add interactable component

src/components/GameCanvas.tsx

@@ -8,10 +8,10 @@ export interface GameCanvasProps {
 
 export const GameCanvas = ({ width, height }: GameCanvasProps) => {
   const canvasRef = useRef<HTMLCanvasElement>(null);
-  const [_game, setGame] = useState<TheAbstractionEngine>();
+  const [game, setGame] = useState<TheAbstractionEngine>();
 
   useEffect(() => {
-    if (canvasRef.current) {
+    if (canvasRef.current && !game) {
       const canvas = canvasRef.current;
       const ctx = canvas.getContext("2d");
       if (ctx) {

src/engine/TheAbstractionEngine.ts

@@ -39,8 +39,10 @@ export class TheAbstractionEngine {
     const player = new Player();
     this.game.addEntity(player);
 
-    const box = new FunctionBox({ x: 5, y: 5 });
+    const box = new FunctionBox({ x: 3, y: 1 });
     this.game.addEntity(box);
+    const box2 = new FunctionBox({ x: 4, y: 1 });
+    this.game.addEntity(box2);
   }
 
   public play() {

src/engine/components/ComponentNames.ts

@@ -4,4 +4,6 @@ export namespace ComponentNames {
   export const Grid = "Grid";
   export const BoundingBox = "BoundingBox";
   export const Control = "Control";
+  export const Highlight = "Highlight";
+  export const Interactable = "Interactable";
 }

src/engine/components/Highlight.ts

@@ -0,0 +1,7 @@
+import { Component, ComponentNames } from ".";
+
+export class Highlight extends Component {
+  constructor() {
+    super(ComponentNames.Highlight);
+  }
+}

src/engine/components/Interactable.ts

@@ -0,0 +1,15 @@
+import { Component, ComponentNames } from ".";
+
+export class Interactable extends Component {
+  private interaction: Function;
+
+  constructor(interaction: Function) {
+    super(ComponentNames.Interactable);
+
+    this.interaction = interaction;
+  }
+
+  public interact() {
+    this.interaction();
+  }
+}

src/engine/components/index.ts

@@ -5,3 +5,5 @@ export * from "./FacingDirection";
 export * from "./Grid";
 export * from "./BoundingBox";
 export * from "./Control";
+export * from "./Highlight";
+export * from "./Interactable";

src/engine/config/constants.ts

@@ -42,7 +42,7 @@ export namespace KeyConstants {
 }
 
 export namespace PhysicsConstants {
-  export const GRID_MOVEMENT_VELOCITY = 2;
+  export const GRID_MOVEMENT_VELOCITY = 1;
 }
 
 export namespace Miscellaneous {

src/engine/config/sprites.ts

@@ -43,6 +43,6 @@ const functionBoxSpriteSpec = {
   width: 64,
   height: 64,
   frames: 3,
-  sheet: "/assets/border.png",
+  sheet: "/assets/function_block.png",
 };
 SPRITE_SPECS.set(Sprites.FUNCTION_BOX, functionBoxSpriteSpec);

src/engine/entities/Entity.ts

@@ -7,14 +7,26 @@ export abstract class Entity {
   public components: Map<string, Component>;
   public name: string;
 
+  protected hooks: Map<string, { add: Function; remove: Function }>;
+
   constructor(name: string, id: string = (Entity.Id++).toString()) {
     this.name = name;
     this.id = id;
     this.components = new Map();
+    this.hooks = new Map();
   }
 
   public addComponent(component: Component) {
+    const hadBeforeSet = this.components.has(component.name);
     this.components.set(component.name, component);
+    if (!hadBeforeSet) {
+      this.hooks.get(component.name)?.add();
+    }
+  }
+
+  public removeComponent(name: string) {
+    this.components.delete(name);
+    this.hooks.get(name)?.remove();
   }
 
