Using The New Flash Stage3D Web Technology To Build Your Own Next 3D Browser MMOG

1. Using The New Flash Stage3D Web Technology To Build Your Own Next 3D Browser MMOG Daosheng Mu, Lead Programmer Eric Chang, CTO XPEC Entertainment Inc.

2. Outline • Brief of Speakers • Introduction of Adobe Flash Stage3D API • XPEC Flash 3D Engine • Optimization for Flash Program • Future Works • Conclusion • Q & A

3. Brief of Speakers • Eric Chang – 19 Years of Game Industry Experiences – Cross-platform 3D Game Engine Development – PC/Console/Web

4. Brief of Speakers • Daosheng Mu – 4.5 Years of Cross-platform 3D Game Engine Development Experiences – PC/Console/Web

5. Why Flash? Native C/C++ vs. Unity vs. Flash Native C/C++ Unity Flash Development Difficulty High Low Mid Ease of Cross Platform Low High High Performance High Mid Low Market Popularity Low Mid High (>95%)

6. Project C4 Demo Video

7. Introduction of Adobe Flash Stage3D API

8. Stage3D • Support all browsers

9. Stage3D • Stage3D includes with GPU-accelerated 3D APIs – Z-buffering – Stencil/Color buffer – Vertex shaders – Fragment shaders – Cube textures – More…

10. Stage3D • Pros: – GPU accelerated API – Relies on DirectX, OpenGL, OpenGL ES – Programmable pipeline • Cons: – No support of alpha test – No support of high-precision texture format

11. Stage3D ResourceNumber allowedTotal memory Vertex buffers 4096 256 MB Index buffers 4096 128 MB Programs 4096 16 MB Textures 4096 128 MB* Cube textures 4096 256 MB Draw call limits 32,768 *350 MB is absolute limit for textures, 340 MB is the result we gather

12. AGAL • Adobe Graphics Assembly Language – No support of ‘if-else’ statements – No support of ‘constants’

13. XPEC Flash 3D Engine

14. Model Pipeline • Action Message Format (AMF): – Native ByteArray compression – Native object serialization 3DS Max Engine Loader Exporter Collada Binary Converter AMF AMF Engine Render

15. XPEC Flash 3D Engine • Application: update/render on CPU • Command buffer: store graphics API instruction Application Command buffer Driver GPU CPU

16. XPEC Flash 3D Engine: Application Object3D • Material • Geometry Update • UpdateDeltaTime • UpdateTransform Scene management • Scene partition • Frustum culling Update • UpdateHierarchy Draw • SetMaterial • SetGeometry Stage3D • Set Stage3D APIs

17. Scene Management • Goal: Minimize draw calls as possible • Indoor Scene – BSP tree • Outdoor Scene – Octree/Quad tree – Cell – Grid

18. Scene Management: Project C4 • Grid partition • Object3D: (MinX, MaxX), (MinY, MaxY) (0, 0) (2, 2) (4, 4) y x

19. Scene Management: Project C4 • Frustum: (MinX, MaxX), (MinY, MaxY) (0, 0) (2, 2) (4, 4) (1,4),(0,4) y x

20. XPEC Flash 3D Engine: Command Buffer Initialize • createVertex/Index Buffer • createTexture • createProgram Begin • clear • setRenderToTexture Draw • setVertex/Index Buffer • setProgram • setProgramConstants • setRenderState • setTextureAt • drawTriangles End • present • Avoid user/kernel mode transition • Decrease shader patching – “Material sorting” • Reduce draw call – “Shared buffers” – “Dynamic batching”

21. Material Sorting • Opaque/Translucent

22. Material Sorting • State management • 1047/2598 draw calls

23. 0 10 20 30 40 50 60 NVIDIA 8800GT - 1047 draw calls NVIDIA 8800GT - 1047 draw calls with material sorting NVIDIA 8800GT - 2598 draw calls NVIDIA 8800GT - 2598 draw calls with material sorting Elapsedtime(ms) CPU waiting GPU Render loop

24. 0 10 20 30 40 50 60 70 80 90 100 NVIDIA 6600GT - 1047 draw calls NVIDIA 6600GT - 1047 draw calls with material sorting NVIDIA 6600GT - 2598 draw calls NVIDIA 6600GT - 2598 draw calls with material sorting Elapsedtime(ms) CPU waiting GPU Render loop

25. Before sorting(ms) After sorting(ms) NVIDIA 8800 GT - 1047 draw calls Render loop elapsed time 16 16 Total elapsed time 41 40 NVIDIA 8800 GT - 2598 draw calls Render loop elapsed time 36 36 Total elapsed time 50 50 Before sorting(ms) After sorting(ms) NVIDIA 6600 GT - 1047 draw calls Render loop elapsed time 34 31 Total elapsed time 53 48 NVIDIA 6600 GT - 2598 draw calls Render loop elapsed time 81 64 Total elapsed time 89 89

26. Shared Buffers • Problem: – Numbers of buffers are limited ResourceNumber allowedTotal memory Vertex buffers 4096 256 MB Index buffers 4096 128 MB Programs 4096 16 MB

27. Shared Buffers Vertex Buffer Index Buffer Vertex Buffer Index Buffer Vertex Buffer Index Buffer

28. Particle System • Each particle property is computed on the CPU at each frame – Alpha, Color, LinearForce, Size, Speed, UV – Facing

