Imagination PowerVR SDK Blog

glMapBuffer


#1

Again a conversion question...

is there any way to do simular things to glMapBuffer?

If yes, how to do this?

Best Regards,

Andi


#2

Obviously you can do the same things as with a mapped VBO with a client side array.


On PowerVR MBX platforms this may be your best option as there is little performance difference between VBOs and client arrays. In other cases the best alternative depends on your actual usage of the mapped buffer.


#3

I was thinking about this in the while as well and i’ll use the client side buffers for the reason of using the mbx platform. we talked about the performance of using vbo on this platform here in the forum a while ago. Remember?



#4
Xmas wrote:
On PowerVR MBX platforms ... there is little performance difference between VBOs and client arrays.



Is that true for MBX Lite platforms also (e.g. iPhone)?



Currently, I'm trying to use VBOs for some of the features of the iPhone port of our game engine, but some parts would be a lot easier if I could just do client-side arrays without VBOs.


#5

Yes, this also applies to MBX Lite. However, note that SGX platforms do benefit from using VBOs.


#6
Xmas wrote:
Yes, this also applies to MBX Lite. However, note that SGX platforms do benefit from using VBOs.



But the iPhone isn't SGX, is it? http://en.wikipedia.org/wiki/PowerVR says the current iPhones and iPod Touches use the Samsung S5L8900.




#7

No.. iPhone isnt SGX it is as you said, MBX lite.

I did lot of tests with VBOs on Nokia MBX Platforms and i could not reach to get a visible benefit out of it, so you really can use client side arrays as well.

What xmas wants to say is, that if your application should be ready for the future and should be able to use performance of future devices better uses VBOs