feat: add app skeleton with balance module, arena and tower

src/balance/values.rs

@@ -0,0 +1,48 @@
+//! The raw balancing numbers (ADR-0001).
+//!
+//! **Every value in this file is a placeholder.** None of them has been tuned, and four of
+//! the numbers this file will eventually hold are not derivable from any source at all
+//! (see issue #8) — they can only be found by playing. Treat a value here as "a number that
+//! lets the skeleton walk", never as a design decision.
+//!
+//! This is the only file in the crate that holds balancing numbers. Gameplay code never
+//! sees these constants; it reads `Res<Balance>` (ADR-0001, decision point 4).
+
+use super::Stat;
+
+/// PLACEHOLDER. Distance from the tower to the rim enemies spawn on, in world units.
+/// Taken from `examples/perf_spike.rs`, where it was chosen so the whole arena fits into a
+/// 1920x1080 window without frustum culling.
+pub(super) const ARENA_RADIUS: Stat = 500.0;
+
+/// PLACEHOLDER. Enemy movement speed in world units per second.
+pub(super) const ENEMY_SPEED: Stat = 50.0;
+
+/// PLACEHOLDER. Enemy health of the one archetype the skeleton knows. The real curve is
+/// per-wave and exponential (spec, "Feststehende Zahlen"); this is the wave-1 base it will
+/// later be derived from.
+pub(super) const ENEMY_HEALTH: Stat = 10.0;
+
+/// PLACEHOLDER. Damage of a single tower shot. ADR-0002 §3: `Damage`, mode `Direct`, base > 0.
+pub(super) const TOWER_DAMAGE: Stat = 5.0;
+
+/// PLACEHOLDER. Seconds between two tower shots.
+///
+/// This is an **interval, not a rate** — ADR-0002 §3 is explicit that the stat is called
+/// `AttackInterval` and not `AttackSpeed`, so that "attack speed x1.25" becomes a divisor on
+/// a duration instead of a second accumulator. The skeleton keeps the same unit.
+pub(super) const TOWER_ATTACK_INTERVAL: Stat = 0.5;
+
+/// PLACEHOLDER. Tower health. ADR-0002 §3: `MaxHealth`, mode `Direct`, base > 0.
+pub(super) const TOWER_HEALTH: Stat = 100.0;
+
+/// PLACEHOLDER. A projectile within this distance of an enemy counts as a hit, in world
+/// units. Taken from `examples/perf_spike.rs`.
+pub(super) const HIT_RADIUS: Stat = 10.0;
+
+/// PLACEHOLDER. Meta currency granted per killed enemy.
+///
+/// The skeleton pays out a flat amount per kill. The spec ("Feststehende Zahlen") calls for
+/// drop-based meta income — a chance per normal enemy, guaranteed per boss, amount scaling
+/// with the wave. That shape needs bosses and waves, neither of which exists yet.
+pub(super) const META_GAIN_PER_KILL: Stat = 1.0;