Make miners cache mined item

Saves two chunk+tile lookups per update, and one chunk+tile lookup per
draw.

src/js/game/buildings/miner.js

@@ -44,9 +44,15 @@ export class MetaMinerBuilding extends MetaBuilding {
     /**
      * Creates the entity at the given location
      * @param {Entity} entity
+     * @param {GameRoot} root
      */
-    setupEntityComponents(entity) {
-        entity.addComponent(new MinerComponent({}));
+    setupEntityComponents(entity, root) {
+        let itemBelow = null;
+        if (root) {
+            const staticComp = entity.components.StaticMapEntity;
+            itemBelow = root.map.getLowerLayerContentXY(staticComp.origin.x, staticComp.origin.y);
+        }
+        entity.addComponent(new MinerComponent({ minedItem: itemBelow }));
         entity.addComponent(
             new ItemEjectorComponent({
                 slots: [{ pos: new Vector(0, 0), direction: enumDirection.top }],

src/js/game/components/miner.js

@@ -15,6 +15,7 @@ export class MinerComponent extends Component {
         return {
             lastMiningTime: types.ufloat,
             chainable: types.bool,
+            minedItem: types.nullable(types.obj(gItemRegistry)),
             itemChainBuffer: types.array(types.obj(gItemRegistry)),
         };
     }
@@ -22,12 +23,15 @@ export class MinerComponent extends Component {
     duplicateWithoutContents() {
         return new MinerComponent({
             chainable: this.chainable,
+            minedItem: this.minedItem
         });
     }
 
     /**
+     * 
+     * @param {{chainable?: boolean, minedItem?: BaseItem}} param0 
      */
-    constructor({ chainable = false }) {
+    constructor({ chainable = false, minedItem = null }) {
         super();
         this.lastMiningTime = 0;
         this.chainable = chainable;
@@ -38,6 +42,11 @@ export class MinerComponent extends Component {
          * @type {Array<BaseItem>}
          */
         this.itemChainBuffer = [];
+
+        /**
+         * @type {BaseItem}
+         */
+        this.minedItem = minedItem;
     }
 
     /**

src/js/game/systems/miner.js

@@ -24,10 +24,8 @@ export class MinerSystem extends GameSystemWithFilter {
             // Check if miner is above an actual tile
 
             const minerComp = entity.components.Miner;
-            const staticComp = entity.components.StaticMapEntity;
 
-            const tileBelow = this.root.map.getLowerLayerContentXY(staticComp.origin.x, staticComp.origin.y);
-            if (!tileBelow) {
+            if (!minerComp.minedItem) {
                 continue;
             }
 
@@ -40,20 +38,9 @@ export class MinerSystem extends GameSystemWithFilter {
             }
 
             if (this.root.time.isIngameTimerExpired(minerComp.lastMiningTime, 1 / miningSpeed)) {
-                const lowerLayerItem = this.root.map.getLowerLayerContentXY(
-                    staticComp.origin.x,
-                    staticComp.origin.y
-                );
-
-                // TODO: Should not be required actually
-                if (!lowerLayerItem) {
-                    // Nothing below;
-                    continue;
-                }
-
-                if (this.tryPerformMinerEject(entity, lowerLayerItem)) {
+                if (this.tryPerformMinerEject(entity, minerComp.minedItem)) {
                     // Analytics hook
-                    this.root.signals.itemProduced.dispatch(lowerLayerItem);
+                    this.root.signals.itemProduced.dispatch(minerComp.minedItem);
 
                     // Actually mine
                     minerComp.lastMiningTime = this.root.time.now();
@@ -114,18 +101,14 @@ export class MinerSystem extends GameSystemWithFilter {
 
                 if (entity && entity.components.Miner) {
                     const staticComp = entity.components.StaticMapEntity;
+                    const minerComp = entity.components.Miner;
                     if (!staticComp.shouldBeDrawn(parameters)) {
                         continue;
                     }
 
-                    const lowerLayerItem = this.root.map.getLowerLayerContentXY(
-                        staticComp.origin.x,
-                        staticComp.origin.y
-                    );
-
-                    if (lowerLayerItem) {
+                    if (minerComp.minedItem) {
                         const padding = 3;
-                        parameters.context.fillStyle = lowerLayerItem.getBackgroundColorAsResource();
+                        parameters.context.fillStyle = minerComp.minedItem.getBackgroundColorAsResource();
                         parameters.context.fillRect(
                             staticComp.origin.x * globalConfig.tileSize + padding,
                             staticComp.origin.y * globalConfig.tileSize + padding,
@@ -134,8 +117,8 @@ export class MinerSystem extends GameSystemWithFilter {
                         );
                     }
 
-                    if (lowerLayerItem) {
-                        lowerLayerItem.draw(
+                    if (minerComp.minedItem) {
+                        minerComp.minedItem.draw(
                             (0.5 + staticComp.origin.x) * globalConfig.tileSize,
                             (0.5 + staticComp.origin.y) * globalConfig.tileSize,
                             parameters