vtkOpenGLExtensionManager Class Reference

#include <vtkOpenGLExtensionManager.h>

Inheritance diagram for vtkOpenGLExtensionManager:

[legend]Collaboration diagram for vtkOpenGLExtensionManager:

[legend]List of all members.

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Detailed Description

Interface class for querying and using OpenGL extensions.

vtkOpenGLExtensionManager acts as an interface to OpenGL extensions. It provides methods to query OpenGL extensions on the current or a given render window and to load extension function pointers. Currently does not support GLU extensions since the GLU library is not linked to VTK.

Before using vtkOpenGLExtensionManager, an OpenGL context must be created. This is generally done with a vtkRenderWindow. Note that simply creating the vtkRenderWindow is not sufficient. Usually you have to call Render before the actual OpenGL context is created. You can specify the RenderWindow with the SetRenderWindow method.

 vtkOpenGLExtensionManager *extensions = vtkOpenGLExtensionManager::New();
 extensions->SetRenderWindow(renwin);

If no vtkRenderWindow is specified, the current OpenGL context (if any) is used.

Generally speaking, when using OpenGL extensions, you will need an vtkOpenGLExtensionManager and the prototypes defined in vtkgl.h.

 #include "vtkOpenGLExtensionManager.h"
 #include "vtkgl.h"

The vtkgl.h include file contains all the constants and function pointers required for using OpenGL extensions in a portable and namespace safe way. vtkgl.h is built from parsed glext.h, glxext.h, and wglext.h files. Snapshots of these files are distributed with vtkSNL, but you can also set CMake options to use other files.

To use an OpenGL extension, you first need to make an instance of vtkOpenGLExtensionManager and give it a vtkRenderWindow. You can then query the vtkOpenGLExtensionManager to see if the extension is supported with the ExtensionSupported method. Valid names for extensions are given in the OpenGL extension registry at http://oss.sgi.com/projects/ogl-sample/registry/ . You can also grep vtkgl.h (which will be in the binary build directory if vtkSNL is not installed) for appropriate names. There are also special extensions GL_VERSION_X_X (where X_X is replaced with a major and minor version, respectively) which contain all the constants and functions for OpenGL versions for which the gl.h header file is of an older version than the driver.

 if (   !extensions->ExtensionSupported("GL_VERSION_1_2")
     || !extensions->ExtensionSupported("GL_ARB_multitexture") ) {
  {
    vtkErrorMacro("Required extensions not supported!");
  }

Once you have verified that the extensions you want exist, before you use them you have to loaded them with the LoadExtension method.

 extensions->LoadExtension("GL_VERSION_1_2");
 extensions->LoadExtension("GL_ARB_multitexture");

Once you have queried and loaded all of the extensions you need, you can delete the vtkExtensionManager. To use a constant of an extension, simply replace the "GL_" prefix with "vtkgl::". Likewise, replace the "gl" prefix of functions with "vtkgl::". In rare cases, an extension will add a type. In this case, add vtkgl:: to the type (i.e. vtkgl::GLchar).

 extensions->Delete();
 ...
 vtkgl::ActiveTexture(vtkgl::TEXTURE0_ARB);

For wgl extensions, replace the "WGL_" and "wgl" prefixes with "vtkwgl::". For glX extensions, replace the "GLX_" and "glX" prefixes with "vtkglX::".

Tests:

vtkOpenGLExtensionManager (Tests)

Definition at line 126 of file vtkOpenGLExtensionManager.h.

Public Types
typedef vtkObject	Superclass
Public Member Functions
virtual const char *	GetClassName ()
virtual int	IsA (const char *type)
virtual int	ExtensionSupported (const char *name)
virtual vtkOpenGLExtensionManagerFunctionPointer	GetProcAddress (const char *fname)
virtual void	LoadExtension (const char *name)
void	PrintSelf (ostream &os, vtkIndent indent)
virtual vtkRenderWindow *	GetRenderWindow ()
virtual void	SetRenderWindow (vtkRenderWindow *renwin)
virtual void	Update ()
virtual char *	GetExtensionsString ()
Static Public Member Functions
static int	IsTypeOf (const char *type)
static vtkOpenGLExtensionManager *	SafeDownCast (vtkObject *o)
static vtkOpenGLExtensionManager *	New ()
Protected Member Functions
	vtkOpenGLExtensionManager ()
virtual	~vtkOpenGLExtensionManager ()
virtual void	ReadOpenGLExtensions ()
Protected Attributes
vtkRenderWindow *	RenderWindow
char *	ExtensionsString
vtkTimeStamp	BuildTime

