How to make Turing sense that you have moved something to a certain position?

[Destro]

What is it you are trying to achieve?
When I move the ball to a certain position, I want to to 'sense' that and draw another line.


What is the problem you are having?
I have absolutely no idea what to use to achieve this.


Describe what you have tried to solve this problem
I tried using the if command.


Post any relevant code (You may choose to attach the file instead of posting the code if it is too long)
This is the section with the code, keep in mind that all variables have been previously stated. It is just a long program. If you need the whole thing, let me know.

Turing:

if chars ('g') then     cls     Draw.Line (100,100,500,100, black)     x := 100     y := 100     Draw.FillOval (x, y, 7, 7, black)     View.Update     if x = 500 and y = 100 then     Draw.Line (500,100,500,500, black)     View.Update     end if     end if

Please specify what version of Turing you are using
4.1.1

Thanks guys!

[Raknarg]

You can have two variables. One keeps track of its old position, one keeps track of its new position. If the new position is different from the old one, then do something.

[Destro]

Could you explain that further? I am new to Turing so I have no idea.


I want it so that when I move the ball to the end of the line, it draws a new line.
This is my full code:

Turing:

setscreen ("graphics:800;600,offscreenonly,nobuttonbar") var x, y : int := 550 %Setting the parameters such as the x and y increments x := 100 %Setting initial coordinate for x y := 100 %Sets initial corodinate for y %sets the screen and declares the variables var chars : array char of boolean %To set keys on keyboard to input a on/off signal var h := false Draw.FillBox (0, 0, 6000, 6000, 55) Draw.FillBox (30, 30, 770, 570, 54) Draw.Box (30, 30, 770, 570, black) var mypic : int := Pic.FileNew ("turings.jpg") var intfont : int intfont := Font.New ("Copperplate Gothic Bold:54") Font.Draw ("Turing", 265, 470, intfont, 42) Font.Draw ("Etch-a-Sketch", 120, 400, intfont, black) Draw.FillBox (270, 130, 537, 353, 55) Pic.Draw (mypic, 280, 140, picCopy) var intfont2 : int intfont2 := Font.New ("Impact:18") Font.Draw ("Use the arrow keys to move and draw. Ball CAN move diagonally", 92, 100, intfont2, black) Font.Draw ("Use the 'C' key to clear the screen. Press any of the arrow keys to begin!", 58, 70, intfont2, black) Font.Draw ("Use 'R' to repeat the instructions any time. Warning: Will Clear Screen!", 62, 40, intfont2, black) %put "Welcome to the Ball Game. Move the Ball around to draw things" %put "Press any of the arrow keys to start and press C to clear the screen." %beginning instructions delay (1500) cls %clears screen loop     Input.KeyDown (chars)     %States the keyboard variable     if chars (KEY_UP_ARROW) then         %When you press the UP key on the keyboard it carries out the following action         y := y + 3         %It increases the previously used y variable by the allocated amount (3) for every press or hold of the Up key         Draw.FillOval (x, y, 7, 7, 54)         %Turns the circle blue for when it goes up to coincide with the rules         delay (8)         %Delays before updating the movement         View.Update         %Updates the position of the ball while removing the previous location         Draw.FillOval (x, y, 7, 7, black)         %Leaves the black trail behind the ball allowing for drawing     end if     if chars (KEY_DOWN_ARROW) then         %When you press the DOWN key, it carries out the following action(s)         y := y - 3         %Decreases the previously used y variable by the allocated number (3) for every press of the key         Draw.FillOval (x, y, 7, 7, 34)         %Makes the circle purple to coincide with the rules set out on the handout         delay (8)         %Delays the action before updating the movement so you can see the ball's movement         View.Update         %Updates the location of the ball while removing the 'previous' ball         Draw.FillOval (x, y, 7, 7, black)         %Leaves the black trail behind the ball allowing for drawing.     end if     if chars (KEY_RIGHT_ARROW) then         x := x + 3         %Makes position of ball move by 3 pixels on the x axis for every time the key is pressed         Draw.FillOval (x, y, 7, 7, 48)         %Changes colours to appropriate green         delay (8)         %Delays the movement a little bit         View.Update         %Updates the position of the ball         Draw.FillOval (x, y, 7, 7, black)         %Leaves the black trail, while getting rid of the green ball     end if     %Makes the ball go left     if chars (KEY_LEFT_ARROW) then         x := x - 3         %Decreases the position of the ball on the x axis resulting in it going left         Draw.FillOval (x, y, 7, 7, 40)         %Draws the original ball         delay (8)         %delays the movement         View.Update         %Updates the position of the ball         Draw.FillOval (x, y, 7, 7, black)         %Leaves a black trail, while getting rid of the red ball     end if     %Prevents the ball from going outside the box     if chars ('c') then         %When the c button is pressed, the following actions are carried out         cls         %It clears the screen         View.Update         %It updates the screen with the clearing of the screen         Draw.FillOval (x, y, 7, 7, black)         %Redraws the circle since the cls gets rid of the circle as well         View.Update         %Updates with the redrawn circle     end if     if chars ('r') then         var intfont3 : int         intfont3 := Font.New ("Ariel:16")         Font.Draw ("Use the arrow keys to move and draw. Use the 'C' key to clear the screen", 60, 560, intfont3, black)         Font.Draw ("Use 'R' to repeat the instructions any time during the game", 110, 530, intfont3, black)         Font.Draw ("Press any of the arrow keys to begin! Have fun!", 160, 500, intfont3, black)         View.Update         delay (3500)         cls         Draw.FillOval (x, y, 7, 7, black)         View.Update     end if     if chars ('g') then         cls         Draw.DashedLine (100, 100, 100, 500, drawDash, black)         x := 100         y := 100         Draw.FillOval (x, y, 7, 7, black)         View.Update             if y >= 500 then             Draw.DashedLine (100, 100, 500, 500, drawDash, black)             View.Update             end if         View.Update     end if     if (x >= maxx - 7) then         x := x - 3         %Sets maximum parameters for x value     end if     if (x = 7) then         x := x + 3         %Sets minimum parameters for x value     end if     if (y >= maxy - 7) then         y := y - 3         %Sets maximum parameters for y value     end if     if (y = 7) then         y := y + 3         %Sets minimum parameters for y value     end if end loop %Ends the entire loop

