Package org.gnome.gdk

Class GLContext

java.lang.Object

io.github.jwharm.javagi.base.ProxyInstance

org.gnome.gobject.TypeInstance

org.gnome.gobject.GObject

org.gnome.gdk.DrawContext

org.gnome.gdk.GLContext

All Implemented Interfaces:

Proxy

Direct Known Subclasses:

GLContext.GLContextImpl

@Generated("io.github.jwharm.JavaGI")
public abstract class GLContext
extends DrawContext

GdkGLContext is an object representing a platform-specific OpenGL draw context.

GdkGLContexts are created for a surface using Surface.createGlContext(), and the context will match the characteristics of the surface.

A GdkGLContext is not tied to any particular normal framebuffer. For instance, it cannot draw to the surface back buffer. The GDK repaint system is in full control of the painting to that. Instead, you can create render buffers or textures and use Gdk.cairoDrawFromGl(org.freedesktop.cairo.Context, org.gnome.gdk.Surface, int, int, int, int, int, int, int) in the draw function of your widget to draw them. Then GDK will handle the integration of your rendering with that of other widgets.

Support for GdkGLContext is platform-specific and context creation can fail, returning null context.

A GdkGLContext has to be made "current" in order to start using it, otherwise any OpenGL call will be ignored.

Creating a new OpenGL context
In order to create a new GdkGLContext instance you need a GdkSurface, which you typically get during the realize call of a widget.

A GdkGLContext is not realized until either makeCurrent() or realize() is called. It is possible to specify details of the GL context like the OpenGL version to be used, or whether the GL context should have extra state validation enabled after calling Surface.createGlContext() by calling realize(). If the realization fails you have the option to change the settings of the GdkGLContext and try again.

Using a GdkGLContext
You will need to make the GdkGLContext the current context before issuing OpenGL calls; the system sends OpenGL commands to whichever context is current. It is possible to have multiple contexts, so you always need to ensure that the one which you want to draw with is the current one before issuing commands:

gdk_gl_context_make_current (context);
 

You can now perform your drawing using OpenGL commands.

You can check which GdkGLContext is the current one by using getCurrent(); you can also unset any GdkGLContext that is currently set by calling clearCurrent().

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	GLContext.Builder<B extends GLContext.Builder<B>>	Inner class implementing a builder pattern to construct a GObject with properties.
static class	GLContext.GLContextImpl	The GLContextImpl type represents a native instance of the abstract GLContext class.

Nested classes/interfaces inherited from class org.gnome.gdk.DrawContext

DrawContext.DrawContextImpl

Nested classes/interfaces inherited from class org.gnome.gobject.GObject

GObject.NotifyCallback, GObject.ObjectClass

Constructor Summary

Constructors

Constructor	Description
GLContext(MemorySegment address)	Create a GLContext proxy instance for the provided memory address.

Method Summary

Modifier and Type	Method	Description
protected GLContext	asParent()	Returns this instance as if it were its parent type.
static GLContext.Builder<? extends GLContext.Builder>	builder()	A GLContext.Builder object constructs a GLContext with the specified properties.
static void	clearCurrent()	Clears the current GdkGLContext.
Set<GLAPI>	getAllowedApis()	Gets the allowed APIs set via gdk_gl_context_set_allowed_apis().
Set<GLAPI>	getApi()	Gets the API currently in use.
static GLContext	getCurrent()	Retrieves the current GdkGLContext.
boolean	getDebugEnabled()	Retrieves whether the context is doing extra validations and runtime checking.
Display	getDisplay()	Retrieves the display the this GLContext is created for
boolean	getForwardCompatible()	Retrieves whether the context is forward-compatible.
void	getRequiredVersion(@Nullable Out<Integer> major, @Nullable Out<Integer> minor)	Retrieves required OpenGL version set as a requirement for the this GLContext realization.
GLContext	getSharedContext()	Deprecated. Use isShared(org.gnome.gdk.GLContext) to check if contexts can be shared.
Surface	getSurface()	Retrieves the surface used by the this GLContext.
static Type	getType()	Get the GType of the GLContext class
boolean	getUseEs()	Checks whether the this GLContext is using an OpenGL or OpenGL ES profile.
void	getVersion(Out<Integer> major, Out<Integer> minor)	Retrieves the OpenGL version of the this GLContext.
boolean	isLegacy()	Whether the GdkGLContext is in legacy mode or not.
boolean	isShared(GLContext other)	Checks if the two GL contexts can share resources.
void	makeCurrent()	Makes the this GLContext the current one.
boolean	realize()	Realizes the given GdkGLContext.
void	setAllowedApis(Set<GLAPI> apis)	Sets the allowed APIs.
void	setAllowedApis(GLAPI... apis)	Sets the allowed APIs.
void	setDebugEnabled(boolean enabled)	Sets whether the GdkGLContext should perform extra validations and runtime checking.
void	setForwardCompatible(boolean compatible)	Sets whether the GdkGLContext should be forward-compatible.
void	setRequiredVersion(int major, int minor)	Sets the major and minor version of OpenGL to request.
void	setUseEs(int useEs)	Requests that GDK create an OpenGL ES context instead of an OpenGL one.

