Expose a property in display plugins to determine if the device is visble to the user

libraries/display-plugins/src/display-plugins/OpenGLDisplayPlugin.h

@@ -29,24 +29,26 @@ protected:
     using TextureEscrow = GLEscrow<gpu::TexturePointer>;
 public:
     OpenGLDisplayPlugin();
-    virtual void activate() override;
-    virtual void deactivate() override;
-    virtual void stop() override;
-    virtual bool eventFilter(QObject* receiver, QEvent* event) override;
+    void activate() override;
+    void deactivate() override;
+    void stop() override;
+    bool eventFilter(QObject* receiver, QEvent* event) override;
+    bool isDisplayVisible() const override { return true; }
 
-    virtual void submitSceneTexture(uint32_t frameIndex, const gpu::TexturePointer& sceneTexture) override;
-    virtual void submitOverlayTexture(const gpu::TexturePointer& overlayTexture) override;
-    virtual float presentRate() override;
 
-    virtual glm::uvec2 getRecommendedRenderSize() const override {
+    void submitSceneTexture(uint32_t frameIndex, const gpu::TexturePointer& sceneTexture) override;
+    void submitOverlayTexture(const gpu::TexturePointer& overlayTexture) override;
+    float presentRate() override;
+
+    glm::uvec2 getRecommendedRenderSize() const override {
         return getSurfacePixels();
     }
 
-    virtual glm::uvec2 getRecommendedUiSize() const override {
+    glm::uvec2 getRecommendedUiSize() const override {
         return getSurfaceSize();
     }
 
-    virtual QImage getScreenshot() const override;
+    QImage getScreenshot() const override;
 
 protected:
 #if THREADED_PRESENT

libraries/display-plugins/src/display-plugins/hmd/HmdDisplayPlugin.h

@@ -22,12 +22,16 @@ public:
     glm::uvec2 getRecommendedUiSize() const override final;
     glm::uvec2 getRecommendedRenderSize() const override final { return _renderTargetSize; }
     void setEyeRenderPose(uint32_t frameIndex, Eye eye, const glm::mat4& pose) override final;
+    bool isDisplayVisible() const override { return isHmdMounted(); }
+
 
     void activate() override;
     void deactivate() override;
 
 protected:
     virtual void hmdPresent() = 0;
+    virtual bool isHmdMounted() const = 0;
+
     void compositeOverlay() override;
     void compositePointer() override;
     void internalPresent() override;

libraries/plugins/src/plugins/DisplayPlugin.h

@@ -65,6 +65,12 @@ public:
     virtual bool isThrottled() const { return false; }
     virtual float getTargetFrameRate() { return 0.0f; }
 
+    /// Returns a boolean value indicating whether the display is currently visible 
+    /// to the user.  For monitor displays, false might indicate that a screensaver,
+    /// or power-save mode is active.  For HMDs it may reflect a sensor indicating
+    /// whether the HMD is being worn
+    virtual bool isDisplayVisible() const { return false; }
+
     // Rendering support
 
     // Stop requesting renders, but don't do full deactivation

plugins/oculus/src/OculusDebugDisplayPlugin.h

@@ -17,6 +17,7 @@ public:
 
 protected:
     void hmdPresent() override {}
+    bool isHmdMounted() const override { return true; }
 
 private:
     static const QString NAME;

plugins/oculus/src/OculusDisplayPlugin.h

@@ -24,6 +24,8 @@ public:
 
 protected:
     void hmdPresent() override;
+    // FIXME update with Oculus API call once it's available in the SDK
+    bool isHmdMounted() const override { return true; }
     void customizeContext() override;
     void uncustomizeContext() override;
     void updateFrameData() override;

plugins/oculusLegacy/src/OculusLegacyDisplayPlugin.h

@@ -35,6 +35,7 @@ public:
 protected:
     virtual void customizeContext() override;
     void hmdPresent() override {}
+    bool isHmdMounted() const override { return true; }
 #if 0
     virtual void uncustomizeContext() override;
     virtual void internalPresent() override;

plugins/openvr/src/OpenVrDisplayPlugin.cpp

@@ -139,4 +139,10 @@ void OpenVrDisplayPlugin::hmdPresent() {
 
     vr::TrackedDevicePose_t currentTrackedDevicePose[vr::k_unMaxTrackedDeviceCount];
     _compositor->WaitGetPoses(currentTrackedDevicePose, vr::k_unMaxTrackedDeviceCount, nullptr, 0);
+    _hmdActivityLevel = _system->GetTrackedDeviceActivityLevel(vr::k_unTrackedDeviceIndex_Hmd);
 }
+
+bool OpenVrDisplayPlugin::isHmdMounted() const {
+    return _hmdActivityLevel == vr::k_EDeviceActivityLevel_UserInteraction;
+}
+

plugins/openvr/src/OpenVrDisplayPlugin.h

@@ -33,9 +33,11 @@ public:
 
 protected:
     void hmdPresent() override;
+    bool isHmdMounted() const override;
 
 private:
     vr::IVRSystem* _system { nullptr };
+    std::atomic<vr::EDeviceActivityLevel> _hmdActivityLevel { vr::k_EDeviceActivityLevel_Unknown };
     static const QString NAME;
     mutable Mutex _poseMutex;
 };