Do not choose direction lock side automatically, instead make it toggleable

src/js/game/hud/parts/building_placer_logic.js

@@ -78,10 +78,10 @@ export class HUDBuildingPlacerLogic extends BaseHUDPart {
         this.lastDragTile = null;
 
         /**
-         * Interpolate the side for direction lock slowly so it doesn't flicker
-         * @type {number}
+         * The side for direction lock
+         * @type {number} (0|1)
          */
-        this.interpolatedDirectionLockSide = 0;
+        this.currentDirectionLockSide = 0;
 
         this.initializeBindings();
     }
@@ -94,6 +94,9 @@ export class HUDBuildingPlacerLogic extends BaseHUDPart {
         const keyActionMapper = this.root.keyMapper;
         keyActionMapper.getBinding(KEYMAPPINGS.placement.rotateWhilePlacing).add(this.tryRotate, this);
         keyActionMapper.getBinding(KEYMAPPINGS.placement.cycleBuildingVariants).add(this.cycleVariants, this);
+        keyActionMapper
+            .getBinding(KEYMAPPINGS.placement.switchDirectionLockSide)
+            .add(this.switchDirectionLockSide, this);
         keyActionMapper
             .getBinding(KEYMAPPINGS.placement.abortBuildingPlacement)
             .add(this.abortPlacement, this);
@@ -146,30 +149,13 @@ export class HUDBuildingPlacerLogic extends BaseHUDPart {
         const worldPos = this.root.camera.screenToWorld(mousePosition);
         const mouseTile = worldPos.toTileSpace();
 
-        if (this.interpolatedDirectionLockSide <= 0) {
+        if (this.currentDirectionLockSide === 0) {
             return new Vector(this.lastDragTile.x, mouseTile.y);
         } else {
             return new Vector(mouseTile.x, this.lastDragTile.y);
         }
     }
 
-    /**
-     * Computes on which side the direction lock should be active
-     * @returns {-1|0|1}
-     */
-    get currentDirectionLockSide() {
-        const mousePosition = this.root.app.mousePosition;
-        if (!mousePosition) {
-            // Not on screen
-            return 0;
-        }
-        const worldPos = this.root.camera.screenToWorld(mousePosition);
-        const mouseTile = worldPos.toTileSpace();
-
-        const fractional = worldPos.sub(mouseTile.toWorldSpaceCenterOfTile());
-        return fractional.x + fractional.y < 0 ? -1 : 1;
-    }
-
     /**
      * Aborts the placement
      */
@@ -199,13 +185,6 @@ export class HUDBuildingPlacerLogic extends BaseHUDPart {
         if (mousePos) {
             this.onMouseMove(mousePos);
         }
-
-        // Prevent flickering by interpolating the side
-        this.interpolatedDirectionLockSide = lerp(
-            this.interpolatedDirectionLockSide,
-            this.currentDirectionLockSide,
-            0.04
-        );
     }
 
     /**
@@ -241,6 +220,10 @@ export class HUDBuildingPlacerLogic extends BaseHUDPart {
         }
     }
 
+    switchDirectionLockSide() {
+        this.currentDirectionLockSide = 1 - this.currentDirectionLockSide;
+    }
+
     /**
      * Checks if the direction lock key got released and if such, resets the placement
      * @param {any} args

src/js/game/hud/parts/keybinding_overlay.js

@@ -92,6 +92,11 @@ export class HUDKeybindingOverlay extends BaseHUDPart {
                 )}</code>
                 <label>${T.ingame.keybindingsOverlay.lockBeltDirection}</label>
             </div>
+
+            <div class="binding placementOnly directionLock">
+                <code class="keybinding">${getKeycode(KEYMAPPINGS.placement.switchDirectionLockSide)}</code>
+                <label>${T.ingame.keybindingsOverlay.plannerSwitchSide}</label>
+            </div>
         `
         );
     }

src/js/game/key_action_mapper.js

@@ -61,6 +61,7 @@ export const KEYMAPPINGS = {
         rotateInverseModifier: { keyCode: 16 }, // SHIFT
         cycleBuildingVariants: { keyCode: key("T") },
         cycleBuildings: { keyCode: 9 }, // TAB
+        switchDirectionLockSide: { keyCode: key("R") },
     },
 
     massSelect: {

translations/base-en.yaml

@@ -284,6 +284,7 @@ ingame:
         delete: Destroy
         pasteLastBlueprint: Paste last blueprint
         lockBeltDirection: Enable belt planner
+        plannerSwitchSide: Flip planner side
 
     # Everything related to placing buildings (I.e. as soon as you selected a building
     # from the toolbar)
@@ -743,6 +744,8 @@ keybindings:
         pasteLastBlueprint: Paste last blueprint
         cycleBuildings: Cycle Buildings
         lockBeltDirection: Enable belt planner
+        switchDirectionLockSide: >-
+            Planner: Switch side
 
         massSelectStart: Hold and drag to start
         massSelectSelectMultiple: Select multiple areas