collision detection

[jonos]

im trying to make a game, but i didn't understand the collision detection tony, dan, and some other people are talking about in tutorials, so i decided to try to make my own. im not sure if this is the right way to go about it, or if this way will cause problems with trying to do some things in the game. it works, but im not sure if it the right way to do it...

code:

var chars : array char of boolean var circlex, circley : int := 100 var radius : int := 20 colorback (black) cls loop     setscreen ("offscreenonly")     View.Update     drawfillbox (20, 20, maxx - 20, maxy - 20, brightred)     drawfilloval (circlex, circley, radius, radius, black)     Input.KeyDown (chars)     if chars (KEY_UP_ARROW) then         if circley + radius > maxy - 20 then             circley := circley - 1         else             circley := circley + 1         end if     elsif chars (KEY_DOWN_ARROW) then         if circley + radius < 60 then             circley := circley + 1         else             circley := circley - 1         end if     elsif chars (KEY_LEFT_ARROW) then         if circlex + radius < 60 then             circlex := circlex + 1         else             circlex := circlex - 1         end if     elsif chars (KEY_RIGHT_ARROW) then         if circlex + radius > maxx - 20 then             circlex := circlex - 1         else             circlex := circlex + 1         end if     end if end loop

if the brevity of the code is not very good, oh well.

[Paul]

oh, so you used the size of the walls? I was just thinking about how to do it with whatdotcolor, you know, the only thing I've thought up of is if a color drawn over that doesnt belong there, then change the coords.

[recneps]

that works. thats basically the "rectangle" because you've made an invisible rectangle around the whole screen area, eg i show as a drawbox ;p

drawbox(0,0,maxx,maxy,7)

thats basically your box. and when it hits the edge of that box, its gonna go back one rather than forward, according to your code.

[Paul]

Jonos, you won't mind if I leech off your post right? It has to do with the same thing. Can anyone tell me how to do collision detection with whatdotcolor?

[jonos]

ill try it with whatdotcolor right now, hold on ten mins. i don't care if you leach off mine, i leached off your title colors

[recneps]

have your walls say, black,....
drawbox(x,y,x2,y2,black)

and your car, say, red
drawoval(x,y,rad,rad,red)

and
if whatdotcolour(x[car]+rad,y[car]+rad) = black then
collision=true
end if

[jonos]

code:

var chars : array char of boolean var circlex, circley : int := 100 var radius : int := 20 colorback (black) cls loop     setscreen ("offscreenonly")     View.Update     drawfillbox (20, 20, maxx - 20, maxy - 20, 12)     drawfilloval (circlex, circley, radius, radius, white)     Input.KeyDown (chars)     if chars (KEY_UP_ARROW) then         if whatdotcolor (circlex, circley + radius + 2) = 12 then             circley := circley + 1         else             circley := circley - 1         end if     elsif chars (KEY_DOWN_ARROW) then         if whatdotcolor (circlex, circley + radius + 2) = 12 then             circley := circley - 1         else             circley := circley + 1         end if     elsif chars (KEY_LEFT_ARROW) then         if whatdotcolor (circley, circlex + radius + 2) = 12 then             circlex := circlex - 1         else             circlex := circlex + 1         end if     elsif chars (KEY_RIGHT_ARROW) then         if whatdotcolor (circley, circlex + radius + 2) = 12 then             circlex := circlex + 1         else             circlex := circlex - 1         end if     end if end loop

this is what i got, but it still doesn't work perfectly, i hope no one beat me to it. play around with it paulbian and maybe you can get it to work.,

[Andy]

your approach only works for mono colored things... what u should do is check to the direction of movement...

[Paul]

Im thinking of doing one of those obstacle courses where you have to manuver the ball, which the size you can change, but the the smaller it is the faster it gets, through a tube that has different sized sections. Just to get familiar with collision detection. To me that's where whatdotcolor could be useful.

[jonos]

can you help us please, cause what i gave doesn't even work, it stops in a place where it shouldn't.

