converter work on demand

src/engine/functions/index.ts

@@ -85,14 +85,14 @@ export abstract class Behaviour {
 
     protected abstract give(resource: Resource, amount: DecimalSource): void;
 
-    abstract produce(times: DecimalSource): void;
-
-    /** Pulls into this behaviour's own storage the same number of cycles this tick's `tick()` call just completed. */
-    abstract pull(resolve: (id: string) => Behaviour | undefined): void;
-
     abstract reset(): void;
 
-    abstract tick(deltaTime: number): void;
+    /**
+     * Advances this behaviour by `deltaTime`. Must pull whatever inputs it needs (via `resolve`)
+     * before advancing its own cycle, so that a cycle only completes once enough input was actually
+     * available — otherwise it stalls and tries again on a later tick.
+     */
+    abstract tick(deltaTime: number, resolve: (id: string) => Behaviour | undefined): void;
 }
 
 export class Converter extends Behaviour {
@@ -101,8 +101,6 @@ export class Converter extends Behaviour {
     public readonly cycleLength: Decimal;
     public readonly inputRates: Partial<Resources>;
     public readonly outputRates: Partial<Resources>;
-    /** Number of full cycles completed by the most recent `tick()` call, consumed by `pull()`. */
-    private pendingCycles: Decimal = Decimal.dZero;
 
     constructor(source: SerializedNodeBehaviour & SerializedConverter) {
         if (source.kind !== 'converter')
@@ -125,30 +123,44 @@ export class Converter extends Behaviour {
             this.outputRates[res as Resource] = new Decimal(rate);
     }
 
-    public tick(deltaTime: number): void {
+    /**
+     * Advances time, pulls as much input as is available toward however many cycles that time
+     * would allow, then completes only as many full cycles as the input actually on hand supports.
+     * Any leftover cycle time is kept for later — a starved converter simply stalls until its
+     * inputs catch up, and then bursts through the backlog once they do.
+     */
+    public tick(deltaTime: number, resolve: (id: string) => Behaviour | undefined): void {
         this.cycleTime = this.cycleTime.add(deltaTime);
-        const fullCycles = this.cycleTime.div(this.cycleLength).floor();
+        const wantedCycles = this.cycleTime.div(this.cycleLength).floor();
-        this.cycleTime = this.cycleTime.sub(fullCycles.mul(this.cycleLength));
 
-        this.pendingCycles = fullCycles;
+        if (wantedCycles.gt(0)) {
-        this.produce(fullCycles);
+            for (const input of this.inputs.pins) {
-    }
+                const source = resolve(input.link.target);
+                if (!source)
+                    continue;
+                const rate = this.inputRates[input.resource] ?? Decimal.dZero;
+                const have = this.storage[input.resource] ?? Decimal.dZero;
+                const stillNeeded = rate.mul(wantedCycles).sub(have).max(0);
+                if (stillNeeded.gt(0))
+                    this.give(input.resource, source.take(input.link.resource, stillNeeded));
+            }
+        }
 
-    /** Fills this converter's own storage from its outputs' production rates. */
+        let affordableCycles = wantedCycles;
-    public produce(times: DecimalSource): void {
-        for (const output of this.outputs.pins)
-            this.give(output.resource, (this.outputRates[output.resource] ?? Decimal.dZero).mul(times));
-    }
-
-    /** Pulls resources into this converter's storage from whatever each input pin is linked to, scaled by the cycles this tick's `tick()` just completed. */
-    public pull(resolve: (id: string) => Behaviour | undefined): void {
         for (const input of this.inputs.pins) {
-            const source = resolve(input.link.target);
-            if (!source)
-                continue;
             const rate = this.inputRates[input.resource] ?? Decimal.dZero;
-            const taken = source.take(input.link.resource, rate.mul(this.pendingCycles));
+            if (rate.eq(0))
-            this.give(input.resource, taken);
+                continue;
+            const have = this.storage[input.resource] ?? Decimal.dZero;
+            affordableCycles = affordableCycles.min(have.div(rate).floor());
+        }
+
+        if (affordableCycles.gt(0)) {
+            for (const input of this.inputs.pins)
+                this.take(input.resource, (this.inputRates[input.resource] ?? Decimal.dZero).mul(affordableCycles));
+            for (const output of this.outputs.pins)
+                this.give(output.resource, (this.outputRates[output.resource] ?? Decimal.dZero).mul(affordableCycles));
+            this.cycleTime = this.cycleTime.sub(affordableCycles.mul(this.cycleLength));
         }
     }
 

src/types/index.ts

@@ -12,6 +12,30 @@ export type Node = {
     behaviour: Behaviour;
 }
 
+/** Orders behaviours so that whatever a behaviour's inputs link to comes before it (a dependency cycle just falls back to encounter order). */
+function orderByDependency(behaviours: Behaviour[]): Behaviour[] {
+    const byId = new Map(behaviours.map((behaviour) => [behaviour.id, behaviour]));
+    const visited = new Set<string>();
+    const order: Behaviour[] = [];
+
+    function visit(behaviour: Behaviour) {
+        if (visited.has(behaviour.id))
+            return;
+        visited.add(behaviour.id);
+        for (const input of behaviour.inputs.pins) {
+            const dependency = byId.get(input.link.target);
+            if (dependency)
+                visit(dependency);
+        }
+        order.push(behaviour);
+    }
+
+    for (const behaviour of behaviours)
+        visit(behaviour);
+
+    return order;
+}
+
 export class Game {
     public time: Decimal;
     public readonly nodes: Node[];
@@ -29,11 +53,12 @@ export class Game {
         this.time = this.time.add(deltaTime);
 
         const behavioursById = new Map(this.nodes.map((node) => [node.behaviour.id, node.behaviour]));
+        const resolve = (id: string) => behavioursById.get(id);
 
-        for (const node of this.nodes)
+        // Producers must tick (and so fill their storage) before whatever pulls from them,
-            node.behaviour.tick(deltaTime);
+        // so resources can flow all the way down a chain within a single tick.
-        for (const node of this.nodes)
+        for (const behaviour of orderByDependency(this.nodes.map((node) => node.behaviour)))
-            node.behaviour.pull((id) => behavioursById.get(id));
+            behaviour.tick(deltaTime, resolve);
     }
 
     public reset() {