GlAccum: Difference between revisions

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{{DISPLAYTITLE:_glAccum}}
{{DISPLAYTITLE:_glAccum}}
The [[_glAccum]] statement operates on the accumulation buffer.
The '''_glAccum''' statement operates on the accumulation buffer.




{{PageSyntax}}
{{PageSyntax}}
: [[SUB]] [[_glAccum]] ({{Parameter|op}} [[AS]] [[_UNSIGNED]] [[LONG]], {{Parameter|value}} [[AS]] [[SINGLE]])
: [[_glAccum]] GLenum {{Parameter|op}}, GLfloat {{Parameter|value}}




{{PageParameters}}
{{PageParameters}}
* OpenGL has many predefined attributes and values, which are used with its command parameters. These are detailed in the respective description.
* 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]].
{{OpenGLTypesPlugin}}




{{PageDescription}}
{{PageDescription}}
* The syntax above shall just clarify the type of the command ([[SUB]] or [[FUNCTION]]) and the correct QB64 [[Variable Types]] to use for the respective parameters.
* OpenGL's documentation is available in several places, so we won't reproduce it here for another time.
* The full description can be found at [https://docs.microsoft.com/en-us/windows/win32/opengl/glaccum Microsoft Docs] and is also valid for QB64.
* The full description for this command can be found at [https://learn.microsoft.com/en-us/windows/win32/opengl/glaccum Microsoft Docs] and is also valid for QB64 usage.




{{PageSeeAlso}}
{{PageSeeAlso}}
* [[_GL|SUB _GL]]
* [[_GL|SUB _GL]]
* [[_glBegin]], [[_glBlendFunc]], [[_glClear]], [[_glClearAccum]]
* [[_glCopyPixels]], [[_glEnd]], [https://learn.microsoft.com/en-us/windows/win32/opengl/glgetbooleanv--glgetdoublev--glgetfloatv--glgetintegerv _glGet], [[_glLogicOp]]
* [https://learn.microsoft.com/en-us/windows/win32/opengl/glpixelstore-functions _glPixelStore], [https://learn.microsoft.com/en-us/windows/win32/opengl/glpixeltransfer _glPixelTransfer], [[_glReadBuffer]], [[_glReadPixels]]
* [[_glScissor]], [[_glStencilOp]]
{{PageNavigation}}

Latest revision as of 00:33, 28 January 2023

The _glAccum statement operates on the accumulation buffer.


Syntax

_glAccum GLenum op, GLfloat value


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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