Surfaceflinger and openGL ES

[Eyal Bellisha]

Hi,

I have a few questions regarding the SurfaceFlinger:

1) I understand that the app writes to the Surface itself and then moves the buffer to the SurfaceFlinger (let's assume I am using a Hardware Canvas or EGL). What is inside the buffer? raw pixels? compiled openGL code?

Can the buffer hold pixels on one transaction and another type of data on another?

2) I read somewhere that the SurfaceFlinger writes to the HWC/DisplayController commands  using the OpenGL ES 1.0 API. Is that true?

If it is, then how are version 3.0 commands translated into version 1.0 commands, and where?

Thank you

[Daniel Doron]

check this out: https://charleszblog.wordpress.com/category/android-2/graphics-android/surfaceflinger/

Daniel. 

[shivpratap chauhan]

Hi,

AFAIK, Inside buffer, there is an opaq handle which represent vendor specific object on gpu, GL app directly render into it and there is update buffer api available for non-gl app which updates these buffers again on update of these buffer gpu objects are also updated using a vender specific implementation.
Then to display apps output, Surfaceflinger creates eglImage and bind gl_texture_external_oes to draw whatever in these handle to display in on screen.

Upto Jellynean Surfaceflinger used OGLES 1.1 api and Kitkat onwards it uses OGLES 2.0 api.

Thank you

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[Roman Mazur]

AFAIK buffer that is fed to SurfaceFlinger usually contains raw pixels.

Here's a nice article about graphics architecture that should answer your questions.

http://source.android.com/devices/graphics/architecture.html