EGLWLInputEventExample: modify WaitforEvent to read the socket

it is not enough to dispatch the pending events in the mainloop.
Event should be also read from the socket with wl_display_read_events
call. This Implementation also avoids the busy loop in main.c, because
WaitforEvent function waits at poll() till an event comes to the socket.

Signed-off-by: Emre Ucan <eucan@de.adit-jv.com>

3 files changed, 37 insertions, 5 deletions

diff --git a/ivi-layermanagement-examples/EGLWLInputEventExample/include/WLEyesRenderer.h b/ivi-layermanagement-examples/EGLWLInputEventExample/include/WLEyesRenderer.h
index e630ecc..ea76110 100644
--- a/ivi-layermanagement-examples/EGLWLInputEventExample/include/WLEyesRenderer.h
+++ b/ivi-layermanagement-examples/EGLWLInputEventExample/include/WLEyesRenderer.h
@@ -27,7 +27,7 @@
 bool InitRenderer();
 bool InitShader();
 bool InitVertexBuffer();
-void WaitForEvent(struct wl_display* wlDisplay);
+void WaitForEvent(struct wl_display* wlDisplay, int fd);
 void TerminateRenderer();
 
 // Pointer event handler
diff --git a/ivi-layermanagement-examples/EGLWLInputEventExample/src/WLEyesRenderer.cpp b/ivi-layermanagement-examples/EGLWLInputEventExample/src/WLEyesRenderer.cpp
index e21f347..a4f6c11 100644
--- a/ivi-layermanagement-examples/EGLWLInputEventExample/src/WLEyesRenderer.cpp
+++ b/ivi-layermanagement-examples/EGLWLInputEventExample/src/WLEyesRenderer.cpp
@@ -24,6 +24,7 @@
 #include "WLEGLSurface.h"
 #include "WLEyes.h"
 #include "WLEyesRenderer.h"
+#include <poll.h>
 
 #define WL_UNUSED(A) (A)=(A)
 
@@ -55,9 +56,39 @@ const struct wl_touch_listener TouchListener = {
     TouchHandleCancel,
 };
 
-void WaitForEvent(struct wl_display* wlDisplay)
+void WaitForEvent(struct wl_display* wlDisplay, int fd)
 {
-    wl_display_dispatch_pending(wlDisplay);
+    int err;
+
+    /* Execute every pending event in the display and stop any other thread from placing
+    * events into this display */
+    while (wl_display_prepare_read(wlDisplay) != 0) {
+        wl_display_dispatch_pending(wlDisplay);
+    }
+
+    if (wl_display_flush(wlDisplay) == -1)
+    {
+        err = wl_display_get_error(wlDisplay);
+        printf("Error communicating with wayland: %d",err);
+        return;
+    }
+
+    /*Wait till an event occurs */
+    struct pollfd pfd[1];
+    pfd[0].fd = fd;
+    pfd[0].events = POLLIN;
+    int pollret = poll(pfd, 1, -1);
+
+    if (pollret != -1 && (pfd[0].revents & POLLIN))
+    {
+        /* Read the upcoming events from the file descriptor and execute them */
+        wl_display_read_events(wlDisplay);
+        wl_display_dispatch_pending(wlDisplay);
+    }
+    else {
+        /*Unblock other threads, if an error happens */
+        wl_display_cancel_read(wlDisplay);
+    }
 }
 
 //////////////////////////////////////////////////////////////////////////////
diff --git a/ivi-layermanagement-examples/EGLWLInputEventExample/src/main.cpp b/ivi-layermanagement-examples/EGLWLInputEventExample/src/main.cpp
index f1b29a1..20c611f 100644
--- a/ivi-layermanagement-examples/EGLWLInputEventExample/src/main.cpp
+++ b/ivi-layermanagement-examples/EGLWLInputEventExample/src/main.cpp
@@ -79,6 +79,8 @@ int main(int argc, char **argv)
     wlContext = new WLContext();
     wlContext->InitWLContext(&PointerListener, &KeyboardListener, &TouchListener);
 
+    int const fd = wl_display_get_fd(wlContext->GetWLDisplay());
+
     ilmClient_init((t_ilm_nativedisplay)wlContext->GetWLDisplay());
 
     eglSurface = new WLEGLSurface(wlContext);
@@ -100,12 +102,11 @@ int main(int argc, char **argv)
     gRunLoop = 1;
     gNeedRedraw = 0;
     while (gRunLoop){
-        WaitForEvent(wlContext->GetWLDisplay());
+        WaitForEvent(wlContext->GetWLDisplay(), fd);
         if (gNeedRedraw && gRunLoop){
             DrawEyes(eglSurface, eyes);
             gNeedRedraw = 0;
         }
-        usleep(50);
     }
 
     TerminateRenderer();