WebGLRenderingContext: getFramebufferAttachmentParameter() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Note: This feature is available in Web Workers.

The WebGLRenderingContext.getFramebufferAttachmentParameter() method of the WebGL API returns information about a framebuffer's attachment.

Syntax

js
getFramebufferAttachmentParameter(target, attachment, pname)

Parameters

target

A GLenum specifying the binding point (target). Possible values:

gl.FRAMEBUFFER

Collection buffer data storage of color, alpha, depth and stencil buffers used to render an image.

When using a WebGL 2 context, the following values are available additionally:

gl.DRAW_FRAMEBUFFER

Equivalent to gl.FRAMEBUFFER. Used as a destination for drawing, rendering, clearing, and writing operations.

gl.READ_FRAMEBUFFER

Used as a source for reading operations.

attachment

A GLenum specifying the attachment point for the texture. Possible values:

  • gl.COLOR_ATTACHMENT0: Texture attachment for the framebuffer's color buffer.
  • gl.DEPTH_ATTACHMENT: Texture attachment for the framebuffer's depth buffer.
  • gl.STENCIL_ATTACHMENT: Texture attachment for the framebuffer's stencil buffer.
  • gl.DEPTH_STENCIL_ATTACHMENT: Texture attachment for both, the depth and stencil buffer.

When using a WebGL 2 context, the following values are available additionally:

  • gl.COLOR_ATTACHMENT1 gl.COLOR_ATTACHMENT2 gl.COLOR_ATTACHMENT3 gl.COLOR_ATTACHMENT4 gl.COLOR_ATTACHMENT5 gl.COLOR_ATTACHMENT6 gl.COLOR_ATTACHMENT7 gl.COLOR_ATTACHMENT8 gl.COLOR_ATTACHMENT9 gl.COLOR_ATTACHMENT10 gl.COLOR_ATTACHMENT11 gl.COLOR_ATTACHMENT12 gl.COLOR_ATTACHMENT13 gl.COLOR_ATTACHMENT14 gl.COLOR_ATTACHMENT15

When using the WEBGL_draw_buffers extension:

  • ext.COLOR_ATTACHMENT0_WEBGL (same as gl.COLOR_ATTACHMENT0) ext.COLOR_ATTACHMENT1_WEBGL ext.COLOR_ATTACHMENT2_WEBGL ext.COLOR_ATTACHMENT3_WEBGL ext.COLOR_ATTACHMENT4_WEBGL ext.COLOR_ATTACHMENT5_WEBGL ext.COLOR_ATTACHMENT6_WEBGL ext.COLOR_ATTACHMENT7_WEBGL ext.COLOR_ATTACHMENT8_WEBGL ext.COLOR_ATTACHMENT9_WEBGL ext.COLOR_ATTACHMENT10_WEBGL ext.COLOR_ATTACHMENT11_WEBGL ext.COLOR_ATTACHMENT12_WEBGL ext.COLOR_ATTACHMENT13_WEBGL ext.COLOR_ATTACHMENT14_WEBGL ext.COLOR_ATTACHMENT15_WEBGL
pname

A GLenum specifying information to query. Possible values:

  • gl.FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE: The type which contains the attached image.
  • gl.FRAMEBUFFER_ATTACHMENT_OBJECT_NAME: The texture or renderbuffer of the attached image (WebGLRenderbuffer or WebGLTexture).
  • gl.FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL: Mipmap level. Default value: 0.
  • gl.FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE: The name of cube-map face of the texture.

When using the EXT_sRGB extension:

  • ext.FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING_EXT: The framebuffer color encoding.

When using a WebGL 2 context, the following values are available additionally:

  • gl.FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE
  • gl.FRAMEBUFFER_ATTACHMENT_BLUE_SIZE
  • gl.FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING
  • gl.FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE
  • gl.FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE
  • gl.FRAMEBUFFER_ATTACHMENT_GREEN_SIZE
  • gl.FRAMEBUFFER_ATTACHMENT_RED_SIZE
  • gl.FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE
  • gl.FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER

When using the OVR_multiview2 extension:

  • ext.FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR: the number of views of the framebuffer object attachment.
  • ext.FRAMEBUFFER_ATTACHMENT_TEXTURE_BASE_VIEW_INDEX_OVR: the base view index of the framebuffer object attachment.

