GlCullFace: Difference between revisions

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(Created page with "'''_glCullFace:''' specify whether front- or back-facing facets can be culled {{PageSyntax}} ::SUB '''_glCullFace''' (BYVAL mode AS _UNSIGNED LONG) :: void '''_glCullFace'''(GLenum {{Parameter|mode}}); ; mode : Specifies whether front- or back-facing facets are candidates for culling. Symbolic constants {{KW|_GL_FRONT}}, {{KW|_GL_BACK}}, and {{KW|_GL_FRONT_AND_BACK}} are accepted. The initial value is {{KW|_GL_BACK}}. {{PageDescription}} '''_glCullFace''' specifi...")
 
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'''_glCullFace:''' specify whether front- or back-facing facets can be culled
{{DISPLAYTITLE:_glCullFace}}
The '''_glCullFace''' statement specifies whether front-facing or back-facing facets can be culled.




{{PageSyntax}}
{{PageSyntax}}
: [[_glCullFace]] GLenum {{Parameter|mode}}


::SUB '''_glCullFace''' (BYVAL mode AS _UNSIGNED LONG)
:: void '''_glCullFace'''(GLenum {{Parameter|mode}});


 
{{PageParameters}}
; mode
* OpenGL is using its own set of variable types to describe its command parameters.
: Specifies whether front- or back-facing facets are candidates for culling. Symbolic constants {{KW|_GL_FRONT}}, {{KW|_GL_BACK}}, and {{KW|_GL_FRONT_AND_BACK}} are accepted. The initial value is {{KW|_GL_BACK}}.
* Use the following table to find the respective QB64 [[Variable Types]].
{{OpenGLTypesPlugin}}




{{PageDescription}}
{{PageDescription}}
 
* OpenGL's documentation is available in several places, so we won't reproduce it here for another time.
'''_glCullFace''' specifies whether front- or back-facing facets are culled (as specified by ''mode'') when facet culling is enabled. Facet culling is initially disabled. To enable and disable facet culling, call the {{KW|_glEnable}} and {{KW|_glDisable}} commands with the argument {{KW|_GL_CULL_FACE}}. Facets include triangles, quadrilaterals, polygons, and rectangles.
* The full description for this command can be found at [https://learn.microsoft.com/en-us/windows/win32/opengl/glcullface Microsoft Docs] and is also valid for QB64 usage.
 
{{KW|_glFrontFace}} specifies which of the clockwise and counterclockwise facets are front-facing and back-facing. See {{KW|_glFrontFace}}.
 
 
{{PageNotes}}
 
If {{Parameter|mode}} is {{KW|_GL_FRONT_AND_BACK}}, no facets are drawn, but other primitives such as points and lines are drawn.
 
 
{{PageErrors}}
 
{{KW|_GL_INVALID_ENUM}} is generated if {{Parameter|mode}} is not an accepted value.
 
 
{{PageUseWith}}
 
{{KW|_glIsEnabled}} with argument {{KW|_GL_CULL_FACE}}
 
{{KW|_glGet}} with argument {{KW|_GL_CULL_FACE_MODE}}




{{PageSeeAlso}}
{{PageSeeAlso}}
 
* [[_GL|SUB _GL]]
[[_GL|SUB _GL]]
* [[_glBegin]], [[_glDisable]], [[_glEnable]], [[_glEnd]]
{{KW|_glEnable|(GL_CULL_FACE)}}, {{KW|_glFrontFace}}
* [[_glFrontFace]], [https://learn.microsoft.com/en-us/windows/win32/opengl/glgetbooleanv--glgetdoublev--glgetfloatv--glgetintegerv _glGet], [[_glIsEnabled]]




{{PageCopyright}}
{{PageNavigation}}

Latest revision as of 00:48, 28 January 2023

The _glCullFace statement specifies whether front-facing or back-facing facets can be culled.


Syntax

_glCullFace GLenum mode


Parameters

  • OpenGL is using its own set of variable types to describe its command parameters.
  • Use the following table to find the respective QB64 Variable Types.
   Table 2: Relations between the OpenGL variable types vs. C/C++ and QB64.
 ┌──────────────┬────────────────┬──────────────────────────────────────────┐
 │    OpenGL    │     C/C++      │     QB64                                 │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLenum       │ unsigned int   │ _UNSIGNED LONG                           │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLboolean    │ unsigned char  │ _UNSIGNED _BYTE                          │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLbitfield   │ unsigned int   │ _UNSIGNED LONG                           │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLbyte       │ signed char    │ _BYTE                                    │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLshort      │ short          │ INTEGER                                  │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLint        │ int            │ LONG                                     │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLsizei      │ int            │ LONG                                     │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLubyte      │ unsigned char  │ _UNSIGNED _BYTE                          │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLushort     │ unsigned short │ _UNSIGNED INTEGER                        │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLuint       │ unsigned int   │ _UNSIGNED LONG                           │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLfloat      │ float          │ SINGLE                                   │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLclampf     │ float          │ SINGLE                                   │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLdouble     │ double         │ DOUBLE                                   │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLclampd     │ double         │ DOUBLE                                   │
 ├──────────────┼────────────────┼──────────────────────────────────────────┤
 │ GLvoid   (1) │ void           │ _OFFSET(any fixed lenght string or _BYTE │
 │              │                │         array element)                   │
 └──────────────┴────────────────┴──────────────────────────────────────────┘
 Note: If a parameter has an asterisk (*) in front, then it's a pointer to
       the designated OpenGL variable type, rather than a value of that type.
       Those must be passed using the _OFFSET(...) notation.

 E.g.  GLuint *anyParam is actually the offset of a _UNSIGNED LONG (~&)
       variable or array, which must be passed as _OFFSET(anyVar~&) or
       _OFFSET(anyArr~&()) respectively.

  (1)  This type is regularly only used for pointers (with asterisk (*)) to
       any byte sized memory data, hence _BYTE or fixed length strings.


Description

  • OpenGL's documentation is available in several places, so we won't reproduce it here for another time.
  • The full description for this command can be found at Microsoft Docs and is also valid for QB64 usage.


See also


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