GPU Display: Better handling of key presses from the console

Author: davidrohr

GPU/GPUTracking/Global/GPUChainTracking.cxx

@@ -861,10 +861,7 @@ int32_t GPUChainTracking::RunChainFinalize()
         } else if (iKey == 'n') {
           break;
         } else if (iKey) {
-          while (GetProcessingSettings().eventDisplay->getSendKey() != 0) {
-            usleep(1000);
-          }
-          GetProcessingSettings().eventDisplay->setSendKey(iKey);
+          GetProcessingSettings().eventDisplay->sendKey(iKey);
         }
       }
     } while (GetProcessingSettings().eventDisplay->getDisplayControl() == 0);

GPU/GPUTracking/display/GPUDisplayInterface.h

@@ -59,10 +59,9 @@ class GPUDisplayFrontendInterface
   virtual void DisplayExit() = 0;
   virtual bool EnableSendKey() = 0;
   virtual int32_t getDisplayControl() const = 0;
-  virtual int32_t getSendKey() const = 0;
   virtual void setDisplayControl(int32_t v) = 0;
   virtual bool IsRunning() const = 0;
-  virtual void setSendKey(int32_t v) = 0;
+  virtual void sendKey(int32_t v) = 0;
   virtual const char* frontendName() const = 0;
 
  protected:

GPU/GPUTracking/display/frontend/GPUDisplayFrontend.cxx

@@ -81,12 +81,19 @@ void GPUDisplayFrontend::waitForFPSLimit()
   std::this_thread::sleep_until(mNextFrameTime);
 }
 
-void GPUDisplayFrontend::HandleSendKey()
+void GPUDisplayFrontend::HandleSendKeys()
 {
-  if (mSendKey) {
-    mDisplay->HandleSendKey(mSendKey);
-    mSendKey = 0;
+  std::lock_guard lock(mSendKeyMutex);
+  for (auto key : mSendKeys) {
+    mDisplay->HandleSendKey(key);
   }
+  mSendKeys.clear();
+}
+
+void GPUDisplayFrontend::sendKey(int32_t v)
+{
+  std::lock_guard lock(mSendKeyMutex);
+  mSendKeys.emplace_back(v);
 }
 
 void GPUDisplayFrontend::HandleKey(uint8_t key) { mDisplay->HandleKey(key); }

GPU/GPUTracking/display/frontend/GPUDisplayFrontend.h

@@ -19,6 +19,8 @@
 #include "GPUDisplayInterface.h"
 #include <memory>
 #include <chrono>
+#include <mutex>
+#include <vector>
 
 namespace o2::gpu
 {
@@ -64,9 +66,8 @@ class GPUDisplayFrontend : public GPUDisplayFrontendInterface
   virtual uint32_t getReqVulkanExtensions(const char**& p) { return 0; };
 
   int32_t getDisplayControl() const override { return mDisplayControl; }
-  int32_t getSendKey() const override { return mSendKey; }
   void setDisplayControl(int32_t v) override { mDisplayControl = v; }
-  void setSendKey(int32_t v) override { mSendKey = v; }
+  void sendKey(int32_t v) override;
 
   frontendTypes frontendType() const { return mFrontendType; }
   const char* frontendName() const override { return mFrontendName; }
@@ -75,11 +76,6 @@ class GPUDisplayFrontend : public GPUDisplayFrontendInterface
   void stopGUI();
   bool isGUIRunning();
 
-  // volatile variables to exchange control informations between display and backend
-  volatile int32_t mDisplayControl = 0; // Control for next event (=1) or quit (=2)
-  volatile int32_t mSendKey = 0;        // Key sent by external entity (usually console), may be ignored by backend.
-  volatile int32_t mNeedUpdate = 0;     // flag that backend shall update the GL window, and call DrawGLScene
-
  protected:
   virtual int32_t FrontendMain() = 0;
   static void* FrontendThreadWrapper(void*);
@@ -118,6 +114,12 @@ class GPUDisplayFrontend : public GPUDisplayFrontendInterface
   static constexpr int32_t KEY_END = 29;
   static constexpr int32_t KEY_SPACE = 32; // fixed at 32
 
+  // volatile variables to exchange control informations between display and backend
+  volatile int32_t mDisplayControl = 0; // Control for next event (=1) or quit (=2)
+  volatile int32_t mNeedUpdate = 0;     // flag that backend shall update the GL window, and call DrawGLScene
+  std::mutex mSendKeyMutex;
+  std::vector<int32_t> mSendKeys; // Keys sent by external entity (usually console), may be ignored by backend.
+
   // Keyboard / Mouse actions
   bool mMouseDn = false;          // Mouse button down
   bool mMouseDnR = false;         // Right mouse button down
@@ -143,7 +145,7 @@ class GPUDisplayFrontend : public GPUDisplayFrontendInterface
 
   void HandleKey(uint8_t key);                     // Callback for handling key presses
   int32_t DrawGLScene();                           // Callback to draw the GL scene
-  void HandleSendKey();                            // Optional callback to handle key press from external source (e.g. stdin by default)
+  void HandleSendKeys();                           // Optional callback to handle key press from external source (e.g. stdin by default)
   void ResizeScene(int32_t width, int32_t height); // Callback when GL window is resized
   int32_t InitDisplay(bool initFailure = false);   // Callback to initialize the GL Display (to be called in StartDisplay)
   void ExitDisplay();                              // Callback to clean up the GL Display

GPU/GPUTracking/display/frontend/GPUDisplayFrontendGlfw.cxx

@@ -296,7 +296,7 @@ int32_t GPUDisplayFrontendGlfw::FrontendMain()
   }
 
   while (!glfwWindowShouldClose(mWindow)) {
-    HandleSendKey();
+    HandleSendKeys();
     if (DrawGLScene()) {
       fprintf(stderr, "Error drawing GL scene\n");
       return (1);

GPU/GPUTracking/display/frontend/GPUDisplayFrontendGlut.cxx

@@ -41,7 +41,7 @@ void GPUDisplayFrontendGlut::displayFunc() // TODO: Functions should be lambdas,
 
 void GPUDisplayFrontendGlut::glutLoopFunc()
 {
-  me->HandleSendKey();
+  me->HandleSendKeys();
   displayFunc();
 }
 

GPU/GPUTracking/display/frontend/GPUDisplayFrontendNone.cxx

@@ -30,7 +30,7 @@ int32_t GPUDisplayFrontendNone::FrontendMain()
   do {
     DrawGLScene();
     waitForFPSLimit();
-    HandleSendKey();
+    HandleSendKeys();
   } while (mDisplayControl != 2);
   return 0;
 }

GPU/GPUTracking/display/frontend/GPUDisplayFrontendWayland.cxx

@@ -414,7 +414,7 @@ int32_t GPUDisplayFrontendWayland::FrontendMain()
     if (wl_display_dispatch_pending(mWayland) == -1 || mDisplayControl == 2) {
       break;
     }
-    HandleSendKey();
+    HandleSendKeys();
     DrawGLScene();
     waitForFPSLimit();
     wl_surface_damage(mSurface, 0, 0, mDisplayWidth, mDisplayHeight);

GPU/GPUTracking/display/frontend/GPUDisplayFrontendX11.cxx

@@ -334,7 +334,7 @@ int32_t GPUDisplayFrontendX11::FrontendMain()
       if (mDisplayControl == 2) {
         break;
       }
-      HandleSendKey();
+      HandleSendKeys();
       if (!XPending(mDisplay)) {
         event.type = Expose;
       } else {