Return value

Depends on the requested information (as specified with pname). Either a GLint, a GLenum, a WebGLRenderbuffer, or a WebGLTexture.

pname parameter Return value
gl.FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE A GLenum indicating the type of the texture. Either gl.RENDERBUFFER, gl.TEXTURE, or if no image is attached, gl.NONE.
gl.FRAMEBUFFER_ATTACHMENT_OBJECT_NAME The texture (WebGLTexture) or renderbuffer (WebGLRenderbuffer) of the attached image.
gl.FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL A GLint indicating the mipmap level. Default value: 0.
gl.FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE A GLenum indicating the name of cube-map face of the texture. Possible values:
  • gl.TEXTURE_CUBE_MAP_POSITIVE_X: Image for the positive X face of the cube.
  • gl.TEXTURE_CUBE_MAP_NEGATIVE_X: Image for the negative X face of the cube.
  • gl.TEXTURE_CUBE_MAP_POSITIVE_Y: Image for the positive Y face of the cube.
  • gl.TEXTURE_CUBE_MAP_NEGATIVE_Y: Image for the negative Y face of the cube.
  • gl.TEXTURE_CUBE_MAP_POSITIVE_Z: Image for the positive Z face of the cube.
  • gl.TEXTURE_CUBE_MAP_NEGATIVE_Z: Image for the negative Z face of the cube.
gl.FRAMEBUFFER_ATTACHMENT_ALPHA_SIZE A GLint indicating the number of bits in the alpha component of the attachment.
gl.FRAMEBUFFER_ATTACHMENT_BLUE_SIZE A GLint indicating the number of bits in the blue component of the attachment.
gl.FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING A GLenum indicating the encoding of components of the specified attachment. Either gl.LINEAR or gl.SRGB.
gl.FRAMEBUFFER_ATTACHMENT_COMPONENT_TYPE A GLenum indicating the format of the components of the specified attachment. Either gl.FLOAT, gl.INT, gl.UNSIGNED_INT, gl.SIGNED_NORMALIZED, or gl.UNSIGNED_NORMALIZED.
gl.FRAMEBUFFER_ATTACHMENT_DEPTH_SIZE A GLint indicating the number of bits in the depth component of the attachment.
gl.FRAMEBUFFER_ATTACHMENT_GREEN_SIZE A GLint indicating the number of bits in the green component of the attachment.
gl.FRAMEBUFFER_ATTACHMENT_RED_SIZE A GLint indicating the number of bits in the red component of the attachment.
gl.FRAMEBUFFER_ATTACHMENT_STENCIL_SIZE A GLint indicating the number of bits in the stencil component of the attachment.
gl.FRAMEBUFFER_ATTACHMENT_TEXTURE_LAYER A GLint indicating the number of the texture layer which contains the attached image.
ext.FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING_EXT A GLenum indicating the framebuffer color encoding. Either gl.LINEAR or ext.SRGB_EXT.
ext.FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR A GLsizei indicating the number of views of the framebuffer object attachment.
ext.FRAMEBUFFER_ATTACHMENT_TEXTURE_BASE_VIEW_INDEX_OVR A GLint indicating the base view index of the framebuffer object attachment.

Exceptions

  • A gl.INVALID_ENUM error is thrown if target is not gl.FRAMEBUFFER, gl.DRAW_FRAMEBUFFER, gl.READ_FRAMEBUFFER or if attachment is not one of the accepted attachment points.

Examples

js
gl.getFramebufferAttachmentParameter(
  gl.FRAMEBUFFER,
  gl.COLOR_ATTACHMENT0,
  gl.FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE,
);

Specifications

Specification
WebGL Specification
# 5.14.6
WebGL 2.0 Specification
# 3.7.4

Browser compatibility

BCD tables only load in the browser

See also