"Dodge Ball" Game- Collision Checking Issues

[boomgreen87]

What is it you are trying to achieve?
I'm taking a programming class for the first time and I've been in the class for about 2 months. I have a lot of free time in class so I am trying to create a "dodge ball" game.


What is the problem you are having?
I can't get the game to properly check when a ball hits the player


Describe what you have tried to solve this problem
Various 'if' statements. An example is in the current code.

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

Turing:

%Dodgeball Game Project View.Set ("graphics,nobuttonbar") var playerpos, points, playerxpos, playerypos : int var ballspeed, ballposition, ballradius : int var gameover : int var chars : array char of boolean var anykey : string (1) points := 0 playerxpos := 585 playerypos := 175 gameover := 0 %Home Screen locate (11, 1) put "" : 30, "Welcome to DODGEBALL" put "" : 29, "Press any key to play!" put "" put "" : 34, "How to play:" put "" : 18, "Use the arrow keys to move. Avoid the balls!" loop     if hasch then         getch (anykey)         exit     else     end if end loop cls loop     %Draws original dodgeballs and determines position and size     randint (ballradius, 20, 40)     randint (ballposition, 1, 315)     ballspeed := 0     drawoval (maxx + 50, maxy - 50 - ballposition, ballradius, ballradius, red)     %Begins loop     loop         cls         %Character commands         Input.KeyDown (chars)         %Moves character down         if chars (KEY_DOWN_ARROW) then             if playerypos > 0 then                 playerypos -= 2             end if         end if         %Moves character up         if chars (KEY_UP_ARROW) then             if playerypos < maxy - 66 then                 playerypos += 2             end if         end if         %Moves character up         if chars (KEY_LEFT_ARROW) then             if playerxpos > 0 then                 playerxpos -= 2             end if         end if         %Moves character up         if chars (KEY_RIGHT_ARROW) then             if playerxpos < maxx - 50 then                 playerxpos += 2             end if         end if         %Draws "character"         drawbox (playerxpos, playerypos, playerxpos + 50, playerypos + 50, black)         %Draws dodgeballs         drawoval (ballspeed, maxy - 50 - ballposition, ballradius, ballradius, red)         ballspeed := ballspeed + 5         delay (7)         exit when ballspeed = 700         %Determines if a dodgeball hits the player         if ballspeed = playerxpos and ballspeed <= playerxpos + 50 and ballposition >= playerypos and ballposition <= playerypos + 50 then             gameover += 1             exit         end if     end loop     %Adds up points     points := points + 1     %Exits to Game Over screen when hit by a dodgeball     if gameover > 0             then         exit     end if end loop

Please specify what version of Turing you are using
4.1.1

[Zren]

The skill you're trying to learn is called Collision Detection.

For a beginner, you should pick between checking for collisions between circles, or between rectangles.

Doing collision detection between a circle and a rectangle (properly) is intermediate level.

Since you want "dodge balls" to be a circle, I'd advise turning your player into a circle as well.

You can learn about Circle collision detection in the Turing Walkthrough.
http://compsci.ca/v3/viewtopic.php?t=13661

Circle collision detection is basically calculating if the distance between the centers of both circles (using the Pythagorean theorem) is smaller or equal to the sum of both radius's.

[boomgreen87]

Okay! Thanks a lot!