Extra Effect Cardmods

Adding an entirely new effect to a card is made easier with cardmods, however, getting those effects to scale as the player might expect and displaying that scaling is more cumbersome to do.

ExtraEffectModifier is intended to make use of DynamicProvider to help make both of these things much easier to implement in a standardized fashion. It also includes features intended to make it easier to handle the stacking of similar modifiers.

An extending class must implement a makeCopy as is standard with cardmods and must also implement an ID to be used for checking stackability, and then must specify what extra effects happen when use is called as well as what text will be added to the card.

ExtraEffectModifier helps you by automatically formatting this text, so you only need to return a string where %s is in place where you would normally put the dynamic variable.

An example extra effect modifier (skipping proper localization) might look like this:

public class ExampleExtraEffect extends ExtraEffectModifier {
    private static final String ID = "stslib:ExampleExtraEffect";

    public ExampleExtraEffect() {
        super(VariableType.DAMAGE, 6);
    }

    @Override
    public void doExtraEffects(AbstractCard card, AbstractPlayer p, AbstractCreature m, UseCardAction useAction) {
        AbstractDungeon.actionManager.addToBottom(new DamageAction(m, new DamageInfo(p, value(card))));
    }

    @Override
    public String getExtraText(AbstractCard card) {
        return "Deal %s damage.";
    }

    @Override
    public String getEffectId(AbstractCard card) {
        return ID;
    }

    @Override
    public AbstractCardModifier makeCopy() {
        return new ExampleExtraEffect();
    }
}

The above code results in this when applied to a strike, including automatic stacking behavior:

Full documentation of the features available to ExtraEffectModifier can be found in its javadocs here.