Implement Texture-From-Pixmap using EGLImage extensions on X11/EGL

There's lots of EGLImage extensions, split between EGL and client
rendering APIs like OpenGL ES & OpenVG. To implement texture-from-
pixmap using EGLImage, both EGL extensions and OpenGL ES extensions
are needed. This patch resolves the EGL extension function pointers
after the display is initialized in QEgl::display(). These are then
exported from QtGui so they can be used in QtOpenGL. The OpenGL ES
extension function pointers are resolved using the usual
qglextensions.cpp mechanism.

Using EGLImage seems to remove a fixed ~10 millisecond overhead per
pixmap bind when compared to using EGLSurface. Exact results per bind
for 100 QPixmaps are:

   8x8   Pixmap: 12   -> 1.71 msecs (EGLSurface -> EGLImage)
  64x64  Pixmap: 11.6 -> 1.83 msecs (EGLSurface -> EGLImage)
 128x128 Pixmap: 12.8 -> 2.74 msecs (EGLSurface -> EGLImage)
 256x256 Pixmap: 16   -> 6.20 msecs (EGLSurface -> EGLImage)

Reviewed-By: Trond

1 files changed, 36 insertions, 0 deletions

diff --git a/src/opengl/qglextensions_p.h b/src/opengl/qglextensions_p.h
index f6926f3..7597b33 100644
--- a/src/opengl/qglextensions_p.h
+++ b/src/opengl/qglextensions_p.h
@@ -68,6 +68,11 @@
 # define APIENTRYP *
 #endif
 
+#ifndef QT_NO_EGL
+// Needed for EGLImageKHR definition:
+#include <QtGui/private/qegl_p.h>
+#endif
+
 #include <QtCore/qglobal.h>
 
 #ifndef GL_ARB_vertex_buffer_object
@@ -210,6 +215,14 @@ typedef void (APIENTRY *_glFramebufferTextureFaceEXT)(GLenum target, GLenum atta
 typedef void (APIENTRY *_glCompressedTexImage2DARB) (GLenum, GLint, GLenum, GLsizei,
                                                      GLsizei, GLint, GLsizei, const GLvoid *);
 
+#ifndef QT_NO_EGL
+// OES_EGL_image
+// Note: We define these to take EGLImage whereas spec says they take a new GLeglImageOES
+//       type, which the EGL image should be cast to.
+typedef void (APIENTRY *_glEGLImageTargetTexture2DOES) (GLenum, EGLImageKHR);
+typedef void (APIENTRY *_glEGLImageTargetRenderbufferStorageOES) (GLenum, EGLImageKHR);
+#endif
+
 QT_BEGIN_NAMESPACE
 
 struct QGLExtensionFuncs
@@ -327,6 +340,12 @@ struct QGLExtensionFuncs
         // Texture compression
         qt_glCompressedTexImage2DARB = 0;
 #endif
+
+#ifndef QT_NO_EGL
+        // OES_EGL_image
+        qt_glEGLImageTargetTexture2DOES = 0;
+        qt_glEGLImageTargetRenderbufferStorageOES = 0;
+#endif
     }
 
 
@@ -447,6 +466,13 @@ struct QGLExtensionFuncs
     // Texture compression
     _glCompressedTexImage2DARB qt_glCompressedTexImage2DARB;
 #endif
+
+#ifndef QT_NO_EGL
+    // OES_EGL_image
+    _glEGLImageTargetTexture2DOES qt_glEGLImageTargetTexture2DOES;
+    _glEGLImageTargetRenderbufferStorageOES qt_glEGLImageTargetRenderbufferStorageOES;
+#endif
+
 };
 
 
@@ -839,6 +865,12 @@ struct QGLExtensionFuncs
 #define glCompressedTexImage2D QGLContextPrivate::extensionFuncs(ctx).qt_glCompressedTexImage2DARB
 #endif
 
+#ifndef QT_NO_EGL
+// OES_EGL_image
+#define glEGLImageTargetTexture2DOES QGLContextPrivate::extensionFuncs(ctx).qt_glEGLImageTargetTexture2DOES
+#define glEGLImageTargetRenderbufferStorageOES QGLContextPrivate::extensionFuncs(ctx).qt_glEGLImageTargetRenderbufferStorageOES
+#endif
+
 extern bool qt_resolve_framebufferobject_extensions(QGLContext *ctx);
 bool qt_resolve_buffer_extensions(QGLContext *ctx);
 
@@ -849,6 +881,10 @@ bool qt_resolve_frag_program_extensions(QGLContext *ctx);
 
 bool qt_resolve_glsl_extensions(QGLContext *ctx);
 
+#ifndef QT_NO_EGL
+bool qt_resolve_eglimage_gl_extensions(QGLContext *ctx);
+#endif
+
 QT_END_NAMESPACE
 
 #endif // QGL_EXTENSIONS_P_H