Methods inherited from class org.gnome.gdk.DrawContext

beginFrame, endFrame, getFrameRegion, isInFrame

Methods inherited from class org.gnome.gobject.GObject

addToggleRef, addWeakPointer, bindProperty, bindProperty, bindProperty, bindPropertyFull, bindPropertyFull, bindPropertyWithClosures, bindPropertyWithClosures, compatControl, connect, connect, connect, constructed, disconnect, dispatchPropertiesChanged, dispose, dupData, dupQdata, emit, emitNotify, finalize_, forceFloating, freezeNotify, get, getData, getMemoryLayout, getProperty, getProperty, getProperty, getQdata, getv, interfaceFindProperty, interfaceInstallProperty, interfaceListProperties, isFloating, newInstance, newInstance, newInstance, newInstance, newv, notify_, notify_, notifyByPspec, onNotify, ref, refSink, removeToggleRef, removeWeakPointer, replaceData, replaceQdata, runDispose, set, setData, setDataFull, setProperty, setProperty, setProperty, setQdata, setQdataFull, setv, stealData, stealQdata, takeRef, thawNotify, unref, watchClosure, weakRef, weakUnref, withProperties

Methods inherited from class org.gnome.gobject.TypeInstance

callParent, callParent, getPrivate, readGClass, writeGClass

Methods inherited from class io.github.jwharm.javagi.base.ProxyInstance

equals, handle, hashCode

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

GLContext

public GLContext(MemorySegment address)

Create a GLContext proxy instance for the provided memory address.

Parameters:

address - the memory address of the native object

Method Details

getType

public static Type getType()

Get the GType of the GLContext class

Returns:

the GType

asParent

protected GLContext asParent()

Returns this instance as if it were its parent type. This is mostly synonymous to the Java super keyword, but will set the native typeclass function pointers to the parent type. When overriding a native virtual method in Java, "chaining up" with super.methodName() doesn't work, because it invokes the overridden function pointer again. To chain up, call asParent().methodName(). This will call the native function pointer of this virtual method in the typeclass of the parent type.

Overrides:

asParent in class DrawContext

clearCurrent

public static void clearCurrent()

Clears the current GdkGLContext.

Any OpenGL call after this function returns will be ignored until makeCurrent() is called.

getCurrent

public static GLContext getCurrent()

Retrieves the current GdkGLContext.

Returns:

the current GdkGLContext

getAllowedApis

public Set<GLAPI> getAllowedApis()

Gets the allowed APIs set via gdk_gl_context_set_allowed_apis().

Returns:

the allowed APIs

getApi

public Set<GLAPI> getApi()

Gets the API currently in use.

If the renderer has not been realized yet, 0 is returned.

Returns:

the currently used API

getDebugEnabled

public boolean getDebugEnabled()

Retrieves whether the context is doing extra validations and runtime checking.

See setDebugEnabled(boolean).

Returns:

true if debugging is enabled

getDisplay

public Display getDisplay()

Retrieves the display the this GLContext is created for

Overrides:

getDisplay in class DrawContext

Returns:

a GdkDisplay

getForwardCompatible

public boolean getForwardCompatible()

Retrieves whether the context is forward-compatible.

See setForwardCompatible(boolean).

Returns:

true if the context should be forward-compatible

getRequiredVersion

public void getRequiredVersion(@Nullable
 @Nullable Out<Integer> major,
 @Nullable
 @Nullable Out<Integer> minor)

Retrieves required OpenGL version set as a requirement for the this GLContext realization. It will not change even if a greater OpenGL version is supported and used after the this GLContext is realized. See getVersion(io.github.jwharm.javagi.base.Out<java.lang.Integer>, io.github.jwharm.javagi.base.Out<java.lang.Integer>) for the real version in use.

See setRequiredVersion(int, int).

Parameters:

major - return location for the major version to request

minor - return location for the minor version to request

getSharedContext

@Deprecated
public GLContext getSharedContext()

Deprecated.

Use isShared(org.gnome.gdk.GLContext) to check if contexts can be shared.

Used to retrieves the GdkGLContext that this this GLContext share data with.

As many contexts can share data now and no single shared context exists anymore, this function has been deprecated and now always returns null.

Returns:

null

getSurface

public Surface getSurface()

Retrieves the surface used by the this GLContext.

