Tutorial 2 ‐ Aircraft (javascript)
Tutorial on how to make basic aircraft (Diamond DA40-NG) using javascript.
You can find the files belonging to this tutorial and complete code in Outerra/anteworld "Code" section in "Tutorials/example_models_js/packages/tutorial_aircraft_js" folder.
You can find information about aircraft interface on Outerra/anteworld wiki in aircraft interface.
You can also find more information in previous JavaScript tutorial (Tutorial 1 ‐ car (javascript) ).
If you are unfamiliar with creating flight model configuration files for your aircraft, you can use Aeromatic.
For more information about using aeromatic, see JSBSim & Aeromatic.
Note: using Aeromatic is not recommended, as it doesn't provide accurate aircraft configurations, but for now, it may serve as a useful starting point for generating aircraft configurations, especially for beginners or those looking to quickly get started with aircraft in Outerra.
For a tutorial on mod files, please refer to mod files tutorial.
Define a constant for PI, will be used for joint rotation
const PI = 3.14159265358979323846;Define global variables
//Bones
let bones = {
propeller : -1,
wheel_front : -1,
wheel_right : -1,
wheel_left : -1,
elevator_right : -1,
elevator_left : -1,
rudder : -1,
aileron_right : -1,
aileron_left : -1,
rudder_pedal_left : -1,
rudder_pedal_right : -1,
brake_pedal_left : -1,
brake_pedal_right : -1,
throttle_handle : -1,
flap_left : -1,
flap_right : -1,
};
//Meshes
let meshes = {
prop_blur : -1,
blade_one : -1,
blade_two : -1,
blade_three : -1,
};
//Sounds
let sounds = {
rumble : -1,
eng_int : -1,
eng_ext : -1,
prop_int : -1,
prop_ext : -1,
};
//Sound sources
let sources = {
rumble_int : -1,
rumble_ext : -1,
eng_int : -1,
eng_ext : -1,
prop_int : -1,
prop_ext : -1,
};Create function to clamp values
function clamp(val, min, max)
{
if(val < min) return min;
else if(val > max) return max;
else return val;
}Create function, that will be used, to start/stop the engine
function engine()
{
//toggle the value every time this function is called
this.started ^= 1;
if(this.started === 1)
{
//For JSBSim aircraft to start, the starter and magneto needs to be activated
//Turn on engine (0 - turn off, 1 - turn on)
this.jsbsim['propulsion/starter_cmd'] = 1;
this.jsbsim['propulsion/magneto_cmd'] = 1;
}
else
{
this.jsbsim['propulsion/starter_cmd'] = 0;
this.jsbsim['propulsion/magneto_cmd'] = 0;
}
}"this.jsbsim['property']" is used, to set/get property belonging to JSBSim interface.
For information on JSBSim, visit the JSBSim & Aeromatic page.
For a list of usable JSBSim properties, refer to the JSBSim properties page.
Debug tip: when the magneto isn't activated, it results in decreased piston engine power, with the rpm not exceeding 1000.
Get joints/bones
bones.propeller = this.get_joint_id('propel');
bones.wheel_front = this.get_joint_id('front_wheel');
bones.wheel_right = this.get_joint_id('right_wheel');
bones.wheel_left = this.get_joint_id('left_wheel');
bones.elevator_right = this.get_joint_id('elevator_right');
bones.elevator_left = this.get_joint_id('elevator_left');
bones.rudder = this.get_joint_id('rudder');
bones.aileron_right = this.get_joint_id('aileron_right');
bones.aileron_left = this.get_joint_id('aileron_left');
bones.flap_left = this.get_joint_id('flap_left');
bones.flap_right = this.get_joint_id('flap_right');
bones.rudder_pedal_left = this.get_joint_id('rudder_pedal_left');
bones.rudder_pedal_right = this.get_joint_id('rudder_pedal_right');
bones.brake_pedal_left = this.get_joint_id('brake_pedal_left');
bones.brake_pedal_right = this.get_joint_id('brake_pedal_right');
bones.throttle_handle = this.get_joint_id('throttle_lever');Get meshes, for that use function get_mesh_id
1.Parameter: - mesh name.
