gltransformfeedbackvaryings(3g) [debian man page]
GLTRANSFORMFEEDBACKV(3G) [FIXME: manual] 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: o The count specified by glTransformFeedbackVaryings is non-zero, but the program object has no vertex or geometry shader. o Any variable name specified in the varyings array is not declared as an output in the vertex shader (or the geometry shader, if active). o Any two entries in the varyings array specify the same varying variable. o 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. o 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/. [FIXME: source] 05/30/2012 GLTRANSFORMFEEDBACKV(3G)
Check Out this Related Man Page
GLBEGINTRANSFORMFEED(3G) OpenGL Manual GLBEGINTRANSFORMFEED(3G) NAME
glBeginTransformFeedback - start transform feedback operation C SPECIFICATION
void glBeginTransformFeedback(GLenum primitiveMode); PARAMETERS
primitiveMode Specify the output type of the primitives that will be recorded into the buffer objects that are bound for transform feedback. C SPECIFICATION
void glEndTransformFeedback(void); DESCRIPTION
Transform feedback mode captures the values of varying variables written by the vertex shader (or, if active, the geometry shader). Transform feedback is said to be active after a call to glBeginTransformFeedback until a subsequent call to glEndTransformFeedback(). Transform feedback commands must be paired. If no geometry shader is present, while transform feedback is active the mode parameter to glDrawArrays() must match those specified in the following table: +-------------------------------------------+---------------------------------------------------+ | | | | Transform Feedback | Allowed Render Primitive | |primitiveMode | modes | | | | +-------------------------------------------+---------------------------------------------------+ |GL_POINTS | GL_POINTS | +-------------------------------------------+---------------------------------------------------+ |GL_LINES | GL_LINES, GL_LINE_LOOP, GL_LINE_STRIP, | | | GL_LINES_ADJACENCY, | | | GL_LINE_STRIP_ADJACENCY | +-------------------------------------------+---------------------------------------------------+ |GL_TRIANGLES | GL_TRIANGLES, GL_TRIANGLE_STRIP, GL_TRIANGLE_FAN, | | | GL_TRIANGLES_ADJACENCY, | | | GL_TRIANGLE_STRIP_ADJACENCY | +-------------------------------------------+---------------------------------------------------+ If a geometry shader is present, the output primitive type from the geometry shader must match those provided in the following table: +-------------------------------------------+-------------------------------------------------+ | | | | Transform Feedback | Allowed Geometry Shader | |primitiveMode | Output Primitive Type | | | | +-------------------------------------------+-------------------------------------------------+ |GL_POINTS | points | +-------------------------------------------+-------------------------------------------------+ |GL_LINES | line_strip | +-------------------------------------------+-------------------------------------------------+ |GL_TRIANGLES | triangle_strip | +-------------------------------------------+-------------------------------------------------+ NOTES
Geometry shaders, and the GL_TRIANGLES_ADJACENCY, GL_TRIANGLE_STRIP_ADJACENCY, GL_LINES_ADJACENCY and GL_LINE_STRIP_ADJACENCY primtive modes are available only if the GL version is 3.2 or greater. ERRORS
GL_INVALID_OPERATION is generated if glBeginTransformFeedback is executed while transform feedback is active. GL_INVALID_OPERATION is generated if glEndTransformFeedback is executed while transform feedback is not active. GL_INVALID_OPERATION is generated by glDrawArrays() if no geometry shader is present, transform feedback is active and mode is not one of the allowed modes. GL_INVALID_OPERATION is generated by glDrawArrays() if a geometry shader is present, transform feedback is active and the output primitive type of the geometry shader does not match the transform feedback primitiveMode. GL_INVALID_OPERATION is generated by glEndTransformFeedback if any binding point used in transform feedback mode does not have a buffer object bound. GL_INVALID_OPERATION is generated by glEndTransformFeedback if no binding points would be used, either because no program object is active of because the active program object has specified no varying variables to record. 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/. AUTHORS
opengl.org opengl.org 06/10/2014 GLBEGINTRANSFORMFEED(3G)