Overrides:

getSurface in class DrawContext

Returns:

a GdkSurface

getUseEs

public boolean getUseEs()

Checks whether the this GLContext is using an OpenGL or OpenGL ES profile.

Returns:

true if the GdkGLContext is using an OpenGL ES profile; false if other profile is in use of if the this GLContext has not yet been realized.

getVersion

public void getVersion(Out<Integer> major,
 Out<Integer> minor)

Retrieves the OpenGL version of the this GLContext.

The this GLContext must be realized prior to calling this function.

Parameters:

major - return location for the major version

minor - return location for the minor version

isLegacy

public boolean isLegacy()

Whether the GdkGLContext is in legacy mode or not.

The GdkGLContext must be realized before calling this function.

When realizing a GL context, GDK will try to use the OpenGL 3.2 core profile; this profile removes all the OpenGL API that was deprecated prior to the 3.2 version of the specification. If the realization is successful, this function will return false.

If the underlying OpenGL implementation does not support core profiles, GDK will fall back to a pre-3.2 compatibility profile, and this function will return true.

You can use the value returned by this function to decide which kind of OpenGL API to use, or whether to do extension discovery, or what kind of shader programs to load.

Returns:

true if the GL context is in legacy mode

isShared

public boolean isShared(GLContext other)

Checks if the two GL contexts can share resources.

When they can, the texture IDs from other can be used in this GLContext. This is particularly useful when passing GdkGLTexture objects between different contexts.

Contexts created for the same display with the same properties will always be compatible, even if they are created for different surfaces. For other contexts it depends on the GL backend.

Both contexts must be realized for this check to succeed. If either one is not, this function will return false.

Parameters:

other - the GdkGLContext that should be compatible with this GLContext

Returns:

true if the two GL contexts are compatible.

makeCurrent

public void makeCurrent()

Makes the this GLContext the current one.

realize

public boolean realize()
                throws GErrorException

Realizes the given GdkGLContext.

It is safe to call this function on a realized GdkGLContext.

Returns:

true if the context is realized

Throws:

GErrorException - see GError

setAllowedApis

public void setAllowedApis(Set<GLAPI> apis)

Sets the allowed APIs. When gdk_gl_context_realize() is called, only the allowed APIs will be tried. If you set this to 0, realizing will always fail.

If you set it on a realized context, the property will not have any effect. It is only relevant during gdk_gl_context_realize().

By default, all APIs are allowed.

Parameters:

apis - the allowed APIs

setAllowedApis

public void setAllowedApis(GLAPI... apis)

Sets the allowed APIs. When gdk_gl_context_realize() is called, only the allowed APIs will be tried. If you set this to 0, realizing will always fail.

If you set it on a realized context, the property will not have any effect. It is only relevant during gdk_gl_context_realize().

By default, all APIs are allowed.

Parameters:

apis - the allowed APIs

setDebugEnabled

public void setDebugEnabled(boolean enabled)

Sets whether the GdkGLContext should perform extra validations and runtime checking.

This is useful during development, but has additional overhead.

The GdkGLContext must not be realized or made current prior to calling this function.

Parameters:

enabled - whether to enable debugging in the context

setForwardCompatible

public void setForwardCompatible(boolean compatible)

Sets whether the GdkGLContext should be forward-compatible.

Forward-compatible contexts must not support OpenGL functionality that has been marked as deprecated in the requested version; non-forward compatible contexts, on the other hand, must support both deprecated and non deprecated functionality.

The GdkGLContext must not be realized or made current prior to calling this function.

Parameters:

compatible - whether the context should be forward-compatible

setRequiredVersion

public void setRequiredVersion(int major,
 int minor)

Sets the major and minor version of OpenGL to request.

Setting major and minor to zero will use the default values.

Setting major and minor lower than the minimum versions required by GTK will result in the context choosing the minimum version.

The this GLContext must not be realized or made current prior to calling this function.

Parameters:

major - the major version to request

minor - the minor version to request

setUseEs

public void setUseEs(int useEs)

Requests that GDK create an OpenGL ES context instead of an OpenGL one.

Not all platforms support OpenGL ES.

The this GLContext must not have been realized.

By default, GDK will attempt to automatically detect whether the underlying GL implementation is OpenGL or OpenGL ES once the this GLContext is realized.

You should check the return value of getUseEs() after calling realize() to decide whether to use the OpenGL or OpenGL ES API, extensions, or shaders.

Parameters:

useEs - whether the context should use OpenGL ES instead of OpenGL, or -1 to allow auto-detection

builder

public static GLContext.Builder<? extends GLContext.Builder> builder()

A GLContext.Builder object constructs a GLContext with the specified properties. Use the various set...() methods to set properties, and finish construction with GLContext.Builder.build().