Note: you can find model meshes in "Scene editor"->"Entity properties"->"Visual LODs".
meshes.prop_blur = this.get_mesh_id('propel_blur');
meshes.blade_one = this.get_mesh_id('main_blade_01#0@0');
meshes.blade_two = this.get_mesh_id('main_blade_02#0@0');
meshes.blade_three = this.get_mesh_id('main_blade_03#0@0');Add lights
//Landing lights
let light_params = {color:{x:1,y:1,z:1}, angle:100, size:0.1, edge:0.25, intensity:5, fadeout:0.05};
this.add_spot_light({x:4.5, y:1.08, z:0.98}, {x:-0.1, y:1, z: 0.3}, light_params);
this.add_spot_light({x:-4.5, y:1.08, z:0.98}, {x:0.1, y:1, z: 0.3}, light_params);
//Navigation lights
light_params = {color:{x:0,y:1,z:0}, size:0.035, edge:1, range:0.0001, intensity:20, fadeout:0.1};
let nav_light_offset =
//Right green navigation light
this.add_point_light({x:5.08, y:0.18, z:1.33}, light_params);
//Left red navigation light
light_params.color = {x:1,y:0,z:0};
this.add_point_light({x:-5.08, y:0.18, z:1.33}, light_params);Load sounds
//engine rumble - in this case it's used for the outside sounds and also the inside
sounds.rumble = this.load_sound("sounds/engine/engn1.ogg");
//Interior sounds - will be heard from inside the plane
//engine
sounds.eng_ext = this.load_sound("sounds/engine/engn1_out.ogg");
//propeller
sounds.prop_ext = this.load_sound("sounds/engine/prop1_out.ogg");
//Exterior sounds - will be heard from outside the plane
//engine
sounds.eng_int = this.load_sound("sounds/engine/engn1_inn.ogg");
//propeller
sounds.prop_int = this.load_sound("sounds/engine/prop1_out.ogg");Add sound emitters
//Interior emitters
//For interior rumbling sound
sources.rumble_int = this.add_sound_emitter_id(bones.propeller, -1, 0.5);
//For interior engine sounds
sources.eng_int = this.add_sound_emitter_id(bones.propeller, -1, 0.5);
//For interior propeller sounds
sources.prop_int = this.add_sound_emitter_id(bones.propeller, -1, 0.5);
//Exterior emitters
//For exterior rumbling sound
sources.rumble_ext = this.add_sound_emitter_id(bones.propeller, 1, 3);
//For exterior engine sounds
sources.eng_ext = this.add_sound_emitter_id(bones.propeller, 1, 3);
//For exterior propeller sounds
sources.prop_ext = this.add_sound_emitter_id(bones.propeller, 1, 3);Note: it is possible, to use one emitter for interior and exterior, like in previous tutorial.
Add action handlers
this.register_axis("air/lights/landing_lights", {minval: 0, maxval: 1, vel: 10, center: 0 }, function(v) { this.light_mask( 0x3,v > 0); });
this.register_axis("air/lights/nav_lights", {minval: 0, maxval: 1, vel: 10, center: 0 }, function(v) { this.light_mask( 0x3,v > 0, nav_light_offset); });
this.register_event("air/engines/on", engine);
this.register_axis("air/controls/aileron", { minval: -1, maxval: 1, cenvel: 0.5, vel: 0.5, positions: 0 }, function(v){
this.jsbsim['fcs/aileron-cmd-norm'] = v;
});
this.register_axis("air/controls/elevator", { minval: -1, maxval: 1, cenvel: 0.5, vel: 0.5, positions: 0 }, function(v){
this.jsbsim['fcs/elevator-cmd-norm'] = -v;
});Note: by default, JSBSim actions are handled internally, allowing gameplay without direct user intervention. However, sometimes it is needed to customize or fine-tune aircraft behavior, therefore in this case, the engine, ailerons and elevator functionality is handled in script
Function initialize is used to define per-instance parameters (same as init_vehicle in vehicle interface)
Get geomob interface
this.geom = this.get_geomob(0);Get JSBSim interface, to be able to work with JSBSim properties
this.jsbsim = this.jsb();Get sound interface
this.snd = this.sound();Set first person camera position
this.set_fps_camera_pos({x:0, y:1, z:1.4});Set initial value for JSBSim properties.
