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Ranged combat: Archery (bow) — projectile, line-of-sight, ranged range #111

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opened 2026-07-20 18:37:36 +02:00 by marco · 2 comments

marco commented

2026-07-20 18:37:36 +02:00

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Part of the Alpha epic (pillar 3). Combat is melee-only (CombatSystem.InRange = melee range). Add ranged combat so PvP has real variety: a bow that hits at distance, requires line of sight, and is dodgeable.

Build a general ranged path in CombatSystem, not a bow special-case — a weapon declares its range and whether it is ranged. Reuse the projectile/targeting precedent from BoltSpell (targeted elemental projectile + LOS + range re-check at resolution) so spells and ranged weapons share the model.

Scope

Weapon range as data on BaseWeapon (melee weapons = 1; bow = N); CombatSystem uses it instead of a fixed melee range.
Add Archery skill and a bow (BaseWeapon subclass) driving hit chance via Archery.
Line-of-sight requirement for ranged swings, checked server-side against statics/map (a target behind a wall can't be hit — ties into the arena statics).
Re-check range/LOS at resolution so a target that breaks LOS or leaves range dodges (mirrors the melee ResolveDue behavior and BoltSpell).
Broadcast the projectile so clients can animate it within AoI (reuse the spell projectile broadcast if possible; bump ProtocolVersion.Current if the wire changes).

Out of scope

Ammo/quiver consumption, arrow items (assume infinite for alpha).
Cover/partial-cover mechanics beyond hard LOS.

Definition of Done

Base DoD applies on top.

A player with a bow hits another player at ranged distance; a melee weapon cannot reach that far (unit-tested against CombatSystem).
A target that steps behind a static/wall or out of range before resolution is not hit.
The projectile is visible to clients within AoI, over the versioned protocol.

Part of the Alpha epic (pillar 3). Combat is melee-only (`CombatSystem.InRange` = melee range). Add **ranged combat** so PvP has real variety: a bow that hits at distance, requires line of sight, and is dodgeable. > Build a general **ranged path** in `CombatSystem`, not a bow special-case — a weapon declares its range and whether it is ranged. Reuse the projectile/targeting precedent from `BoltSpell` (targeted elemental projectile + LOS + range re-check at resolution) so spells and ranged weapons share the model. ## Scope - Weapon range as data on `BaseWeapon` (melee weapons = 1; bow = N); `CombatSystem` uses it instead of a fixed melee range. - Add `Archery` skill and a bow (`BaseWeapon` subclass) driving hit chance via Archery. - Line-of-sight requirement for ranged swings, checked server-side against statics/map (a target behind a wall can't be hit — ties into the arena statics). - Re-check range/LOS at resolution so a target that breaks LOS or leaves range dodges (mirrors the melee `ResolveDue` behavior and `BoltSpell`). - Broadcast the projectile so clients can animate it within AoI (reuse the spell projectile broadcast if possible; **bump `ProtocolVersion.Current`** if the wire changes). ## Out of scope - Ammo/quiver consumption, arrow items (assume infinite for alpha). - Cover/partial-cover mechanics beyond hard LOS. ## Definition of Done _Base DoD applies on top._ - [ ] A player with a bow hits another player at ranged distance; a melee weapon cannot reach that far (unit-tested against `CombatSystem`). - [ ] A target that steps behind a static/wall or out of range before resolution is not hit. - [ ] The projectile is visible to clients within AoI, over the versioned protocol.

marco added this to the Alpha milestone

2026-07-20 18:37:36 +02:00

marco added the

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alpha:wave-2

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2026-07-20 18:37:36 +02:00

marco referenced this issue

2026-07-20 19:06:26 +02:00

Static content system (runtime): sparse statics, server collision, client render #89

marco referenced this issue

2026-07-20 19:06:46 +02:00

Alpha — epic: PvP arena for friends #107

marco referenced this issue

2026-07-22 13:37:07 +02:00

Static content system (runtime): sparse statics, server collision, client render #89

marco referenced this issue

2026-07-22 17:17:08 +02:00

AoI: line-of-sight filter (don't stream entities through walls) #150

marco commented

2026-07-22 17:25:46 +02:00

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Owner

Note (from the arena LoS discussion): server-side attack line-of-sight is now centralized for spells in the new TargetedSpell base (one place does target+range+LoS; bolts derive from it). When Archery lands here, build the ranged path to reuse a shared reach check (range + LoS) across melee / bolt / arrow rather than re-implementing it — the same 'no hitting through a wall' rule the arena cover depends on. Don't duplicate the LoS check per attack type.

