Scanning the framebuffer for changes
Posted on 2006-06-22
I'm developing a remote desktop app similar to VNC. I'm trying to scan the framebuffer for changes but it takes a REALLY long time. I'm using methods similar to other VNC apps, with the difference that I can't go through X, but need look directly at the framebuffer.
I mmap the local framebuffer to a char* buffer, but for some reason comparing portions of it to what I have in my "check against" buffer take much longer than I expected.
What I mean is, using memcmp to compare two data buffers I've created takes almost no time, whereas comparing a data buffer I've created to a portion of the mmap'ed framebuffer takes many times longer.
Are there VNC or VNC-like apps out there that don't go through X, and are they any good?
Do I need to go even lower, to the drivers?
Many many thanks for your help.