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GLTRANSFORMFEEDBACKV(3G)                         OpenGL 3.3                         GLTRANSFORMFEEDBACKV(3G)



NAME
       glTransformFeedbackVaryings - specify values to record in transform feedback buffers

C SPECIFICATION
       void glTransformFeedbackVaryings(GLuintprogram, GLsizeicount, const char **varyings,
                                        GLenumbufferMode);

PARAMETERS
       program
           The name of the target program object.

       count
           The number of varying variables used for transform feedback.

       varyings
           An array of count zero-terminated strings specifying the names of the varying variables to use
           for transform feedback.

       bufferMode
           Identifies the mode used to capture the varying variables when transform feedback is active.
           bufferMode must be GL_INTERLEAVED_ATTRIBS or GL_SEPARATE_ATTRIBS.

DESCRIPTION
       The names of the vertex or geometry shader outputs to be recorded in transform feedback mode are
       specified using glTransformFeedbackVaryings. When a geometry shader is active, transform feedback
       records the values of selected geometry shader output variables from the emitted vertices. Otherwise,
       the values of the selected vertex shader outputs are recorded.

       The state set by glTranformFeedbackVaryings is stored and takes effect next time glLinkProgram() is
       called on program. When glLinkProgram() is called, program is linked so that the values of the
       specified varying variables for the vertices of each primitive generated by the GL are written to a
       single buffer object if bufferMode is GL_INTERLEAVED_ATTRIBS or multiple buffer objects if bufferMode
       is GL_SEPARATE_ATTRIBS.

       In addition to the errors generated by glTransformFeedbackVaryings, the program program will fail to
       link if:

       •   The count specified by glTransformFeedbackVaryings is non-zero, but the program object has no
           vertex or geometry shader.

       •   Any variable name specified in the varyings array is not declared as an output in the vertex
           shader (or the geometry shader, if active).

       •   Any two entries in the varyings array specify the same varying variable.

       •   The total number of components to capture in any varying variable in varyings is greater than the
           constant GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS and the buffer mode is
           GL_SEPARATE_ATTRIBS.

       •   The total number of components to capture is greater than the constant
           GL_MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS and the buffer mode is GL_INTERLEAVED_ATTRIBS.


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

ERRORS
       GL_INVALID_VALUE is generated if program is not the name of a program object.


       GL_INVALID_VALUE is generated if bufferMode is GL_SEPARATE_ATTRIBS and count is greater than the
       implementation-dependent limit GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS.

ASSOCIATED GETS
       glGetTransformFeedbackVarying()

SEE ALSO
       glBeginTransformFeedback(), glEndTransformFeedback(), glGetTransformFeedbackVarying()


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                         GLTRANSFORMFEEDBACKV(3G)