GlGetError: Difference between revisions

Latest revision as of 00:59, 28 January 2023

The _glGetError function returns error information.

Syntax

GLenum result = _glGetError

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.

@@ Line 1: / Line 1: @@
-'''_glGetError:''' return error information
+{{DISPLAYTITLE:_glGetError}}
+The '''_glGetError''' function returns error information.
 {{PageSyntax}}
+: GLenum {{Parameter|result}} = [[_glGetError]]
-  FUNCTION _glGetError~&
-  GLenum '''_glGetError'''({{Parameter|void}});
+{{PageParameters}}
+* 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}}
+* 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 [https://learn.microsoft.com/en-us/windows/win32/opengl/glgeterror Microsoft Docs] and is also valid for QB64 usage.
-'''_glGetError''' returns the value of the error flag. Each detectable error is assigned a numeric code and symbolic name. When an error occurs, the error flag is set to the appropriate error code value. No other errors are recorded until '''_glGetError''' is called, the error code is returned, and the flag is reset to {{KW|_GL_NO_ERROR}}. If a call to '''_glGetError''' returns {{KW|_GL_NO_ERROR}}, there has been no detectable error since the last call to '''_glGetError''', or since the GL was initialized.
-To allow for distributed implementations, there may be several error flags. If any single error flag has recorded an error, the value of that flag is returned and that flag is reset to {{KW|_GL_NO_ERROR}} when '''_glGetError''' is called. If more than one flag has recorded an error, '''_glGetError''' returns and clears an arbitrary error flag value. Thus, '''_glGetError''' should always be called in a loop, until it returns {{KW|_GL_NO_ERROR}}, if all error flags are to be reset.
+{{PageSeeAlso}}
+* [[_GL|SUB _GL]]
+* [[_glBegin]], [[_glEnd]]
-Initially, all error flags are set to {{KW|_GL_NO_ERROR}}.
-The following errors are currently defined:
+{{PageNavigation}}
-; {{KW|_GL_NO_ERROR}}
-: No error has been recorded. The value of this symbolic constant is guaranteed to be 0.
-; {{KW|_GL_INVALID_ENUM}}
-: An unacceptable value is specified for an enumerated argument. The offending command is ignored and has no other side effect than to set the error flag.
-; {{KW|_GL_INVALID_VALUE}}
-: A numeric argument is out of range. The offending command is ignored and has no other side effect than to set the error flag.
-; {{KW|_GL_INVALID_OPERATION}}
-: The specified operation is not allowed in the current state. The offending command is ignored and has no other side effect than to set the error flag.
-; {{KW|_GL_INVALID_FRAMEBUFFER_OPERATION}}
-: The framebuffer object is not complete. The offending command is ignored and has no other side effect than to set the error flag.
-; {{KW|_GL_OUT_OF_MEMORY}}
-: There is not enough memory left to execute the command. The state of the GL is undefined, except for the state of the error flags, after this error is recorded.
-; {{KW|_GL_STACK_UNDERFLOW}}
-: An attempt has been made to perform an operation that would cause an internal stack to underflow.
-; {{KW|_GL_STACK_OVERFLOW}}
-: An attempt has been made to perform an operation that would cause an internal stack to overflow.
-When an error flag is set, results of a GL operation are undefined only if {{KW|_GL_OUT_OF_MEMORY}} has occurred. In all other cases, the command generating the error is ignored and has no effect on the GL state or frame buffer contents. If the generating command returns a value, it returns 0. If '''_glGetError''' itself generates an error, it returns 0.
-{{PageCopyright}}
-Copyright 1991-2006 Silicon Graphics, Inc. Copyright 2012 Khronos Group. This document is licensed under the SGI Free Software B License. For details, see [http://oss.sgi.com/projects/FreeB/ http://oss.sgi.com/projects/FreeB/].

GlGetError: Difference between revisions

Latest revision as of 00:59, 28 January 2023

Contents

Syntax

Parameters

Description

See also

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GlGetError: Difference between revisions

Latest revision as of 00:59, 28 January 2023

Syntax

Parameters

Description

See also

Navigation menu

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