[jonos]

code:

var chars : array char of boolean var circlex, circley : int := 100 var radius : int := 20 colorback (black) cls loop     setscreen ("offscreenonly")     View.Update     drawfillbox (20, 20, maxx - 20, maxy - 20, 12)     drawfilloval (circlex, circley, radius, radius, white)     Input.KeyDown (chars)     if chars (KEY_UP_ARROW) then         if whatdotcolor (circlex + radius + 1, circley + radius + 1) not= 7 then             circley := circley + 1         else             circley := circley - 1         end if     elsif chars (KEY_DOWN_ARROW) then         if whatdotcolor (circlex + radius + 1, circley - radius - 1) not= 7 then             circley := circley - 1         else             circley := circley + 1         end if     elsif chars (KEY_LEFT_ARROW) then         if whatdotcolor (circley + radius + 1, circlex - radius - 1) not= 7 then             circlex := circlex - 1         else             circlex := circlex + 1         end if     elsif chars (KEY_RIGHT_ARROW) then         if whatdotcolor (circley + radius + 1, circlex + radius + 1) not= 7 then             circlex := circlex + 1         else             circlex := circlex - 1         end if     end if end loop

just one small thing to fix cause the circle stops in this one place on the y axis all the time

[Paul]

I just made a minor change to the if structure, cause you used elsif, it doesnt move diagonally.

code:

var chars : array char of boolean var circlex, circley : int := 100 var radius : int := 20 colorback (black) cls loop     setscreen ("offscreenonly")     View.Update     drawfillbox (20, 20, maxx - 20, maxy - 20, 12)     drawfilloval (circlex, circley, radius, radius, white)     Input.KeyDown (chars)     if chars (KEY_UP_ARROW) then         if whatdotcolor (circlex + radius + 1, circley + radius + 1) not= 7 then             circley := circley + 1         else             circley := circley - 1         end if     end if     if chars (KEY_DOWN_ARROW) then         if whatdotcolor (circlex + radius + 1, circley - radius - 1) not= 7 then             circley := circley - 1         else             circley := circley + 1         end if     end if     if chars (KEY_LEFT_ARROW) then         if whatdotcolor (circley + radius + 1, circlex - radius - 1) not= 7 then             circlex := circlex - 1         else             circlex := circlex + 1         end if     end if     if chars (KEY_RIGHT_ARROW) then         if whatdotcolor (circley + radius + 1, circlex + radius + 1) not= 7 then             circlex := circlex + 1         else             circlex := circlex - 1         end if     end if end loop

[jonos]

yeah, i was trying some stuff to make it go diagonal, thanks. i got it working, i just had to make the window smaller, which probably isn't the best way to do it, but whatever

code:

var chars : array char of boolean var circlex, circley : int := 100 var radius : int := 20 setscreen ("offscreenonly") setscreen ("graphics:400;400") colorback (black) cls loop     View.Update     drawfillbox (20, 20, maxx - 20, maxy - 20, 12)     drawfilloval (circlex, circley, radius, radius, white)     Input.KeyDown (chars)     if chars (KEY_UP_ARROW) then         if whatdotcolor (circlex + radius + 1, circley + radius + 1) not= 7 then             circley := circley + 1         else             circley := circley - 1         end if     elsif chars (KEY_DOWN_ARROW) then         if whatdotcolor (circlex + radius + 1, circley - radius - 1) not= 7 then             circley := circley - 1         else             circley := circley + 1         end if     elsif chars (KEY_LEFT_ARROW) then         if whatdotcolor (circley - radius - 1, circlex - radius - 1) not= 7 then             circlex := circlex - 1         else             circlex := circlex + 1         end if     elsif chars (KEY_RIGHT_ARROW) then         if whatdotcolor (circley + radius + 1, circlex + radius + 1) not= 7 then             circlex := circlex + 1         else             circlex := circlex - 1         end if     end if end loop

maybe someone will know how to do it better.

[TheXploder]

it's still wierd somethimes the up button make it move through the wall or the up button makes it move down.. really weird, and I've never see anyone do collisions with whatdotcolour...

[jonos]

yeah, i see what you mean, i think it's just turing though, because i don't see how it could be wrong. ive thought it over pretty hard