Package org.lwjgl.egl

Class KHRDisplayReference

java.lang.Object

org.lwjgl.egl.KHRDisplayReference

public class KHRDisplayReference
extends java.lang.Object

Native bindings to the KHR_display_reference extension.

The existing semantics of EGLDisplay object lifetimes work well for applications in which one module manages all EGL usage, and in which EGL displays are expected to remain available until application termination once they are instantiated. However, EGL does not provide reasonable semantics in the case where applications rely on toolkit libraries which use EGL independently from the application itself.

This issue can be solved by adding a per-EGLDisplay reference counter which is incremented by Initialize calls. Resource destruction can then be deferred until a corresponding number of Terminate calls is made. However, switching to this behavior universally could cause backwards incompatibility problems with existing applications that assume a single eglTerminate will immediately free resources regardless of how many times the display has been initialized.

We therefore must support both behaviors. A new attribute specified when the EGLDisplay is obtained will indicate whether or not reference counting is enabled. If an application requests the EGLDisplay multiple times with different values for this attribute, two separate displays will be returned. The one potential drawaback is that these displays will have independent resource spaces, so objects allocated from one cannot be used by the other. However, the goal here is to support modules that access EGL independently. In such a use case, they are not likely to need to share resources with another module, particularly one that uses a different method for accessing the display.

Requires EXT_platform_base or EGL 1.5

Field Summary

Fields

Modifier and Type	Field	Description
static int	EGL_TRACK_REFERENCES_KHR	Accepted as an attribute in the attrib_list parameter of GetPlatformDisplay and the name parameter of QueryDisplayAttribKHR.

Method Summary

Modifier and Type	Method	Description
static boolean	eglQueryDisplayAttribKHR(long dpy, int name, PointerBuffer value)
static int	neglQueryDisplayAttribKHR(long dpy, int name, long value)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EGL_TRACK_REFERENCES_KHR

public static final int EGL_TRACK_REFERENCES_KHR

Accepted as an attribute in the attrib_list parameter of GetPlatformDisplay and the name parameter of QueryDisplayAttribKHR.

See Also:

Constant Field Values

Method Detail

neglQueryDisplayAttribKHR

public static int neglQueryDisplayAttribKHR(long dpy,
                                            int name,
                                            long value)

eglQueryDisplayAttribKHR

public static boolean eglQueryDisplayAttribKHR(long dpy,
                                               int name,
                                               PointerBuffer value)