From 702da3a663372e1a477dee5fdff77a979cc8b9d5 Mon Sep 17 00:00:00 2001
From: Daosheng Mu <daoshengmu@gmail.com>
Date: Thu, 14 Nov 2019 10:32:26 -0800
Subject: [PATCH] Making Oculus Quest support haptic feedback.

---
 .../oculusvr/cpp/DeviceDelegateOculusVR.cpp   | 58 ++++++++++++++++++-
 1 file changed, 56 insertions(+), 2 deletions(-)

diff --git a/app/src/oculusvr/cpp/DeviceDelegateOculusVR.cpp b/app/src/oculusvr/cpp/DeviceDelegateOculusVR.cpp
index cab14b47d..624205a24 100644
--- a/app/src/oculusvr/cpp/DeviceDelegateOculusVR.cpp
+++ b/app/src/oculusvr/cpp/DeviceDelegateOculusVR.cpp
@@ -644,6 +644,9 @@ struct DeviceDelegateOculusVR::State {
     ovrInputTrackedRemoteCapabilities capabilities = {};
     vrb::Matrix transform = vrb::Matrix::Identity();
     ovrInputStateTrackedRemote inputState = {};
+    uint64_t inputFrameID = 0;
+    float remainingVibrateTime = 0.0f;
+    double lastHapticUpdateTimeStamp = 0.0f;
 
     bool Is6DOF() const {
       return (capabilities.ControllerCapabilities & ovrControllerCaps_HasPositionTracking) &&
@@ -689,7 +692,6 @@ struct DeviceDelegateOculusVR::State {
   device::CPULevel minCPULevel = device::CPULevel::Normal;
   device::DeviceType deviceType = device::UnknownType;
 
-
   void UpdatePerspective() {
     float fovX = vrapi_GetSystemPropertyFloat(&java, VRAPI_SYS_PROP_SUGGESTED_EYE_FOV_DEGREES_X);
     float fovY = vrapi_GetSystemPropertyFloat(&java, VRAPI_SYS_PROP_SUGGESTED_EYE_FOV_DEGREES_Y);
@@ -965,6 +967,16 @@ struct DeviceDelegateOculusVR::State {
     }
   }
 
+  double GetTimeStamp() {
+    timespec spec = {};
+    const double kNanosecondsToSeconds = 1.0e9;
+    double timeStamp = 0.0f;
+    if (clock_gettime(CLOCK_MONOTONIC, &spec) == 0) {
+      timeStamp = (double) spec.tv_sec + (spec.tv_nsec / kNanosecondsToSeconds);
+    }
+    return timeStamp;
+  }
+
   void UpdateControllers(const vrb::Matrix & head) {
     UpdateDeviceId();
     if (!controller) {
@@ -1034,7 +1046,6 @@ struct DeviceDelegateOculusVR::State {
           const bool yTouched = (controllerState.inputState.Touches & ovrTouch_Y) != 0;
           const bool menuPressed = (controllerState.inputState.Buttons & ovrButton_Enter) != 0;
 
-
           controller->SetButtonState(controllerState.index, ControllerDelegate::BUTTON_X, 3, xPressed, xTouched);
           controller->SetButtonState(controllerState.index, ControllerDelegate::BUTTON_Y, 4, yPressed, yTouched);
 
@@ -1061,6 +1072,46 @@ struct DeviceDelegateOculusVR::State {
 
         const bool thumbRest = (controllerState.inputState.Touches & ovrTouch_ThumbUp) != 0;
         controller->SetButtonState(controllerState.index, ControllerDelegate::BUTTON_OTHERS, 5, thumbRest, thumbRest);
+
+        // Only Oculus 6 DOF (Quest) has haptic feedback.
+        controller->SetHapticCount(controllerState.index, 1);
+        uint64_t  inputFrameID = 0;
+        float pulseDuration = 0.0f, pulseIntensity = 0.0f;
+        controller->GetHapticFeedback(controllerState.index, inputFrameID, pulseDuration, pulseIntensity);
+        if (inputFrameID > 0 && pulseIntensity > 0.0f && pulseDuration > 0) {
+          if (controllerState.inputFrameID != inputFrameID) {
+            // When there is a new input frame id from haptic vibration,
+            // that means we start a new session for a vibration.
+            controllerState.inputFrameID = inputFrameID;
+            controllerState.remainingVibrateTime = pulseDuration;
+            controllerState.lastHapticUpdateTimeStamp = GetTimeStamp();
+          } else {
+            // We are still running the previous vibration.
+            // So, it needs to reduce the delta time from the last vibration.
+            const double timeStamp = GetTimeStamp();
+            controllerState.remainingVibrateTime -= (timeStamp - controllerState.lastHapticUpdateTimeStamp);
+            controllerState.lastHapticUpdateTimeStamp = timeStamp;
+          }
+          if (controllerState.remainingVibrateTime > 0.0f) {
+            if (vrapi_SetHapticVibrationSimple(ovr, controllerState.index, pulseIntensity > 1.0f ? 1.0f : pulseIntensity)
+                == ovrError_InvalidOperation) {
+              VRB_ERROR("vrapi_SetHapticVibrationBuffer failed.");
+            }
+          } else {
+            // The remaining time is zero, stop the vibration.
+            if (vrapi_SetHapticVibrationSimple(ovr, controllerState.index, 0.0f) == ovrError_InvalidOperation) {
+              VRB_ERROR("vrapi_SetHapticVibrationBuffer failed.");
+            }
+            controllerState.remainingVibrateTime = 0.0f;
+          }
+        } else if (controllerState.remainingVibrateTime > 0.0f) {
+          // While the haptic feedback is terminated from the client side,
+          // but it still have remaining time, we need to ask for stopping vibration.
+          if (vrapi_SetHapticVibrationSimple(ovr, controllerState.index, 0.0f) == ovrError_InvalidOperation) {
+            VRB_ERROR("vrapi_SetHapticVibrationBuffer failed.");
+          }
+          controllerState.remainingVibrateTime = 0.0f;
+        }
       } else {
         triggerPressed = (controllerState.inputState.Buttons & ovrButton_A) != 0;
         triggerTouched = triggerPressed;
@@ -1084,6 +1135,9 @@ struct DeviceDelegateOculusVR::State {
         }
         axes[0] = trackpadTouched ? trackpadX * 2.0f - 1.0f : 0.0f;
         axes[1] = trackpadTouched ? trackpadY * 2.0f - 1.0f : 0.0f;
+
+        // Oculus Go has no haptic feedback.
+        controller->SetHapticCount(controllerState.index, 0);
       }
       controller->SetButtonState(controllerState.index, ControllerDelegate::BUTTON_TRIGGER, 1, triggerPressed, triggerTouched,
                                  controllerState.inputState.IndexTrigger);