en Basic UI

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What is UIHandle?

This is a general UI system. Inheriting from UIHandle allows the code to be automatically managed by the UI system, handling both logical updates and drawing updates.

When using UIHandle, the two functions we need to pay the most attention to are Update and Draw, which are responsible for logic updates and drawing updates, respectively.

Below is an example of usage from InnoVaultExample.

internal class ExampleUI : UIHandle
{
    // This property by default points to Vanilla_Mouse_Text, which is the mouse text layer.
    // Its return value determines which update collection the UI will run in. 
    // Don't attempt to change this value during gameplay, it won't have any effect. 
    // The UI's update collection is only allocated once when the game loads.
    public override LayersModeEnum LayersMode => base.LayersMode;

    // Override the texture to point to the custom UI panel texture.
    public override Texture2D Texture => Mod.Assets.Request<Texture2D>("Asset/ExampleUIPanel").Value;

    internal bool _active; // Determines whether the UI is active.
    internal float _sengs; // Controls the UI transition effect.

    // The UI is considered active if `_active` is true or `_sengs` is greater than 0.
    public override bool Active => _active || _sengs > 0;

    // This method updates the UI's position and transition effect.
    public override void Update() {
        // It's important to respect the DrawPosition field and ensure a consistent draw origin.
        DrawPosition = new Vector2(Main.screenWidth / 2, Main.screenHeight / 2) + new Vector2(0, -600 + 600 * _sengs);
        if (_active) {
            // If active, increase `_sengs` to create a smooth transition.
            if (_sengs < 1) {
                _sengs += 0.02f;
            }
        }
        else {
            // If not active, decrease `_sengs` to fade the UI out.
            if (_sengs > 0) {
                _sengs -= 0.02f;
            }
        }
    }

    // This method draws the UI panel with a fade effect based on `_sengs`.
    public override void Draw(SpriteBatch spriteBatch) {
        spriteBatch.Draw(Texture, DrawPosition, null, Color.White * _sengs, 0, Vector2.Zero, 2 * _sengs, SpriteEffects.None, 0);
    }
}

This usage example is best viewed in conjunction with ExampleButtonUI.

Together, they demonstrate how different UI elements should interact with each other.