Страницы справочника OS X

Эта страница руководства является частью версии 5.0 Инструментов XCode

Читать страницы руководства

GLBLITFRAMEBUFFER(3G)                            OpenGL 3.3                            GLBLITFRAMEBUFFER(3G)



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

C SPECIFICATION
       void glBlitFramebuffer(GLint srcX_, GLint srcY_, GLint srcX1, GLint srcY1, GLint dstX_, GLint dstY_,
                              GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter);

PARAMETERS
       srcX_, srcY_, srcX1, srcY1
           Specify the bounds of the source rectangle within the read buffer of the read framebuffer.

       dstX_, dstY_, 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 (srcX_; srcY_) and (srcX1; srcY1) to the destination rectangle bounded by
       the locations (dstX_; dstY_) 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.

NOTES
       glBindVertexArray is available only if the GL version is 3.0 or greater.

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_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 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 (C) 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/.



OpenGL 3.3                                       03/08/2011                            GLBLITFRAMEBUFFER(3G)