Note (from the arena LoS discussion): server-side attack line-of-sight is now centralized for **spells** in the new `TargetedSpell` base (one place does target+range+LoS; bolts derive from it). When Archery lands here, build the ranged path to **reuse a shared reach check (range + LoS)** across melee / bolt / arrow rather than re-implementing it — the same 'no hitting through a wall' rule the arena cover depends on. Don't duplicate the LoS check per attack type.

marco commented

2026-07-23 19:41:33 +02:00

Author

Owner

Design review — agreed (ranged combat / Archery)

Owner decisions: bow range 8 (≤ AoI radius); LOS checked unconditionally in the combat path (no-op for melee, since adjacent tiles have no interior cell); a single generic Projectile wire message serves both spells and ranged (replaces SpellBolt); ammo/arrow-item stays out of scope (infinite arrows for alpha) — we only ship the bow item art + the flying-arrow projectile effect art.

Recommendation (build)

SkillName — append Archery; SkillCatalog — add its row (auto-seeds on new players; no save-version bump — enum appended at the end keeps ordinals stable).
BaseWeapon — add abstract int Range. Sword/Greatsword return 1. New Bow : BaseWeapon (Kind "bow", TwoHanded, Skill => Archery, Range => 8, own damage/cooldown, real bow Graphic). Auto-discovered by ItemCatalog; /give bow works with no command change.
Mobile — projected WeaponRange (unarmed baseline 1), set by Arm(...). Derived, re-applied by RestoreEquipped; not persisted.
CombatSystem — inject TileMap; InRange compares attacker.WeaponRange; add unconditional HasLineOfSight gate in both TryStartSwing and ResolveDue. Carry a ranged/projectile marker on the attack outcome so transport emits the projectile.
Shared/Protocol — Projectile(Guid SourceId, Guid TargetId, string Art, int Damage, bool Hit) replacing SpellBolt; art is a data-driven id string (no client type-switch). Bump ProtocolVersion.Current 10 → 11.
WorldTick — on ranged swing resolution emit Projectile(Art="arrow_shot") to PlayersWithin(attackerPosition, radius); spells migrate SpellBolt→Projectile (Art="fire_bolt"/"water_bolt"). Melee keeps Attacked.
Client — dispatcher migrates SpellBolt→Projectile, VFX draws the effect by art id; projectile timing/interp in Client.Core.
Assets — extract real UO bow + arrow-effect art, descriptive names (wood_bow, arrow_shot), update docs/uo-asset-map.md.

