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 © 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/.

AUTHORS

       opengl.org