Platform Help

[B-Man 31]

What is it you are trying to achieve?
Trying to get the ball to land on the platform


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

Turing:

%MAKE A JUMPING GAME class player     import Input     export all     const gravity := 2     const radius := 5     const movespeed := 5     const jumpspeed := 20     type aPlayer :         record             x, y, xsp, ysp : real         end record     var user : aPlayer     user.xsp := 0     user.ysp := 0     user.x := maxx div 2     user.y := 0     var chars : array char of boolean     proc move         Input.KeyDown (chars)         if chars (KEY_UP_ARROW) and user.y = radius then %JUMP             user.ysp := jumpspeed         end if         if chars (KEY_LEFT_ARROW) then %MOVER LEFT             user.xsp := -movespeed         elsif chars (KEY_RIGHT_ARROW) then %MOVE RIGHT             user.xsp := movespeed         else             user.xsp := 0         end if         %MOVE THE PLAYER         user.ysp -= gravity         user.x += user.xsp         user.y += user.ysp         %SET BOUNDERIES         %RIGHT AND LEFT         if user.x + radius > maxx then             user.x := maxx - radius         elsif user.x - radius < 0 then             user.x := radius         end if         %UP AND DOWN         if user.y + radius > maxy then             user.y := maxy - radius         elsif user.y - radius < 0 then             user.y := radius         end if     end move     proc draw         drawoval (round (user.x), round (user.y), radius, radius, black)     end draw end player class platform        inherit player     import Math     export all     type aPlatform :         record             x1, x2, y, clr : int         end record     var pform : aPlatform     proc drawplatform (X1, X2, Y, CLR : int)         pform.x1 := X1 % RIGHT SIDE         pform.x2 := X2 % LEFT SIDE         pform.y := Y % HEIGHT         pform.clr := CLR % COLOUR         drawline (pform.x1, pform.y, pform.x2, pform.y, pform.clr)     end drawplatform %%%%%%%%%THIS PART HERE %%%%%%%%%%%%%%%%     proc detect         if Math.DistancePointLine (user.x, (user.y - radius), pform.x1, pform.y, pform.x2, pform.y) < 1 then % COLLISION DETECTION             user.ysp := 0             user.y := pform.y + radius                       end if     end detect end platform setscreen ("offscreenonly") var aplayer : ^player new player, aplayer var aplatform : flexible array 1 .. 1 of ^platform new platform, aplatform (upper (aplatform)) loop     player (aplayer).move     player (aplayer).draw     platform (aplatform (upper (aplatform))).drawplatform (50, 100, 50, 255)     platform (aplatform (upper (aplatform))).detect     View.Update     cls     Time.DelaySinceLast (10) end loop

[mirhagk]

look into linear collision detection

here

calculating distance does not work very well in instances like this one.

[B-Man 31]

Thats all fine and dandy, but i would like to know WHY it isnt working because ive used this before in a brick game and it worked perfectly.

[B-Man 31]

I Ended up solving it, here is the code for anyone who9 wishes to see it:

Turing:

%MAKE A JUMPING GAME class platform     export all     type aPlatform :         record             x1, x2, y, clr : int         end record     var pform : aPlatform     proc drawplatform (X1, X2, Y, CLR : int)         pform.x1 := X1 % RIGHT SIDE         pform.x2 := X2 % LEFT SIDE         pform.y := Y % HEIGHT         pform.clr := CLR % COLOUR         drawline (pform.x1, pform.y, pform.x2, pform.y, pform.clr)     end drawplatform end platform var aplatform : flexible array 1 .. 1 of ^platform new platform, aplatform (upper (aplatform)) class player     import Input, aplatform, platform, Math     export all     const gravity := 2     const radius := 5     const movespeed := 5     const jumpspeed := 20     type aPlayer :         record             x, y, xsp, ysp : real         end record     var user : aPlayer     user.xsp := 0     user.ysp := 0     user.x := maxx div 2     user.y := 0     var chars : array char of boolean     var t1 := 0     proc move         Input.KeyDown (chars)         if chars (KEY_UP_ARROW) and user.ysp < 1 and Time.Elapsed - t1 > 200 then  %JUMP             t1 := Time.Elapsed             user.ysp := jumpspeed         end if         if chars (KEY_LEFT_ARROW) then %MOVER LEFT             user.xsp := -movespeed         elsif chars (KEY_RIGHT_ARROW) then %MOVE RIGHT             user.xsp := movespeed         else             user.xsp := 0         end if         %MOVE THE PLAYER         user.ysp -= gravity         user.x += user.xsp         user.y += user.ysp         %SET BOUNDERIES         %RIGHT AND LEFT         if user.x + radius > maxx then             user.x := maxx - radius         elsif user.x - radius < 0 then             user.x := radius         end if         %UP AND DOWN         if user.y + radius > maxy then             user.y := maxy - radius         elsif user.y - radius < 0 then             user.y := radius         end if     end move     proc draw         drawoval (round (user.x), round (user.y), radius, radius, black)     end draw     proc detect         for i : 1 .. (upper (aplatform)) %FOR EVERY PLATFROM             if Math.DistancePointLine (user.x, (user.y - radius), platform (aplatform (i)).pform.x1, platform (aplatform (i)).pform.y, platform (aplatform (i)).pform.x2,                     platform (aplatform (i)).pform.y) < 2.5 and user.ysp < 0 then                 user.y := platform (aplatform (i)).pform.y + radius                 user.ysp := 0             end if         end for     end detect end player setscreen ("offscreenonly") var aplayer : ^player new player, aplayer loop     aplayer -> move     aplayer -> draw     aplatform (upper (aplatform)) -> drawplatform (50, 100, 50, 255)     aplayer -> detect     View.Update     cls     Time.DelaySinceLast (10) end loop

[DemonWasp]

Put this right above your collision detection line:

Turing:

Text.Locate ( 1, 1 )         put "(",user.x,",",user.y,")"

Move around. Oops. Those values didn't change, did they? Well, why not?!

Because your object design is wrong.

You have class platform inherit player. This establishes the following relationship: "All platforms are players". I sincerely hope that this is not what you intended.

The practical upshot is that in platform.detect(), platform is referencing the values of its own user variable, rather than those of the player variable you created elsewhere in your code. You will need to pass the platform the coordinates of the object it is (potentially) colliding with.

[mirhagk]

the collision detection is looking pretty good actually. It's been a while since I've used non-linear collision detection actually. Once you learn it you can't stop coding with it. (lol kinda like turing)

[B-Man 31]

i know, i ended up solving it with help from a guy in my class who is much stronger in OOP than i am.

[mirhagk]

I find OOP kinda strange. I mean obviously stuff like weapons and vehicles that could have sub-classes of it should be OOP but I find too many people just drool over OOP just because it's complicated.

[DemonWasp]

At the high school level it's probably true that the complication of OOP is what drives a lot of people. Later on, however, OOP is actually a pretty decent framework for solving complicated problems. The difference is in scale: one would hope that most high school projects never exceed around 4000-5000 lines of code, while in the real world of programming, projects often exceed 1000 times those numbers. At that size, proper encapsulation and separation of responsibilities becomes critical.

[mirhagk]

Yeah but in turing.... lol I just get pained when people make a module for someone to use, except they make it OOP, which just makes it harder for someone to use in their program.

[B-Man 31]

ok, im just using OOP to get practise with it, as ill be moving on to C++ next year for my programming class at school. ill be starting to learn over the summer to have a little bit of a head start, but because i feel i am stronger in turing, im am trying to get the basics down of OOP.