Fix pre-loop encoder cleanup

Author: floppyhammer

demo/android/app/src/main/cpp/native_engine.cpp

@@ -90,5 +90,7 @@ bool NativeEngine::init_app(bool use_vulkan) {
 
     init_app_common(window_size);
 
+    pf_queue->wait_idle();
+
     return true;
 }

demo/native/main.cpp

@@ -40,6 +40,9 @@ int main() {
         blit->set_texture(dst_texture);
     }
 
+    // Make sure encoders submitted are all finished before the main loop starts and the ring buffers starts to work.
+    queue->wait_idle();
+
     // Main loop.
     while (!window->should_close()) {
         window_builder->poll_events();

pathfinder/gpu/queue.h

@@ -21,6 +21,8 @@ class Queue {
 
     virtual void begin_frame(uint32_t current_frame_index) {}
 
+    virtual void wait_idle() {}
+
 protected:
     uint32_t current_frame_index_{};
 };

pathfinder/gpu/vk/queue.cpp

@@ -55,4 +55,8 @@ void QueueVk::begin_frame(uint32_t current_frame_index) {
     encoders_in_flight_[current_frame_index_ % frames_in_flight_].clear();
 }
 
+void QueueVk::wait_idle() {
+    vkQueueWaitIdle(vk_graphics_queue_);
+}
+
 } // namespace Pathfinder

pathfinder/gpu/vk/queue.h

@@ -14,6 +14,8 @@ class QueueVk : public Queue {
 
     void begin_frame(uint32_t current_frame_index) override;
 
+    void wait_idle() override;
+
 private:
     VkDevice vk_device_{};