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# docs.GL

OpenGL ES 3
OpenGL ES 2

# glFramebufferTexture2D

## Name

glFramebufferTexture2D — attach a texture image to a framebuffer object

## C Specification

`void glFramebufferTexture2D(` | GLenum target,
| GLenum attachment,
| GLenum textarget,
| GLuint texture,
| GLint level`)`;

## Parameters

`target`

  Specifies the framebuffer target. The symbolic constant must be `GL_FRAMEBUFFER`.

`attachment`

  Specifies the attachment point to which an image from `texture` should be attached. Must be one of the following symbolic constants: `GL_COLOR_ATTACHMENT0`, `GL_DEPTH_ATTACHMENT`, or `GL_STENCIL_ATTACHMENT`.

`textarget`

  Specifies the texture target. Must be one of the following symbolic constants: `GL_TEXTURE_2D`, `GL_TEXTURE_CUBE_MAP_POSITIVE_X`, `GL_TEXTURE_CUBE_MAP_NEGATIVE_X`, `GL_TEXTURE_CUBE_MAP_POSITIVE_Y`, `GL_TEXTURE_CUBE_MAP_NEGATIVE_Y`, `GL_TEXTURE_CUBE_MAP_POSITIVE_Z`, or `GL_TEXTURE_CUBE_MAP_NEGATIVE_Z`.

`texture`

  Specifies the texture object whose image is to be attached.

`level`

  Specifies the mipmap level of the texture image to be attached, which must be 0.

## Description

`glFramebufferTexture2D` attaches the texture image specified by `texture` and `level` as one of the logical buffers of the currently bound framebuffer object. `attachment` specifies whether the texture image should be attached to the framebuffer object's color, depth, or stencil buffer. A texture image may not be attached to the default framebuffer object name 0.

If `texture` is not 0, the value of `GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE` for the specified attachment point is set to `GL_TEXTURE`, the value of `GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME` is set to `texture`, and the value of `GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL` is set to `level`. If `texture` is a cube map texture, the value of `GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE` is set to `textarget`; otherwise it is set to the default value `GL_TEXTURE_CUBE_MAP_POSITIVE_X`. Any previous attachment to the `attachment` logical buffer of the currently bound framebuffer object is broken.

If `texture` is 0, the current image, if any, attached to the `attachment` logical buffer of the currently bound framebuffer object is detached. The value of `GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE` is set to `GL_NONE`. The value of `GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME` is set to 0. `GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL` and `GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE` are set to the default values 0 and `GL_TEXTURE_CUBE_MAP_POSITIVE_X`, respectively.

## Notes

Special precautions need to be taken to avoid attaching a texture image to the currently bound framebuffer while the texture object is currently bound and potentially sampled by the current vertex or fragment shader. Doing so could lead to the creation of a "feedback loop" between the writing of pixels by rendering operations and the simultaneous reading of those same pixels when used as texels in the currently bound texture. In this scenario, the framebuffer will be considered framebuffer complete, but the values of fragments rendered while in this state will be undefined. The values of texture samples may be undefined as well.

If a texture object is deleted while its image is attached to the currently bound framebuffer, then it is as if `glFramebufferTexture2D` had been called with a `texture` of 0 for the attachment point to which this image was attached in the currently bound framebuffer object. In other words, the texture image is detached from the currently bound framebuffer. Note that the texture image is specifically not detached from any non-bound framebuffers. Detaching the image from any non-bound framebuffers is the responsibility of the application.

## Errors

`GL_INVALID_ENUM` is generated if `target` is not `GL_FRAMEBUFFER`.

`GL_INVALID_ENUM` is generated if `textarget` is not an accepted texture target and `texture` is not 0.

`GL_INVALID_ENUM` is generated if `attachment` is not an accepted attachment point.

`GL_INVALID_VALUE` is generated if `level` is not 0 and `texture` is not 0.

`GL_INVALID_OPERATION` is generated if the default framebuffer object name 0 is bound.

`GL_INVALID_OPERATION` is generated if `texture` is neither 0 nor the name of an existing texture object.

`GL_INVALID_OPERATION` is generated if `texture` is the name of an existing two-dimensional texture object but `textarget` is not `GL_TEXTURE_2D` or if `texture` is the name of an existing cube map texture object but `textarget` is `GL_TEXTURE_2D`.

## Associated Gets

glGetFramebufferAttachmentParameteriv

## Examples

Create a framebuffer object with a texture-based color attachment and a texture-based depth attachment. Using texture-based attachments allows sampling of those textures in shaders.

    // fbo_width and fbo_height are the desired width and height of the FBO.
    // For Opengl <= 4.4 or if the GL_ARB_texture_non_power_of_two extension
    // is present, fbo_width and fbo_height can be values other than 2^n for
    // some integer n.

    // Build the texture that will serve as the color attachment for the framebuffer.
    GLuint texture_map;
    glGenTextures(1, &texture_map);
    glBindTexture(GL_TEXTURE_2D, texture_map);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, fbo_width, fbo_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);

    glBindTexture(GL_TEXTURE_2D, 0);

    // Build the texture that will serve as the depth attachment for the framebuffer.
    GLuint depth_texture;
    glGenTextures(1, &depth_texture);
    glBindTexture(GL_TEXTURE_2D, depth_texture);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, fbo_width, fbo_height, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, NULL);
    glBindTexture(GL_TEXTURE_2D, 0);

    // Build the framebuffer.
    GLuint framebuffer;
    glGenFramebuffers(1, &framebuffer);
    glBindFramebuffer(GL_FRAMEBUFFER, (GLuint)framebuffer);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture_map, 0);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depth_texture, 0);

    GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
    if (status != GL_FRAMEBUFFER_COMPLETE)
        // Error

    glBindFramebuffer(GL_FRAMEBUFFER, 0);

## Tutorials

Songho - OpenGL Frame Buffer Object (FBO)
open.gl - Framebuffers

## See Also

glBindFramebuffer, glBindTexture, glCheckFramebufferStatus, glDeleteFramebuffers, glDeleteTextures, glFramebufferRenderbuffer, glGenerateMipmap, glGetFramebufferAttachmentParameteriv, glTexImage2D

## Copyright

Copyright © 2008 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. https://opencontent.org/openpub/.

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