SelectionState

namespace Griff.Scenes;

public sealed class SelectionState

What’s selected, the way real-time strategy games select, and the rules for changing it: a click picks one (adding it or taking it out with AddToSelection held, and a double-click picking every one of its kind on screen), a box picks what’s inside, and control groups are kept and picked again by number. It knows nothing of the mouse, keys or what can be selected: an ISelectionRules says what’s where. SelectionControls keeps one, and so does the Strategy module’s Commander, so both select alike; a script’s own selecting can keep one too.

Properties

DoubleClickSeconds

public double DoubleClickSeconds { get; set; }

How close in seconds two clicks on the same thing make a double-click (no more apart than this).

DoubleTapSeconds

public double DoubleTapSeconds { get; set; }

How close in seconds two picks of a control group make a double-tap (less apart than this).

DragFrom

public Vector2? DragFrom { get; set; }

Where a box being dragged out started (in the world), or null.

LastClickTime

public double LastClickTime { get; }

When the last click was, in the clock’s seconds.

LastClicked

public Entity? LastClicked { get; }

The last thing clicked (or null for nothing), for telling a double-click.

LastGroup

public int LastGroup { get; }

The control group last picked, or -1.

LastGroupTime

public double LastGroupTime { get; }

When the last control group was picked, in the clock’s seconds.

Selected

public IReadOnlyList<Entity> Selected { get; }

What’s selected, first picked first.

Methods

Box

public void Box(ISelectionRules rules, Vector2 from, Vector2 to, bool add)

A box dragged from from to to: what’s inside; with add, added to what’s kept.

Click

public void Click(ISelectionRules rules, Vector2 point, bool add, double now)

A click at point at now: what’s there alone; with add, added to the selection or taken out of it, where the rules allow; a second click on it soon enough, every one of its kind. A click on nothing clears the selection (unless adding).

Group

public IReadOnlyList<Entity> Group(int number)

Control group number; empty if it hasn’t been kept.

KeepGroup

public IReadOnlyList<Entity> KeepGroup(ISelectionRules rules, int number)

Keeps what’s selected (what the rules keep of it) as control group number, and returns it.

PickGroup

public bool PickGroup(ISelectionRules rules, int number, bool add, double now, out Vector2? center)

Picks control group number again (adding it to the selection with add), dropping what’s gone from it. Picked twice quickly, center is the middle of the group, to move the camera to. False if no such group was kept.

Release

public void Release(ISelectionRules rules, Vector2 at, float clickDistance, bool add, double now)

Ends the box being dragged out (from DragFrom) with the mouse let go at at: a click where it started if it moved less than clickDistance, otherwise a box. Nothing if none was.

Set

public bool Set(IEnumerable<Entity> entities)

Selects entities (each once), dropping the rest; true if that changed anything.

SetGroup

public void SetGroup(int number, IEnumerable<Entity> entities)

Keeps entities as control group number.