----------------------------------- keyboardwalker Sun Jan 27, 2013 6:53 pm Mass 2D hit detection ----------------------------------- Okay so I am trying to find the best way to do 2D hit detection very quickly. I currently have two methods one is with the the array of dots and checks to see if the movement location is okay by checking to see if any of the dots are in the array are in that X and Y location The other with colour. The issue with using the array locations is that you are doing a check for every single dot to see if any of the other dots are in that location. So far the best method I have found for hit detection with dots is actually colour which can be unreliable in some cases but it works. So what I was wondering is there a faster way or a just as fast way but more reliable? This is what I have done for colour hit detection: %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %Click on the screen to move the dots to the mouse %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% const SCREENH := 400 const SCREENW := 400 %SCREENW * SCREENH %This is the number of dots %Shoud really be called NUMDOTS :) %If it is really slow change it to a lower number const NUMBOXS := 2000 %The array of boxes var BoxX : array 1 .. NUMBOXS of int var BoxY : array 1 .. NUMBOXS of int %Their colours var BoxColour : int setscreen ("graphics:400;400,nobuttonbar,offscreenonly") procedure Grid_Dots var Counter : nat var XCur : int var YCur : int XCur := 1 YCur := SCREENH Counter := 1 randint (BoxColour, 1, 255) loop BoxX (Counter) := XCur BoxY (Counter) := YCur XCur := XCur + 1 Counter := Counter + 1 if XCur > SCREENW then XCur := 1 YCur := YCur - 1 end if exit when Counter > NUMBOXS end loop end Grid_Dots procedure Draw_Dots %It goes through the array of created dots and draws a dot there var Counter : nat Counter := 1 cls loop drawdot (BoxX (Counter), BoxY (Counter), BoxColour) Counter := Counter + 1 exit when Counter = NUMBOXS end loop end Draw_Dots procedure Follow_Mouse %Variables for mousewhere var MouseX : int var MouseY : int var MouseButton : int %The movement that the dots will try to move. const SPEED := 2 loop mousewhere (MouseX, MouseY, MouseButton) if MouseX > 0 and MouseX < SCREENW and MouseY > 0 and MouseY < SCREENH and MouseButton = 1 then %This goes through each individual dot to see if %It makes any contact. % for Indy : 1 .. NUMBOXS %This draws a white dot in the dot's location %This is used to prevent having to clear the screen every % movement. drawdot (BoxX (Indy), BoxY (Indy), 0) if MouseY > BoxY (Indy) then %This checks to see if where it wants to go is dot coloured. if not whatdotcolour (BoxX (Indy), BoxY (Indy) + SPEED) = BoxColour then BoxY (Indy) := BoxY (Indy) + SPEED %This checks to see if where it wants to go is dot coloured but it goes 1 dot closer %Consider this take 2 elsif whatdotcolour (BoxX (Indy), BoxY (Indy) + SPEED - 1) = 0 then BoxY (Indy) := BoxY (Indy) + SPEED - 1 end if elsif MouseY < BoxY (Indy) then if not whatdotcolour (BoxX (Indy), BoxY (Indy) - SPEED) = BoxColour then BoxY (Indy) := BoxY (Indy) - SPEED elsif not whatdotcolour (BoxX (Indy), BoxY (Indy) - SPEED + 1) = BoxColour then BoxY (Indy) := BoxY (Indy) - SPEED + 1 end if end if if MouseX > BoxX (Indy) then if not whatdotcolour (BoxX (Indy) + SPEED, BoxY (Indy)) = BoxColour then BoxX (Indy) := BoxX (Indy) + SPEED elsif not whatdotcolour (BoxX (Indy) + SPEED - 1, BoxY (Indy)) = BoxColour then BoxX (Indy) := BoxX (Indy) + SPEED - 1 end if elsif MouseX < BoxX (Indy) then if not whatdotcolour (BoxX (Indy) - SPEED, BoxY (Indy)) = BoxColour then BoxX (Indy) := BoxX (Indy) - SPEED elsif not whatdotcolour (BoxX (Indy) - SPEED + 1, BoxY (Indy)) = BoxColour then BoxX (Indy) := BoxX (Indy) - SPEED + 1 end if end if drawdot (BoxX (Indy), BoxY (Indy), BoxColour) end for else delay (100) end if View.Update %It will exit when you press a key exit when hasch end loop end Follow_Mouse Grid_Dots Draw_Dots Follow_Mouse ----------------------------------- Insectoid Sun Jan 27, 2013 8:44 pm RE:Mass 2D hit detection ----------------------------------- Using an array is your best bet. You don't have to check everything though. If your character is all the way on the left, he can't possibly hit anything on the right, so why bother checking against objects on the right? ----------------------------------- keyboardwalker Sun Jan 27, 2013 9:47 pm Re: RE:Mass 2D hit detection ----------------------------------- Using an array is your best bet. You don't have to check everything though. If your character is all the way on the left, he can't possibly hit anything on the right, so why bother checking against objects on the right? Here is my hit detection with arrays but it can't compare to hit detection with colour. How can I optimize it so that it is faster? I don't know how to apply what you just said. Try running the two and see the difference I really want the fastest way. const NUMDOT := 200 var DotX : array 1 .. NUMDOT of nat var DotY : array 1 .. NUMDOT of nat var MouseX, MouseY, MouseButton : int var Count : nat var Hit : boolean var Temp : int for I : 1 .. NUMDOT randint (Temp, 1, 400) DotY (I) := Temp randint (Temp, 1, 400) DotX (I) := Temp end for setscreen ("offscreenonly") loop mousewhere (MouseX, MouseY, MouseButton) if MouseButton = 1 then for i : 1 .. NUMDOT if DotX (i) > MouseX then Count := 1 Hit := false loop if DotX (i) - 1 = DotX (Count) and DotY (i) = DotY (Count) then Hit := true end if Count := Count + 1 exit when Count = NUMDOT or Hit end loop if not Hit then DotX (i) := DotX (i) - 1 end if elsif DotX (i) < MouseX then Count := 1 Hit := false loop if DotX (i) + 1 = DotX (Count) and DotY (i) = DotY (Count) then Hit := true end if Count := Count + 1 exit when Count = NUMDOT or Hit end loop if not Hit then DotX (i) := DotX (i) + 1 end if end if if DotY (i) > MouseY then Count := 1 Hit := false loop if DotY (i) - 1 = DotY (Count) and DotX (i) = DotX (Count) then Hit := true end if Count := Count + 1 exit when Count = NUMDOT or Hit end loop if not Hit then DotY (i) := DotY (i) - 1 end if elsif DotY (i) < MouseY then Count := 1 Hit := false loop if DotY (i) + 1 = DotY (Count) and DotX (i) = DotX (Count) then Hit := true end if Count := Count + 1 exit when Count = NUMDOT or Hit end loop if not Hit then DotY (i) := DotY (i) + 1 end if end if end for end if cls for I : 1 .. NUMDOT drawdot (DotX (I), DotY (I), black) end for View.Update exit when hasch end loop ----------------------------------- Insectoid Mon Jan 28, 2013 1:27 pm RE:Mass 2D hit detection ----------------------------------- You could try breaking the screen up into a grid of smaller squares. Figure out what squares your objects are in, then figure out which square(s) your character is in, and only check for collisions with objects in the same square(s) as your character.