handle buttons

main.c

@@ -83,6 +83,16 @@ int main(void) {
     IntMasterEnable();
 
     while (true) {
+        // handle buttons
+        Button button = (Button) 0;
+        while (fifo_get(&button)) {
+            switch (button) {
+                case S2:
+                    drawRequested = 1;
+                    break;
+            }
+        }
+
         GrContextForegroundSet(&sContext, ClrBlack);
         GrRectFill(&sContext, &rectFullScreen); // fill screen with black