properly support huge sideways friction

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@10037 d7cf8633-e32d-0410-b094-e92efae38249

diff --git a/cl_input.c b/cl_input.c
index 5c4d449d0d71cb792910b2d29ad15c4816399e88..6aaf8139353171031b46ee7c500bd42a8c41a237 100644 (file)
--- a/cl_input.c
+++ b/cl_input.c
@@ -1169,18 +1169,23 @@ void CL_ClientMovement_Physics_PM_Accelerate(cl_clientmovement_state_t *s, vec3_
                // negative: only apply so much sideways friction to stay below the speed you could get by "braking"
        {
                vec_t f, fmin;
-               f = 1 - s->cmd.frametime * wishspeed * sidefric;
+               f = max(0, 1 + s->cmd.frametime * wishspeed * sidefric);
                fmin = (vel_xy_backward*vel_xy_backward - vel_straight*vel_straight) / VectorLength2(vel_perpend);
+               // assume: fmin > 1
+               // vel_xy_backward*vel_xy_backward - vel_straight*vel_straight > vel_perpend*vel_perpend
+               // vel_xy_backward*vel_xy_backward > vel_straight*vel_straight + vel_perpend*vel_perpend
+               // vel_xy_backward*vel_xy_backward > vel_xy * vel_xy
+               // obviously, this cannot be
                if(fmin <= 0)
                        VectorScale(vel_perpend, f, vel_perpend);
                else
                {
                        fmin = sqrt(fmin);
-                       VectorScale(vel_perpend, bound(fmin, f, 1.0f), vel_perpend);
+                       VectorScale(vel_perpend, max(fmin, f), vel_perpend);
                }
        }
        else
-               VectorScale(vel_perpend, 1 - s->cmd.frametime * wishspeed * sidefric, vel_perpend);
+               VectorScale(vel_perpend, max(0, 1 - s->cmd.frametime * wishspeed * sidefric), vel_perpend);
 
        VectorMA(vel_perpend, vel_straight, wishdir, s->velocity);