Provided by: opengl-4-man-doc_1.0~svn33624-1_all 
NAME
glGetTransformFeedbackiv - query the state of a transform feedback object.
C SPECIFICATION
void glGetTransformFeedbackiv(GLuint xfb, GLenum pname, GLint *param);
void glGetTransformFeedbacki_v(GLuint xfb, GLenum pname, GLuint index, GLint *param);
void glGetTransformFeedbacki64_v(GLuint xfb, GLenum pname, GLuint index, GLint64 *param);
PARAMETERS
xfb
The name of an existing transform feedback object, or zero for the default transform
feedback object.
pname
Property to use for the query. Must be one of the values:
GL_TRANSFORM_FEEDBACK_BUFFER_BINDING, GL_TRANSFORM_FEEDBACK_BUFFER_START,
GL_TRANSFORM_FEEDBACK_BUFFER_SIZE, GL_TRANSFORM_FEEDBACK_PAUSED,
GL_TRANSFORM_FEEDBACK_ACTIVE.
index
Index of the transform feedback stream (for indexed state).
param
The address of a buffer into which will be written the requested state information.
DESCRIPTION
In order to use the Transform Feedback functionality, you need to configure the Transform
Feedback Buffer indexed bindings. This can be achieved by either using glBindBufferBase or
glBindBuffersBase to associate whole buffer object storage to one of the Transform
Feedback Binding Points, or by calling glBindBufferRange or glBindBuffersRange to use a
region of a buffer object storage for the binding. You may want to (but are not required
to) bind a Transform Feedback Object first, in order to cache the binding configuration.
This usually allows you to restore the Transform Feedback configuration faster, than if
you were to execute a list of API calls necessary to set up the Transform Feedback state
of your liking.
This reference page discusses two types of getters that operate on Transform Feedback
Objects and their bindings.
The first class operates on general Transform Feedback binding point and includes
glGetTransformFeedbackiv function. glGetTransformFeedbackiv can be used to retrieve
information about Transform Feedback object bound to the general Transform Feedback
binding point, as configured with a glBindTransformFeedback call. In this case, you can
check:
• What the ID of the currently bound Transform Feedback Object is;
(GL_TRANSFORM_FEEDBACK_BUFFER_BINDING)
• Whether the Transform Feedback process is currently paused;
(GL_TRANSFORM_FEEDBACK_PAUSED)
• Whether the Transform Feedback process has been begun and is currently undergoing;
(GL_TRANSFORM_FEEDBACK_ACTIVE)
The latter class, which includes glGetTransformFeedbacki_v and glGetTransformFeedbacki64_v
functions, can be used to check what the current configuration of each of the buffer
object regions bound to Transform Feedback Buffer binding points is. This allows you to
query for the following information:
• glGetTransformFeedbacki_v only: What the ID of the Buffer Object bound to a Transform
Feedback Binding Point of user-specified index is;
(GL_TRANSFORM_FEEDBACK_BUFFER_BINDING).
• glGetTransformFeedbacki64_v only: What the start offset configured for the binding is;
(GL_TRANSFORM_FEEDBACK_BUFFER_START);
• glGetTransformFeedbacki64_v only: What the length of the region used for the binding
is; (GL_TRANSFORM_FEEDBACK_BUFFER_SIZE);
ERRORS
GL_INVALID_OPERATION error is generated if xfb is not zero or the name of an existing
transform feedback object.
GL_INVALID_ENUM error is generated by glGetTransformFeedbackiv if pname is not
GL_TRANSFORM_FEEDBACK_PAUSED or GL_TRANSFORM_FEEDBACK_ACTIVE.
GL_INVALID_ENUM error is generated by glGetTransformFeedbacki_v if pname is not
GL_TRANSFORM_FEEDBACK_BUFFER_BINDING.
GL_INVALID_ENUM error is generated by glGetTransformFeedbacki64_v if pname is not
GL_TRANSFORM_FEEDBACK_BUFFER_START or GL_TRANSFORM_FEEDBACK_BUFFER_SIZE.
GL_INVALID_VALUE error is generated by glGetTransformFeedbacki_v and
glGetTransformFeedbacki64_v if index is greater than or equal to the number of binding
points for transform feedback (the value of GL_MAX_TRANSFORM_FEEDBACK_BUFFERS).
VERSION SUPPORT
┌───────────────────────────┬───────────────────────────────────────────────────────────────────────┐
│ │ OpenGL Version │
├───────────────────────────┼─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┤
│Function │ 2.0 │ 2.1 │ 3.0 │ 3.1 │ 3.2 │ 3.3 │ 4.0 │ 4.1 │ 4.2 │ 4.3 │ 4.4 │ 4.5 │
│/ │ │ │ │ │ │ │ │ │ │ │ │ │
│Feature │ │ │ │ │ │ │ │ │ │ │ │ │
│Name │ │ │ │ │ │ │ │ │ │ │ │ │
├───────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│glGetTransformFeedbackiv │ - │ - │ - │ - │ - │ - │ - │ - │ - │ - │ - │ ✔ │
├───────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│glGetTransformFeedbacki_v │ - │ - │ - │ - │ - │ - │ - │ - │ - │ - │ - │ ✔ │
├───────────────────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
│glGetTransformFeedbacki64v │ - │ - │ - │ - │ - │ - │ - │ - │ - │ - │ - │ ✔ │
└───────────────────────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘
SEE ALSO
glBindBufferBase(), glBindBufferRange(), glBindBuffersBase(), glBindBuffersRange(),
glBindTransformFeedback()
COPYRIGHT
Copyright © 2014 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/.
COPYRIGHT
Copyright © 2014 Khronos Group
[FIXME: source] 01/03/2018 GLGETTRANSFORMFEEDBA(3G)