From 4c337f357995b18fb24497a1bb1469cf2236f750 Mon Sep 17 00:00:00 2001
From: Tangent Wantwight <tangent128@gmail.com>
Date: Sat, 15 Feb 2020 13:54:59 -0500
Subject: [PATCH] Factor strategies into helper object instead of requiring
 methods on types

---
 src/Ecs/Lockstep.ts | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/Ecs/Lockstep.ts b/src/Ecs/Lockstep.ts
index c9e54ec..1a70613 100644
--- a/src/Ecs/Lockstep.ts
+++ b/src/Ecs/Lockstep.ts
@@ -29,9 +29,13 @@ export const enum TickType {
     PREDICTED,
 }
 
-export type Advancer<Input, State> = (state: State, input: Input) => void;
+interface LockstepProcessor<Input, State> {
+    compareInput(a: Input, b: Input): boolean;
+    cloneState(source: State): State;
+    advanceState(state: State, input: Input): void;
+}
 
-export class LockstepState<Input extends Equals, State extends DeepCopy<State>> {
+export class LockstepState<Input, State> {
 
     private inputIndex = -1;
     private inputLog: Input[] = [];
@@ -40,21 +44,21 @@ export class LockstepState<Input extends Equals, State extends DeepCopy<State>>
     private renderIndex = -1;
     private renderState: State;
 
-    constructor(private initialState: State, private advancer: Advancer<Input, State>) {
-        this.canonState = initialState.deepCopy({});
-        this.renderState = initialState.deepCopy({});
+    constructor(private initialState: State, private engine: LockstepProcessor<Input, State>) {
+        this.canonState = engine.cloneState(initialState);
+        this.renderState = engine.cloneState(initialState);
     }
 
     public addCanonInput(input: Input): void {
         this.canonIndex++;
 
         // advance canonical game state
-        this.advancer(this.canonState, input);
+        this.engine.advanceState(this.canonState, input);
 
         if(this.canonIndex <= this.renderIndex) {
             // we're rendering predicted states, so if the input changes we need to invalidate the rendered state
-            if(!equals(this.inputLog[this.canonIndex], input)) {
-                this.renderState = this.canonState.deepCopy({});
+            if(!this.engine.compareInput(this.inputLog[this.canonIndex], input)) {
+                this.renderState = this.engine.cloneState(this.canonState);
                 this.renderIndex = this.canonIndex;
             }
         }
@@ -81,7 +85,7 @@ export class LockstepState<Input extends Equals, State extends DeepCopy<State>>
 
         while(this.renderIndex < targetIndex) {
             this.renderIndex++;
-            this.advancer(this.renderState, this.inputLog[this.renderIndex]);
+            this.engine.advanceState(this.renderState, this.inputLog[this.renderIndex]);
         }
 
         return this.renderState;