GLAPI/glTransformFeedbackVaryings
| Core in version | 4.6 | |
|---|---|---|
| Core since version | 3.0 | |
glTransformFeedbackVaryings: specify values to record in transform feedback buffers
Function Definition
void glTransformFeedbackVaryings(GLuint program, GLsizei count, const char **varyings, GLenum bufferMode);
- 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 final active Vertex Processing shader stage outputs to be recorded in transform feedback mode are specified using glTransformFeedbackVaryings.
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 Processing shader stages.
- Any variable name specified in the varyings array is not declared as an output in the final active Vertex Processing vertex shader (or the geometry shader, if active) or is not one of the special varying names mentioned below.
- Any two entries in the varyings array specify the same varying variable, unless it is one of the special varying names.
- 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
See Also
glBeginTransformFeedback, glGetTransformFeedbackVarying, glLinkProgram
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/.