Simple Mouse.Where Program Help

[V1RU5]

What is it you are trying to achieve?
Basically, when the mouse is clicked, the ball should move in the direction of the mouse and fall down with gravity without holding the mouse button


What is the problem you are having?
I do not know what to do :S


Describe what you have tried to solve this problem
I tried making a program but it didnt work so any help would be appreciated


Post any relevant code (You may choose to attach the file instead of posting the code if it is too long)

Turing:

<Add your code here>

Please specify what version of Turing you are using
4.1.1

[DemonWasp]

Start with the idea of "iterative simulation". What this means is that you're going to break time up into "ticks" or "frames", each of which is perhaps a 30th of a second long - short enough that ticks start to "blend together" to the human eye.

On each tick, the ball will move slightly dependent on conditions in the program. The screen will be cleared and the ball will be drawn at its new position. This looks like the following:

Turing:

View.Set ( "offscreenonly" )   % part of the common anti-flicker fix loop     % update ball position here     %   this is where you'd put your Mouse.Where and logic...which I will not be writing for you     % draw ball here     %   you'll probably want either Draw.FillOval or Pic.Draw     % update screen, then clear it for the next frame     View.Update()     Draw.Cls() end loop

This gives the illusion of animation and makes it obvious where you should put the logic controlling the position of the ball.

[Cezna]

Here is a piece of code for a particle engine that should give you an idea of what you need:

code:

function getAngle (x, y : real) : real     if x = 0 and y = 0 then         result 0     elsif x = 0 and y > 0 then         result 90     elsif x < 0 and y = 0 then         result 180     elsif x = 0 and y < 0 then         result 270     elsif x > 0 and y > 0 then         result arctand (y / x)     elsif x < 0 and y > 0 then         result 180 + arctand (y / x)     elsif x < 0 and y < 0 then         result 180 + arctand (y / x)     elsif x > 0 and y < 0 then         result 360 + arctand (y / x)     else         result 0     end if end getAngle proc Moving     angle := getAngle (mx - x, my - y)     if button = 1 then % this attracts the object         vx += cosd (angle) * strength         vy += sind (angle) * strength     elsif button = 10 then % this repels the object         vx -= cosd (angle) * strength         vy -= sind (angle) * strength     end if     x += vx     y += vy end Moving proc Gravity     if y > 0 then         vy -= gravity     end if end Gravity loop     cls     Mouse.Where (mx, my, button)     if button = 1 then         Moving     end if     Gravity     drawdot (round (x), round (y), clr)     delay (40)     View.Update end loop

I recommend setting gravity at something like .7 or .8, but anything above 1 will be pretty substantial

[V1RU5]

DemonWasp @ Mon Jun 07, 2010 9:00 am wrote:

Start with the idea of "iterative simulation". What this means is that you're going to break time up into "ticks" or "frames", each of which is perhaps a 30th of a second long - short enough that ticks start to "blend together" to the human eye.

On each tick, the ball will move slightly dependent on conditions in the program. The screen will be cleared and the ball will be drawn at its new position. This looks like the following:

Turing:

View.Set ( "offscreenonly" )   % part of the common anti-flicker fix loop     % update ball position here     %   this is where you'd put your Mouse.Where and logic...which I will not be writing for you     % draw ball here     %   you'll probably want either Draw.FillOval or Pic.Draw     % update screen, then clear it for the next frame     View.Update()     Draw.Cls() end loop

This gives the illusion of animation and makes it obvious where you should put the logic controlling the position of the ball.

Turing:

var xPos : int var yPos : int var button : int var x, y : int View.Set ( "offscreenonly" )   % part of the common anti-flicker fix loop     % update ball position here     %   this is where you'd put your Mouse.Where and logic...which I will not be writing for you     Mouse.Where (xPos, yPos, button)         x := xPos + 5     y := yPos + 5     % draw ball here     Draw.FillOval (x, y, 10, 10, blue)         % update screen, then clear it for the next frame     View.Update()     Draw.Cls() end loop

I don't get what I am doing wrong

[TheGuardian001]

V1RU5 wrote:

Turing:

x := xPos + 5     y := yPos + 5

You aren't moving towards xPos and yPos, you're setting it equal to xPos and yPos.

You need to check whether the ball is currently above or below, and whether it is left or right, then move it slightly (using +=/-=, not :=) towards wherever the mouse is.

