void OpenVrDisplayPlugin::beginFrameRender(uint32_t frameIndex) {
double displayFrequency = _system->GetFloatTrackedDeviceProperty(vr::k_unTrackedDeviceIndex_Hmd, vr::Prop_DisplayFrequency_Float);
double frameDuration = 1.f / displayFrequency;
double vsyncToPhotons = _system->GetFloatTrackedDeviceProperty(vr::k_unTrackedDeviceIndex_Hmd, vr::Prop_SecondsFromVsyncToPhotons_Float);
FrameInfo frame;
#if THREADED_PRESENT
// 3 frames of prediction + vsyncToPhotons = 44ms total
const double NUM_PREDICTION_FRAMES = 3.0f;
frame.predictedDisplayTime = NUM_PREDICTION_FRAMES * frameDuration + vsyncToPhotons;
#else
frame.predictedDisplayTime = frameDuration + vsyncToPhotons;
#endif
vr::TrackedDevicePose_t predictedTrackedDevicePose[vr::k_unMaxTrackedDeviceCount];
_system->GetDeviceToAbsoluteTrackingPose(vr::TrackingUniverseStanding, frame.predictedDisplayTime, predictedTrackedDevicePose, vr::k_unMaxTrackedDeviceCount);
// copy and process predictedTrackedDevicePoses
for (int i = 0; i < vr::k_unMaxTrackedDeviceCount; i++) {
_trackedDevicePose[i] = predictedTrackedDevicePose[i];
_trackedDevicePoseMat4[i] = _sensorResetMat * toGlm(_trackedDevicePose[i].mDeviceToAbsoluteTracking);
_trackedDeviceLinearVelocities[i] = transformVectorFast(_sensorResetMat, toGlm(_trackedDevicePose[i].vVelocity));
_trackedDeviceAngularVelocities[i] = transformVectorFast(_sensorResetMat, toGlm(_trackedDevicePose[i].vAngularVelocity));
}
frame.headPose = _trackedDevicePoseMat4[0];
_currentRenderFrameInfo.set(frame);
Lock lock(_mutex);
_frameInfos[frameIndex] = frame;
}
glm::mat4 OpenVrDisplayPlugin::getHeadPose(uint32_t frameIndex) const {
float displayFrequency = _system->GetFloatTrackedDeviceProperty(vr::k_unTrackedDeviceIndex_Hmd, vr::Prop_DisplayFrequency_Float);
float frameDuration = 1.f / displayFrequency;
float vsyncToPhotons = _system->GetFloatTrackedDeviceProperty(vr::k_unTrackedDeviceIndex_Hmd, vr::Prop_SecondsFromVsyncToPhotons_Float);
#if THREADED_PRESENT
// TODO: this seems awfuly long, 44ms total, but it produced the best results.
const float NUM_PREDICTION_FRAMES = 3.0f;
float predictedSecondsFromNow = NUM_PREDICTION_FRAMES * frameDuration + vsyncToPhotons;
#else
uint64_t frameCounter;
float timeSinceLastVsync;
_system->GetTimeSinceLastVsync(&timeSinceLastVsync, &frameCounter);
float predictedSecondsFromNow = 3.0f * frameDuration - timeSinceLastVsync + vsyncToPhotons;
#endif
vr::TrackedDevicePose_t predictedTrackedDevicePose[vr::k_unMaxTrackedDeviceCount];
_system->GetDeviceToAbsoluteTrackingPose(vr::TrackingUniverseSeated, predictedSecondsFromNow, predictedTrackedDevicePose, vr::k_unMaxTrackedDeviceCount);
// copy and process predictedTrackedDevicePoses
for (int i = 0; i < vr::k_unMaxTrackedDeviceCount; i++) {
_trackedDevicePose[i] = predictedTrackedDevicePose[i];
_trackedDevicePoseMat4[i] = _sensorResetMat * toGlm(_trackedDevicePose[i].mDeviceToAbsoluteTracking);
_trackedDeviceLinearVelocities[i] = transformVectorFast(_sensorResetMat, toGlm(_trackedDevicePose[i].vVelocity));
_trackedDeviceAngularVelocities[i] = transformVectorFast(_sensorResetMat, toGlm(_trackedDevicePose[i].vAngularVelocity));
}
return _trackedDevicePoseMat4[0];
}
Pose Pose::transform(const glm::mat4& mat) const {
auto rot = glmExtractRotation(mat);
Pose pose(transformPoint(mat, translation),
rot * rotation,
transformVectorFast(mat, velocity),
rot * angularVelocity);
pose.valid = valid;
return pose;
}