Invariants Check

Scope ✓ — only #111's ranged path; ammo/arrow-item deferred. Unifying the projectile is within the issue's "reuse the spell projectile broadcast" intent.
Server-authoritative ✓ — client sends only Attack(TargetId); server decides range from equipped weapon, validates Chebyshev range + LOS at start AND re-validates at resolution. Pending-swing guard + cooldown throttle the intent.
GM authorization N/A — no admin action; /give bow reuses admin-gated GiveCommand.
Identity model N/A.
Protocol versioned ✗→resolved — replacing SpellBolt with Projectile changes the spell wire and adds ranged ⇒ bump ProtocolVersion.Current 10→11 same change; type in Shared/Protocol.
String catalog ✓ — no new player-facing copy (silent whiff like melee; reuse OutOfRange/NoLineOfSight if any feedback added).
Single-threaded sim ✓ — range/LOS/resolution on the sim thread; CombatSystem gains no lock; injected TileMap read-only.
World.cs HARD GATE ✓ — new logic in CombatSystem; World.TryStartSwing stays a delegate; map passed via ctor.
Screen HARD GATE (client) ✓ — dispatcher migrates the handler SpellBolt→Projectile; arrow animation in the VFX component; no case/draw pass in GameScreen.
Client engine-independence ✓ — projectile timing/interp math in Client.Core, unit-tested; only the draw call in MonoGame Client.
Gameplay/Networking separation ✓ — rules in CombatSystem/Spells; wire + AoI send in WorldTick/Networking.
Act on the instance ✓ — WeaponRange projected onto the Mobile via Arm(...), no side dict; Archery in the mobile's SkillSet.
Extend by type, not switch ✓ — Projectile carries a data-driven art-id string (client draws static/<art> generically, no per-type switch); bow = auto-discovered subclass; Archery = enum + one catalog row.
Server-paced actions ✓ — shot advances on ticks via PendingSwing.ResolveAtTick; can't be client-compressed; projectile publicly observable within AoI.
Persistence (GameServer) ✓ — bow persists as an Item (kind string, auto-discovered), no Item version bump; Archery serializes in the existing count-prefixed skill list, no PlayerMobile version bump (append enum at end; old saves seed default). No cross-player refs, no tick-loop IO.
Persistence (Auth) N/A.
Process separation N/A.
Typed options ✓ — weapon range is a constant on the type; unarmed baseline in CombatOptions; no IConfiguration read.
Broadcasts absolute / AoI / transient ✓ — Projectile is a transient event, sent only to PlayersWithin(sourcePos, AoiRadius) at emit time, absolute ids, no HP/deltas, never global. No new reconciled entity → InterestDiff unchanged.
Multi-platform ✓ — pure .NET / MonoGame; no OS-specific API.
Assets required ✗→must-resolve — bow item art + arrow projectile art must be real extracted UO art in assets.isoa; no placeholder shape; missing static/<id> simply not drawn.
Asset naming HARD GATE ✗→must-resolve — descriptive names (wood_bow, arrow_shot), never bare bow/arrow; mirror in docs/uo-asset-map.md.
ModernUO reference ✓ — weapon-arms-the-mobile + skill-vs-skill hit chance; diverge by keeping resolution-time range/LOS re-checks (server-paced honesty, #75).
Docs & DoD same change ✓ — update combat doc + uo-asset-map.md; DoD already in issue; gm-commands.md unchanged (/give data-driven).

Server-side validation (trust boundary)

Intent: Attack(TargetId) (unchanged, no position/range/result). Server validates at swing start: both engageable & alive, no pending swing, ChebyshevDistance ≤ equipped-weapon range, HasLineOfSight vs authoritative TileMap. Re-validates at resolution: same range + LOS + liveness — a target that broke LOS/range whiffs (no arrow, no damage). Hit is a server RNG roll on Archery vs defender skill; damage applied server-side. Forged/out-of-range/no-LOS targets dropped with continue, tick intact.

Verification plan

Unit (against CombatSystem/World) — primary level, no networking:
- Bow hits at range 8 (clear LOS); sword (Range 1) at that distance refused by TryStartSwing. [DoD #1]
- Trust boundary: target leaves range between start and ResolveDue → whiff; target steps behind a blocking static → whiff; melee at range 1 still lands (LOS no-op). [DoD #2]
- Shot blocked by a wall at start is refused at start. Archery drives hit chance (0 vs high ≈ min; high ≈ high).
- Persistence round-trip: equip bow + gain Archery → serialize/deserialize → WeaponSkill == Archery, WeaponRange == 8 re-derived, Archery value restored; an old blob without Archery loads with the seeded default (no version bump).
- Spell regression: Projectile replaces SpellBolt without breaking fire/water bolt resolution + damage display.
WebSocket flow (CreateWebSocketClient) — in-AoI observer receives Projectile (+ Attacked for melee); out-of-AoI receives nothing; stale-version client rejected 426. [DoD #3]
Screenshots (visible → required) — debug harness, fresh DB (delete world.sav* + Auth/game DBs). Two clients: /give bow → equip → /setskill archery 1000, position at range with clear LOS, Attack → capture (a) arrow in flight, (b) hit + floating damage; reposition behind the arena wall → capture (c) the shot whiffing (no arrow / no damage). Flag if the harness can't yet drive equip+attack across two clients.

