Acceleration/Deacceleration

[carstenht]

Im making a small "physics" app that accelerates a picture box, and then deaccelerate it until it stops. I have the acceleration working, but the deacceleration is giving me problems:

// Accelerate
private void timer1_Tick(object sender, EventArgs e)
        {
            cmdStartStop.Text = "Stop Simulation";
            box.Left += x;
            velocity += acceleration;
            x += velocity;
            lblPos.Text = "Position: " + x;
            lblVel.Text = "Velocity: " + velocity;
            lblAcc.Text = "Acceleration: " + acceleration;

        }

private void timer2_Tick(object sender, EventArgs e)
// Deaccelerate
        {
            while (velocity > 0)
            {
                box.Left += x;
                velocity -= acceleration;
                x += velocity;
                lblPos.Text = "Position: " + x;
                lblVel.Text = "Velocity: " + velocity;
                lblAcc.Text = "Acceleration: " + acceleration;

            }
        }

I start and stop the simulation with a button.
timer2 is disabled at load
button activates timer1
button then deactivate timer1 and activate timer2

[Harsh Gupta]

Don't loop inside a function that itself is looping.

Instead of while loop, you should check if velocity is greater than 0 or not.

private void timer2_Tick(object sender, EventArgs e)

if (velocity > 0)
{
   box.Left += x;
   velocity -= acceleration;
   x += velocity;
   lblPos.Text = "Position: " + x;
   lblVel.Text = "Velocity: " + velocity;
   lblAcc.Text = "Acceleration: " + acceleration;
}

This should work for you, I have both timers disabled initially.

private int acceleration = 1;
        int velocity;
        int x;
        private void Form1_Load(object sender, EventArgs e)
        {
            cmdStartStop.Text = "Start";
        }
 
        private void timer1_Tick(object sender, EventArgs e)
        {
            box.Left += x;
            velocity += acceleration;
            x += velocity;
            lblPos.Text = "Position: " + x;
            lblVel.Text = "Velocity: " + velocity;
            lblAcc.Text = "Acceleration: " + acceleration;
        }
 
        private void timer2_Tick(object sender, EventArgs e)
        {
            if(velocity > 0)
            {
                box.Left += x;
                velocity -= acceleration;
                x += velocity;
                lblPos.Text = "Position: " + x;
                lblVel.Text = "Velocity: " + velocity;
                lblAcc.Text = "Acceleration: " + acceleration;
 
            }
        }
 
        private void cmdStartStop_Click(object sender, EventArgs e)
        {
            switch (cmdStartStop.Text)
            {
                case "Start":
                    {
                        cmdStartStop.Text = "Stop";
                        timer2.Enabled = false;
                        timer1.Enabled = true;
                        break;
                    }
                case "Stop":
                    {
                        cmdStartStop.Text = "Start";
                        timer1.Enabled = false;
                        timer2.Enabled = true;
                        break;
                    }
            }
        }

[carstenht]

that worked thanks just weird that the loop made it not work tough

[carstenht]

altough its not a very smooth deacceleration . kinda stops realy fast - cant seem to find a good value to deaccelerate with

[carstenht]

    if(velocity > 0)
            {
                
                box.Left += x;
                velocity += -acceleration;
                x += velocity;
                lblPos.Text = "Position: " + x;
                lblVel.Text = "Velocity: " + velocity + " pixels/frame";
                lblAcc.Text = "Acceleration: " + acceleration + " pixels/frame^2";

            }

is only executed once, even if velocity > 0

[penagate]

Of course it is. That's what an if(){} block does: evaluates the condition and executes the block if the result of the condition is true.

for(;;;){}, while(){}, and do{}while() are loops. if(){} is not.

What Harsh is saying is that you have the if(){} block inside a timer event handler. The timer event is fired regularly until the timer is disabled, hence there's no need to loop within it. The alternative method would be to loop without a timer, but then you'd lose control over its speed (unless you use some more advanced trick).