   public getComponent<T extends Component>(name: string): T {

src/engine/entities/FunctionBox.ts

@@ -1,6 +1,12 @@
 import { IMAGES, SPRITE_SPECS, SpriteSpec, Sprites } from "../config";
 import { Entity, EntityNames } from ".";
-import { BoundingBox, Grid, Sprite } from "../components";
+import {
+  BoundingBox,
+  ComponentNames,
+  Grid,
+  Interactable,
+  Sprite,
+} from "../components";
 import { Coord2D } from "../interfaces";
 
 export class FunctionBox extends Entity {
@@ -8,9 +14,13 @@ export class FunctionBox extends Entity {
     Sprites.FUNCTION_BOX,
   ) as SpriteSpec;
 
-  constructor(gridPosition: Coord2D) {
+  private code: string;
+
+  constructor(gridPosition: Coord2D, code: string) {
     super(EntityNames.FunctionBox);
 
+    this.code = code;
+
     this.addComponent(
       new BoundingBox(
         {
@@ -39,5 +49,18 @@ export class FunctionBox extends Entity {
         FunctionBox.spriteSpec.frames,
       ),
     );
+
+    this.hooks.set(ComponentNames.Highlight, {
+      add: () => {
+        this.addComponent(new Interactable(() => this.viewInsides()));
+      },
+      remove: () => {
+        this.removeComponent(ComponentNames.Interactable);
+      },
+    });
+  }
+
+  public viewInsides() {
+    console.log("I am a function box!");
   }
 }

src/engine/systems/FacingDirection.ts

@@ -51,6 +51,7 @@ export class FacingDirection extends System {
           : angleToDirection(angle);
 
         facingDirection.setDirection(direction);
+        entity.addComponent(facingDirection);
 
         const oldSprite = entity.getComponent<Sprite>(ComponentNames.Sprite);
         const sprite = facingDirection.directionSprites.get(direction)!;

src/engine/systems/Grid.ts

@@ -1,9 +1,12 @@
 import { System, SystemNames } from ".";
 import { Game } from "..";
+import { Entity } from "../entities";
 import { PhysicsConstants } from "../config";
 import {
   BoundingBox,
   ComponentNames,
+  FacingDirection,
+  Highlight,
   Grid as GridComponent,
 } from "../components";
 import { Coord2D, Direction, Dimension2D } from "../interfaces";
@@ -28,9 +31,109 @@ export class Grid extends System {
   public update(dt: number, game: Game) {
     this.putUninitializedEntitiesInGrid(game);
     this.rebuildGrid(game);
+
+    this.highlightEntitiesLookedAt(game);
+    this.propogateEntityMovements(game);
+
     this.updateMovingEntities(dt, game);
   }
 
