Imagination PowerVR SDK Blog

video vertical sync

#1

hi,

 

I'm work on Opengl ES 1.1 PC emuration downloaded from IMG site(OGLES_WINDOWS_PCEMULATION_2.07.27.0484.msi).

I add eglSwapInterval(eglDisplay, 2); at initialization code (just before  // Draws a triangle for 800 frames comment)of OGLESHelloTriangle_Windows.cpp under TrainingCource2_HelloTriangle directory.

I expected a triangle drawing of 800 frames to become slow but

there was no change at the drawing speed.

 

Is the usage of API wrong?

 

If anyone knows the way to slow the frame rate using eglSwapInterval,
please let me know.

 

Best regards,

Zakky

 

 
#2

Hi Zakky,





The usage of the API seems ok. The values that can be accepted by this function depend on the values of EGL_MIN_SWAP_INTERVAL and EGL_MAX_SWAP_INTERVAL (as explained here). Also, I’m not 100% sure, but I think the maximum supported value may be capped depending on the driver implementation.





Just out of curiosity, what are you trying to achieve by limiting the frame rate? You may find limiting the frame rate within your application a more suitable approach in many cases instead of relying on the driver to do this for you as this will give you much more control over the final frame rate of your applicationJoe2010-11-24 11:27:26