2011 Khronos Group.
glDrawTransformFeedbackStreamInstanced 3G
glDrawTransformFeedbackStreamInstanced render multiple instances of primitives using a count derived from a specifed stream of a transform feedback object

## C Specification

void `glDrawTransformFeedbackStreamInstanced` GLenum mode GLuint id GLuint stream GLsizei primcount

## Parameters

mode

  Specifies what kind of primitives to render. Symbolic constants `GL_POINTS`, `GL_LINE_STRIP`, `GL_LINE_LOOP`, `GL_LINES`, `GL_LINE_STRIP_ADJACENCY`, `GL_LINES_ADJACENCY`, `GL_TRIANGLE_STRIP`, `GL_TRIANGLE_FAN`, `GL_TRIANGLES`, `GL_TRIANGLE_STRIP_ADJACENCY`, `GL_TRIANGLES_ADJACENCY`, and `GL_PATCHES` are accepted.

id

  Specifies the name of a transform feedback object from which to retrieve a primitive count.

stream

  Specifies the index of the transform feedback stream from which to retrieve a primitive count.

primcount

  Specifies the number of instances of the geometry to render.

## Description

`glDrawTransformFeedbackStreamInstanced` draws multiple copies of a range of primitives of a type specified by mode using a count retrieved from the transform feedback stream specified by stream of the transform feedback object specified by id. Calling `glDrawTransformFeedbackStreamInstanced` is equivalent to calling glDrawArraysInstanced with mode and primcount as specified, first set to zero, and count set to the number of vertices captured on vertex stream stream the last time transform feedback was active on the transform feedback object named by id.

Calling glDrawTransformFeedbackInstanced is equivalent to calling `glDrawTransformFeedbackStreamInstanced` with stream set to zero.

## Errors

`GL_INVALID_ENUM` is generated if mode is not an accepted value.

`GL_INVALID_VALUE` is generated if id is not the name of a transform feedback object.

`GL_INVALID_VALUE` is generated if stream is greater than or equal to the value of `GL_MAX_VERTEX_STREAMS`.

`GL_INVALID_OPERATION` is generated if a non-zero buffer object name is bound to an enabled array and the buffer object's data store is currently mapped.

`GL_INVALID_OPERATION` is generated if a geometry shader is active and mode is incompatible with the input primitive type of the geometry shader in the currently installed program object.

`GL_INVALID_OPERATION` is generated if mode is `GL_PATCHES` and no tessellation control shader is active.

`GL_INVALID_OPERATION` is generated if glEndTransformFeedback has never been called while the transform feedback object named by id was bound.

## See Also

glDrawArrays, glDrawArraysInstanced, glDrawElements, glDrawRangeElements, glDrawTransformFeedback, glDrawTransformFeedbackStream.

## Copyright

Copyright 2010-2011 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/.