Hi,
No matter if I use relative mouse mode or not on OSX (10.9) I still get acceleration, rendering gaming useless on OSX.
There has been hacks to get around this, for instance by saving current Acceleration curve and then applying 0.0 or -1.0 as curve to enable linear response, but it works differently across OSX versions and doesn’t seem stable.
Now I talked to Forest Hale (LordHavoc) about this, mentioning that fodquake (http://fodquake.net (use latest repo code), code is in in_osx.c) directly parses HID messages from USB and therefor can access the raw data without acceleration applied. He mentioned an email from John Carmack with a link to a tech note from Apple about how to do this, I’ll paste the conversation
20:50 <@LordHavoc> you’re reminding me of an email from John Carmack now when I was working on QuakeLive
20:50 <@LordHavoc> yes, there is a way to get raw mouse, but you have to use the HID subsystem on OSX to get the raw USB packets and parse them yourself
20:51 < dimman> That sounds exactly like what he’s doing
20:51 <@LordHavoc> almost certainly, yes
20:51 <@LordHavoc> it was an API that was never documented properly
20:52 <@LordHavoc> dimman: here’s the tech note - https://developer.apple.com/library/mac/technotes/tn2187/_index.html
20:52 <@LordHavoc> dimman: I’d go ahead and put it in, then start a thread on the SDL mailing list (or forum - the two are linked) about raw mouse on OSX, it’s a worthwhile subject
20:54 <@LordHavoc> dimman: but this should be brought to attention
20:54 <@LordHavoc> dimman: this sort of platform-specific code (and especially driver-level stuff like USB HID parsing) is what belongs in SDL2 itself
Any comments? Interesting?