webcam: make driver camera optional (#35455)

* webcam: driverCamera optional

* webcam: update README

tools/webcam/README.md

@@ -1,22 +1,22 @@
 # Run openpilot with webcam on PC
 
 What's needed:
-- Ubuntu 24.04 ([WSL2 is not supported](https://github.com/commaai/openpilot/issues/34216))
+- Ubuntu 24.04 ([WSL2 is not supported](https://github.com/commaai/openpilot/issues/34216)) or macOS
 - GPU (recommended)
-- Two USB webcams, at least 720p and 78 degrees FOV (e.g. Logitech C920/C615)
-- [Car harness](https://comma.ai/shop/products/comma-car-harness) with black panda to connect to your car
-- [Panda paw](https://comma.ai/shop/products/panda-paw) or USB-A to USB-A cable to connect panda to your computer
-That's it!
+- One USB webcam, at least 720p and 78 degrees FOV (e.g. Logitech C920/C615, NexiGo N60)
+- [Car harness](https://comma.ai/shop/products/comma-car-harness)
+- [panda](https://comma.ai/shop/panda)
+- USB-A to USB-A cable to connect panda to your computer
 
 ## Setup openpilot
 - Follow [this readme](../README.md) to install and build the requirements
-- Install OpenCL Driver
+- Install OpenCL Driver (Ubuntu)
 ```
 sudo apt install pocl-opencl-icd
 ```
 
 ## Connect the hardware
-- Connect the road facing camera first, then the driver facing camera
+- Connect the camera first
 - Connect your computer to panda
 
 ## GO
@@ -24,12 +24,12 @@ sudo apt install pocl-opencl-icd
 USE_WEBCAM=1 system/manager/manager.py
 ```
 - Start the car, then the UI should show the road webcam's view
-- Adjust and secure the webcams.
+- Adjust and secure the webcam
 - Finish calibration and engage!
 
 ## Specify Cameras
 
-Use the `ROAD_CAM`, `DRIVER_CAM`, and optional `WIDE_CAM` environment variables to specify which camera is which (ie. `DRIVER_CAM=2` uses `/dev/video2` for the driver-facing camera):
+Use the `ROAD_CAM` (default 0) and optional `DRIVER_CAM`, `WIDE_CAM` environment variables to specify which camera is which (ie. `ROAD_CAM=1` uses `/dev/video1`, on Ubuntu, for the road camera):
 ```
-USE_WEBCAM=1 ROAD_CAM=4 WIDE_CAM=6 system/manager/manager.py
+USE_WEBCAM=1 ROAD_CAM=1 system/manager/manager.py
 ```

tools/webcam/camerad.py

@@ -9,14 +9,19 @@ from cereal import messaging
 from openpilot.tools.webcam.camera import Camera
 from openpilot.common.realtime import Ratekeeper
 
+ROAD_CAM = os.getenv("ROAD_CAM", "0")
 WIDE_CAM = os.getenv("WIDE_CAM")
+DRIVER_CAM = os.getenv("DRIVER_CAM")
+
 CameraType = namedtuple("CameraType", ["msg_name", "stream_type", "cam_id"])
+
 CAMERAS = [
-  CameraType("roadCameraState", VisionStreamType.VISION_STREAM_ROAD, os.getenv("ROAD_CAM", "0")),
-  CameraType("driverCameraState", VisionStreamType.VISION_STREAM_DRIVER, os.getenv("DRIVER_CAM", "2")),
+  CameraType("roadCameraState", VisionStreamType.VISION_STREAM_ROAD, ROAD_CAM)
 ]
 if WIDE_CAM:
   CAMERAS.append(CameraType("wideRoadCameraState", VisionStreamType.VISION_STREAM_WIDE_ROAD, WIDE_CAM))
+if DRIVER_CAM:
+  CAMERAS.append(CameraType("driverCameraState", VisionStreamType.VISION_STREAM_DRIVER, DRIVER_CAM))
 
 class Camerad:
   def __init__(self):