Possible division by zero on robot speed handling causing crashes

[FelipeMartins96]

grSim/src/robot.cpp

Lines 472 to 473 in 206c8dc

	vx *= new_v / v;
	vy *= new_v / v;

How to reproduce:
Send v_x and v_y zero to a robot with current speed > AccBrakeAbsoluteMax * delta_t

[g3force]

oh, sry... I've missed that. 🤦

I can prepare a patch in the next days or if you like, you can also provide a patch yourself via Pull Request.

[FelipeMartins96]

I've tried some solutions, but they haven't worked so far, I'll try testing other ideas later

[g3force]

Could you test the following fix?

        if (v > 0) {
            vx *= new_v / v;
            vy *= new_v / v;
        } else {
            vx = cvv[0] * (new_v / cv);
            vy = cvv[1] * (new_v / cv);
        }

[FelipeMartins96]

it didn't work properly, I think it is because cvv is in global coordinates while vx and vy are local, I'll try converting it

[FelipeMartins96]

        if (v > 0) {
            vx *= new_v / v;
            vy *= new_v / v;
        } else {
            // convert global to local
            dReal k, angle;
            angle = getDir(k);
            angle *= _DEG2RAD;
            dReal cvx = cvv[0]*cos(angle) + cvv[1]*sin(angle);
            dReal cvy = -cvv[0]*sin(angle) + cvv[1]*cos(angle);

            vx = cvx * (new_v / cv);
            vy = cvy * (new_v / cv);
        }

I think this fix works