Edit: in case you don't know, the += and -= operators:

code:

x := x + 5 y := y + 5

The above code is exactly the same as:

code:

x += 5 y += 5

It's just a short form.

[V1RU5]

TheGuardian001 @ Mon Jun 07, 2010 5:54 pm wrote:

V1RU5 wrote:

Turing:

x := xPos + 5     y := yPos + 5

You aren't moving towards xPos and yPos, you're setting it equal to xPos and yPos.

You need to check whether the ball is currently above or below, and whether it is left or right, then move it slightly (using +=/-=, not :=) towards wherever the mouse is.

Edit: in case you don't know, the += and -= operators:

code:

x := x + 5 y := y + 5

The above code is exactly the same as:

code:

x += 5 y += 5

It's just a short form.

Okay I did that but now the oval sticks to the mouse, I want it to shoot when the mouse is clicked

Turing:

var xPos : int var yPos : int var button : int View.Set ( "offscreenonly" )   % part of the common anti-flicker fix loop     % update ball position here     %   this is where you'd put your Mouse.Where and logic...which I will not be writing for you     Mouse.Where (xPos, yPos, button)         xPos += 5     yPos += 5     % draw ball here     Draw.FillOval (xPos, yPos, 10, 10, blue)         % update screen, then clear it for the next frame     View.Update()     Draw.Cls() end loop

[USEC_OFFICER]

You need two more variables to replace the xpos and ypos. When you click, the two variables become the current xpos and ypos, then you can affect those two variables all you want.

[TheGuardian001]

V1RU5 @ Mon Jun 07, 2010 7:03 pm wrote:

Turing:

xPos += 5     yPos += 5

xPos and yPos are the position of the mouse. You don't want to change that. You had it right before with two variables. The problem is what you're doing to them.

Let's go back to what you originally had:

Turing:

x := xPos + 5 y := yPos + 5

The problem here is the := does not work in the same way as, say, accelerating a car. It doesn't slowly change the value of x and y until they match xPos and yPos. It simply changes them instantly to that value.

Instead, you should first check if the ball needs to move up, or down (y > yPos means it has to move down, otherwise, it should move up.)

Now that you know which way it needs to go, you can change its value. Lets say it needs to move down ( if y > yPos.) You should do something like:

Turing:

y -= 5 %subtract 5 from the balls y value. Next time we draw it, it will be 5 pixels down from where it was before.

You can change that 5 to whatever you want (nothing too big, or it'll fly right past the mouse)

Then you just do the same for the x value.

[V1RU5]

Turing:

var xPos : int var yPos : int var button : int var x : int := 0 var y : int := 0 View.Set ( "offscreenonly" )   % part of the common anti-flicker fix loop     % update ball position here     %   this is where you'd put your Mouse.Where and logic...which I will not be writing for you     Mouse.Where (xPos, yPos, button)         if button = 1 then     if y > yPos then     y -= 2     elsif y < yPos then     y += 2     elsif x > xPos then     x -= 2     elsif x < xPos then     x += 2     end if     end if     % draw ball here     Draw.FillOval (x, y, 10, 10, blue)         % update screen, then clear it for the next frame     View.Update()     Draw.Cls() end loop

K now it goes up first and then goes right, how do I make it go diagonally.

[TheGuardian001]

X and Y are independant of each other. X should be in its own if, and Y should be in its own if. With elsifs, only the first true condition is ever executed.

[V1RU5]

TheGuardian001 @ Mon Jun 07, 2010 7:43 pm wrote:

X and Y are independant of each other. X should be in its own if, and Y should be in its own if. With elsifs, only the first true condition is ever executed.

K thanks so much its working now, one last question, how do I add gravity?

[TheGuardian001]

Well, gravity is just always moving stuff down. Based on what you've done so far, how do you think this could be accomplished?

[V1RU5]

TheGuardian001 @ Mon Jun 07, 2010 8:08 pm wrote:

Well, gravity is just always moving stuff down. Based on what you've done so far, how do you think this could be accomplished?

Okay so basically I have to make the ball y = 0 for it to touch the ground and it should move and bit on the x axis also depending on the way it is getting shot at. Do you have msn or something cause msn is faster. If you have msn, pm me yours. Thanks

[V1RU5]

anyone? I need help with gravity

[Cezna]

You need to subtract a constant gravity value (probably something like .7 or .8) from the y velocity every cycle of the main loop.
Then you can tell it not to enact gravity if the ball is on top of something such as the ground or an object.