Initial support for VR headsets

doc/getting_started/running_experiments.md

@@ -139,3 +139,52 @@ eeg_device = EEG(device=board_name)
 # Run stimulus presentation
 n170.present(duration=record_duration, eeg=eeg_device, save_fn=save_fn)
 ```
+
+
+## Using virtual reality
+
+### Heads up display
+
+A heads-up display can be used for presenting experiments in a similar way to a monitor, without much modification.
+
+#### Features to be added in future releases:
+
+* Controller input
+* Controller haptic feedback
+
+### Prerequisites:
+* Oculus Rift compatible VR headset, e.g. Oculus Rift or Meta Quest series.
+* Native Windows installation with meta link compatible video card.
+* EEG device, e.g. OpenBCI Cyton or Muse
+
+If an experiment has the use_vr argument in its present method, it can have its stimulus presented to a subject's VR headset.
+The N170 experiment for example, can have its stimulus displayed on the VR headset with a simple modification to the 'use_vr' argument, when presenting an experiment:
+
+```python
+# Run stimulus presentation with VR enabled.
+n170.present(duration=record_duration, eeg=eeg_device, save_fn=save_fn, use_vr=True)
+```
+
+### 
+
+### Steps for running experiment in VR
+
+1. Launch the Oculus app on the Windows computer and the IDE or CLI to be used for running the experiment.
+2. Turn on the VR headset and put it on your head to make sure it is on and active, then take it off.
+3. Go to the 'Devices' view in the Oculus app, it will show the headset as connected and active, along with any inactive or connected controllers.
+4. Go to the 'Settings' view, under the 'Beta' title, enable 'Pass through over Oculus Link', double tapping the headset later with a fingertip will activate passthrough.
+5. Put the VR headset onto the head, activate passthrough to help with wearing the eeg device.
+6. Place the EEG device on top of the head.
+7. Ensure the electrodes are touching the scalp ok and not being blocked by the headset strap.
+8. From inside the VR headset's 'quick settings' dashboard, select 'Quest Link' and connect to the Oculus server running on windows, via air link or link cable.
+9. Once the Oculus menu has finished loading on the VR headset, open the built-in Oculus desktop app by using the touch controllers or gamepad.
+10. Try opening an eeg device raw data viwer and verify that the electrodes are receiving a good signal without too much noise, eg 'OpenBCI GUI'.
+11. Run the EEG-ExPy experiment from the command line or IDE, it should load and take control from the Oculus desktop app.
+12. Follow the experiment instructions, and press a key if necessary to begin the experiment and collect valid data.
+
+### Other experiments can have VR added too.
+
+1. Load/prepare stimulus in the same function as previously (def load_stimulus(self))
+2. Present stimulus in the same function as previously(def present_stimulus(self, current_trial: int))
+3. VR can be enabled for the experiment as part of the initializer to the base Experiment class, by default it is not enabled(use_vr=False) and will function the same as previously before VR functionality was added.
