glBlitFramebuffer - OpenGL 4 Reference Pages

## Name

glBlitFramebuffer, glBlitNamedFramebuffer — copy a block of pixels from one framebuffer object to another

## C Specification

`void glBlitFramebuffer(` | GLint srcX0,
| GLint srcY0,
| GLint srcX1,
| GLint srcY1,
| GLint dstX0,
| GLint dstY0,
| GLint dstX1,
| GLint dstY1,
| GLbitfield mask,
| GLenum filter`)`;

`void glBlitNamedFramebuffer(` | GLuint readFramebuffer,
| GLuint drawFramebuffer,
| GLint srcX0,
| GLint srcY0,
| GLint srcX1,
| GLint srcY1,
| GLint dstX0,
| GLint dstY0,
| GLint dstX1,
| GLint dstY1,
| GLbitfield mask,
| GLenum filter`)`;

## Parameters

`readFramebuffer`

  Specifies the name of the source framebuffer object for `glBlitNamedFramebuffer`.

`drawFramebuffer`

  Specifies the name of the destination framebuffer object for `glBlitNamedFramebuffer`.

`srcX0`, `srcY0`, `srcX1`, `srcY1`

  Specify the bounds of the source rectangle within the read buffer of the read framebuffer.

`dstX0`, `dstY0`, `dstX1`, `dstY1`

  Specify the bounds of the destination rectangle within the write buffer of the write framebuffer.

`mask`

  The bitwise OR of the flags indicating which buffers are to be copied. The allowed flags are `GL_COLOR_BUFFER_BIT`, `GL_DEPTH_BUFFER_BIT` and `GL_STENCIL_BUFFER_BIT`.

`filter`

  Specifies the interpolation to be applied if the image is stretched. Must be `GL_NEAREST` or `GL_LINEAR`.

## Description

`glBlitFramebuffer` and `glBlitNamedFramebuffer` transfer a rectangle of pixel values from one region of a read framebuffer to another region of a draw framebuffer.

For `glBlitFramebuffer`, the read and draw framebuffers are those bound to the `GL_READ_FRAMEBUFFER` and `GL_DRAW_FRAMEBUFFER` targets respectively.

For `glBlitNamedFramebuffer`, `readFramebuffer` and `drawFramebuffer` are the names of the read read and draw framebuffer objects respectively. If `readFramebuffer` or `drawFramebuffer` is zero, then the default read or draw framebuffer respectively is used.

`mask` is the bitwise OR of a number of values indicating which buffers are to be copied. The values are `GL_COLOR_BUFFER_BIT`, `GL_DEPTH_BUFFER_BIT`, and `GL_STENCIL_BUFFER_BIT`. The pixels corresponding to these buffers are copied from the source rectangle bounded by the locations (`srcX0`, `srcY0`) and (`srcX1`, `srcY1`) to the destination rectangle bounded by the locations (`dstX0`, `dstY0`) and (`dstX1`, `dstY1`). The lower bounds of the rectangle are inclusive, while the upper bounds are exclusive.

The actual region taken from the read framebuffer is limited to the intersection of the source buffers being transferred, which may include the color buffer selected by the read buffer, the depth buffer, and/or the stencil buffer depending on mask. The actual region written to the draw framebuffer is limited to the intersection of the destination buffers being written, which may include multiple draw buffers, the depth buffer, and/or the stencil buffer depending on mask. Whether or not the source or destination regions are altered due to these limits, the scaling and offset applied to pixels being transferred is performed as though no such limits were present.

If the sizes of the source and destination rectangles are not equal, `filter` specifies the interpolation method that will be applied to resize the source image , and must be `GL_NEAREST` or `GL_LINEAR`. `GL_LINEAR` is only a valid interpolation method for the color buffer. If `filter` is not `GL_NEAREST` and `mask` includes `GL_DEPTH_BUFFER_BIT` or `GL_STENCIL_BUFFER_BIT`, no data is transferred and a `GL_INVALID_OPERATION` error is generated.

If `filter` is `GL_LINEAR` and the source rectangle would require sampling outside the bounds of the source framebuffer, values are read as if the `GL_CLAMP_TO_EDGE` texture wrapping mode were applied.

When the color buffer is transferred, values are taken from the read buffer of the specified read framebuffer and written to each of the draw buffers of the specified draw framebuffer.

If the source and destination rectangles overlap or are the same, and the read and draw buffers are the same, the result of the operation is undefined.

## Errors

`GL_INVALID_OPERATION` is generated by `BlitNamedFramebuffer` if `readFramebuffer` or `drawFramebuffer` is not zero or the name of an existing framebuffer object.

`GL_INVALID_OPERATION` is generated if `mask` contains any of the `GL_DEPTH_BUFFER_BIT` or `GL_STENCIL_BUFFER_BIT` and `filter` is not `GL_NEAREST`.

`GL_INVALID_OPERATION` is generated if `mask` contains `GL_COLOR_BUFFER_BIT` and any of the following conditions hold:

- The read buffer contains fixed-point or floating-point values and any draw buffer contains neither fixed-point nor floating-point values.

- The read buffer contains unsigned integer values and any draw buffer does not contain unsigned integer values.

- The read buffer contains signed integer values and any draw buffer does not contain signed integer values.

`GL_INVALID_OPERATION` is generated if `mask` contains `GL_DEPTH_BUFFER_BIT` or `GL_STENCIL_BUFFER_BIT` and the source and destination depth and stencil formats do not match.

`GL_INVALID_OPERATION` is generated if `filter` is `GL_LINEAR` and the read buffer contains integer data.

`GL_INVALID_OPERATION` is generated if the effective value of `GL_SAMPLES` for the read and draw framebuffers is not identical.

`GL_INVALID_OPERATION` is generated if the value of `GL_SAMPLE_BUFFERS` for both read and draw buffers is greater than zero and the dimensions of the source and destination rectangles is not identical.

`GL_INVALID_FRAMEBUFFER_OPERATION` is generated if the specified read and draw framebuffers are not framebuffer complete.

## Version Support

| OpenGL Version
--- | ---
Function / Feature Name | 2.0 | 2.1 | 3.0 | 3.1 | 3.2 | 3.3 | 4.0 | 4.1 | 4.2 | 4.3 | 4.4 | 4.5
`glBlitFramebuffer` | - | - | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔ | ✔
`glBlitNamedFramebuffer` | - | - | - | - | - | - | - | - | - | - | - | ✔

## See Also

glReadPixels glCheckFramebufferStatus, glGenFramebuffers glBindFramebuffer glDeleteFramebuffers

## Copyright

Copyright © 2010-2014 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. http://opencontent.org/openpub/.