//Turn off engine (commands are normalized)
this.jsbsim['propulsion/starter_cmd'] = 0;
//Turn off magneto
this.jsbsim['propulsion/magneto_cmd'] = 0;
//Set initial throttle value to 0
this.jsbsim['fcs/throttle-cmd-norm[0]'] = 0;
//Set initial throttle value to 0
this.jsbsim['fcs/mixture-cmd-norm'] = 0;
//Set initial right brake value to 0
this.jsbsim['fcs/right-brake-cmd-norm'] = 0;
//Set initial left brake value to 0
this.jsbsim['fcs/left-brake-cmd-norm'] = 0;Set default pitch value for sound emitters
this.snd.set_pitch(sources.rumble_ext, 1);
this.snd.set_pitch(sources.rumble_int, 1);
this.snd.set_pitch(sources.eng_ext, 1);
this.snd.set_pitch(sources.eng_int, 1);
this.snd.set_pitch(sources.prop_ext, 1);
this.snd.set_pitch(sources.prop_int, 1);Set default gain value for sound emitters
this.snd.set_gain(sources.rumble_ext, 1);
this.snd.set_gain(sources.rumble_int, 1);
this.snd.set_gain(sources.eng_ext, 1);
this.snd.set_gain(sources.eng_int, 1);
this.snd.set_gain(sources.prop_ext, 1);
this.snd.set_gain(sources.prop_int, 1);Get values from JSBSim properties
//Get engine rpm from JSBSim
let propeller_rpm = this.jsbsim['propulsion/engine[0]/propeller-rpm'];
//Get wheel speed from JSBSim
let wheel_speed = this.jsbsim['gear/unit[0]/wheel-speed-fps'];
//Get elevator rotation in radians
let elev_pos_rad = this.jsbsim['fcs/elevator-pos-rad'];Rotate & move joints
//rotate_joint - bone rotates by given angle every time (incremental, given angle is added to joint current orientation)
this.geom.rotate_joint(bones.propeller, dt * (2 * PI) * (propeller_rpm ), {y:1});
this.geom.rotate_joint(bones.wheel_front, dt * PI * (wheel_speed / 5), {x:-1});
this.geom.rotate_joint(bones.wheel_right, dt * PI * (wheel_speed / 5), {x:-1});
this.geom.rotate_joint(bones.wheel_left, dt * PI * (wheel_speed / 5), {x:-1});
//rotate_joint_orig - rotate to given angle (from default orientation)
this.geom.rotate_joint_orig(bones.elevator_right, elev_pos_rad, {x:1});
this.geom.rotate_joint_orig(bones.elevator_left, elev_pos_rad, {x:1});
this.geom.rotate_joint_orig(bones.rudder, this.jsbsim['fcs/rudder-pos-rad'], {z:-1});
this.geom.rotate_joint_orig(bones.aileron_right, this.jsbsim['fcs/right-aileron-pos-rad'], {x:-1});
this.geom.rotate_joint_orig(bones.aileron_left, this.jsbsim['fcs/left-aileron-pos-rad'], {x:1});
this.geom.rotate_joint_orig(bones.flap_left, this.jsbsim['fcs/flap-pos-rad'], {x:1,y:0,z:0});
this.geom.rotate_joint_orig(bones.flap_right, this.jsbsim['fcs/flap-pos-rad'], {x:1,y:0,z:0});
this.geom.rotate_joint_orig(bones.brake_pedal_left, this.jsbsim['fcs/left-brake-cmd-norm'] * 0.7, {x:-1});
this.geom.rotate_joint_orig(bones.brake_pedal_right, this.jsbsim['fcs/right-brake-cmd-norm'] * 0.7, {x:-1});
//Rudder has 2 pedals for turning, therefore depending on the rudder position value from JSBSim, the left or right pedal will move
if(this.jsbsim['fcs/rudder-pos-rad'] > 0)
{
this.geom.move_joint_orig(bones.rudder_pedal_left, {y:(this.jsbsim['fcs/rudder-pos-rad']/5)} );
}
else if(this.jsbsim['fcs/rudder-pos-rad'] < 0)
{
this.geom.move_joint_orig(bones.rudder_pedal_right, {y:-(this.jsbsim['fcs/rudder-pos-rad']/5)} );
}Move throttle handle, depending on the throttle command value
this.geom.move_joint_orig(bones.throttle_handle, {y:(this.jsbsim['fcs/throttle-cmd-norm[0]'] / 7)});Note: in this case the pitch/roll handle rotates without the need of scripting, because it's binded with inputs in the model.
