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glBlitFramebuffer

Name

glBlitFramebuffer — copy a block of pixels from the read framebuffer to the draw framebuffer

C Specification

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

Parameters

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 transfers a rectangle of pixel values from one region of the read framebuffer to another region in the draw framebuffer. 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 read framebuffer and written to each of the draw buffers of the draw framebuffer.

If SAMPLE_BUFFERS for the read framebuffer is greater than zero and SAMPLE_BUFFERS for the draw framebuffer is zero, the samples corresponding to each pixel location in the source are converted to a single sample before being written to the destination.

Errors

GL_INVALID_VALUE is generated if mask contains any bits other than GL_COLOR_BUFFER_BIT, GL_DEPTH_BUFFER_BIT or GL_STENCIL_BUFFER_BIT.

GL_INVALID_ENUM is generated if filter is not GL_LINEAR or GL_NEAREST.

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 the source and destination buffers are identical.

GL_INVALID_FRAMEBUFFER_OPERATION is generated if the objects bound to GL_DRAW_FRAMEBUFFER_BINDING or GL_READ_FRAMEBUFFER_BINDING are not framebuffer complete.

GL_INVALID_OPERATION is generated if mask contains GL_DEPTH_BUFFER_BIT or GL_DEPTH_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 GL_SAMPLE_BUFFERS for the read buffer is greater than zero and the formats of draw and read buffers are not identical, or the source and destination rectangles are not defined with the same (X0, Y0) and (X1, Y1) bounds.

GL_INVALID_OPERATION is generated if the value of GL_SAMPLE_BUFFERS for the draw buffer is greater than zero.

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.

Examples

Create a framebuffer object with a renderbuffer-based color attachment and a renderbuffer-based depth attachment.
glBindFramebuffer(GL_READ_FRAMEBUFFER, source_fbo);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, destination_fbo);

glBlitFramebuffer(0, 0, source_fbo_width, source_fbo_height, 0, 0, destination_fbo_width, destination_fbo_height, GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT, GL_NEAREST);

API Version Support

OpenGL ES API Version
Function Name 2.0 3.0 3.1
glBlitFramebuffer -
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