of the texture/the number of textures in a TEXTURE_2D_ARRAY.
border
A GLint (en-US) specifying the width of the border. Must be 0.
imageSize
A GLsizei (en-US) specifying the number of bytes to read from the buffer bound to gl.PIXEL_UNPACK_BUFFER.
offset
A GLintptr (en-US) specifying the offset in bytes from which to read from the buffer bound to gl.PIXEL_UNPACK_BUFFER.
pixels
An ArrayBufferView that be used as a data store for the compressed image data in memory.

Return value

None.

Examples

var ext = (
  gl.getExtension('WEBGL_compressed_texture_s3tc') ||
  gl.getExtension('MOZ_WEBGL_compressed_texture_s3tc') ||
  gl.getExtension('WEBKIT_WEBGL_compressed_texture_s3tc')
);

var 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

Specification Status Comment
WebGL 1.0
compressedTexImage2D
Recommendation Initial definition for WebGL.
OpenGL ES 2.0
glCompressedTexImage2D
Standard Man page of the (similar) OpenGL ES 2.0 API.
OpenGL ES 3.0
glCompressedTexImage2D
Standard Man page of the (similar) OpenGL ES 3.0 API.

Browser compatibility

compressedTexImage2D

BCD tables only load in the browser

compressedTexImage3D

BCD tables only load in the browser

See also