Use set_mesh_visible_id function, to set propeller blur mesh visible, when condition is true and invisible otherwise.
1.parameter - mesh ID
2.parameter - condition
this.geom.set_mesh_visible_id(meshes.prop_blur, propeller_rpm > 200.0);
this.geom.set_mesh_visible_id(meshes.blade_one, propeller_rpm < 300.0);
this.geom.set_mesh_visible_id(meshes.blade_two, propeller_rpm < 300.0);
this.geom.set_mesh_visible_id(meshes.blade_three, propeller_rpm < 300.0);When engine runs, control sounds, based on the camera position & sound effects, based on engine RPM.
if(propeller_rpm > 0)
{
//Interior
if (this.get_camera_mode() === 0 )
{
//Turn off the exterior emitters, when player camera is inside the plane
this.snd.stop(sources.eng_ext);
this.snd.stop(sources.prop_ext);
this.snd.stop(sources.rumble_ext);
//Calculate and set pitch for interior engine emitter (clamped between 1 and 2)
this.snd.set_pitch(sources.eng_int, clamp(1 + propeller_rpm /4000, 1, 2));
//Calculate and set gain for interior engine emitter (clamped between 0 and 0.5)
this.snd.set_gain(sources.eng_int, clamp(propeller_rpm /5000, 0, 0.5));
//If there is no sound already playing on given emitter, play loop
if(!this.snd.is_playing(sources.eng_int))
{
//Play interior engine sound in a loop
this.snd.play_loop(sources.eng_int, sounds.eng_int);
}
//Set gain for interior propeller emitter
this.snd.set_gain(sources.prop_int, clamp(propeller_rpm /7000, 0, 0.5));
if(!this.snd.is_playing(sources.prop_int))
{
//Play interior propeller sound in a loop
this.snd.play_loop(sources.prop_int, sounds.prop_int);
}
//Set gain for interior rumble emitter
this.snd.set_gain (sources.rumble_int, clamp(propeller_rpm /6000, 0, 0.5));
if(!this.snd.is_playing(sources.rumble_int))
{
//Play rumble sound in a loop on interior emitter
this.snd.play_loop(sources.rumble_int, sounds.rumble);
}
}
//Exterior
else
{
//Turn off the interior emitters, when camera is outside the plane
this.snd.stop (sources.eng_int);
this.snd.stop (sources.prop_int);
this.snd.stop (sources.rumble_int);
//Set pitch for exterior engine emitter
this.snd.set_pitch(sources.eng_ext, clamp(1 + propeller_rpm /1000, 1, 3));
//Set gain for exterior engine emitter
this.snd.set_gain (sources.eng_ext, clamp(propeller_rpm /450, 0.05, 2));
if(!this.snd.is_playing(sources.eng_ext))
{
//Play exterior engine sound in a loop
this.snd.play_loop(sources.eng_ext, sounds.eng_ext);
}
//Set gain for exterior propeller emitter
this.snd.set_gain (sources.prop_ext, clamp(propeller_rpm /900, 0, 2));
if(!this.snd.is_playing(sources.prop_ext))
{
//Play exterior propeller sound in a loop
this.snd.play_loop(sources.prop_ext, sounds.prop_ext);
}
//Set gain for exterior rumble emitter
this.snd.set_gain (sources.rumble_ext, clamp(propeller_rpm /1200, 0, 2));
if(!this.snd.is_playing(sources.rumble_ext))
{
//Play rumble sound in a loop on exterior emitter
this.snd.play_loop(sources.rumble_ext, sounds.rumble);
}
}
}
else
{
//Stop all sounds playing on given emitters, when engine is turned off and propeller stops rotating
this.snd.stop(sources.eng_ext);
this.snd.stop(sources.eng_int);
this.snd.stop(sources.prop_ext);
this.snd.stop(sources.prop_int);
this.snd.stop(sources.rumble_ext);
this.snd.stop(sources.rumble_int);
} Test