+

eegnb/experiments/Experiment.py

@@ -8,30 +8,36 @@
 obj.run()
 """
 
-from abc import ABC, abstractmethod
+from abc import abstractmethod
+from typing import Callable
 from psychopy import prefs
 #change the pref libraty to PTB and set the latency mode to high precision
 prefs.hardware['audioLib'] = 'PTB'
 prefs.hardware['audioLatencyMode'] = 3
 
-import os
 from time import time
-from glob import glob
-from random import choice
-from optparse import OptionParser
 import random
 
 import numpy as np
 from pandas import DataFrame
-from psychopy import visual, core, event
+from psychopy import visual, event
 
 from eegnb import generate_save_fn
-from eegnb.devices.eeg import EEG
+
 
 class BaseExperiment:
 
-    def __init__(self, exp_name, duration, eeg, save_fn, n_trials, iti, soa, jitter):
-        """ Initializer for the Base Experiment Class """
+    def __init__(self, exp_name, duration, eeg, save_fn, n_trials: int, iti: float, soa: float, jitter: float,
+                 use_vr=False):
+        """ Initializer for the Base Experiment Class
+
+        Args:
+            n_trials (int): Number of trials/stimulus
+            iti (float): Inter-trial interval
+            soa (float): Stimulus on arrival
+            jitter (float): Random delay between stimulus
+            use_vr (bool): Use VR for displaying stimulus
+        """
 
         self.exp_name = exp_name
         self.instruction_text = """\nWelcome to the {} experiment!\nStay still, focus on the centre of the screen, and try not to blink. \nThis block will run for %s seconds.\n
@@ -43,7 +49,8 @@ def __init__(self, exp_name, duration, eeg, save_fn, n_trials, iti, soa, jitter)
         self.iti = iti
         self.soa = soa
         self.jitter = jitter
-
+        self.use_vr = use_vr
+
     @abstractmethod
     def load_stimulus(self):
         """ 
@@ -76,7 +83,9 @@ def setup(self, instructions=True):
         self.trials = DataFrame(dict(parameter=self.parameter, timestamp=np.zeros(self.n_trials)))
 
         # Setting up Graphics 
-        self.window = visual.Window([1600, 900], monitor="testMonitor", units="deg", fullscr=True) 
+        self.window = (
+            visual.Rift(monoscopic=True, headLocked=True) if self.use_vr
+            else visual.Window([1600, 900], monitor="testMonitor", units="deg", fullscr=True))
 
         # Loading the stimulus from the specific experiment, throws an error if not overwritten in the specific experiment
         self.stim = self.load_stimulus()
@@ -112,20 +121,36 @@ def show_instructions(self):
         # Disabling the cursor during display of instructions
         self.window.mouseVisible = False
 
-        # Displaying the instructions on the screen
-        text = visual.TextStim(win=self.window, text=self.instruction_text, color=[-1, -1, -1])
+        # Waiting for the user to press the spacebar to start the experiment
+        while len(event.getKeys(keyList="space")) == 0:
+            # Displaying the instructions on the screen
+            text = visual.TextStim(win=self.window, text=self.instruction_text, color=[-1, -1, -1])
+            self.__draw(lambda: self.__draw_instructions(text))
+
+            # Enabling the cursor again
+            self.window.mouseVisible = True
+
+    def __draw_instructions(self, text):
         text.draw()
         self.window.flip()
-
-        # Waiting for the user to press the spacebar to start the experiment
-        event.waitKeys(keyList="space")
 
-        # Enabling the cursor again
-        self.window.mouseVisible = True
-
+    def __draw(self, present_stimulus: Callable):
+        """
+        Set the current eye position and projection for all given stimulus,
+        then draw all stimulus and flip the window/buffer
+         """
+        if self.use_vr:
+            tracking_state = self.window.getTrackingState()
+            self.window.calcEyePoses(tracking_state.headPose.thePose)
+            self.window.setDefaultView()
+        present_stimulus()
+
     def run(self, instructions=True):
         """ Do the present operation for a bunch of experiments """
 
+        def iti_with_jitter():
+            return self.iti + np.random.rand() * self.jitter
+
         # Setup the experiment, alternatively could get rid of this line, something to think about
         self.setup(instructions)
 
@@ -137,29 +162,38 @@ def run(self, instructions=True):
 
         print("EEG Stream started")
 
+        # Run trial until a key is pressed or experiment duration has expired.
         start = time()
-
-        # Iterate through the events
-        for ii, trial in self.trials.iterrows():
-
-            # Intertrial interval
-            core.wait(self.iti + np.random.rand() * self.jitter)
-
-            # Stimulus presentation overwritten by specific experiment
-            self.present_stimulus(ii, trial)
-
-            # Offset
-            core.wait(self.soa)
-            self.window.flip()
-
-            # Exiting the loop condition, looks ugly and needs to be fixed
-            if len(event.getKeys()) > 0 or (time() - start) > self.record_duration:
-                break
-
-            # Clearing the screen for the next trial    
-            event.clearEvents()
-
-        # Closing the EEG stream 
+        current_trial = current_trial_end = -1
+        current_trial_begin = None
+
+        # Current trial being rendered
+        rendering_trial = -1
+        while len(event.getKeys()) == 0 and (time() - start) < self.record_duration:
+
+            current_experiment_seconds = time() - start
+            # Do not present stimulus until current trial begins(Adhere to inter-trial interval).
