[Mesa-dev] [PATCH] EGL/Android: Add EGL_EXT_buffer_age extension

[Xiaosong Wei]

This patch implements the EGL_EXT_buffer_age extension for Android.
https://www.khronos.org/registry/EGL/extensions/EXT/EGL_EXT_buffer_age.txt
---
 src/egl/drivers/dri2/egl_dri2.h         |  9 ++++++
 src/egl/drivers/dri2/platform_android.c | 51 ++++++++++++++++++++++++++++++++-
 2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/src/egl/drivers/dri2/egl_dri2.h b/src/egl/drivers/dri2/egl_dri2.h
index f3d09dc..992e5b3 100644
--- a/src/egl/drivers/dri2/egl_dri2.h
+++ b/src/egl/drivers/dri2/egl_dri2.h
@@ -295,6 +295,15 @@ struct dri2_egl_surface
 
    /* EGL-owned buffers */
    __DRIbuffer           *local_buffers[__DRI_BUFFER_COUNT];
+
+   /* Used to record all the buffers created by ANativeWindow and their ages.
+    * Usually Android uses at most triple buffers in ANativeWindow
+    * so hardcode the number of color_buffers to 3.
+    */
+   struct {
+      struct ANativeWindowBuffer *buffer;
+      int age;
+   } color_buffers[3], *back;
 #endif
 
 #if defined(HAVE_SURFACELESS_PLATFORM)
diff --git a/src/egl/drivers/dri2/platform_android.c b/src/egl/drivers/dri2/platform_android.c
index 79fe81a..109b419 100644
--- a/src/egl/drivers/dri2/platform_android.c
+++ b/src/egl/drivers/dri2/platform_android.c
@@ -165,6 +165,33 @@ droid_window_dequeue_buffer(struct dri2_egl_surface *dri2_surf)
    dri2_surf->window->lockBuffer(dri2_surf->window, dri2_surf->buffer);
 #endif
 
+   /* Record all the buffers created by ANativeWindow and update back buffer
+    * for updating buffer's age in swap_buffers.
+    */
+   EGLBoolean updated = EGL_FALSE;
+   for (int i = 0; i < ARRAY_SIZE(dri2_surf->color_buffers); i++) {
+      if (!dri2_surf->color_buffers[i].buffer) {
+         dri2_surf->color_buffers[i].buffer = dri2_surf->buffer;
+      }
+      if (dri2_surf->color_buffers[i].buffer == dri2_surf->buffer) {
+         dri2_surf->back = &dri2_surf->color_buffers[i];
+         updated = EGL_TRUE;
+         break;
+      }
+   }
+
+   if (!updated) {
+      /* In case of all the buffers were recreated by ANativeWindow, reset
+       * the color_buffers
+       */
+      for (int i = 0; i < ARRAY_SIZE(dri2_surf->color_buffers); i++) {
+         dri2_surf->color_buffers[i].buffer = NULL;
+         dri2_surf->color_buffers[i].age = 0;
+      }
+      dri2_surf->color_buffers[0].buffer = dri2_surf->buffer;
+      dri2_surf->back = &dri2_surf->color_buffers[0];
+   }
+
    return EGL_TRUE;
 }
 
@@ -201,6 +228,7 @@ droid_window_enqueue_buffer(_EGLDisplay *disp, struct dri2_egl_surface *dri2_sur
 
    dri2_surf->buffer->common.decRef(&dri2_surf->buffer->common);
    dri2_surf->buffer = NULL;
+   dri2_surf->back = NULL;
 
    mtx_lock(&disp->Mutex);
 
@@ -547,6 +575,20 @@ droid_image_get_buffers(__DRIdrawable *driDrawable,
    return 1;
 }
 
+static EGLint
+droid_query_buffer_age(_EGLDriver *drv,
+                          _EGLDisplay *disp, _EGLSurface *surface)
+{
+   struct dri2_egl_surface *dri2_surf = dri2_egl_surface(surface);
+
+   if (update_buffers(dri2_surf) < 0) {
+      _eglError(EGL_BAD_ALLOC, "droid_query_buffer_age");
+      return 0;
+   }
+
+   return dri2_surf->back->age;
+}
+
 static EGLBoolean
 droid_swap_buffers(_EGLDriver *drv, _EGLDisplay *disp, _EGLSurface *draw)
 {
@@ -556,6 +598,12 @@ droid_swap_buffers(_EGLDriver *drv, _EGLDisplay *disp, _EGLSurface *draw)
    if (dri2_surf->base.Type != EGL_WINDOW_BIT)
       return EGL_TRUE;
 
+   for (int i = 0; i < ARRAY_SIZE(dri2_surf->color_buffers); i++) {
+      if (dri2_surf->color_buffers[i].age > 0)
+         dri2_surf->color_buffers[i].age++;
+   }
+   dri2_surf->back->age = 1;
+
    dri2_flush_drawable_for_swapbuffers(disp, draw);
 
    if (dri2_surf->buffer)
@@ -989,7 +1037,7 @@ static struct dri2_egl_display_vtbl droid_display_vtbl = {
    .swap_buffers_region = dri2_fallback_swap_buffers_region,
    .post_sub_buffer = dri2_fallback_post_sub_buffer,
    .copy_buffers = dri2_fallback_copy_buffers,
-   .query_buffer_age = dri2_fallback_query_buffer_age,
+   .query_buffer_age = droid_query_buffer_age,
    .query_surface = droid_query_surface,
    .create_wayland_buffer_from_image = dri2_fallback_create_wayland_buffer_from_image,
    .get_sync_values = dri2_fallback_get_sync_values,
@@ -1080,6 +1128,7 @@ dri2_initialize_android(_EGLDriver *drv, _EGLDisplay *dpy)
    dpy->Extensions.ANDROID_framebuffer_target = EGL_TRUE;
    dpy->Extensions.ANDROID_image_native_buffer = EGL_TRUE;
    dpy->Extensions.ANDROID_recordable = EGL_TRUE;
+   dpy->Extensions.EXT_buffer_age = EGL_TRUE;
 
    /* Fill vtbl last to prevent accidentally calling virtual function during
     * initialization.
-- 
1.9.1