Re: Faster rendering to screen

[Chris Seaton <chris chrisseaton com>]

> Does SDL not go via X?

Yes, or framebuffer, or Windows API, just like GTK, so they can work 
together.

> > The mplayer people use a hardware overlay,
> Which is what precisely?

A hardware overlay is a bitmap that isn't drawn to the screen in the 
usual sense but instead you specify where on the screen to put it and 
the hardware combines it with the traditionally drawn stuff at the last 
stage before the image is sent to the physical display device.

This special bitmap lives in the graphics card so it's very fast, and 
because there is no blitting and is controlled by the hardware it 
updates without any flicker.

SDL has functions to create an overlay and then copy bitmaps to it. You 
simply copy a new bitmap to it 30 times a second.

It's fast enough for mplayer.

The only catch is that an overlay is very close to the hardware and you 
have to play by its rules, including using whatever funny pixel format 
that it wants.

Chris Seaton