black screen on VirtualBox 6.1.0

edit

Hey, When I want to launch Gazebo (from PX4 stack) on VirtualBox (guest: ubuntu 18.04 LTS) from this script:

#!/bin/bash
# run multiple instances of the 'px4' binary, but w/o starting the simulator.
# It assumes px4 is already built, with 'make px4_sitl_default'

# The simulator is expected to send to TCP port 4560+i for i in [0, N-1]
# For example gazebo can be run like this:
#./Tools/gazebo_sitl_multiple_run.sh -n 10 -m iris

function cleanup() {
    pkill -x px4
    pkill gzclient
}

if [ "$1" == "-h" ] || [ "$1" == "--help" ]
then
    echo "Usage: $0 [-n <num_vehicles>] [-m <vehicle_model>]"
    exit 1
fi

while getopts n:m: option
do
    case "${option}"
    in
        n) NUM_VEHICLES=${OPTARG};;
        m) VEHICLE_MODEL=${OPTARG};;
    esac
done

num_vehicles=${NUM_VEHICLES:=3}
export PX4_SIM_MODEL=${VEHICLE_MODEL:=iris}

if [ "$PX4_SIM_MODEL" != "iris" ]
then
    echo "Currently only iris vehicle model is supported!"
    exit 1
fi

SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
src_path="$SCRIPT_DIR/.."


build_path=${src_path}/build/px4_sitl_default
mavlink_udp_port=14560
mavlink_tcp_port=4560
world="empty"

echo "killing running instances"
pkill -x px4 || true

sleep 1

source ${src_path}/Tools/setup_gazebo.bash ${src_path} ${src_path}/build/px4_sitl_default

echo "Starting gazebo"
gzserver ${src_path}/Tools/sitl_gazebo/worlds/${world}.world --verbose &
sleep 5

n=0
while [ $n -lt $num_vehicles ]; do
    working_dir="$build_path/instance_$n"
    [ ! -d "$working_dir" ] && mkdir -p "$working_dir"

    pushd "$working_dir" &>/dev/null
    echo "starting instance $n in $(pwd)"
    ../bin/px4 -i $n -d "$src_path/ROMFS/px4fmu_common" -w sitl_${PX4_SIM_MODEL}_${n} -s etc/init.d-posix/rcS >out.log 2>err.log &
    python3 ${src_path}/Tools/sitl_gazebo/scripts/xacro.py ${src_path}/Tools/sitl_gazebo/models/rotors_description/urdf/${PX4_SIM_MODEL}_base.xacro \
        rotors_description_dir:=${src_path}/Tools/sitl_gazebo/models/rotors_description mavlink_udp_port:=$(($mavlink_udp_port+$n)) \
        mavlink_tcp_port:=$(($mavlink_tcp_port+$n))  -o /tmp/${PX4_SIM_MODEL}_${n}.urdf

    echo "Spawning ${PX4_SIM_MODEL}_${n}"

    gz model --spawn-file=/tmp/${PX4_SIM_MODEL}_${n}.urdf --model-name=${PX4_SIM_MODEL}_${n} -x 0.0 -y ${n} -z 0.0

    popd &>/dev/null

    n=$(($n + 1))
done

trap "cleanup" SIGINT SIGTERM EXIT

echo "Starting gazebo client"
gzclient

I end with black world view; weirdly, when I run Gazebo by clicking at icon, everything renders OK...