29. Particle System • Index buffer – Indices will not be changed • Vertex buffer – Problem: • Particle amount depends on frame • Upload data to vertex buffer frequently

30. Particle System Static Index Buffer Dynamic Vertex Buffer Vertex Data

31. Skinned Model • Problem: – Lesser vertex constants allowed • 128 constants per vertex program – Global vertex constants • Lighting, Fog, Const

32. Skinned Model • 4x3 Matrix • Bone count per geometry is limited to 29 – “Split mesh” 128 constants / 3 = 42.6666 bones 3 * 29 bones = 87 constants

33. Shadow Map

34. Shadow Map present() End frame setRenderToBackBuffer() Set shadow map setRenderToTexture() Clear shadow map Draw to shadow map clear() Clear back buffer

35. Shadow Map • Problem: – Texture format: RGBA8 – Artifact • Aliasing • Popping while moving

36. • Size: 1024x1024 • RGBA8  R32 Shadow Map

37. Shadow Map • Percentage Closer Filtering (PCF) solution: – Hard shadow – Aliasing – Popping while moving

38. Shadow Map • PCF pw = 1/mapWidth ph = 1/mapHeight • Result = 0.5 * texel( 0, 0) + 0.125 * texel( -pw, +ph) + 0.125 * texel(-pw, -ph) + 0.125 * texel( +pw, +ph) + 0.125 * texel(+pw, -ph) (-pw , +ph) (+pw , +ph) (0, 0) (+pw , -ph)(-pw , -ph)

39. Shadow Map • PCF based solution: 0 20 40 60 80 100 NVIDIA 6600GT - 1047 draw calls NVIDIA 6600GT - 1047 draw calls with PCF NVIDIA 8800GT - 1047 draw calls NVIDIA 8800GT - 1047 draw calls with PCF Elapsedtime(ms) CPU waiting GPU Render loop

40. Toon Shading • Single pass – Problem: Dependent on no. of face • Two passes – Scale vertex position following the vertex normal – Not dependent on no. of face 𝑣 ∶ 𝑣𝑖𝑒𝑤 𝑣𝑒𝑐𝑡𝑜𝑟 𝜃 𝑖𝑓 𝜃 > 𝑡ℎ𝑟𝑒𝑠ℎ𝑜𝑙𝑑, 𝑑𝑟𝑎𝑤 𝑡𝑜𝑜𝑛 𝑐𝑜𝑙𝑜𝑟 𝑁 : 𝑣𝑒𝑟𝑡𝑒𝑥 𝑛𝑜𝑟𝑚𝑎𝑙

41. Toon Shading • Enable back face • Scale vertex position • Draw color Toon • Enable front face • Draw material General Result

42. Alpha Test • Problem: – Stage3D without alpha test – “kil opcode in AGAL” • Performance penalty on mobile device

43. Alpha Test • Solution: Render loop time(ms) Total time(ms) 6600GT alpha test 17~19 47 6600GT alpha blend 18~19 65~67 8800GT alpha test 0.16 37 8800GT alpha blend 0.3 36 •304 draw calls •Alpha-test performance is better on desktop Replace alpha-test with alpha-blend

44. Post Effect OriginGlowDOFColor Filter

45. Static Lightmap • Pros: – Pre-computation – Global illumination • Cons: – More textures

46. Optimization for Flash Program

47. Optimization for Flash Program • Problem: – For Each is slow • “Use for-loop to replace it” – Memory management • “Recycle manager” • “Strengthen garbage collection”

48. Optimization for Flash Program • Solution: – Recycle manager • Reduce garbage collection loading • Save objects initial time • public function recycleObject3D( obj:IObject3D ):void • public function requestObject3D( classType:int , searchKey:*, renderHandle:int = 0 ):*

49. Optimization for Flash Program • Solution: – Strengthen garbage collection • Avoid inner function • Force to dereference function pointer • Dereference attribute in object destructor

50. • Avoid inner function • Force to dereference function pointer Without inner function Use inner function

51. Optimization for Flash Program • Experiment: before vs. after – Switching among levels Before improvement: After improvement :

52. Rapid loading

53. Rapid loading • Streaming – Data compression • PNG: swf compression: 20%~55% • Package: zip compression: 25~30% – Batch loading • Separate resource to several packages • Download what you really need

54. Rapid loading Enter to avatar stage Enter to game stage After loading picture finished 5Mb/s Elapsed time (sec) 15 6 12 • game code • ui • game scene • scene textures

55. Future Works • Adobe Texture Format (ATF) – Support for compressed/mipmap textures on the different GPU chipset • FlasCC – C++  AS3 Compilation • AS3 Workers – Multi-thread support • MovieClip – Replace with Stage3D UI framework, ex: Starling

56. Conclusion • Cross-Device/Cross-OS/Cross-Browser – Browser + Cloud Computing – Write Once, Run Anywhere • Flash vs. HTML5 • Cross-Compiling Technology Trend – C/C++ + Flash/ActionScript – C/C++ + HTML5/JavaScript

57. Acknowledgements • XPEC - Project C4 Team • XPEC - RDO Team

58. Q & A Ellison_Mu@xpec.com Eric_Chang@xpec.com