egl: Inform the client API when ancillary buffers may become undefined.
This is part of the EGL spec, and is useful for a tiled renderer to avoid
the memory bandwidth cost of storing the depth/stencil buffers.
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index 2a6811c..86e5f24 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -1087,6 +1087,42 @@
return dri2_dpy->vtbl->swap_interval(drv, dpy, surf, interval);
}
+/**
+ * Asks the client API to flush any rendering to the drawable so that we can
+ * do our swapbuffers.
+ */
+void
+dri2_flush_drawable_for_swapbuffers(_EGLDisplay *disp, _EGLSurface *draw)
+{
+ struct dri2_egl_display *dri2_dpy = dri2_egl_display(disp);
+ struct dri2_egl_surface *dri2_surf = dri2_egl_surface(draw);
+
+ if (dri2_dpy->flush) {
+ if (dri2_dpy->flush->base.version >= 4) {
+ /* We know there's a current context because:
+ *
+ * "If surface is not bound to the calling thread’s current
+ * context, an EGL_BAD_SURFACE error is generated."
+ */
+ _EGLContext *ctx = _eglGetCurrentContext();
+ struct dri2_egl_context *dri2_ctx = dri2_egl_context(ctx);
+
+ /* From the EGL 1.4 spec (page 52):
+ *
+ * "The contents of ancillary buffers are always undefined
+ * after calling eglSwapBuffers."
+ */
+ dri2_dpy->flush->flush_with_flags(dri2_ctx->dri_context,
+ dri2_surf->dri_drawable,
+ __DRI2_FLUSH_DRAWABLE |
+ __DRI2_FLUSH_INVALIDATE_ANCILLARY,
+ __DRI2_THROTTLE_SWAPBUFFER);
+ } else {
+ dri2_dpy->flush->flush(dri2_surf->dri_drawable);
+ }
+ }
+}
+
static EGLBoolean
dri2_swap_buffers(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSurface *surf)
{