+  private highlightEntitiesLookedAt(game: Game) {
+    const highlightableEntities = new Set<string>();
+
+    game.forEachEntityWithComponent(
+      ComponentNames.FacingDirection,
+      (entity) => {
+        if (!entity.hasComponent(ComponentNames.Grid)) {
+          return;
+        }
+
+        const grid = entity.getComponent<GridComponent>(ComponentNames.Grid)!;
+        const facingDirection = entity.getComponent<FacingDirection>(
+          ComponentNames.FacingDirection,
+        )!;
+        const lookingAt = this.getNewGridPosition(
+          grid.gridPosition,
+          facingDirection.currentDirection,
+        );
+        if (
+          facingDirection.currentDirection === Direction.NONE ||
+          this.isOutOfBounds(lookingAt)
+        ) {
+          return;
+        }
+
+        this.grid[lookingAt.y][lookingAt.x].forEach((id) => {
+          highlightableEntities.add(id);
+        });
+      },
+    );
+
+    highlightableEntities.forEach((id) => {
+      const entity = game.getEntity(id)!;
+      if (!entity.hasComponent(ComponentNames.Highlight)) {
+        entity.addComponent(new Highlight());
+      }
+    });
+
+    game.forEachEntityWithComponent(ComponentNames.Highlight, (entity) => {
+      if (!highlightableEntities.has(entity.id)) {
+        entity.removeComponent(ComponentNames.Highlight);
+      }
+    });
+  }
+
+  private propogateEntityMovements(game: Game) {
+    const movingEntities: Entity[] = [];
+    game.forEachEntityWithComponent(ComponentNames.Grid, (entity) => {
+      const grid = entity.getComponent<GridComponent>(ComponentNames.Grid)!;
+      if (grid.movingDirection !== Direction.NONE) {
+        movingEntities.push(entity);
+      }
+    });
+
+    // for each moving entity, check the entities in the grid cell it's moving to
+    // if they are pushable, move them in the same direction
+    // continue until no more pushable entities are found
+    for (const entity of movingEntities) {
+      const grid = entity.getComponent<GridComponent>(ComponentNames.Grid)!;
+      let nextGridPosition = this.getNewGridPosition(
+        grid.gridPosition,
+        grid.movingDirection,
+      );
+      while (!this.isOutOfBounds(nextGridPosition)) {
+        const { x, y } = nextGridPosition;
+        const entities = Array.from(this.grid[y][x]).map(
+          (id) => game.getEntity(id)!,
+        );
+
+        const pushableEntities = entities.filter((entity) => {
+          if (!entity.hasComponent(ComponentNames.Grid)) return false;
+
+          const { pushable, movingDirection } =
+            entity.getComponent<GridComponent>(ComponentNames.Grid)!;
+          return movingDirection === Direction.NONE && pushable;
+        });
+        if (pushableEntities.length === 0) {
+          break;
+        }
+
+        for (const pushableEntity of pushableEntities) {
+          const pushableGrid = pushableEntity.getComponent<GridComponent>(
+            ComponentNames.Grid,
+          )!;
+          pushableGrid.movingDirection = grid.movingDirection;
+          pushableEntity.addComponent(pushableEntity);
+        }
+
+        nextGridPosition = this.getNewGridPosition(
+          nextGridPosition,
+          grid.movingDirection,
+        );
+      }
+    }
+  }
+
   private putUninitializedEntitiesInGrid(game: Game) {
     game.forEachEntityWithComponent(ComponentNames.Grid, (entity) => {
       const grid = entity.getComponent<GridComponent>(ComponentNames.Grid)!;
@@ -71,23 +174,10 @@ export class Grid extends System {
         ComponentNames.BoundingBox,
       )!;
 
-      let { x: newX, y: newY } = grid.gridPosition;
-      switch (grid.movingDirection) {
-        case Direction.LEFT:
-          newX -= 1;
-          break;
-        case Direction.UP:
-          newY -= 1;
-          break;
-        case Direction.DOWN:
-          newY += 1;
-          break;
-        case Direction.RIGHT:
-          newX += 1;
-          break;
-      }
-
-      const newGridPosition = { x: newX, y: newY };
+      const newGridPosition = this.getNewGridPosition(
+        grid.gridPosition,
+        grid.movingDirection,
+      );
       if (this.isOutOfBounds(newGridPosition)) {
         grid.movingDirection = Direction.NONE;
         entity.addComponent(grid);
@@ -137,6 +227,26 @@ export class Grid extends System {
     });
   }
 
+  private getNewGridPosition(prev: Coord2D, direction: Direction) {
+    let { x: newX, y: newY } = prev;
+    switch (direction) {
+      case Direction.LEFT:
+        newX -= 1;
+        break;
+      case Direction.UP:
+        newY -= 1;
+        break;
+      case Direction.DOWN:
+        newY += 1;
+        break;
+      case Direction.RIGHT:
+        newX += 1;
+        break;
+    }
+
+    return { x: newX, y: newY };
+  }
+
   private isEntityPastCenterWhenMoving(
     direction: Direction,
     gridPosition: Coord2D,
@@ -185,7 +295,7 @@ export class Grid extends System {
     this.grid.forEach((row) =>
       row.forEach((cell) => {
         for (const id of cell) {
-          if (!movedEntities.has(id)) {
+          if (movedEntities.has(id)) {
             cell.delete(id);
           }
         }
@@ -194,7 +304,8 @@ export class Grid extends System {
     movedEntities.forEach((id) => {
       const entity = game.getEntity(id)!;
       const grid = entity.getComponent<GridComponent>(ComponentNames.Grid)!;
-      this.grid[grid.gridPosition.y][grid.gridPosition.x].add(id);
+      const { x, y } = grid.gridPosition;
+      this.grid[y][x].add(id);
     });
   }
 }

