03 · Abilities

Eight abilities on one caster, each showing a different part of the ability system.

Scene Scenes/03_Abilities. Assets Content/03_Abilities and Content/Shared.

What it teaches

• An ability is a definition that says when and at what it can be cast, plus effect assets that say what happens.
• Cast times, channels, cooldowns and the global cooldown are fields on the definition.
• Projectiles, splash, cones and falloff are fields on the effect.
• Taking damage interrupts a cast or channel and refunds its cost, unless the ability pushes back or ignores damage instead.
• Effects need no code: cues on the ability and its area effects play particle prefabs for cast starts, casts, impacts and areas.
• Ground abilities can be aimed first. A ring shows the area and turns red out of range; a click casts.

Assets

Every ability uses Resource Kind MP, Triggers GCD on and Ignores GCD off. Damage Reaction is Interrupt on every ability except Drain Life. Every splash has Target Mask Everything and Friendly Fire off, so it only hits units of other factions.

Their ids are ability.firebolt, ability.arcane_missile, ability.frost_nova, ability.blizzard, ability.drain_life, ability.cleave, ability.heal and ability.meteor.

Chilled, a Buff Definition: Id buff.chilled, Default Duration 4, Stacking Policy Refresh, Modifiers Move Speed -0.5 with Is Percentage on, CC Category Slow.

Arcanist, the player’s Unit Definition:

The targets:

Effects

Every effect prefab is in Kit/Vfx. The cues, by field:

Unit cues play through the VtUnitPresenter on the Unit prefab. Area cues play at the centre of the area; the Loop Cue stays on Blizzard’s area until it ends. Drain Life’s impact plays on every channel tick, because the tick damage belongs to the ability.

Scene

Ground 40 × 40.

Build it yourself

1. Build the Unit, Player, FireProjectile and ArcaneProjectile prefabs as in Build the prefabs.
2. Create the eight effects, Chilled, and the eight abilities with Create → Vantage → Abilities and the values above. Drag each effect into its ability’s Effects, or into Tick Effects for Drain Life.
3. Create Arcanist and list the abilities under Granted Abilities.
4. Create the three target definitions.
5. Build the scene as in Build the shared layout with a 40 × 40 Level.
6. Place the player, add eight slots to its VtAbilityHotkeys, drag the abilities in, and set Ground Targeting to Aim And Confirm. Check that the Player prefab has VtGroundTargetIndicator.
7. Place the group, the moving target with a patrol, and the sparring partner, and set the camera’s Default Height to 17.
8. For the effects, make a particle prefab per row of the effects table, or use any effect prefabs you have, and fill the cue fields. Author area prefabs for a radius of 1 and tick Scale To Area on their cues.

Try

• Keys 1 to 8 cast. Point at a unit for single-target abilities.
• Press 4 or 8, move the ring to where the spell should land, and left-click. The ring is the area and turns red out of range. Right-click or Esc cancels; pressing the key again casts.
• Firebolt the moving target: it can walk out of the way of a straight projectile. Arcane Missile follows it.
• Start a cast next to the sparring partner: its hits interrupt the cast and refund the mana.
• Channel Drain Life next to the sparring partner: its hits shorten the channel instead of stopping it.
• Cast again during the global cooldown and read the refusal.
• Frost Nova the moving target and watch it slow down.
• F10 hides every panel, R resets the scene.

In your own game

A new behaviour is a new effect class, not a change to the ability system. See Extending.