The Zandalar project

The Zandalar Project is a codename for the new Input archtecture and GUI navigation features.

Input Aggregator & events

Use Cases

The use cases are described by steps. For each step there might be some actions done at different levels:

• Raw input = the data that comes directly from the input system the application is using (OIS, glfw, etc.).
• Input Injection = the `InjectedInputReceiver`-ish function called with the right parameters
  • For backwards compatibility-ish, we can persist the same interface(InjectedInputReceiver), but provide in it a default implementation that generates the input events for the current interface's functions.
• InputEvent = the `InputEvent` type generated from the injected input. This is the final step, and this is fed to the CEGUI library.

Clicking a button using a mouse

Step description	Raw input	Input Injection	InputEvent fed to CEGUI
Move the mouse over the button	Mouse movement	injectMouseMove/injectMousePosition	PointerMovementInputEvent
Press the LMB	Mouse button press	injectMouseButtonDown(LMB)	PointerActivationInputEvent
Release the LMB	Mouse button release	injectMouseButtonUp(LMB)	PointerDeactivationInputEvent
The button is clicked (Click event is triggered)	N/A	N/A	N/A

Clicking/activating a button using the keyboard (new feature)

Step description	Raw input	Input Injection	InputEvent fed to CEGUI
Focus the button	Uses the use case "Focus a button using the keyboard/gamepad"
Press the ENTER key (1)	Key Button press	injectKeyDown(Enter)	SemanticInputEvent(Confirm)
Release the ENTER key ***	Key Button release	injectKeyUp(Enter)	ReleasedButtonInputEvent(Confirm) **** (check the semantics table)
The button is clicked (Click event is triggered)	N/A	N/A	N/A

(1) the key will be defined as per the NavigationStrategy (GUINavigation project part). If there is no such key defined, the event will be ignored.

Clicking/activating a button using a gamepad

The same as previous Clicking/activating a button using the keyboard, but with the difference that it uses a Gamepad button instead of a Keyboard one.

Type text into a textbox

Step description	Raw input	Input Injection	InputEvent fed to CEGUI
Focus the textbox	Uses the use case "Focus a textbox using the keyboard/gamepad"
Press a character key	Char press	injectChar(chr)	TextInputEvent(chr)
Press backspace (delete last char)	Key Button press	injectKeyDown(key)	SemanticInputEvent(DeleteLastCharacter)

Scroll horizontally with the mouse wheel

Step description	Raw input	Input Injection	InputEvent fed to CEGUI
Rotate the wheel	Wheel rotation delta	injectMouseWheelChange(delta)	ScrollInputEvent(direction, delta)

Proposed design

Events

For start, the following events will cover all existing functions in the 'InjectedInputReceiver' interface:

Input Event name	Data	Functions covered
PointerMovementInputEvent	Position : Vector2 Delta : Vector2	injectMouseMove injectMousePosition
SemanticInputEvent	Value: Enum/int (see below table)	injectMouseButtonDown injectKeyDown injectMouseButtonUp injectKeyUp injectMouseButtonClick injectMouseButtonDoubleClick injectMouseButtonTripleClick
TextInputEvent	Text : string/char	injectChar
ScrollInputEvent	Delta : int Direction : ScrollDirection(0 - horizontal, 1 - vertical)	injectMouseWheelChange

Unmapped (yet) functions:

• injectMouseLeaves

Semantics Table

The following table represents the semantic values (members of an ENUM) and the raw event(s) from which they are generated.

injectMouseButtonDown + injectMouseButtonUp

• PointerActivate
• SelectMultipleItems (SHIFT + click)
• SelectCumulative (CTRL+CLICK)

injectMouseButtonClick

• PointerActivate

injectMouseButtonDoubleClick

• PointerActivate
• SelectWord (double click)

injectMouseButtonTripleClick

• PointerActivate
• SelectAll (triple click)

Question: Maybe we should create a standalone event type for pointer activation which also 'records' the number of activations? (for example in the case of double/triple click). The editbox uses double/triple click to select all text. Maybe let semantic action 'select all?'

Question2: What we do with the right/middle/extra mouse buttons (TabControl uses middle and nobutton buttons)?:

• Introduce the idea of 'PointerSource' which can be left/right/middle
• Add separate values: LeftPointerActivation, RightPointerActivation, etc? (I'd go for this)

injectMouseButtonUp

• PointerDeactivate

injectKeyDown + injectKeyUp

• DeleteLastCharacter (backspace)
• DeletePreviousCharacter (del)
• Confirm/Submit (Enter/tab/numpad enter -> This should go into the GUI navigation module)
• SelectLeftCharacter (SHIFT + left arrow)
• SelectRightCharacter (SHIFT + right arrow)
• GoToPreviousCharacter (left arrow)
• GoToPreviousWord (CTRL + left arrow)
• GoToNextCharacter (right arrow)
• GoToNextWord (CTRL + right arrow)
• GoToStartOfLine (home)
• GoToEndOfLine (end)
• SelectAll (CTRL+A)
• Back (escape)

• Undo (CTRL+Z)
• Redo (CTRL+Y)
• Cut (CTRL+X)
• Copy (CTRL+C)
• Paste (CTRL+V)

Decisions

Combining keyboard, gamepad and mouse button pressed actions

We have three ways of handling this.

• Using two types of events (Pressed/ReleasedButtonInputEvent) AND SemanticInputEvent
  • We have a "big" enum which contains all possible values for a keyboard, mouse and the gamepad
  • The 'raw' events (Pressed/ReleasedButtonInputEvent are triggered every time
  • The semantic events are generated only based on a mapping configuration: (button_id) -> (semantic_value). If a specific (button_id) present in the mapping is pressed then a semantic event will be generated with the specified (semantic_value).
    • (button_id) is a member of the "big" enum
    • (semantic_value) is a user-defined value. Inside CEGUI's system we'll have an enum which is used instead of magic numbers. Users could define their own enum which has indices starting from the last CEGUI's enum member number.
• Using just the raw types of event (Pressed/ReleasedInputEvent) WITHOUT SemanticInputEvent
  • This would involve ignoring the explicit click calls, and rather generate them inside the system.
• Using just SemanticInputEvent WITHOUT raw events.

GUI navigation

Use cases

Focus a button using the keyboard/gamepad

Just calling focus()

Navigate a form

Prerequisite: first control in the current window is focused; navigation is configured.

• Pressed("Tab") = focus next ("next")
• Pressed("CTRL + Tab") = focus previous ("previous")

Steps:

• Press `Tab`
• The next control is focused.

Navigate a 2D Menu

Prerequisite: first control in the current window is focused; navigation is configured:

• Pressed("left") = go left ("left")
• Pressed("right") = go left ("right")
• Pressed("top") = go left ("top")
• Pressed("up") = go left ("up")
• ^The same items but with the gamepad's D-Pad configuration instead of the keys

Steps

• Press a configured key/gamepad button.
• The control in the specified direction is focused.