     # Request present
     if HMD.capabilities.canPresent
         if not HMD.isPresenting
-            try
-                HMD.requestPresent [{source: ctx.canvas}]
-            catch e
-                throw e
+            HMD.requestPresent [{source: ctx.canvas}]
     else
         # TODO: support non-presenting VR displays?
         return Promise.reject "Non-presenting VR displays are not supported"

        # v.set_clear false, false
        v.rect = [0, 0, 0.5, 1]
        # right eye viewport
        camera = right_cam = @scene.active_camera.clone()
        camera.rotation_order = 'Q'
        mat4.identity camera.matrix_parent_inverse
        quat.identity camera.rotation

    ctx = scene.context
    if ctx.vr_screen?.HMD.isPresenting
        return Promise.resolve()
    {HMD} = options
    if not HMD?
        if not displays?
            return Promise.reject "Call hasVR first."
        for display in displays
            if display instanceof VRDisplay and display.capabilities.canPresent
                HMD = display
                break
    if not HMD?
        return Promise.reject "No HMDs detected. Conect an HMD,
            turn it on and try again."
