Input Polling / Input Controller

One of the basic features a game needs is the control of inputs. And it is not done with just checking which key is pressed or where the mouse is. Most games need much more than just reacting on clicks.

Imagine a combat game, where you allow users to have key-combos for special attacks and animations.

Therefor we provide the easy to use TGorillaInputController component to access keyboard, mouse and gamepad feedbacks. Also in combination!

The input controller sets up handlers for keyboard, mouse and gamepad, and enables all by default.

FInput.Supported := [TGorillaInputDeviceType.Keyboard, TGorillaInputDeviceType.Mouse,
  TGorillaInputDeviceType.GamePad];

If you do not need any of the device, you can disable them, by reducing the “Supported” enumeration set. For example, if you only want to check for gamepad events:

FInput.Supported := [TGorillaInputDeviceType.GamePad];

A HotKey is a combination of simultanously active inputs. Each HotKey can manage inputs from keyboard, mouse and/or gamepad. An input is a hardware message:

• For keyboards, inputs are the pressed keys
• For mouse, inputs are pressed mouse buttons
• For gamepad, inputs are pressed gamepad buttons

You can define up to 4 inputs per device. Which means you can handle up to 12 simultanously active input messages.

In case you define an input in two different HotKeys, the system will detect the more important Hotkey. The importance is defined by the number of set inputs.

If a HotKey was detected, the controller will call the OnTriggered event and/or an attached TAction instance.

You are allowed to setup your HotKeys at design- and runtime.

Set the LockTime property (in milliseconds) to suppress a hotkey for a specific time. Because input commands come very often, f.e. if a button on the gamepad was pressed. As long as you hold the button the system will recognize the hotkey for this button. For sequence detection this may be a problem. Therefor we want to lock the gamepad hotkey for a certain time.

Because HotKeys were implemented by the TCollection component of Delphi, you can setup your combinations at design time.

1. Drag a TGorillaInputController component onto your form and doubleclick the “HotKeys” property.
2. In the Delphi Collection-Editor you can now add a new TGorillaHotKeyItem.
3. Type in a unique name to identify your hotkey, create a OnTriggered event or attach a TAction component to it.
4. In the next step we should add the input combination by double clicking the “Combinations” property.
5. Here we can now add a new TGorillaHotKeyInputItem.
6. In the item select the “Kind” of device.
7. and add the message input code (tables below)
8. Repeat it for any further inputs you wish to combine.

uses
  Gorilla.Controller.Input,
  Gorilla.Controller.Input.Consts;
 
procedure TForm1.DoOnHotKey(const AItem : TGorillaHotKeyItem; const ACurrentInput : TGorillaHotKeyRaw);
begin
  DebugOutput(Format('>>> HotKey: %s <<< === %s', [AItem.DisplayName, ACurrentInput.ToString()]));
end;
 
procedure TForm1.FormCreate(Sender: TObject);
var 
  FInput : TGorillaInputController;
  LHotKey : TGorillaHotKeyItem;
 
  [...]
 
  FInput := TGorillaInputController.Create(Self);
 
  LHotKey := FInput.AddHotKey('TEST1');
  LHotKey.OnTriggered := DoOnHotKey;
  LHotKey.AddInput(TGorillaInputDeviceType.Keyboard, Ord(GORILLA_INPUT_KEY_ALT));
  LHotKey.AddInput(TGorillaInputDeviceType.Keyboard, Ord(GORILLA_INPUT_KEY_C));
  LHotKey.AddInput(TGorillaInputDeviceType.Keyboard, Ord(GORILLA_INPUT_KEY_RETURN));
end;
 
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  FInput.DisposeOf();
  FInput := nil;
end;

Besides the HotKey settings the component supports persistent/continuous messages. A persistent message is a continuously notified message from the system and not a temporary message like a click or key-press.

Persistent messages can not be notified by HotKeys. You need to request those separately.

Supported persistent messages are:

You can request those messages at runtime, like in the following code:

var LMPos  : TPoint;
    LMsg   : TGorillaInputMessage;
begin
  // request latest mouse position
  if FInput.GetPersistentMessage(TGorillaInputDeviceType.Mouse, GORILLA_INPUT_MOUSE_POSITION, LMsg) then
  begin
    LMPos := LMsg.Data.AsType<TPoint>();
  end
  else LMPos := TPoint.Zero;
 
  // show mouse position in form caption
  Self.Caption := Format('Gorilla 3D - Mouse: [%d;%d]', [LMPos.X, LMPos.Y]);

All available InputCodes (TGorillaInputCode) for HotKeys are defined in the Gorilla.Controller.Input.Consts unit.

