I'm using PixelToaster (a C++ library to draw to a framebuffer) for a simple 3D (ehm.. 2.5D) raycasting engine. I use the old school WASD key configuration to move the camera around (W=forward, S=backward, A=turn left, D=turn right) however I want to use the mouse for the modern freelock approach (WASD for moving and strafing, the mouse to turn head around).
I noticed that PixelToaster gives a mouselistener in which only the ABSOLUTE mouse coordinate x,y are given (relative to the window width,height). Using such coordinate system is not what I want because the turning stops as soon as the mouse x coordinate reaches the margin of the screen. (in all the commercial games you can turn around endlessly by swiping continuously the mouse in one direction).
How can I get the same behaviour using the PixelToaster mouse listener?
What you need is fairly simple to implement.
Simply reset the mouse pointer to the centre of the screen when you hit the margins.
Note that for this to work you should not "map" your 2D screen space coordinates to the angular rotation of your character. Instead have an accumulator that keeps adding up incremental changes in angle (calculated from 2D screen space movements of the mouse pointer).
Alternate Approach: You could detect when you are at the edges of your screen and keep rotating the character until you leave that edge. This way you don't need to reset the mouse pointer. For some reason I assumed that you wouldn't have a cross-hair in your game so I suggested my former approach first. :)