[Raknarg]

Just a quick note, you can comment on everything if you want, but you don't need to comment on things that are self explanatory (or if your teacher really wants you to do it)

Well let's look at your code. You have a main loop here. You can consider one iteration through the loop a frame. Each frame, you detect the user's key presses. If they press the right key, they move. You also have an x variable that keeps track of what the x position of the ball is.

Let's think about two frames. What could happen between each frame? Sometimes the player will chose to move, sometimes not. Let'salso say you had another pair of x and y variables that remembered what the position of the ball was last time. We can compare what the position is now with the old ones, and do a little analysis. What happens if they're different? That means they moves. What happens if they're he same? it means they didn't move. You can do something different in each case. For instance, here's a quick program to show you how this might work:

Turing:

setscreen ("offscreenonly") var oldx, oldy, x, y, b : int Mouse.Where (x, y, b) oldx := x oldy := y loop     Mouse.Where (x, y, b)     if x not= oldx or y not= oldy then         Draw.Line (oldx, oldy, x, y, black)     else         Draw.FillOval (x, y, 2, 2, black)     end if     oldx := x     oldy := y     View.Update     cls     delay (15) end loop

see if you can analyze how this code works. If you need explanation, just ask.

[Raknarg]

Sorry, I realize I likely misread your intention.

Are you saying that if the ball moves to, let's say, position 300,400 you want to do something at that moment?

[Destro]

Yeah, that's exactly what I want.

[Nathan4102]

Somewhere in your main loop, assuming one loop is one frame, you need to have:

Turing:

Mouse.Where(x, y, b) if (x = 300) and (y = 400) then     ... end if

Replace the ... with your code you want happening when x is 300 and y is 400.

[Destro]

Do I need the Mouse.Where? My program has nothing to do with the mouse :(

[evildaddy911]

no, the x and y coordinates should be replaced with whatever you are checking the location of

[Destro]

Alright, I made it work, by moving it out of the "if chars ('g') then" command. Thanks guys!

However, I want it only to draw another line when you activate the game by pressing 'g'. By moving it out, it draws the line all the time.

[Nathan4102]

Apologies, I was going off Raknargs post. Can you show us your new main loop?