HotKeys are a nice feature, but only work for simultaneous inputs.

Imagine you build a combat game, where attacks or defences are represented by input-combos. For example a user needs to press Button A, then Button B and then Button X to do roundhouse kick. Therefor sequences come in place. Sequences are a descriptive plan of hotkeys, where the order is important.

So Sequence #1

Button A + Button B + Button X

is not the same like

Button B + Button A + Button X

Notes: You are allowed declare an input multiple times in a sequence.

Each sequence can hold up to 16 HotKeys.

procedure TForm1.DoOnSequence(const ASequence : TGorillaInputSequenceItem);
begin
  DebugOutput(Format('>>> Sequence: %s <<<', [ASequence.DisplayName]));
end;
 
[...]
 
var LSequence: TGorillaInputSequenceItem;
    LSeq1HK1, LSeq1HK2, LSeq1HK3 : TGorillaHotKeyItem;
 
  [...]
 
  // create hotkey #1
  LSeq1HK1 := FInput.AddHotKey('STRIDE LEFT');
  LSeq1HK1.AddInput(TGorillaInputDeviceType.Keyboard, Ord(GORILLA_INPUT_KEY_A));
 
  // create hotkey #2
  LSeq1HK2 := FInput.AddHotKey('FORWARD');
  LSeq1HK2.AddInput(TGorillaInputDeviceType.Keyboard, Ord(GORILLA_INPUT_KEY_W));
 
  // create hotkey #3
  LSeq1HK3 := FInput.AddHotKey('STRIDE RIGHT');
  LSeq1HK3.AddInput(TGorillaInputDeviceType.Keyboard, Ord(GORILLA_INPUT_KEY_D));
 
  // create the sequence and add the relevant hotkeys
  LSequence := FInput.AddSequence('TEST SEQUENCE', [LSeq1HK1, LSeq1HK2, LSeq1HK3]);
  LSequence.OnTriggered := DoOnSequence;

Now that we've covered hotkeys and sequences, another way of detecting inputs are the raw feedback events of the input controller itself.

The input controller provides a few feedback events that work parallel to the mentioned hotkey or sequence detection.

Declaring a feedback event method needs further unit integration in most cases for the used types and constants:

• Gorilla.Controller
• Gorilla.Controller.Input.Consts
• Gorilla.Controller.Input.Types

TGorillaInputMode = (Activated, Deactivated);
 
  TGorillaMouseState = (LButtonDown, LButtonUp, RButtonDown, RButtonUp,
    MButtonDown, MButtonUp, X1ButtonDown, X1ButtonUp, X2ButtonDown, X2ButtonUp,
    LButtonDblClick, RButtonDblClick, MButtonDblClick, X1ButtonDblClick,
    X2ButtonDblClick, MouseMove, MouseWheel);
 
TGorillaMouseStates = set of TGorillaMouseState;
 
TGorillaGamePadButton = (
    None,
    // directional pad up
    DPadUp,
    // directional pad down
    DPadDown,
    // directional pad left
    DPadLeft,
    // directional pad right
    DPadRight,
    // start button
    StartButton,
    // mode button
    ModeButton,
    // back button
    BackButton,
    // left thumbstick pressed
    LeftThumbStick,
    // right thumbstick pressed
    RightThumbStick,
    // left shoulder button
    LeftShoulder,
    // right shoulder button
    RightShoulder,
    // button A
    ButtonA,
    // button B
    ButtonB,
    // button X
    ButtonX,
    // button Y
    ButtonY
    );
 
TGorillaGamePadButtons = set of TGorillaGamePadButton;

On Windows platform we're using low level hooks for keyboard and mouse detection, to support high-performance and accuracy.

But this comes with a major issue: In many cases debugging is getting very slow, because hooks have a 1000ms timeout by default and hooks not getting paused during debugging.

This leads to lagging mouse and keyboard input.

Currently this can not be solved out of the box!

But you can add a registry entry to your system, like this:

1. Open RegEdit.exe (Windows)
2. Move to the path: “HKEY_CURRENT_USER\Control Panel\Desktop\”
3. Add a new value of type DWORD with the name “LowLevelHooksTimeout”
4. Enter a value which stands for the timeout in milliseconds (f.e. 50ms)
5. A system restart is required!

Next: Pathfinding