oracular (3) glClipControl.3G.gz

Provided by: opengl-4-man-doc_1.0~svn33624-2_all bug

NAME
       glClipControl - control clip coordinate to window coordinate behavior


C SPECIFICATION
       void glClipControl(GLenum origin, GLenum depth);


PARAMETERS
       origin
           Specifies the clip control origin. Must be one of GL_LOWER_LEFT or GL_UPPER_LEFT.

       depth
           Specifies the clip control depth mode. Must be one of GL_NEGATIVE_ONE_TO_ONE or GL_ZERO_TO_ONE.


DESCRIPTION
       glClipControl controls the clipping volume behavior and the clip coordinate to window coordinate
       transformation behavior.

       The view volume is defined by $$z_{min} \leq z_c \leq w_c$$ where $z_{min} = -w_c$ when depth is
       GL_NEGATIVE_ONE_TO_ONE, and $z_{min} = 0$ when depth is GL_ZERO_TO_ONE.

       The normalized device coordinate $y_d$ is given by $$y_d = { { f \times y_c } \over w_c }$$ where $f = 1$
       when origin is GL_LOWER_LEFT, and $f = -1$ when origin is GL_UPPER_LEFT.

       The window coordinate $z_w$ is given by $$z_w = s \times z_d + b$$ where $s = { { f - n } \over 2 }$ and
       $b = { {n + f} \over 2 }$ when depth is GL_NEGATIVE_ONE_TO_ONE, and $s = f - n$ and $b = n$ when depth is
       GL_ZERO_TO_ONE. $n$ and $f$ are the near and far depth range values set with glDepthRange().

       Finally, the polygon area computation defined by gl_FrontFacing() to determine if a polygon is front- or
       back-facing has its sign negated when origin is GL_UPPER_LEFT.


NOTES
       The default GL clip volume definition is for a origin of GL_LOWER_LEFT and a depth of
       GL_NEGATIVE_ONE_TO_ONE.

       An origin of GL_UPPER_LEFT and a depth of GL_ZERO_TO_ONE corresponds to Direct3D's clip volume
       definition.

       An origin of GL_UPPER_LEFT and a depth of GL_NEGATIVE_ONE_TO_ONE corresponds to the upper-left origin of
       the window coordinate system of Microsoft Windows and the X Window System.

       There is extensive discussion of the uses and further consequences of the different clip volume settings
       in the GL_ARB_clip_control extension specification in the OpenGL Registry at URL
       http://www.opengl.org/registry/.


ERRORS
       An GL_INVALID_ENUM error is generated if origin is not GL_LOWER_LEFT or GL_UPPER_LEFT.

       An GL_INVALID_ENUM error is generated if depth is not GL_NEGATIVE_ONE_TO_ONE or GL_ZERO_TO_ONE.


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          │     │     │     │     │     │     │     │     │     │     │     │     │
       ├──────────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┤
       │glClipControl │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  -  │  ✔  │
       └──────────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┘


SEE ALSO
       gl_ClipDistance(), gl_CullDistance(), gl_FrontFacing(), glDepthRange().


       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 © 2014 Khronos Group

[FIXME: source]                                    04/26/2024                                  GLCLIPCONTROL(3G)