Canvas HUD
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Rendering a basic HUD with a Canvas.
# ==============================================================================
# Head up display
# ==============================================================================
var pow2 = func(x) { return x * x; };
var vec_length = func(x, y) { return math.sqrt(pow2(x) + pow2(y)); };
var round0 = func(x) { return math.abs(x) > 0.01 ? x : 0; };
var clamp = func(x, min, max) { return x < min ? min : (x > max ? max : x); }
var HUD = {
canvas_settings: {
"name": "HUD",
"size": [1024, 1024],
"view": [480, 360],
"mipmapping": 1
},
new: func(placement)
{
var m = {
parents: [HUD],
canvas: canvas.new(HUD.canvas_settings)
};
m.canvas.addPlacement(placement);
m.canvas.setColorBackground(0.36, 1, 0.3, 0.02);
m.root =
m.canvas.createGroup()
.setScale(1, 1/math.cos(25 * math.pi/180))
.setTranslation(240, 180)
.set("font", "LiberationFonts/LiberationMono-Regular.ttf")
.setDouble("character-size", 18)
.setDouble("character-aspect-ration", 0.9)
.set("stroke", "rgba(0,255,0,0.9)");
m.text =
m.root.createChild("group")
.set("fill", "rgba(0,255,0,0.9)");
# Heading
m.hdg =
m.text.createChild("text")
.setDrawMode(3)
.setPadding(2)
.setAlignment("center-top")
.setTranslation(0, -140);
# Airspeed
m.airspeed =
m.text.createChild("text")
.setAlignment("right-center")
.setTranslation(-180, 0);
# Groundspeed
m.groundspeed =
m.text.createChild("text")
.setAlignment("left-center")
.setTranslation(-220, 90);
# Vertical speed
m.vertical_speed =
m.text.createChild("text")
.setFontSize(10, 0.9)
.setAlignment("right-center")
.setTranslation(205, 50);
# Radar altidude
m.rad_alt =
m.text.createChild("text")
.setAlignment("right-center")
.setTranslation(220, 70);
# Waterline / Pitch indicator
m.root.createChild("path")
.moveTo(-24, 0)
.horizTo(-8)
.lineTo(-4, 6)
.lineTo(0, 0)
.lineTo(4, 6)
.lineTo(8, 0)
.horizTo(24)
.setStrokeLineWidth(0.9);
# Flightpath/Velocity vector
m.fpv = m.root.createChild("group", "FPV");
m.fpv.createChild("path")
.moveTo(8, 0)
.arcSmallCCW(8, 8, 0, -16, 0)
.arcSmallCCW(8, 8, 0, 16, 0)
.moveTo(-8, 0)
.horiz(-16)
.moveTo(8, 0)
.horiz(16)
.setStrokeLineWidth(0.9);
# Energy/Acceleration cues
m.energy_cue =
m.fpv.createChild("path")
.setStrokeLineWidth(1);
m.acc =
m.fpv.createChild("path")
.setStrokeLineWidth(1);
# Horizon
m.horizon_group = m.root.createChild("group");
m.h_trans = m.horizon_group.createTransform();
m.h_rot = m.horizon_group.createTransform();
# Pitch lines
for(var i = 5; i <= 10; i += 5)
{
m.horizon_group.createChild("path")
.moveTo(24, -i * 18)
.horiz(48)
.vert(7)
.moveTo(-24, -i * 18)
.horiz(-48)
.vert(7)
.setStrokeLineWidth(1.5);
}
# Horizon line
m.horizon_group.createChild("path")
.moveTo(-500, 0)
.horizTo(500)
.setStrokeLineWidth(1.5);
m.input = {
pitch: "/orientation/pitch-deg",
roll: "/orientation/roll-deg",
hdg: "/orientation/heading-deg",
