GlDrawArrays: Difference between revisions

Latest revision as of 00:50, 28 January 2023

The _glDrawArrays statement specifies multiple primitives to render.

Syntax

_glDrawArrays GLenum mode, GLint first, GLsizei count

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: @@
-'''_glDrawArrays:''' render primitives from array data
+{{DISPLAYTITLE:_glDrawArrays}}
+The '''_glDrawArrays''' statement specifies multiple primitives to render.
 {{PageSyntax}}
+: [[_glDrawArrays]] GLenum {{Parameter|mode}}, GLint {{Parameter|first}}, GLsizei {{Parameter|count}}
-::  SUB _glDrawArrays (BYVAL mode AS _UNSIGNED LONG, BYVAL first AS LONG, BYVAL count AS LONG)
-::  void '''_glDrawArrays'''(GLenum {{Parameter|mode}}, GLint {{Parameter|first}}, GLsizei {{Parameter|count}});
+{{PageParameters}}
-; mode
+* OpenGL is using its own set of variable types to describe its command parameters.
-: Specifies what kind of primitives to render. Symbolic constants {{KW|_GL_POINTS}}, {{KW|_GL_LINE_STRIP}}, {{KW|_GL_LINE_LOOP}}, {{KW|_GL_LINES}}, {{KW|_GL_LINE_STRIP_ADJACENCY}}, {{KW|_GL_LINES_ADJACENCY}}, {{KW|_GL_TRIANGLE_STRIP}}, {{KW|_GL_TRIANGLE_FAN}}, {{KW|_GL_TRIANGLES}}, {{KW|_GL_TRIANGLE_STRIP_ADJACENCY}}, {{KW|_GL_TRIANGLES_ADJACENCY}} and {{KW|_GL_PATCHES}} are accepted.
+* Use the following table to find the respective QB64 [[Variable Types]].
-; first
+{{OpenGLTypesPlugin}}
-: Specifies the starting index in the enabled arrays.
-; count
-: Specifies the number of indices to be rendered.
 {{PageDescription}}
+* OpenGL's documentation is available in several places, so we won't reproduce it here for another time.
-'''_glDrawArrays''' specifies multiple geometric primitives with very few subroutine calls. Instead of calling a GL procedure to pass each individual vertex, normal, texture coordinate, edge flag, or color, you can prespecify separate arrays of vertices, normals, and colors and use them to construct a sequence of primitives with a single call to '''_glDrawArrays'''.
+* The full description for this command can be found at [https://learn.microsoft.com/en-us/windows/win32/opengl/gldrawarrays Microsoft Docs] and is also valid for QB64 usage.
-When '''_glDrawArrays''' is called, it uses {{Parameter|count}} sequential elements from each enabled array to construct a sequence of geometric primitives, beginning with element {{Parameter|first}}. {{Parameter|mode}} specifies what kind of primitives are constructed and how the array elements construct those primitives.
-Vertex attributes that are modified by '''_glDrawArrays''' have an unspecified value after '''_glDrawArrays''' returns. Attributes that aren't modified remain well defined.
-{{PageNotes}}
-{{KW|_GL_LINE_STRIP_ADJACENCY}}, {{KW|_GL_LINES_ADJACENCY}}, {{KW|_GL_TRIANGLE_STRIP_ADJACENCY}} and {{KW|_GL_TRIANGLES_ADJACENCY}} are available only if the GL version is 3.2 or greater.
-{{PageErrors}}
-{{KW|_GL_INVALID_ENUM}} is generated if {{Parameter|mode}} is not an accepted value.
-{{KW|_GL_INVALID_VALUE}} is generated if {{Parameter|count}} is negative.
-{{KW|_GL_INVALID_OPERATION}} is generated if a non-zero buffer object name is bound to an enabled array and the buffer object's data store is currently mapped.
-{{KW|_GL_INVALID_OPERATION}} is generated if a geometry shader is active and {{Parameter|mode}} is incompatible with the input primitive type of the geometry shader in the currently installed program object.
 {{PageSeeAlso}}
+* [[_GL|SUB _GL]]
-[[_GL|SUB _GL]]
+* [[_glArrayElement]], [[_glBegin]], [[_glColorPointer]], [[_glEdgeFlagPointer]]
-{{KW|_glBindVertexArray}}, {{KW|_glDrawArraysIndirect}}, {{KW|_glDrawArraysInstanced}}, {{KW|_glDrawArraysInstancedBaseInstance}}, {{KW|_glMultiDrawArrays}}, {{KW|_glMultiDrawArraysIndirect}}
+* [[_glEnd]], [[_glGetPointerv]], [[_glGetString]], [[_glIndexPointer]]
+* [[_glNormalPointer]], [[_glTexCoordPointer]], [[_glVertexPointer]]
-{{PageCopyright}}
+{{PageNavigation}}

GlDrawArrays: Difference between revisions

Latest revision as of 00:50, 28 January 2023

Contents

Syntax

Parameters

Description

See also

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GlDrawArrays: Difference between revisions

Latest revision as of 00:50, 28 January 2023

Syntax

Parameters

Description

See also

Navigation menu

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