created an new EGL extension called ANDROID_swap_rectangle

ANDROID_swap_rectangle allows to specify the rectangle affected by eglSwapBuffers(), anything outside of this rectangle is unchanged. in particular EGL_BUFFER_DESTROYED only applies to that rectangle. This extension as well as EGL_BUFFER_PRESERVED allow major optimizations on surfaceflinger, which can redraw only the dirty area during compositing.

However, ANDROID_swap_rectangle allows further optimizations in EGL by reducing the amount of copy-back needed. ANDROID_swap_rectangle is particularily important for software implementations.

2 files changed, 25 insertions, 0 deletions

diff --git a/opengl/libs/EGL/egl.cpp b/opengl/libs/EGL/egl.cpp
index 74aed20..8c37f2e 100644
--- a/opengl/libs/EGL/egl.cpp
+++ b/opengl/libs/EGL/egl.cpp
@@ -60,6 +60,7 @@ static char const * const gExtensionString  =
         "KHR_image_base "
         "KHR_image_pixmap "
         "EGL_ANDROID_image_native_buffer "
+        "EGL_ANDROID_swap_rectangle "
         ;
 
 // ----------------------------------------------------------------------------
@@ -1568,3 +1569,23 @@ EGLBoolean eglDestroyImageKHR(EGLDisplay dpy, EGLImageKHR img)
 
      return EGL_FALSE;
 }
+
+
+// ----------------------------------------------------------------------------
+// ANDROID extensions
+// ----------------------------------------------------------------------------
+
+EGLBoolean eglSetSwapRectangleANDROID(EGLDisplay dpy, EGLSurface draw,
+        EGLint left, EGLint top, EGLint width, EGLint height)
+{
+    if (!validate_display_surface(dpy, draw))
+        return EGL_FALSE;    
+    egl_display_t const * const dp = get_display(dpy);
+    egl_surface_t const * const s = get_surface(draw);
+    if (s->cnx->hooks->egl.eglSetSwapRectangleANDROID) {
+        return s->cnx->hooks->egl.eglSetSwapRectangleANDROID(dp->dpys[s->impl],
+                s->surface, left, top, width, height);
+    }
+    return EGL_FALSE;
+}
+
diff --git a/opengl/libs/egl_entries.in b/opengl/libs/egl_entries.in
index 3b4551b..1fe2b57 100644
--- a/opengl/libs/egl_entries.in
+++ b/opengl/libs/egl_entries.in
@@ -50,3 +50,7 @@ EGL_ENTRY(EGLBoolean,  eglLockSurfaceKHR,   EGLDisplay, EGLSurface, const EGLint
 EGL_ENTRY(EGLBoolean,  eglUnlockSurfaceKHR, EGLDisplay, EGLSurface)
 EGL_ENTRY(EGLImageKHR, eglCreateImageKHR,   EGLDisplay, EGLContext, EGLenum, EGLClientBuffer, const EGLint *)
 EGL_ENTRY(EGLBoolean,  eglDestroyImageKHR,  EGLDisplay, EGLImageKHR)
+
+/* ANDROID extensions */
+
+EGL_ENTRY(EGLBoolean, eglSetSwapRectangleANDROID, EGLDisplay, EGLSurface, EGLint, EGLint, EGLint, EGLint)