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Member Typedef Documentation

typedef vtkObject vtkOpenGLExtensionManager::Superclass

Reimplemented from vtkObject. Definition at line 129 of file vtkOpenGLExtensionManager.h.

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Constructor & Destructor Documentation

vtkOpenGLExtensionManager::vtkOpenGLExtensionManager (   )  [protected]

virtual vtkOpenGLExtensionManager::~vtkOpenGLExtensionManager (   )  [protected, virtual]

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Member Function Documentation

virtual const char* vtkOpenGLExtensionManager::GetClassName (   )  [virtual]

Reimplemented from vtkObject.

static int vtkOpenGLExtensionManager::IsTypeOf (  const char *  type  )  [static]

Return 1 if this class type is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeRevisionMacro found in vtkSetGet.h. Reimplemented from vtkObject.

virtual int vtkOpenGLExtensionManager::IsA (  const char *  type  )  [virtual]

Return 1 if this class is the same type of (or a subclass of) the named class. Returns 0 otherwise. This method works in combination with vtkTypeRevisionMacro found in vtkSetGet.h. Reimplemented from vtkObject.

static vtkOpenGLExtensionManager* vtkOpenGLExtensionManager::SafeDownCast (  vtkObject *  o  )  [static]

Reimplemented from vtkObject.

static vtkOpenGLExtensionManager* vtkOpenGLExtensionManager::New (   )  [static]

Create an object with Debug turned off, modified time initialized to zero, and reference counting on. Reimplemented from vtkObject.

void vtkOpenGLExtensionManager::PrintSelf (  ostream &  os, vtkIndent  indent )  [virtual]

Methods invoked by print to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes. Reimplemented from vtkObject.

virtual vtkRenderWindow* vtkOpenGLExtensionManager::GetRenderWindow (   )  [virtual]

Set/Get the render window to query extensions on. If set to null, justs queries the current render window.

virtual void vtkOpenGLExtensionManager::SetRenderWindow (  vtkRenderWindow *  renwin  )  [virtual]

virtual void vtkOpenGLExtensionManager::Update (   )  [virtual]

Updates the extensions string.

virtual char* vtkOpenGLExtensionManager::GetExtensionsString (   )  [virtual]

Returns a string listing all available extensions. Call Update first to validate this string.

virtual int vtkOpenGLExtensionManager::ExtensionSupported (  const char *  name  )  [virtual]

Returns true if the extension is supported, false otherwise.

virtual vtkOpenGLExtensionManagerFunctionPointer vtkOpenGLExtensionManager::GetProcAddress (  const char *  fname  )  [virtual]

Returns a function pointer to the OpenGL extension function with the given name. Returns NULL if the function could not be retrieved.

virtual void vtkOpenGLExtensionManager::LoadExtension (  const char *  name  )  [virtual]

Loads all the functions associated with the given extension into the appropriate static members of vtkgl.

virtual void vtkOpenGLExtensionManager::ReadOpenGLExtensions (   )  [protected, virtual]

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Member Data Documentation

vtkRenderWindow* vtkOpenGLExtensionManager::RenderWindow [protected]

Definition at line 166 of file vtkOpenGLExtensionManager.h.

char* vtkOpenGLExtensionManager::ExtensionsString [protected]

Definition at line 168 of file vtkOpenGLExtensionManager.h.

vtkTimeStamp vtkOpenGLExtensionManager::BuildTime [protected]

Definition at line 170 of file vtkOpenGLExtensionManager.h.

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The documentation for this class was generated from the following file:

• dox/Rendering/vtkOpenGLExtensionManager.h

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