Brewing Your Own Game Engie eng
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The document discusses the advantages and disadvantages of using both cheap commercial engines and open source engines for developing cross-platform indie games. It emphasizes the importance of composition over inheritance in game object systems, the necessity of integrating scripting with native code, and the challenges related to debugging, memory limitations, and performance optimization in game development. The talk also highlights tools and techniques for effective content pipeline management and performance troubleshooting.
Brewing Your Own Game Engie eng
- 1. Brewing Your Own Game Engine The Pros & Cons of Using Open Source Software to Rapidly Develop Cross-platform Indie Games and Tools Ye Feng
- 2. What’s In The Talk • No rocket science From practical experience • Arguable
- 3. Who We Are
- 4. Project OneTap 2D Action One Casual Button Simple Puzzle Customizable Levels
- 6. Wise Man Builds His House On The Rock • Option 1: Cheap Commercial Engine • Option 2: Open Source Engine
- 7. Cheap Commercial Engine • Pros Cons IDE • Offline IDE • Cross platform(when • Portability(when not officially officially supported) supported) • No source code Moderate • Pure script driven license fee
- 8. Open Source Engine • Pros Cons Source code • No IDE • Cross • Pure native code platform driven Free • Open Source License
- 9. Choice • Option 1: Cheap Commercial Engine Option 2: Open Source Engine • Option 3: Open Source Engine + Game Support Layer • Allegro ✔ • http://alleg.sourceforge.net/
- 10. Demo
- 11. Why • Script + native code IDE for specific game type • In-game editor • Performance • etc...
- 12. What’s In It • Game Object System Script Integration • Physics Integration • Content pipeline tools Others • Simple Scene Management • Action System Script Key-Value Dictionary • etc...
- 14. Inheritance & Gameplay Development • Gameplay dev nature: iteration Iteration causes changes • Inheritance: not change-friendly
- 15. Good
- 16. Bad
- 23. Design Pattern Favor object composition over class inheritance
- 24. Game Object & Game Component • Composition instead of inheritance A object of gameplay logic • Is composed by multiple functional components Component #1 Game Component #2 Object Component #3
- 25. Game Object & Game Component • Add/remove component in runtime • Key to build an IDE
- 26. Composition To The Rescue
- 27. Basic Components • Positioning info: Transform 2D rendering: Sprite • Bitmap info: Bitmap Source • Input processing: Event Receiver Rigid body entity: Body • Collider entity: Fixture • Particle effect: Particle Emitter • etc...
- 28. User Components • Arbitrary stuff that gameplay needs Rotation forever • A goal in level • The behavior of characters A spike need to be avoided • Line drawer needed by editor etc...
- 29. Demo
- 31. Dilemma of Native • Compilation time • Runtime modification • Advanced language feature • “Glue” code
- 32. 2-tiers System To The Rescue • Core: native code • Editor and gameplay: script • Lua
- 33. Related Works • Communication between native and script • Export tools/libraries • Script API
- 34. Communication - Native & Script • Simple interfaces/engine API • tolua • http://www.tecgraf.puc-rio.br/~celes/ • Simple, no compilation cost • Complex interfaces • Lua C API
- 35. Related Works cont. • Serialization • Load/save, editor • Support for advanced features • Reference • Function object, closure • etc...
- 36. Serialization • Pluto • https://github.com/hoelzro/pluto • Write serialization code for every component • 1000 lines of Lua code
- 37. Prefabricated Object • Take snapshot of object • Parameters • References • Hierarchy • Assisted object design • Level editor ➔ object editor
- 38. Patching Patching binary ➔ patching data
- 39. Demo
- 40. Content Pipeline Tools
- 41. DCC Tools Flash?
- 42. Pipeline Flash ☹ Export IDE Animation Manually Created Atlas Game Photoshop Static
- 43. Solution • swfdec • Open source Flash player • LGPL • swfdec-dumper • Surface ➔ disk • https://github.com/fengye/swfdec-dum
- 44. Pipeline 2.0 ☺ Flash swfdec ☹ Animation dumper Manually IDE Created Atlas Game Photoshop Static
- 45. Atlas Tool • Stitch bitmap into Atlas • Automation • Transparent process
- 46. Texture Atlas Gen • nVidia Texture Atlas Tools • File format support☺ • Mipmap☺ • Free☺ • Only for sprite sheets☹ • Pack algorithm
- 47. Pipeline 3.0 ☺ Flash swfdec dumper ☺ Animation Texture IDE Atlas Gen Photoshop Game Static
- 48. Questions?
- 49. Issues • Debugger • Coroutine/fiber • Reference leak • Script loader
- 50. Communication Between Components • Query for interface • Increase coupling • Register message • Order of notification is not defined
- 51. iPhone Version
- 52. Naive Port • Mac➔iPhone • 20 FPS + Crashes • Possible causes: • Memory out of bound • Script slowdown • Performance of rendering
- 53. Memory Limitation • Unified memory architecture • User program up to 112M - iPhone 4
- 54. Beyond Memory Limitation • 2D Games - bitmap texture heavy Preallocate bitmap space • 22 x 1M x 4 bpp = 88M • Atlas Stitch small bitmap into atlas • Automation tool is a must
- 55. Beyond Memory Limitation • Memory fragmentation Heap allocation & deallocation • Script • dmalloc • Drop-in, just works
- 56. Detect Perf. Issue • Instruments Mac/iPhone • Code intrusive profiler
- 57. Detect Perf. Issue • Found by intrusive profiler: High draw call count • Found by instruments: • Renderer utilization 100% • Tiler utilization 9 ％
- 58. Reduce Draw Call • Common trick in desktop app Implementation • Collect draw calls • Sort, cluster calls with same bitmap Batch draw • Target: reduce pipeline stall caused by switching textures
- 59. Reduce Draw Call • Before • After
- 60. Rendering Optimization • Fillrate Number of texels written to memory per second • Desktop app, pixel-shader heavy • Fillrate bottleneck ✔ • Reduce framebuffer size ➔ boost frame rate
- 61. Fillrate Optimization • Hardware limit: 221M/sec 60 FPS: 3.6M/frame • 30 FPS: 7.2M/frame • 2D Game Alpha-blend heavy • Hard to utilize Z-buffer
- 62. Fillrate Optimization • Reduce overdraw Use Z-buffer for strictly opaque objects • Modify art asset guideline
- 63. Demo
Editor's Notes
- #24: GoF ：我们的经验显示，设计师经常过分强调将继承作为重用技术，而事实上，如果着重以对象组合作为重用技术，则可以获得更多的可重用性以及简单的设计。