Neslib.Sdl3.Haptic

Reference

Neslib.Sdl3.Haptic

The SDL haptic subsystem manages haptic (force feedback) devices.

The basic usage is as follows:

• Initialize the subsystem (TSdlInitFlag.Haptic).
• Open a haptic device.
• TSdlHaptic.Open to open from index.
• TSdlHaptic.OpenFromJoystick to open from an existing joystick.
• Create an effect (TSdlHapticEffect).
• Upload the effect with TSdlHaptic.CreateEffect.
• Run the effect with TSdlHaptic.RunEffect.
• (Optionally) free the effect with TSdlHaptic.FreeEffect (it is also automatically freed when the haptic device is closed).
• Close the haptic device with TSdlHaptic.Close.

Simple rumble example:

{ Open the device }
var Devices := TSdlHapticID.Devices;
if (Devices = nil) then
  Exit;

var Haptic := TSdlHaptic.Open(Devices[0]);
try
  { Initialize simple rumble }
  Haptic.InitRumble;

  { Play effect at 50% strength for 2 seconds }
  Haptic.PlayRumble(0.5, 2000);

  SdlDelay(2000);
finally
  Haptic.Close;
end;

Complete example:

function TestHaptic(const AJoystick: TSdlJoystick)
begin
  { Open the device }
  var Haptic := TSdlHaptic.OpenFromJoystick(AJoystick);
  try
    { See if it can do sine waves }
    if (not (TSdlHapticFeature.Sine in Haptic.Features)) then
      Exit(False);

    { Create the effect }
    var Effect: TSdlHapticEffect;
    FillChar(Effect, SizeOf(Effect), 0);
    Effect.Kind := TSdlHapticKind.Sine;

    { Use polar coordinates }
    Effect.Periodic.Direction.Kind := TSdlHapticDirectionKind.Polar;

    { Force comes from south }
    Effect.Periodic.Direction.Dir[0] := 18000;

    { Repeats every 1 second }
    Effect.Periodic.Period := 1000; 

    { 20000/32767 strength }
    Effect.Periodic.Magnitude := 20000; 

    { 5 seconds long }
    Effect.Periodic.Length := 5000; 

    { Takes 1 second to get max strength }
    Effect.Periodic.AttackLength := 1000; 

    { Takes 1 second to fade away }
    Effect.Periodic.FadeLength := 1000; 

    { Upload the effect }
    var EffectID := Haptic.CreateEffect(Effect);

    { Test the effect }
    Haptic.RunEffect(EffectID, 1);

    { Wait for the effect to finish }
    SdlDelay(5000);

    { We destroy the effect, although closing
      the device also does this. }
    Haptic.FreeEffect(EffectID);
  finally
    { Close the device }
    Haptic.Close;
  end;

  { Success }
  Result := True;
end;

Note that the SDL haptic subsystem is not thread-safe.