## Design review — agreed (ranged combat / Archery) Owner decisions: bow range **8** (≤ AoI radius); LOS checked **unconditionally** in the combat path (no-op for melee, since adjacent tiles have no interior cell); a single **generic `Projectile`** wire message serves both spells and ranged (replaces `SpellBolt`); ammo/arrow-item stays **out of scope** (infinite arrows for alpha) — we only ship the bow item art + the flying-arrow projectile effect art. ### Recommendation (build) 1. `SkillName` — append `Archery`; `SkillCatalog` — add its row (auto-seeds on new players; no save-version bump — enum appended at the end keeps ordinals stable). 2. `BaseWeapon` — add `abstract int Range`. `Sword`/`Greatsword` return `1`. New `Bow : BaseWeapon` (`Kind "bow"`, `TwoHanded`, `Skill => Archery`, `Range => 8`, own damage/cooldown, real bow `Graphic`). Auto-discovered by `ItemCatalog`; `/give bow` works with no command change. 3. `Mobile` — projected `WeaponRange` (unarmed baseline `1`), set by `Arm(...)`. Derived, re-applied by `RestoreEquipped`; not persisted. 4. `CombatSystem` — inject `TileMap`; `InRange` compares `attacker.WeaponRange`; add unconditional `HasLineOfSight` gate in **both** `TryStartSwing` and `ResolveDue`. Carry a ranged/projectile marker on the attack outcome so transport emits the projectile. 5. `Shared/Protocol` — `Projectile(Guid SourceId, Guid TargetId, string Art, int Damage, bool Hit)` **replacing** `SpellBolt`; art is a data-driven id string (no client type-switch). **Bump `ProtocolVersion.Current` 10 → 11.** 6. `WorldTick` — on ranged swing resolution emit `Projectile(Art="arrow_shot")` to `PlayersWithin(attackerPosition, radius)`; spells migrate `SpellBolt`→`Projectile` (`Art="fire_bolt"/"water_bolt"`). Melee keeps `Attacked`. 7. Client — dispatcher migrates `SpellBolt`→`Projectile`, VFX draws the effect by art id; projectile timing/interp in `Client.Core`. 8. Assets — extract real UO bow + arrow-effect art, descriptive names (`wood_bow`, `arrow_shot`), update `docs/uo-asset-map.md`. ### Invariants Check 1. Scope ✓ — only #111's ranged path; ammo/arrow-item deferred. Unifying the projectile is within the issue's "reuse the spell projectile broadcast" intent. 2. Server-authoritative ✓ — client sends only `Attack(TargetId)`; server decides range from equipped weapon, validates Chebyshev range + LOS at start AND re-validates at resolution. Pending-swing guard + cooldown throttle the intent. 3. GM authorization N/A — no admin action; `/give bow` reuses admin-gated `GiveCommand`. 4. Identity model N/A. 5. Protocol versioned ✗→resolved — replacing `SpellBolt` with `Projectile` changes the spell wire and adds ranged ⇒ **bump `ProtocolVersion.Current` 10→11** same change; type in `Shared/Protocol`. 6. String catalog ✓ — no new player-facing copy (silent whiff like melee; reuse `OutOfRange`/`NoLineOfSight` if any feedback added). 7. Single-threaded sim ✓ — range/LOS/resolution on the sim thread; `CombatSystem` gains no lock; injected `TileMap` read-only. 8. World.cs HARD GATE ✓ — new logic in `CombatSystem`; `World.TryStartSwing` stays a delegate; map passed via ctor. 9. Screen HARD GATE (client) ✓ — dispatcher migrates the handler `SpellBolt`→`Projectile`; arrow animation in the VFX component; no `case`/draw pass in `GameScreen`. 10. Client engine-independence ✓ — projectile timing/interp math in `Client.Core`, unit-tested; only the draw call in MonoGame `Client`. 11. Gameplay/Networking separation ✓ — rules in `CombatSystem`/`Spells`; wire + AoI send in `WorldTick`/`Networking`. 12. Act on the instance ✓ — `WeaponRange` projected onto the `Mobile` via `Arm(...)`, no side dict; Archery in the mobile's `SkillSet`. 