Advice/Guidance - ability system design

[bolom009]

Hello everyone :)
I wanna rise a small topic about ability system in ECS, so maybe someone know good article, book, video about designing ability system using ECS architecture?

I am experiencing some difficulties with skill modification, when you have described skill that consuming mana and for example player chose modification that will change skill to consume health instead of mana but increased spell damage of skill in 35%.

Here are a few links that I analyzed
https://habr.com/ru/articles/848572/
https://habr.com/ru/articles/454876/
https://habr.com/ru/articles/771342/

Example of my code what I did (props Damage and Mana taking from yaml config)

type HeavyStrike struct {
	Damage int32 `mapstructure:"damage"`
	ManaCost   int32 `mapstructure:"mana_cost"`

	damageEvent *ecs.Map[components.DamageEvent] `mapstructure:",remain"`
	target      *ecs.Map[components.Target]      `mapstructure:",remain"`
	mana        *ecs.Map[components.Mana]        `mapstructure:",remain"`
}

func (h *HeavyStrike) Init(w *ecs.World) {
	h.damageEvent = h.damageEvent.New(w)
	h.target = h.target.New(w)
	h.mana = h.mana.New(w)
}

func (h *HeavyStrike) Name() string {
	return "heavy_strike"
}

func (h *HeavyStrike) CheckCast(caster ecs.Entity) bool {
	mana := h.mana.Get(caster)
	return int32(mana.Current) >= h.ManaCost
}

func (h *HeavyStrike) Consume(caster ecs.Entity) {
	mana := h.mana.Get(caster)
	mana.Remove(float32(h.ManaCost))
}

func (h *HeavyStrike) Execute(caster ecs.Entity, point geom.Vector2, level int) {
	target := h.target.Get(caster)
	if target.Entity.IsZero() {
		return
	}

	h.damageEvent.NewEntity(&components.DamageEvent{
		Amount:   h.Damage,
		Modifier: combat.DamageModifierNormal,
		Type:     combat.DamageTypePure,
		Attacker: caster,
		Target:   target.Entity,
	})
}

[mlange-42]

Sorry, but I do not really understand what you want to do and what the question is. The Google translation of the posts you linked is also very weak, so don't get your intent from this, too.

Can't you express this by swapping out components on an entity? Why do you create a new entitiy, shouldn't it rather an existing entity like the player?

[bolom009]

I'm trying to understand how to organize ability system using ECS and honestly I tried to find this info but is sooo hard. What is the best way? Keep skill as another entity and link it to entity or? I did Skills component that I applied to player entity and iterate it to check if its possible to use skill and I faced with problem when I wanna add to skill new behaviour that i described below. It could be another modifier like less damage but lifesteal or else :) If you have an experience with creation ability system please can you share your minds)))

[mlange-42]

Sorry, but I still don't understant what you want to do, or what you mean by an ability system.

Could you share an example that is implemented without ECS? If you don't now how to implement it without ECS, maybe you should ask in some general game dev forum for that first? Usually, it is quite straight forward to go from non-ECS to ECS when the basic principles are clear.

[bolom009]

Ok, so I'm moving forward in this topic and going to share the results after all tests and final design :)