Energy and damage

main.js

@@ -108,6 +108,11 @@ function update() {
     const explosionType = EXPLOSION_TYPES[weapon.explosion.type];
 
     if (!explosionType.update(explosion)) {
+      for (let player of players) {
+        if (player.energy > 0) {
+          player.energy -= explosionType.damage(explosion, player) || 0;
+        }
+      }
       explosion = null;
       state = 'land-collapse';
     }
@@ -128,7 +133,11 @@ function update() {
         stable = false;
       }
     }
-    if (stable) state = 'end-turn';
+    if (stable) state = 'destroy-players';
+  }
+
+  else if (state === 'destroy-players') {
+    state = 'end-turn';
   }
 
   else if (state === 'end-turn') {
@@ -143,6 +152,10 @@ function update() {
 
     state = 'start-turn';
   }
+
+  else {
+    throw new Error(`Invalid state, ${state}`);
+  }
 }
 
 function draw() {
@@ -154,7 +167,8 @@ function draw() {
 }
 
 function drawPlayer(player) {
-  const {x, y, a, c} = player;
+  const {x, y, a, c, energy} = player;
+  if (energy <= 0) return;
   const [px, py] = vec(x, y-3, a+180, 3);
   drawLine(foreground, x, y-3, Math.round(px), Math.round(py), c);
   drawRect(foreground, x-3, y-2, 6, 3, c);

math.js

@@ -27,6 +27,10 @@ export function wrap(min, x, max) {
   return ((x-min + max-min) % (max-min)) + min;
 }
 
+export function within(x, y, tx, ty, r) {
+  return Math.abs(x-tx) < r && Math.abs(y-ty) < r;
+}
+
 export function parable(t, x, y, a, v, w=0, g=9.8) {
   const fx = x + t*v * Math.cos(a) - 0.5 * -w * t*t;
   const fy = y + t*v * Math.sin(a) - 0.5 * -g * t*t;

weapons.js

@@ -1,5 +1,6 @@
 import {drawCircle} from './gfx.js';
 import {clipTerrain} from './terrain.js';
+import {within} from './math.js';
 
 export function drawExplosion(ctx, x, y, r) {
   const color = 255 - (16 * (r % 16));
@@ -29,6 +30,11 @@ export const EXPLOSION_TYPES = {
       drawExplosion(foreground, x, y, cr);
       clipTerrain(terrain, (ctx) => drawExplosion(ctx, x, y, cr));
     },
+    damage(explosion, player) {
+      if (within(explosion.x, explosion.y, player.x, player.y, explosion.r)) {
+        return 100;
+      }
+    }
   },
   dirt: {
     create(spec, x, y) {
@@ -43,5 +49,6 @@ export const EXPLOSION_TYPES = {
       drawExplosion(foreground, x, y, cr);
       drawExplosion(terrain, x, y, cr);
     },
+    damage(explosion, player) {}
   },
 }