BAFPUG 2015

1. Fast rendering with
Starling
BAFPUG 2015
Sergey Gonchar
http://gonchar.me

2. Stage3D API
• Since 2011 (Flash Player 11)
• Unified API for managing texture memory, vertex
shading, pixel shading, and mesh rendering
• Transparently executed using OpenGL and DirectX

3. Each frame
— clear backbuffer by calling Context3D.clear
— set gpu state through Context3D API
— call drawTriangles()
— repeat until the scene is entirely rendered
— call the present() method to display the rendered scene on the
stage. It copies the backbuffer to a framebuffer

4. Context3D profiles
• BASELINE_CONSTRAINED for web - windows
• BASELINE for web - mac
• MAX PROFILE for mobile

6. Profiling Tools
• Adobe Scout
https://creative.adobe.com/ru/products/scout
• Intel GPA https://software.intel.com/en-us/gpa
• Xcode OpenGL Tools
https://developer.apple.com/opengl/
• RenderDoc http://cryengine.com/renderdoc

7. http://gamua.com/starling/

8. How does QuadBatch work?
• Collects quads with the same state(same texture,
blendMode, shader)
• Transforms all vertices to one space and upload
to VertexBuffer
• Render

10. Starling VertexBufferDescr
• va0 - x,y
• va1 - r,g,b,a
• va2 - u,v

11. Constants approach
• Create one common vertexBuffer during application
init, upload data once
• Batch quads and images by the same state and set
program constants
array(x,y,width,height,uv,tintcolor,rotation)
• Render

12. New VertexBufferDescr
• va0 - x,y,index

13. How does it work?

24. PixelPerfect Touch CPU
Approach
• hitTest Quads
• hitTest texture
• repeat until find

25. PixelPerfect Touch GPU!
• Use simple shader which renders images with
single color
• Optimization: collect candidates by bounds
• Render targets to 1x1 texture on desktop or 4x4
texture on mobile
• Read back & sample color from texture

26. Scene

27. Touch test

28. Books
http://www.amazon.com/Practical-
Rendering-Computation-Direct3D-
11/dp/1568817207
http://www.amazon.com/Adobe-
Stage3D-Molehill-Programming-
Beginners/dp/1849691681

29. Thank you!
• Blog http://gonchar.me/
• Follow me http://twitter.com/UnknownFlasher
• Stage3D http://facebook.com/groups/stage3d
• FlashDaily http://flashdaily.net