feat: add hearts HUD and water-gap instant death hazard

js/game.js

@@ -1,16 +1,30 @@
 const canvas = document.getElementById('game');
 const ctx = canvas.getContext('2d');
 const scoreEl = document.getElementById('score');
+const heartsEl = document.getElementById('hearts');
 
 const keys = new Set();
 const gravity = 1900;
 const groundY = 420;
+const worldWidth = 6000;
+
+const waterGaps = [
+  { x: 700, width: 130 },
+  { x: 1300, width: 150 },
+  { x: 2100, width: 170 },
+  { x: 3000, width: 140 },
+  { x: 3900, width: 200 }
+];
 
 const state = {
   running: true,
+  dead: false,
+  deadReason: '',
   lastTs: performance.now(),
   score: 0,
   stepCarry: 0,
+  cameraX: 0,
+  hearts: 3,
   player: {
     x: 160,
     y: 0,
@@ -33,7 +47,6 @@ window.addEventListener('keydown', (e) => {
     e.preventDefault();
   }
   keys.add(e.key);
-
   if (e.key === 'ArrowUp' && state.player.onGround) {
     state.player.vy = -state.player.jumpPower;
     state.player.onGround = false;
@@ -46,21 +59,44 @@ function drawBackground() {
   ctx.fillRect(0, 0, canvas.width, canvas.height);
   ctx.fillStyle = '#88d34f';
   ctx.fillRect(0, groundY, canvas.width, canvas.height - groundY);
+
+  // Water gaps
+  for (const gap of waterGaps) {
+    const sx = gap.x - state.cameraX;
+    if (sx + gap.width < 0 || sx > canvas.width) continue;
+    ctx.fillStyle = '#2e8bcf';
+    ctx.fillRect(sx, groundY, gap.width, canvas.height - groundY);
+  }
 }
 
 function drawTRex(p) {
+  const sx = p.x - state.cameraX;
   ctx.fillStyle = '#35535f';
-  ctx.fillRect(p.x, p.y, p.width, p.height);
+  ctx.fillRect(sx, p.y, p.width, p.height);
   ctx.fillStyle = '#27404a';
-  ctx.fillRect(p.x + p.width - 12, p.y + 14, 7, 7); // eye
+  ctx.fillRect(sx + p.width - 12, p.y + 14, 7, 7);
-  ctx.fillRect(p.x + 10, p.y + p.height - 8, 14, 8); // foot1
+  ctx.fillRect(sx + 10, p.y + p.height - 8, 14, 8);
-  ctx.fillRect(p.x + p.width - 24, p.y + p.height - 8, 14, 8); // foot2
+  ctx.fillRect(sx + p.width - 24, p.y + p.height - 8, 14, 8);
+}
+
+function updateHeartsUI() {
+  heartsEl.textContent = '❤'.repeat(state.hearts) + '🖤'.repeat(Math.max(0, 3 - state.hearts));
+}
+
+function kill(reason) {
+  state.running = false;
+  state.dead = true;
+  state.deadReason = reason;
+}
+
+function isOverWater(player) {
+  const centerX = player.x + player.width / 2;
+  return waterGaps.some((g) => centerX >= g.x && centerX <= g.x + g.width);
 }
 
 function updatePlayer(dt) {
   const p = state.player;
   let move = 0;
-
   if (keys.has('ArrowLeft')) move -= 1;
   if (keys.has('ArrowRight')) move += 1;
 
@@ -74,7 +110,7 @@ function updatePlayer(dt) {
   p.vx = move * p.speed;
   const oldX = p.x;
   p.x += p.vx * dt;
-  p.x = Math.max(0, Math.min(canvas.width - p.width, p.x));
+  p.x = Math.max(0, Math.min(worldWidth - p.width, p.x));
 
   if (p.x > oldX) {
     state.stepCarry += p.x - oldX;
@@ -91,26 +127,47 @@ function updatePlayer(dt) {
     p.y = groundY - p.height;
     p.vy = 0;
     p.onGround = true;
+
+    if (isOverWater(p)) {
+      kill('SPLASH! Water is instant death.');
+    }
+  } else {
+    p.onGround = false;
   }
+
+  state.cameraX = Math.max(0, Math.min(worldWidth - canvas.width, p.x - 240));
+}
+
+function drawDeathText() {
+  if (!state.dead) return;
+  ctx.fillStyle = 'rgba(0,0,0,0.55)';
+  ctx.fillRect(0, 0, canvas.width, canvas.height);
+  ctx.fillStyle = '#fff';
+  ctx.font = 'bold 42px Arial';
+  ctx.fillText('Game Over', 360, 220);
+  ctx.font = '24px Arial';
+  ctx.fillText(state.deadReason, 280, 270);
 }
 
 function tick(ts) {
-  if (!state.running) return;
   const dt = Math.min((ts - state.lastTs) / 1000, 0.05);
   state.lastTs = ts;
 
-  updatePlayer(dt);
+  if (state.running) updatePlayer(dt);
 
   ctx.clearRect(0, 0, canvas.width, canvas.height);
   drawBackground();
   drawTRex(state.player);
+  drawDeathText();
 
   scoreEl.textContent = `Score: ${state.score}`;
+  updateHeartsUI();
 
   requestAnimationFrame(tick);
 }
 
 requestAnimationFrame((ts) => {
   state.lastTs = ts;
+  updateHeartsUI();
   requestAnimationFrame(tick);
 });