Collisions...

[slender0123]

Hello there person who is possibly reading this.. I am farely new to turing, i can get a jumping process going and such, so im trying to make a platformer game, kinda like IWBTG (I Wanna Be The Guy) The only problem is, I couldnt do collisions for the life of me! I can somewhat get it, but its not good enough, I want it so that if a circle hits a line ( as so shown in the program below) It would stop moving down and it could jump on the line, ONLY on the line. if it where to go off the line, it would fall back to the begging. And that if it hits the bottom of the line, it just bounces off and goes back down, I think it would probibly be easier with a Draw.FillBox so i might try that, i just need some guidence in my collisions..

Turing:

const Gravity := 2 var x, y := 100 var y_velocity := 0 var keys : array char of boolean var tiles : array 0..35, 0..35 of int setscreen ("offscreenonly,graphics:500;500") var height := 150 var Length := 150 loop     Input.KeyDown (keys)     if keys (KEY_UP_ARROW) and y <= 0 then         y_velocity := 30     end if     if keys (KEY_LEFT_ARROW) and x > 0 then         x -= 10     end if     if keys (KEY_RIGHT_ARROW) and x < maxx then         x+= 10     end if             y_velocity -= Gravity      y += y_velocity      if y < 0 then          y := 0         y_velocity := 0     end if               Draw.FillOval(x,y,15,15,blue)     drawline(50,height,Length,height,blue)     View.Update     delay (5)     cls end loop

im currently using 4.1.1.

[Raknarg]

You could do a bunch of complex math to solve it. The easy way is to use the built in function Math.DistancePointLine (xp, yp, x1, y1, x2, y2).

You give the function an x and y coordinate for the point, and then the x and y coordinates of the line. This will give you the distance between the point and the line.

We can use this. Lets say you have a circle that has a radius of 10 pixels. Every frame you could check the distance between the circle and the line. If the distance is equal to or less than 10, that means they have collided.

[slender0123]

code:

if Math.DistancePointLine (y,x, 50, 100,150,100) < 15 then       put "We have detection!"       end if

Thats what i got so far, but i find the line detection is still a little off. it doesnt go the the far left of the line, it starts maybe a quarter into the line...

[Raknarg]

Well the first thing you should do is reverse the x and y coordinates, it looks like you got them backwards

[slender0123]

OH! Lol!! Now i feel just silly Lol. thanks!

[Raknarg]

aha simple mistakes That's one of the most annoyingkind of errors because it's not a syntax error, so it's harder to figure out whats wrong

[slender0123]

True that! Now, to figure out how to get it so you can jump ON the line =p

[Raknarg]

Well if you have a boolean that keeps track of whether he's in the air or not, then you could just set it to false if he collides with a line

[slender0123]

OR i could simply just...

code:

if Math.DistancePointLine (x,y, 50, 100,150,100) < 15 then       y := 100       y_velocity := 0       if keys (KEY_UP_ARROW) and y <= 100 then          y_velocity := 30       end if     end if

Lastly, under the line.. hmm