VRExternalDisplay.rs

impl VRDisplay for VRExternalDisplay {

  fn data(&self) -> VRDisplayData {
        let mut data = VRDisplayData::default();
        let state: &mozgfx::VRDisplayState  = &self.shmem().state.displayState;
        data.display_name = state.mDisplayName.iter().map(|x| *x as char).collect();
        data.display_id = self.display_id;
        data.connected = state.mIsConnected;

        // FIXME: better option than != 0?
        data.capabilities.has_position = state.mCapabilityFlags | mozgfx::VRDisplayCapabilityFlags_Cap_Position != 0; 
        data.capabilities.can_present = state.mCapabilityFlags | mozgfx::VRDisplayCapabilityFlags_Cap_Present != 0;
        data.capabilities.has_orientation = state.mCapabilityFlags | mozgfx::VRDisplayCapabilityFlags_Cap_Orientation != 0;
        data.capabilities.has_external_display = false; // FIXME: How do I know? And why?

        data.stage_parameters = Some(VRStageParameters {
            sitting_to_standing_transform: state.mSittingToStandingTransform.clone(),
            size_x: state.mStageSize.width, // FIXME: Not sure about that, size_x is width?
            size_z: state.mStageSize.height, // FIXME: Not sure about that, size_z is height?
        });

        data.left_eye_parameters.offset = [state.mEyeTranslation[0].x, state.mEyeTranslation[0].y, state.mEyeTranslation[0].y];
        data.left_eye_parameters.render_width = state.mEyeResolution.width as u32; // FIXME: Not sure about that
        data.left_eye_parameters.render_height = state.mEyeResolution.height as u32; // FIXME: Not sure about that
        data.left_eye_parameters.field_of_view.up_degrees = state.mEyeFOV[0].upDegrees;
        data.left_eye_parameters.field_of_view.right_degrees = state.mEyeFOV[0].rightDegrees;
        data.left_eye_parameters.field_of_view.down_degrees = state.mEyeFOV[0].downDegrees;
        data.left_eye_parameters.field_of_view.left_degrees = state.mEyeFOV[0].leftDegrees;

        data.right_eye_parameters.offset = [state.mEyeTranslation[1].x, state.mEyeTranslation[1].y, state.mEyeTranslation[1].y];
        data.right_eye_parameters.render_width = state.mEyeResolution.width as u32; // FIXME: Not sure about that
        data.right_eye_parameters.render_height = state.mEyeResolution.height as u32; // FIXME: Not sure about that
        data.right_eye_parameters.field_of_view.up_degrees = state.mEyeFOV[1].upDegrees;
        data.right_eye_parameters.field_of_view.right_degrees = state.mEyeFOV[1].rightDegrees;
        data.right_eye_parameters.field_of_view.down_degrees = state.mEyeFOV[1].downDegrees;
        data.right_eye_parameters.field_of_view.left_degrees = state.mEyeFOV[1].leftDegrees;
        
        data
    }
    ...
}

VRStageParameters can be None. We are not setting it now. You can check it with Cap_StageParameters

render_width is ok

Should we add parenthesis into state.mCapabilityFlags | mozgfx::VRDisplayCapabilityFlags_Cap_Position != 0;?

(state.mCapabilityFlags | mozgfx::VRDisplayCapabilityFlags_Cap_Position) != 0;

It should be with and: (state.mCapabilityFlags & mozgfx::VRDisplayCapabilityFlags_Cap_Position) != 0

data.capabilities.has_external_display = true There is a Cap_External flag