Collison Detection, Help

[miller6]

What is it you are trying to achieve?
I am trying to get an image to move around and act just like the ball in brick breaker.


What is the problem you are having?
Using collision detection to make sure it does not go off the screen.


Describe what you have tried to solve this problem
I ahve tried using a variety of different techniques in order to make the image move.


Post any relevant code (You may choose to attach the file instead of posting the code if it is too long)
So far i have to procedures and collision detection for the top and bottom butt he bottom is not working.

Turing:

var WinId : int WinId := Window.Open ("position:centre;centre,graphics:1010;695") var pic : int pic := Pic.FileNew ("sflake.gif") var pic_x := 18 var pic_y := 24 var pic_width : int := 52 var borderx1 := maxx var bordery1, borderx2 := 20 % x1 and y1 coordinate for box var bordery2 := maxy var bordery3 := maxy - 20 % y2 coordinate for box var borderx4 := maxx - 20 % x2 coordinate for box var x_angle, y_angle, x_angle2, y_angle2, x_angle3, y_angle3 : int := 1 Pic.Draw (pic, pic_x, pic_y, picCopy) Draw.Box (borderx2, bordery1, borderx4, bordery3, black) x_angle := Rand.Int (-3, -1) y_angle := Rand.Int (-3, 3) x_angle2 := Rand.Int (-3, 3) y_angle2 := Rand.Int (-3, -1) x_angle3 := Rand.Int (1, 3) y_angle3 := Rand.Int (1, 3) proc MoveFlake1  % MOVES SNOWFLAKE AROUND     var counter := 0     loop         counter := counter + 1         Pic.Draw (pic, pic_x + counter, pic_y + counter, picCopy)  %animates flake         delay (5)         View.Update         exit when pic_y + counter + pic_width >= maxy - 19     end loop     pic_x := pic_x + counter  % saves coordinates     pic_y := pic_y + counter     View.Update end MoveFlake1 proc MoveFlake2 %HITS TOP     % counter is now to make it decrease     var counter := 0     loop         counter := counter + 1         pic_x := pic_x + x_angle2         pic_y := pic_y + y_angle2         Pic.Draw (pic, pic_x - counter, pic_y - counter, picCopy)         delay (5)         View.Update         exit when pic_y + counter + pic_width >= bordery3 or pic_y < bordery1     end loop     View.Update     pic_x := pic_x + counter     pic_y := pic_y + counter end MoveFlake2 proc MoveFlake3 % HITS BOTTOM     var counter := 0     loop         counter := counter + 1         pic_x := pic_x + x_angle2         pic_y := pic_y + y_angle3         Pic.Draw (pic, pic_x + counter, pic_y + counter, picCopy)         delay (5)         View.Update         exit when pic_y + counter + Pic.Height (pic) <= bordery1         % or pic_x < 20         %pic_y     end loop     View.Update     pic_x := pic_x + counter     pic_y := pic_y + counter end MoveFlake3 proc MoveFlake4 % HITS RIGHT end MoveFlake4 proc MoveFlake5 %HITS LEFT end MoveFlake5 loop % collision detection and procedure call lines         if pic_y < bordery1 then % HITS BOTTOM         MoveFlake3     elsif pic_y + pic_width > bordery3 then % HITS TOP         MoveFlake2     elsif pic_y < bordery3 and pic_x < borderx4 then         MoveFlake1     end if end loop

Please specify what version of Turing you are using
4.1.1

[TheGuardian001]

Instead of having 4 separate procedures for each direction, you should be using 1 procedure to move the flake, and using different velocity values to change direction.

So first, create a variable for each X velocity and Y velocity. Set them both equal to 1 (you can set them to whatever you want, but this is a good starting point to get it working. Having a positive x and y velocity means that the flake will move Up and to the Right.

Whenever the flake hits the side of the screen, you should multiply the X velocity by -1. This will switch whether it is moving left or right.
Whenever the flake hits the top or bottom of the screen, you should multiply Y velocity by -1, which switches whether it moves up or down.

Once you've done that, the one remaining movement procedure should follow this sort of structure:

code:

proc Move_flake     flake_x_coord += x_Velocity     flake_y_coord += y_Velocity     if flake hits side         invert x velocity     end if     if flake hits top or bottom         invert y velocity     end if end Move_flake

It should be pointed out that there is no loop in that procedure structure. you should be looping calls to the procedure, not looping the contents of the procedure.

[miller6]

Do i still incorporate the different angles so that each time it hits it bounces off a new direction (just like the ball in brick breaker) if so, where?

This is the new codding i changed.

Turing:

var WinId : int WinId := Window.Open ("position:centre;centre,graphics:1010;695") var pic : int pic := Pic.FileNew ("sflake.gif") var pic_x := 18 var pic_y := 24 var pic_width : int := 52 var borderx1 := maxx var bordery1, borderx2 := 20 % x1 and y1 coordinate for box var bordery2 := maxy var bordery3 := maxy - 20 % y2 coordinate for box var borderx4 := maxx - 20 % x2 coordinate for box % var boderx4 := maxx - 20 var x_angle, y_angle, x_angle2, y_angle2, x_angle3, y_angle3 : int := 1 var x_velocity, y_velocity : int := 1 Pic.Draw (pic, pic_x, pic_y, picCopy) Draw.Box (borderx2, bordery1, borderx4, bordery3, black) x_angle := Rand.Int (-3, -1) y_angle := Rand.Int (-3, 3) x_angle2 := Rand.Int (-3, 3) y_angle2 := Rand.Int (-3, -1) x_angle3 := Rand.Int (1, 3) y_angle3 := Rand.Int (1, 3) proc MoveFlake1     var counter := 0     loop         counter := counter + 1         Pic.Draw (pic, pic_x + counter, pic_y + counter, picCopy)  %animates flake         delay (5)         View.Update         exit when pic_y + counter + Pic.Height (pic) >= maxy - 19     end loop     pic_x := pic_x + counter  % saves coordinates     pic_y := pic_y + counter     View.Update end MoveFlake1 proc MoveFlake2     pic_x := pic_x + x_velocity     pic_y := pic_y + y_velocity     if pic_x + pic_width >= borderx4 or pic_x <= borderx2 then         x_velocity := -1     elsif pic_y + pic_width >= bordery3 or pic_y <= bordery1 then         y_velocity := -1     end if end MoveFlake2 loop MoveFlake1 MoveFlake2 end loop

[TheGuardian001]

As I said, you can use any value you want for the velocities. 1, 1 is just easier to work with for the purposes of my example. It will work with any number though.
You can incorporate these by simply setting the X and Y velocities to the random values as required. So instead of simply inverting the X/Y velocity when the flake hits a wall, set it to a random number, with the correct sign, depending on the direction it is moving.

So for example

code:

%X velocity should be positive, it's moving right now. if hits_left_side then     x_vel = random_number(1,3) %but this means it's moving left else if hits_right_side then     %so we want these negative.     x_vel = random_number(-3,-1) end if

One question though, what exactly is the loop with counter doing? Depending on what it's doing, there might be a better way to do that without having a loop inside of a procedure (loops inside procedures are generally not good ideas, they make everything else stop and wait for them)