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 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 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 value of
GL_SAMPLES for
the read and draw buffers is not identical.
GL_INVALID_OPERATION is generated if
GL_SAMPLE_BUFFERS for both
read and draw buffers greater than zero and the dimensions of the source and
destination rectangles is not 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.
SEE ALSO¶
glReadPixels()
glCheckFramebufferStatus(),
glGenFramebuffers()
glBindFramebuffer()
glDeleteFramebuffers()
COPYRIGHT¶
Copyright © 2010 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/.