13. Extend by type, not switch ✓ — `Projectile` carries a data-driven art-id string (client draws `static/<art>` generically, no per-type switch); bow = auto-discovered subclass; Archery = enum + one catalog row. 14. Server-paced actions ✓ — shot advances on ticks via `PendingSwing.ResolveAtTick`; can't be client-compressed; projectile publicly observable within AoI. 15. Persistence (GameServer) ✓ — bow persists as an `Item` (kind string, auto-discovered), no `Item` version bump; Archery serializes in the existing count-prefixed skill list, **no `PlayerMobile` version bump** (append enum at end; old saves seed default). No cross-player refs, no tick-loop IO. 16. Persistence (Auth) N/A. 17. Process separation N/A. 18. Typed options ✓ — weapon range is a constant on the type; unarmed baseline in `CombatOptions`; no `IConfiguration` read. 19. Broadcasts absolute / AoI / transient ✓ — `Projectile` is a transient event, sent only to `PlayersWithin(sourcePos, AoiRadius)` at emit time, absolute ids, no HP/deltas, never global. No new reconciled entity → `InterestDiff` unchanged. 20. Multi-platform ✓ — pure .NET / MonoGame; no OS-specific API. 21. Assets required ✗→must-resolve — bow item art + arrow projectile art must be real extracted UO art in `assets.isoa`; no placeholder shape; missing `static/<id>` simply not drawn. 22. Asset naming HARD GATE ✗→must-resolve — descriptive names (`wood_bow`, `arrow_shot`), never bare `bow`/`arrow`; mirror in `docs/uo-asset-map.md`. 23. ModernUO reference ✓ — weapon-arms-the-mobile + skill-vs-skill hit chance; diverge by keeping resolution-time range/LOS re-checks (server-paced honesty, #75). 24. Docs & DoD same change ✓ — update combat doc + `uo-asset-map.md`; DoD already in issue; `gm-commands.md` unchanged (`/give` data-driven). ### Server-side validation (trust boundary) Intent: `Attack(TargetId)` (unchanged, no position/range/result). Server validates at swing start: both engageable & alive, no pending swing, `ChebyshevDistance ≤ equipped-weapon range`, `HasLineOfSight` vs authoritative `TileMap`. Re-validates at resolution: same range + LOS + liveness — a target that broke LOS/range whiffs (no arrow, no damage). Hit is a server RNG roll on Archery vs defender skill; damage applied server-side. Forged/out-of-range/no-LOS targets dropped with `continue`, tick intact. ### Verification plan - **Unit (against `CombatSystem`/`World`)** — primary level, no networking: - Bow hits at range 8 (clear LOS); sword (Range 1) at that distance refused by `TryStartSwing`. [DoD #1] - Trust boundary: target leaves range between start and `ResolveDue` → whiff; target steps behind a blocking static → whiff; melee at range 1 still lands (LOS no-op). [DoD #2] - Shot blocked by a wall at start is refused at start. Archery drives hit chance (0 vs high ≈ min; high ≈ high). - Persistence round-trip: equip bow + gain Archery → serialize/deserialize → `WeaponSkill == Archery`, `WeaponRange == 8` re-derived, Archery value restored; an old blob without Archery loads with the seeded default (no version bump). - Spell regression: `Projectile` replaces `SpellBolt` without breaking fire/water bolt resolution + damage display. - **WebSocket flow (`CreateWebSocketClient`)** — in-AoI observer receives `Projectile` (+ `Attacked` for melee); out-of-AoI receives nothing; stale-version client rejected 426. [DoD #3] - **Screenshots (visible → required)** — debug harness, fresh DB (delete `world.sav*` + Auth/game DBs). Two clients: `/give bow` → equip → `/setskill archery 1000`, position at range with clear LOS, `Attack` → capture (a) arrow in flight, (b) hit + floating damage; reposition behind the arena wall → capture (c) the shot whiffing (no arrow / no damage). Flag if the harness can't yet drive equip+attack across two clients.

marco referenced this issue from a pull request that will close it,

2026-07-23 23:06:06 +02:00

feat: ranged combat (archery) — bow, line-of-sight, generic projectile #175

marco closed this issue

2026-07-23 23:09:16 +02:00

marco referenced this issue from a commit

2026-07-23 23:09:18 +02:00

feat: ranged combat (archery) — bow, line-of-sight, generic projectile (#175)