Inside Rawkets - onGameStart

Rawkets presentation from onGameStart 2011 in Poland.

Transcript

3. Created by Phil Banks (@emirpprime)
5. Experimentation Rawkets is a graduate from my lab
6. What is Rawkets? Rawkes, WebSockets, and Rockets
10. Technology Some of the tech involved in Web gaming
11. Canvas 2D graphics platform
12. Flash audio Sound effects and background music
13. WebSockets Multiplayer communication
14. Node.js Game logic and network communication
15. Issues Making games can be a challenge
16. Networking Not as easy as I thought
17. Message protocol Structured and short communication
18. types = { PING: 1, SYNC: 2, SYNC_COMPLETED: 3, NEW_PLAYER: 4, UPDATE_PLAYER: 5, UPDATE_INPUT: 6, REMOVE_PLAYER: 7 }; Enumeration
19. { z: 1, id: 1234567890, t: 1316763202872, s: { x: 5, y: 34, v: 3, a: 0.46 } } Message package
20. Compression Reducing data as much as possible
21. Rate limiting Cutting down on communication
22. 1 1 MESSAGES IN 1 MESSAGES OUT 1
23. 1 2 2 1 MESSAGES IN 2 MESSAGES OUT 4
24. 1 4 4 1 1 4 4 1 MESSAGES IN 4 MESSAGES OUT 16
25. MESSAGES IN 30 MESSAGES OUT 900 1 30 30 1 1 30 30 1
26. MESSAGES IN 100 MESSAGES OUT 10000 1 100 100 1 1 100 100 1
27. Intelligence Letting the game prioritise messages
28. Respecting TCP WebSockets uses TCP. Deal with it
29. Obey the order You can’t do much about it
30. Use Socket.IO It intelligently drops messages
31. Cheaters A blessing and a curse
32. Globals and closures Keeping code wide open is bad
33. (function() { var rawkets = rawkets || {}, r = rawkets; rawkets.namespace = function(namespace_str) { var parts = namespace_str.split("."), parent = rawkets, i; if (parts[0] === "rawkets") { parts = parts.slice(1); }; for (i = 0; i < parts.length; i++) { if (typeof parent[parts[i]] === "undefined") { parent[parts[i]] = {}; }; parent = parent[parts[i]]; }; return parent; }; window.rawkets = window.r = rawkets; })(window);
34. Client authority Power isn’t always a good thing
35. Server authority Relinquish that power
36. Input Move Update +0 +40 +80 40ms 40ms 80ms total round-trip Inherent latency
37. Client prediction Server authority isn’t enough
38. Prediction happens here Input Move Update +0 +40 +80 40ms 40ms Instant movement
39. Correction When prediction goes wrong
40. var correction = function(time, state, input, entity, rk4) { ... if (Math.abs(state.x - lastMove.state.x) > 2) { ... var currentTime = time, currentInput = input; entity.setState(state); // Rewind entity state var move, // Current move frameTime; // Time between correction and stored move for (m = 0; m < moveCount; m++) { move = moves[m]; frameTime = (move.time - currentTime) / 1000; // Update physics based on corrected time, input and state ... currentTime = move.time; currentInput = move.input; move.state = entity.getState(); }; }; };
41. Stability Keeping the game running
42. mmonit.com/monit
43. check host rawkets.com with address 127.0.0.1 start program = "/etc/init.d/rawkets start" stop program = "/etc/init.d/rawkets stop" if failed port 8000 type tcp for 2 times within 3 cycles then restart Monit script
44. #!/bin/sh case "$1" in start) cd /rawkets /usr/local/bin/node rawkets.js 2>&1 >> /var/log/node.log & exit 1 ;; stop) /usr/bin/pkill -f 'node rawkets.js' exit 1 ;; esac exit 1 Init.d script
45. github.com/indexzero/forever
46. forever start rawkets.js Forever
47. github.com/hookio/hook.io
48. Why Flash audio? HTML5 Audio isn’t quite ready yet
49. Loads more HTML5 games teach you a lot
50. The future What I’d like to see in JavaScript gaming
51. Something fun I’ve been working on a little tool
52. Game profiler
53. Webkit timeline-like
54. Rob Hawkes Rawkets.com HTML5 & WebSockets game Twitter sentiment analysis Delving into your soul RECENT PROJECTS Rawkes.com Personal website and blog MORE COOL STUFF ExplicitWeb.co.uk Web development podcast Rawket Scientist Technical Evangelist at Mozilla @robhawkes
55. Become a canvas master RAWKES.COM/FOUNDATIONCANVAS Out now Paperback and digital formats Learn how to animate Make two cool space games Foundation HTML5 Canvas
56. November is HTML5 canvas Every month Next month is CSS Media Queries Win prizes (like an Android) DEVELOPER.MOZILLA.ORG/EN-US/DEMOS/DEVDERBY Mozilla Dev Derby
57. Hand-picked experts @ASKMDN & #ASKMDN ON TWITTER One hour every fortnight Web development topics Great discussions Ask MDN ASKMDN onGameStart special (hopefully)