Provided by: opengl-4-man-doc_1.0~svn33624-1_all bug

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                                         │
       ├───────────────────────────┼─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┤
       │Function2.02.13.03.13.23.34.04.14.24.34.44.5 │
       │/                          │     │     │     │     │     │     │     │     │     │     │     │     │
       │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)