+            if current_trial_end < current_experiment_seconds:
+                current_trial += 1
+                current_trial_begin = current_experiment_seconds + iti_with_jitter()
+                current_trial_end = current_trial_begin + self.soa
+
+            # Do not present stimulus after trial has ended(stimulus on arrival interval).
+            elif current_trial_begin < current_experiment_seconds:
+
+                # if current trial number changed get new choice of image.
+                if rendering_trial < current_trial:
+                    # Some form of presenting the stimulus - sometimes order changed in lower files like ssvep
+                    # Stimulus presentation overwritten by specific experiment
+                    self.__draw(lambda: self.present_stimulus(current_trial, current_trial))
+                    rendering_trial = current_trial
+            else:
+                self.__draw(lambda: self.window.flip())
+
+        # Clearing the screen for the next trial
+        event.clearEvents()
+
+        # Closing the EEG stream
         if self.eeg:
             self.eeg.stop()
 

eegnb/experiments/visual_n170/n170.py

@@ -9,11 +9,6 @@
 from time import time
 from glob import glob
 from random import choice
-from optparse import OptionParser
-import random
-
-import numpy as np
-from pandas import DataFrame
 from psychopy import visual, core, event
 
 from eegnb.devices.eeg import EEG
@@ -27,12 +22,12 @@ class VisualN170(Experiment.BaseExperiment):
 
     def __init__(self, duration=120, eeg: Optional[EEG]=None, save_fn=None,
 
-            n_trials = 2010, iti = 0.4, soa = 0.3, jitter = 0.2):
+            n_trials = 2010, iti = 0.4, soa = 0.3, jitter = 0.2, use_vr = False):
 
         # Set experiment name        
         exp_name = "Visual N170"
         # Calling the super class constructor to initialize the experiment variables
-        super(VisualN170, self).__init__(exp_name, duration, eeg, save_fn, n_trials, iti, soa, jitter)
+        super(VisualN170, self).__init__(exp_name, duration, eeg, save_fn, n_trials, iti, soa, jitter, use_vr)
 
     def load_stimulus(self):
 

eegnb/experiments/visual_p300/p300.py

@@ -21,10 +21,10 @@ class VisualP300(Experiment.BaseExperiment):
 
     def __init__(self, duration=120, eeg: Optional[EEG]=None, save_fn=None,
 
-            n_trials = 2010, iti = 0.4, soa = 0.3, jitter = 0.2):
+            n_trials = 2010, iti = 0.4, soa = 0.3, jitter = 0.2, use_vr = False):
 
         exp_name = "Visual P300"
-        super().__init__(exp_name, duration, eeg, save_fn, n_trials, iti, soa, jitter)
+        super().__init__(exp_name, duration, eeg, save_fn, n_trials, iti, soa, jitter, use_vr)
 
     def load_stimulus(self):
 

eegnb/experiments/visual_ssvep/ssvep.py

@@ -17,18 +17,20 @@
 
 class VisualSSVEP(Experiment.BaseExperiment):
 
-    def __init__(self, duration=120, eeg: Optional[EEG]=None, save_fn=None, n_trials = 2010, iti = 0.5, soa = 3.0, jitter = 0.2):
+    def __init__(self, duration=120, eeg: Optional[EEG]=None, save_fn=None, n_trials = 2010, iti = 0.5, soa = 3.0, jitter = 0.2, use_vr=False):
 
+        self.use_vr = use_vr
         exp_name = "Visual SSVEP"
-        super().__init__(exp_name, duration, eeg, save_fn, n_trials, iti, soa, jitter)
+        super().__init__(exp_name, duration, eeg, save_fn, n_trials, iti, soa, jitter, use_vr)
 
     def load_stimulus(self):
 
