WebGLRenderingContext: getFramebufferAttachmentParameter() method

{{APIRef("WebGL")}}{{AvailableInWorkers}}

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

Syntax

Parameters

• target

  • : A {{domxref("WebGL_API/Types", "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 {{domxref("WebGL2RenderingContext", "WebGL 2 context", "", 1)}}, 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 {{domxref("WebGL_API/Types", "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 {{domxref("WebGL2RenderingContext", "WebGL 2 context", "", 1)}}, 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 {{domxref("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 {{domxref("WebGL_API/Types", "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 ({{domxref("WebGLRenderbuffer")}} or {{domxref("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 {{domxref("EXT_sRGB")}} extension:

    • ext.FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING_EXT: The framebuffer color encoding.

    When using a {{domxref("WebGL2RenderingContext", "WebGL 2 context", "", 1)}}, 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 {{domxref("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 {{domxref("WebGL_API/Types", "GLint")}}, a {{domxref("WebGL_API/Types", "GLenum")}}, a {{domxref("WebGLRenderbuffer")}}, or a {{domxref("WebGLTexture")}}.

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

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

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

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