Add pegs

src/common/physics/engine.c

@@ -142,6 +142,16 @@ EXPORT(rigid_body_add_force) void rigid_body_add_force(rigid_body* rb, float fx,
     rb->force.y += fy;
 }
 
+
+EXPORT(rigid_body_add_global_force) void rigid_body_add_global_force(float fx, float fy) {
+    rigid_body* current = rigid_body_head;
+
+    while (current) {
+        rigid_body_add_force(current, fx, fy);
+        current = current->next;
+    }
+}
+
 EXPORT(rigid_body_set_collision_callback) void rigid_body_set_collision_callback(rigid_body_collision_callback_t callback) {
     rigid_body_collision_callback = callback;
 }

src/common/physics/index.ts

@@ -3,22 +3,18 @@ import E from './engine.c';
 namespace Physics {
     const TYPE_CIRCLE = 1;
     const TYPE_PLANE = 2;
-    const bodies = new Set<number>();
 
     export function newCircle(x: number, y: number, radius: number, mass: number = 1.0): number {
         const body = E.rigid_body_new_circle(x, y, 0, 0, mass, radius);
-        bodies.add(body);
         return body;
     }
 
     export function newPlane(x: number, y: number, nx: number, ny: number): number {
         const body = E.rigid_body_new_plane(x, y, nx, ny);
-        bodies.add(body);
         return body;
     }
 
     export function deleteBody(body: number) {
-        bodies.delete(body);
         E.rigid_body_free(body);
     }
 
@@ -27,9 +23,7 @@ namespace Physics {
     }
 
     export function addGlobalForce(fx: number, fy: number) {
-        for (const body of bodies) {
-            E.rigid_body_add_force(body, fx, fy);
-        }
+        E.rigid_body_add_global_force(fx, fy);
     }
 
     export function update(dt: number) {
@@ -58,10 +52,6 @@ namespace Physics {
         return { id: body, x, y, vx, vy, mass };
     }
 
-    export function getBodies() {
-        return Array.from(bodies).map(getBody);
-    }
-
     export function setCollisionCallback(cb: (a: number, b: number) => void) {
         const cbPtr = E.table.grow(1, new WebAssembly.Function({ parameters: ['i32', 'i32'], results: [] }, cb));
         E.rigid_body_set_collision_callback(cbPtr);

src/common/utils.ts

@@ -32,6 +32,8 @@ export const shuffle = <T>(array: T[]): T[] => {
 
     return shuffledArray;
 }
+export const mapNumber = (num: number, inMin: number, inMax: number, outMin: number, outMax: number) =>
+    (num - inMin) * (outMax - outMin) / (inMax - inMin) + outMin;
 
 export function zip<T1, T2, T3>(a1: Iterable<T1>, a2: Iterable<T2>, a3: Iterable<T3>): Generator<[T1, T2, T3]>;
 export function zip<T1, T2>(a1: Iterable<T1>, a2: Iterable<T2>): Generator<[T1, T2]>;

src/games/dropballs/index.ts

@@ -1,7 +1,30 @@
 import { createCanvas } from "@common/display/canvas";
 import { gameLoop } from "@common/game";
 import Physics from "@common/physics";
+import { mapNumber } from "@common/utils";
 
+interface Ball {
+    body: number;
+    damage: number;
+    health: number;
+}
+
+interface Peg {
+    body: number;
+    health: number;
+}
+
+interface State extends Record<string, unknown> {
+    canvas: HTMLCanvasElement;
+    ctx: CanvasRenderingContext2D;
+    bottom: number;
+    balls: Set<Ball>;
+    pegs: Set<Peg>;
+
+    pegHealth: number;
+    ballHealth: number;
+    ballDamage: number;
+}
 
 let lastTick = performance.now();
 function update() {
@@ -13,46 +36,126 @@ function update() {
     setTimeout(update, 5);
 }
 
+const killBody = (state: State, body: Peg | Ball) => {
+    state.balls.delete(body as Ball);
+    state.pegs.delete(body as Peg);
+    Physics.deleteBody(body.body);
+}
 
