Android internals 07 - Android graphics (rev_1.1)


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Course: Android Internals
Lecture 7: Android Graphics

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  • Hi, I am a beginer in android.
    At the moment I am doing a project, an native C daemon for Android, that needs to
    collect the state of the phone like: is the audio ON (music plays), what is the current
    level of the output sound, is the gps ON, the CPU freq, is the screen ON etc.
    For some of them, I easily found the corresponding files in the sysfs and procfs, and I can get the values. But, for example like for the audio I cannot find this values. How to connect to the HAL api inside the kernel module.
    Please can you give me some guideline how to do that? How to check if music is running?

    Thank you,
    Are you sure you want to  Yes  No
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Android internals 07 - Android graphics (rev_1.1)

  1. 1. Android internals Egor Elizarov SPbSU 2012
  2. 2. Legal info Android internals by Egor Elizarov is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License You are free to – copy, distribute, display, and perform the work – make derivative works Under the following conditions – Attribution. You must give the original author credit – Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one All pictures and trademarks are the property of their respective owners. Use of these trademarks and pictures is subject to owners permissions. Corrections, suggestions, contributions and translations are welcome! 2 Egor Elizarov SPbSU 2012
  3. 3. Lecture 7 Graphic Subsystem OpenGL HW acceleration yegor.yelizarov(at)gmail.comRev: 1.1Last update: 06/01/2012 3 Egor Elizarov SPbSU 2012
  4. 4. Previous time Linux IPC primitives Binder Application layer Service manager Middleware level Kernel level Typical Android sybsystem 4 Egor Elizarov SPbSU 2012
  5. 5. Graphic subsystem Provides buffer to application for drawing Provides interfaces for draw primitives Controls and composes surfaces (windows) Provides 2D & 3D primitives Uses HW acceleration where acceptable 5 Egor Elizarov SPbSU 2012
  6. 6. Main players Surface Flinger Window Manager Activity Manager 6 Egor Elizarov SPbSU 2012
  7. 7. Surface Virtual buffer we can draw on Can be marshalled/unmarlled in Parcel One Activity can have more then one Surface 7 Egor Elizarov SPbSU 2012
  8. 8. Surface Flinger Allocates surfaces Composes surfaces Can combines 2D/3D surfaces Can use HW acceleration for surface composition 8 Egor Elizarov SPbSU 2012
  9. 9. Window Manager Dispatches input events to clients Provides transition animation capabilities Window Manager Policy handles common key events in PhoneWindowManager (Home/Back/Volume) 9 Egor Elizarov SPbSU 2012
  10. 10. Activity manager Manages activity life cycle Manages activity stacking Dispatches intents Spawn processes 10 Egor Elizarov SPbSU 2012
  11. 11. Composition example 11 Egor Elizarov SPbSU 2012
  12. 12. Simple view 12 Egor Elizarov SPbSU 2012
  13. 13. Khronos OpenGL API Khronos Group - not for profit industry consortium creating open standards. OpenGL – 2D/3D graphics API OpenGLES – 2D/3D graphics API for embedded systems EGL – interface between OpenGLES and native platform window system 13 Egor Elizarov SPbSU 2012
  14. 14. Graphic libraries SKIA - 2D graphic library PixelFlinger – android software renderer Codeflinger – simple graphic JIT Gralloc – android graphics memory allocator Mesa – open source OpenGL implementation 14 Egor Elizarov SPbSU 2012
  15. 15. Renderscript Renderscript is new API targeted at high- performance 3D rendering and compute operations. Renderscript provides: • 3D rendering API on top of HW acceleration • compute API (similar to CUDA) • familiar language in C99 15 Egor Elizarov SPbSU 2012
  16. 16. Java/middleware interaction 16 Egor Elizarov SPbSU 2012
  17. 17. Double buffering 17 Egor Elizarov SPbSU 2012
  18. 18. Composition approach Dirty regions – regions that should be redrawn Use Z ordering to compose layers Use HW composer to compose layers if possible frameworks/base/services/surfaceflinger/Surface Flinger.cpp 18 Egor Elizarov SPbSU 2012
  19. 19. SW vs HW OpenGL 19 Egor Elizarov SPbSU 2012
  20. 20. Middleware level 20 Egor Elizarov SPbSU 2012
  21. 21. 3D acceleration 21 Egor Elizarov SPbSU 2012
  22. 22. 2D acceleration 22 Egor Elizarov SPbSU 2012
  23. 23. HAL/kernel interaction 23 Egor Elizarov SPbSU 2012
  24. 24. Overlay vs Framebuffer surface Two different type of surfaces in Android < 3.0 Overlay – Picture in YUV format (Video, Camera) – Video4Linux devices (/dev/video*) Framebuffer surfaces – Picture in RGB format – Framebuffer device (/dev/fb*) Composition is performed by HW 24 Egor Elizarov SPbSU 2012
  25. 25. HWComposer (Omap4) 25 Egor Elizarov SPbSU 2012
  26. 26. Emulator GL acceleration In ICS Android team added GL acceleration for Emulator Emulator uses x86 host GL acceleration relying on host hardware accelerated libraries 26 Egor Elizarov SPbSU 2012
  27. 27. Android-emulator approach 27 Egor Elizarov SPbSU 2012
  28. 28. Android-x86 approach 28 Egor Elizarov SPbSU 2012
  29. 29. Next Time System start up Media subsystem 29 Egor Elizarov SPbSU 2012
  30. 30. Useful links graphics 63.html Http:// z8x93s 30 Egor Elizarov SPbSU 2012
  31. 31. Useful links (2) F-ENT-F0824.pdf s_SNPS_20111027.pdf renderscript.html http://android- 31 Egor Elizarov SPbSU 2012
  32. 32. Thanks to Sergey Matyukevich for review and advices ( Nikolay F. Fominykh for review and advices Nikita Shulga for advices and notes ( Grigory Tolstolytkin for advices and notes ( tolstolytkin/2a/b41/74) 32 Egor Elizarov SPbSU 2012