Corrected which_fb behavior when frames are dropped

Author: j005u

jni/hw/dji_display.c

@@ -276,14 +276,16 @@ void dji_display_open_framebuffer_injected(dji_display_state_t *display_state, d
     }
 }
 
-void dji_display_push_frame(dji_display_state_t *display_state, uint8_t which_fb) {
+uint8_t dji_display_push_frame(dji_display_state_t *display_state, uint8_t which_fb) {
     duss_frame_buffer_t *fb = which_fb ? display_state->fb_1 : display_state->fb_0;
     duss_hal_mem_sync(fb->buffer, 1);
     if (display_state->frame_waiting == 0) {
         display_state->frame_waiting = 1;
         duss_hal_display_push_frame(display_state->disp_instance_handle, display_state->plane_id, fb);
+        return !which_fb;
     } else {
         DEBUG_PRINT("!!! Dropped frame due to pending frame push!\n");
+        return which_fb;
     }
 }
 

jni/hw/dji_display.h

@@ -20,7 +20,7 @@ typedef struct dji_display_state_s {
     uint8_t frame_waiting;
 } dji_display_state_t;
 
-void dji_display_push_frame(dji_display_state_t *display_state, uint8_t which_fb);
+uint8_t dji_display_push_frame(dji_display_state_t *display_state, uint8_t which_fb);
 void dji_display_open_framebuffer(dji_display_state_t *display_state, duss_disp_plane_id_t plane_id);
 void dji_display_open_framebuffer_injected(dji_display_state_t *display_state, duss_disp_instance_handle_t *disp, duss_hal_obj_handle_t ion_handle, duss_disp_plane_id_t plane_id);
 void dji_display_close_framebuffer(dji_display_state_t *display_state);

jni/osd_dji_overlay_udp.c

@@ -252,8 +252,7 @@ static void render_screen() {
     if (display_mode == DISPLAY_DISABLED) {
         clear_framebuffer();
     }
-    dji_display_push_frame(dji_display, which_fb);
-    which_fb = !which_fb;
+    which_fb = dji_display_push_frame(dji_display, which_fb);
     DEBUG_PRINT("drew a frame\n");
     clock_gettime(CLOCK_MONOTONIC, &last_render);
 }