-const setup = () => {
+const onCollision = (state: State, b1: number, b2: number) => {
+    const ball = state.balls.values().find(b => b.body === b1 || b.body === b2);
+    const peg = state.pegs.values().find(b => b.body === b1 || b.body === b2);
+
+    if (ball && (b1 === state.bottom || b2 === state.bottom)) {
+        killBody(state, ball);
+    } else if (peg && ball) {
+        peg.health -= ball.damage;
+        ball.health -= 1;
+        if (peg.health <= 0) {
+            killBody(state, peg);
+        }
+        if (ball.health <= 0) {
+            killBody(state, ball);
+        }
+    }
+}
+
+const generatePegs = (state: State) => {
+    const { canvas } = state;
+    state.pegs.clear();
+
+    const gap = 45;
+    const vgap = gap * Math.cos(Math.PI / 6);
+    let offset = 0;
+    for (let y = canvas.height / 3; y <= canvas.height - gap; y += vgap) {
+        for (let i = offset; i <= canvas.width / 2; i += gap) {
+            const x1 = canvas.width / 2 + i;
+            state.pegs.add({
+                body: Physics.newCircle(x1, y, 3, Number.POSITIVE_INFINITY),
+                health: state.pegHealth,
+            });
+
+            const x2 = canvas.width / 2 - i;
+            if (Math.abs(x1 - x2) < gap) continue;
+            state.pegs.add({
+                body: Physics.newCircle(x2, y, 3, Number.POSITIVE_INFINITY),
+                health: state.pegHealth,
+            });
+        }
+        offset = gap / 2 - offset;
+    }
+}
+
+const setup = (): State => {
     const canvas = createCanvas(640, 480);
     const ctx = canvas.getContext('2d');
     if (!ctx) {
         throw new Error('Failed to get canvas context');
     }
 
+    const state: State = {
+        canvas,
+        ctx,
+        bottom: 0,
+        pegs: new Set(),
+        balls: new Set(),
+        pegHealth: 3,
+        ballHealth: 10,
+        ballDamage: 1,
+    };
+
     ctx.imageSmoothingEnabled = false;
     canvas.addEventListener('contextmenu', e => {
         e.stopPropagation();
         e.preventDefault();
     });
     canvas.addEventListener('mouseup', () => {
-        Physics.newCircle(canvas.width / 2 + Math.random() - 0.5, 50, 10, 1);
+        const body = Physics.newCircle(canvas.width / 2 + Math.random() - 0.5, 50, 10, 1);
+        const health = state.ballHealth;
+        const damage = state.ballDamage;
+        const ball: Ball = {
+            body,
+            health,
+            damage,
+        }
+        state.balls.add(ball);
         return false;
     });
 
+    generatePegs(state);
+
+    state.bottom = Physics.newPlane(0, canvas.height, 0, -1);
     Physics.newPlane(0, 0, 1, 0);
     Physics.newPlane(0, 0, 0, 1);
-    Physics.newPlane(0, canvas.height, 0, -1);
     Physics.newPlane(canvas.width, 0, -1, 0);
 
+    Physics.setCollisionCallback((a, b) => onCollision(state, a, b));
+
     update();
 
-    return { canvas, ctx };
+    return state;
 }
 
-const frame = (dt: number, state: ReturnType<typeof setup>) => {
+const frame = (dt: number, state: State) => {
     Physics.addGlobalForce(0, 100);
     Physics.update(dt);
 
     const { ctx, canvas } = state;
-    ctx.fillStyle = `black`;
+    ctx.fillStyle = `#111`;
     ctx.fillRect(0, 0, canvas.width, canvas.height);
-    for (const { id, x, y, radius } of Physics.getBodies()) {
+    for (const peg of state.pegs) {
+        const { x, y, radius } = Physics.getBody(peg.body);
+        if (!radius) continue;
+
+        ctx.fillStyle = `hsl(0, 0%, ${mapNumber(peg.health, 0, state.pegHealth, 0, 100)}%)`;
+        fillCircle(ctx, x, y, radius);
+    }
+    for (const ball of state.balls) {
+        const { id, x, y, radius } = Physics.getBody(ball.body);
+        if (!radius) continue;
+
         ctx.fillStyle = `hsl(${id % 360}, 100%, 50%)`;
-        if (radius) {
-            fillCircle(ctx, x, y, radius);
-        }
+        fillCircle(ctx, x, y, radius);
     }
 }