-        self.grating = visual.GratingStim(win=self.window, mask="circle", size=80, sf=0.2)
+        grating_sf = 400 if self.use_vr else 0.2
+        self.grating = visual.GratingStim(win=self.window, mask="circle", size=80, sf=grating_sf)
+        self.grating_neg = visual.GratingStim(win=self.window, mask="circle", size=80, sf=grating_sf, phase=0.5)
 
-        self.grating_neg = visual.GratingStim(win=self.window, mask="circle", size=80, sf=0.2, phase=0.5)
-
-        fixation = visual.GratingStim(win=self.window, size=0.2, pos=[0, 0], sf=0.2, color=[1, 0, 0], autoDraw=True)
+        self.fixation = visual.GratingStim(win=self.window, pos=[0, 0], sf=grating_sf, color=[1, 0, 0])
+        self.fixation.size = 0.02 if self.use_vr else 0.2
 
         # Generate the possible ssvep frequencies based on monitor refresh rate
         def get_possible_ssvep_freqs(frame_rate, stim_type="single"):
@@ -65,7 +67,10 @@ def init_flicker_stim(frame_rate, cycle, soa):
             return {"cycle": cycle, "freq": stim_freq, "n_cycles": n_cycles}
 
         # Set up stimuli
-        frame_rate = np.round(self.window.getActualFrameRate())  # Frame rate, in Hz
+
+        # Frame rate, in Hz
+        # GetActualFrameRate() crashes in psychxr due to 'EndFrame called before BeginFrame'
+        frame_rate = np.round(self.window.displayRefreshRate if self.use_vr else self.window.getActualFrameRate())
         freqs = get_possible_ssvep_freqs(frame_rate, stim_type="reversal")
         self.stim_patterns = [
         init_flicker_stim(frame_rate, 2, self.soa),
@@ -102,14 +107,22 @@ def present_stimulus(self, idx, trial):
 
         # Present flickering stim
         for _ in range(int(self.stim_patterns[ind]["n_cycles"])):
-            self.grating.setAutoDraw(True)
+
             for _ in range(int(self.stim_patterns[ind]["cycle"][0])):
+                if self.use_vr:
+                    tracking_state = self.window.getTrackingState()
+                    self.window.calcEyePoses(tracking_state.headPose.thePose)
+                    self.window.setDefaultView()
+                self.grating.draw()
+                self.fixation.draw()
                 self.window.flip()
-            self.grating.setAutoDraw(False)
-            self.grating_neg.setAutoDraw(True)
+
             for _ in range(self.stim_patterns[ind]["cycle"][1]):
+                if self.use_vr:
+                    tracking_state = self.window.getTrackingState()
+                    self.window.calcEyePoses(tracking_state.headPose.thePose)
+                    self.window.setDefaultView()
+                self.grating_neg.draw()
+                self.fixation.draw()
                 self.window.flip()
-            self.grating_neg.setAutoDraw(False)
-        pass
-
-        self.window.flip()
+        pass

examples/visual_n170/00x__n170_run_experiment.py

@@ -30,7 +30,7 @@
 eeg_device = EEG(device=board_name)
 
 # Experiment type
-experiment = VisualN170(duration=record_duration, eeg=eeg_device, save_fn=save_fn)
+experiment = VisualN170(duration=record_duration, eeg=eeg_device, save_fn=save_fn, use_vr=False)
 
 ###################################################################################################  
 # Run experiment

requirements.txt

@@ -58,3 +58,6 @@ recommonmark
 versioneer
 rst2pdf
 docutils
+
+# Oculus/Quest VR support - currently only supported on Windows.
+psychxr>=0.2.4rc2; platform_system == "Windows"