extensions/EXT/EXT_clip_volume_hint.txt

Name

    EXT_clip_volume_hint

Name Strings

    GL_EXT_clip_volume_hint

Version

    Microsoft revision 1.00, April 17, 1996 (hockl)
    $Date: 1999/12/28 01:40:35 $ $Revision: 1.4 $

Number

    79

Dependencies

    None.

Overview

    EXT_clip_volume_hint provides a mechanism for applications to
    indicate that they do not require clip volume clipping for
    primitives. It allows applications to maximize performance in
    situations where they know that clipping is unnecessary.
    EXT_clip_volume_hint is only an indication, though, and
    implementations are free to ignore it.

New Procedures and Functions

    None.

New Tokens

    Accepted by the target parameter of Hint and the pname parameter of
    GetBooleanv, GetDoublev, GetFloatv and GetIntegerv:
        CLIP_VOLUME_CLIPPING_HINT_EXT   0x80F0

Additions to Chapter 2 of the GL Specification (OpenGL Operation)

    Before the last paragraph of Section 2.11, 'Clipping,' the following
    text is added:

        The EXT_clip_volume_hint extension can be used to indicate that
        a primitive falls inside the current clip volume. In this case,
        an implementation might not clip the primitive to the clip
        volume, and the behavior of the GL is undefined if the primitive
        extends beyond the clip volume.

    In the fourth (clipping) paragraph of Section 2.12, 'Current Raster
    Position,' the following text is added before the last sentence
    "Figure 2.7 summarizes..."

        Raster position clipping is not affected by the
        CLIP_VOLUME_CLIPPING_HINT_EXT hint in the EXT_clip_volume_hint
        extension.

Additions to Chapter 3 of the GL Specification (Rasterization)

    None.

Additions to Chapter 4 of the GL Specification (Per-Fragment
Operations and the Framebuffer)

    None.

Additions to Chapter 5 of the GL Specification (Special Functions)

    Section 5.6, 'Hints,' should be changed to add the following
    hint description:

        CLIP_VOLUME_CLIPPING_HINT_EXT, indicating whether clipping to
        the clip volume is necessary.

Additions to Chapter 6 of the GL Specification (State and State
Requests)

    In table 6.18, 'Hints,' the following entry is added:

        CLIP_VOLUME_CLIPPING_HINT_EXT|Z3|GetIntegerv|DONT_CARE|
        Clip volume clipping hint|5.6|hint

Revision History
----------------
    Original draft, revision 0.9, March 1, 1996 (drewb)
        Created.
    Minor revision, revision 0.91, March 8, 1996 (drewb)
    Hint revision, revision 0.95, April 12, 1996 (drewb)
        Changed from Enable-based to Hint-based.  Clarified
        behavior of RasterPos.
    More revision, revision 0.96, April 16, 1996 (hockl)
        Changed extension and enumerant names.  Added robustness.
        Changed it to have no effect on RasterPos.
    More revision, revision 1.00, April 17, 1996 (hockl)
        Removed robustness requirement.