speed_n: "velocities/speed-north-fps",
speed_e: "velocities/speed-east-fps",
speed_d: "velocities/speed-down-fps",
alpha: "/orientation/alpha-deg",
beta: "/orientation/side-slip-deg",
ias: "/velocities/airspeed-kt",
gs: "/velocities/groundspeed-kt",
vs: "/velocities/vertical-speed-fps",
rad_alt: "/instrumentation/radar-altimeter/radar-altitude-ft",
wow_nlg: "/gear/gear[4]/wow",
airspeed: "/velocities/airspeed-kt",
target_spd: "/autopilot/settings/target-speed-kt",
acc: "/fdm/jsbsim/accelerations/udot-ft_sec2"
};
foreach(var name; keys(m.input))
m.input[name] = props.globals.getNode(m.input[name], 1);
return m;
},
update: func()
{
me.airspeed.setText(sprintf("%d", me.input.ias.getValue()));
me.groundspeed.setText(sprintf("G %3d", me.input.gs.getValue()));
me.vertical_speed.setText(sprintf("%.1f", me.input.vs.getValue() * 60.0 / 1000));
var rad_alt = me.input.rad_alt.getValue();
if( rad_alt and rad_alt < 5000 ) # Only show below 5000AGL
rad_alt = sprintf("R %4d", rad_alt);
else
rad_alt = nil;
me.rad_alt.setText(rad_alt);
me.hdg.setText(sprintf("%03d", me.input.hdg.getValue()));
me.h_trans.setTranslation(0, 18 * me.input.pitch.getValue());
var rot = -me.input.roll.getValue() * math.pi / 180.0;
me.h_rot.setRotation(rot);
# flight path vector (FPV)
var vel_gx = me.input.speed_n.getValue();
var vel_gy = me.input.speed_e.getValue();
var vel_gz = me.input.speed_d.getValue();
var yaw = me.input.hdg.getValue() * math.pi / 180.0;
var roll = me.input.roll.getValue() * math.pi / 180.0;
var pitch = me.input.pitch.getValue() * math.pi / 180.0;
var sy = math.sin(yaw); var cy = math.cos(yaw);
var sr = math.sin(roll); var cr = math.cos(roll);
var sp = math.sin(pitch); var cp = math.cos(pitch);
var vel_bx = vel_gx * cy * cp
+ vel_gy * sy * cp
+ vel_gz * -sp;
var vel_by = vel_gx * (cy * sp * sr - sy * cr)
+ vel_gy * (sy * sp * sr + cy * cr)
+ vel_gz * cp * sr;
var vel_bz = vel_gx * (cy * sp * cr + sy * sr)
+ vel_gy * (sy * sp * cr - cy * sr)
+ vel_gz * cp * cr;
var dir_y = math.atan2(round0(vel_bz), math.max(vel_bx, 0.01)) * 180.0 / math.pi;
var dir_x = math.atan2(round0(vel_by), math.max(vel_bx, 0.01)) * 180.0 / math.pi;
me.fpv.setTranslation(dir_x * 18, dir_y * 18);
var speed_error = 0;
if( me.input.target_spd.getValue() != nil )
speed_error = 4 * clamp(
me.input.target_spd.getValue() - me.input.airspeed.getValue(),
-15, 15
);
me.energy_cue.reset();
# if( math.abs(speed_error) > 3 )
me.energy_cue.moveTo(-22, 0)
.vert(speed_error)
.horiz(3)
.vertTo(0);
var acc = me.input.acc.getValue() or 0;
me.acc.reset()
.moveTo(-34, -acc * 5 - 4)
.line(8, 4)
.line(-8, 4);
settimer(func me.update(), 0);
}
};
var init = setlistener("/sim/signals/fdm-initialized", func() {
removelistener(init); # only call once
var hud_pilot = HUD.new({"node": "HUD.l.canvas"});
hud_pilot.update();
# var hud_copilot = HUD.new({"node": "HUD.l.canvas.001"});
# hud_copilot.update();
});