WebGLRenderingContext: getFramebufferAttachmentParameter() method

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

Syntax

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.

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

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

Specifications

Browser compatibility

See also

• WebGLRenderingContext.createFramebuffer()
• WebGLRenderingContext.deleteFramebuffer()
• WebGLRenderingContext.isFramebuffer()
• Other buffers: WebGLBuffer, WebGLRenderbuffer
• EXT_sRGB
• WEBGL_draw_buffers