src/engine/systems/Input.ts

@@ -1,6 +1,6 @@
 import { SystemNames, System } from ".";
 import { Game } from "..";
-import { ComponentNames } from "../components";
+import { ComponentNames, Grid, Interactable } from "../components";
 import { Control } from "../components/Control";
 import { Action, KeyConstants } from "../config";
 import { Entity } from "../entities";
@@ -31,11 +31,30 @@ export class Input extends System {
 
   public update(_dt: number, game: Game) {
     game.forEachEntityWithComponent(ComponentNames.Control, (entity) =>
-      this.handleInput(entity),
+      this.handleMovement(entity),
+    );
+    game.forEachEntityWithComponent(ComponentNames.Interactable, (entity) =>
+      this.handleInteraction(entity),
     );
   }
 
-  public handleInput(entity: Entity) {
+  private handleInteraction(entity: Entity) {
+    const interactable = entity.getComponent<Interactable>(
+      ComponentNames.Interactable,
+    );
+
+    const interact = this.hasSomeKey(
+      KeyConstants.ActionKeys.get(Action.INTERACT),
+    );
+
+    if (!interact) {
+      return;
+    }
+
+    interactable.interact();
+  }
+
+  public handleMovement(entity: Entity) {
     const controlComponent = entity.getComponent<Control>(
       ComponentNames.Control,
     );
@@ -50,8 +69,11 @@ export class Input extends System {
       Action.MOVE_RIGHT,
       Action.MOVE_DOWN,
     ].map((action) => this.hasSomeKey(KeyConstants.ActionKeys.get(action)));
-    if (hasGrid) {
-      const gridComponent = entity.getComponent(ComponentNames.Grid);
+    if (!hasGrid) {
+      return;
+    }
+
+    const gridComponent = entity.getComponent<Grid>(ComponentNames.Grid)!;
     if (gridComponent.movingDirection !== Direction.NONE) {
       return;
     }
@@ -80,7 +102,6 @@ export class Input extends System {
 
     entity.addComponent(gridComponent);
   }
-  }
 
   private hasSomeKey(keys?: string[]): boolean {
     if (keys) {

src/engine/systems/Render.ts

@@ -2,6 +2,7 @@ import { System, SystemNames } from ".";
 import { BoundingBox, ComponentNames, Sprite } from "../components";
 import { Game } from "..";
 import { clamp } from "../utils";
+import { DrawArgs } from "../interfaces";
 
 export class Render extends System {
   private ctx: CanvasRenderingContext2D;
@@ -38,10 +39,11 @@ export class Render extends System {
         return;
       }
 
-      const drawArgs = {
+      const drawArgs: DrawArgs = {
         center: boundingBox.center,
         dimension: boundingBox.dimension,
         rotation: boundingBox.rotation,
+        tint: entity.hasComponent(ComponentNames.Highlight) ? "red" : undefined,
       };
 
       sprite.draw(this.ctx, drawArgs);

src/main.tsx

@@ -1,9 +1,4 @@
-import React from "react";
 import ReactDOM from "react-dom/client";
 import { App } from "./App.tsx";
 import "./css/style.css";
-ReactDOM.createRoot(document.getElementById("root")!).render(
-  <React.StrictMode>
-    <App />
-  </React.StrictMode>,
-);
+ReactDOM.createRoot(document.getElementById("root")!).render(<App />);