----------------------------------- Mazer Sat Dec 22, 2007 10:46 am [Tutorial] How to Jump ----------------------------------- If your game involves any kind of movement you should already be keeping track of the following variables: players x and y position players x and y velocity It seems as though alot of you forget about the second one. Go ahead and add it now. Now then... % some constants, tweak this to your liking const GROUND_HEIGHT := 120 const RUN_SPEED := 10 const JUMP_SPEED := 30 const GRAVITY := 2 var win := Window.Open ("graphics:640;480,offscreenonly") var chars : array char of boolean % player position and velocity var posx, posy : int var velx, vely : real posx := 20 velx := 0 posy := 400 vely := 0 loop Input.KeyDown (chars) if chars ('q') then exit end if % to make the player move if chars (KEY_LEFT_ARROW) then velx := -RUN_SPEED elsif chars (KEY_RIGHT_ARROW) then velx := RUN_SPEED else velx := 0 end if % remember, in order to jump you MUST be on the ground when pressing UP if chars (KEY_UP_ARROW) and posy = GROUND_HEIGHT then vely := JUMP_SPEED end if % subtract your "gravity" constant from the velocity EACH frame vely -= GRAVITY posx += round (velx) posy += round (vely) % simple "collision" check. just makes sure the player stays above ground if posy < GROUND_HEIGHT then posy := GROUND_HEIGHT vely := 0 end if % different colours just to illustrate whether or not you may jump if posy = GROUND_HEIGHT then drawfillbox (posx - 10, posy, posx + 10, posy + 20, green) else drawfillbox (posx - 10, posy, posx + 10, posy + 20, red) end if drawline (0, GROUND_HEIGHT, maxx, GROUND_HEIGHT, blue) View.Update delay (25) cls end loop Window.Close (win) That's a really simple example, but it should be enough to get going. If you can't adapt that to account for things like floating platforms or ceilings or pits (ie, real collision detection) then you've probably picked a project that is too complicated for you right now. ----------------------------------- Zampano Sat Dec 22, 2007 10:37 pm Re: [Tutorial] How to Jump ----------------------------------- A tutorial like this is is very helpful, as are all that teach one how to perform tasks without processes. I do have three questions, though. First, is there anyway to do the same things you did but without declaring a costly 'real' variable? If the user decides not to jump, vely will continue to decrease and decrease even though it will not be used (unless one jumps). Surely there is a way to avoid something as redundant as that. Second, what is the purpose of of velx if you could simply increment posx by the value of ground speed? Third, what is the purpose of declaring those four constants if there values are already constants by themselves? I think that though a tutorial such as this does not fit into the Turing Walkthrough, tutorials like these should be listed elsewhere; perhaps in some sort of index to solutions to common programming goals. ----------------------------------- Tony Sun Dec 23, 2007 12:31 am Re: [Tutorial] How to Jump ----------------------------------- is there anyway to do the same things you did but without declaring a costly 'real' variable? If the user decides not to jump, vely will continue to decrease and decrease no, if the character stays on the ground, the y-velocity will be 0. If it was to decrease, the character would obviously fall down through the ground. what is the purpose of of velx if you could simply increment posx by the value of ground speed? the value of ground speed is velx. what is the purpose of declaring those four constants if there values are already constants by themselves? the purpose of declaring those four constants is that their values are already constant. remember how you can't change the values of constants? Yeah, it's just like that. ----------------------------------- Mazer Sun Dec 23, 2007 12:36 am Re: [Tutorial] How to Jump ----------------------------------- First, is there anyway to do the same things you did but without declaring a costly 'real' variable? Go with integers if you really want. It's actually pretty pointless since I'm rounding anyways. If the user decides not to jump, vely will continue to decrease and decrease even though it will not be used (unless one jumps). Surely there is a way to avoid something as redundant as that. You're doing loads of processing in a game regardless of whether the user is doing anything. In the big scheme of things, decreasing vely probably won't count for much of a performance hit. If you prefer, you can put it inside that if statement so that it only decreases when the player is above the ground. Second, what is the purpose of of velx if you could simply increment posx by the value of ground speed? I just wanted to be consistent; the y position isn't directly controlled by keyboard input so I wanted to do the same with the x position. And maybe you'll want to add friction to your game. Or prevent the player from moving horizontally whilst airborne. Third, what is the purpose of declaring those four constants if there values are already constants by themselves? That's the whole point. I could easily get rid of those constants and replace every occurrence of GROUND_HEIGHT with 120, but what happens next week when I want to change the ground height in my suddenly larger game? Besides tweaking variables, this makes for easier reading. 120 is the height in pixels of the "surface" in this game, but it's also the minimum height in centimeters for an officer of the Royal Canadian Mounted Police and I don't want to waste one second thinking about which I'm referring to. In fact, the minimum height was 180 centimeters and that rule hasn't actually applied in a really really long time, but I felt like using that in my example. I think that though a tutorial such as this does not fit into the Turing Walkthrough, tutorials like these should be listed elsewhere; perhaps in some sort of index to solutions to common programming goals. I don't give a damn about the Turing Walkthrough. What concerns me is the number of retards who come in here and suggest the use of a for loop for something like jumping. DON'T ****ING DO THAT I WILL SLAP YOU. Not that it matters anyways; the people in question wouldn't look at common problems just like they wouldn't look at this tutorial. They want a solution, not a learning experience. ----------------------------------- rcbhs Wed Jan 02, 2008 7:59 am Re: [Tutorial] How to Jump ----------------------------------- Ratards cause we are new and are basing our ideas off of what we have seen in other programs? Harsh. ----------------------------------- Clayton Wed Jan 02, 2008 12:03 pm Re: [Tutorial] How to Jump ----------------------------------- Ratards cause we are new and are basing our ideas off of what we have seen in other programs? Harsh. Not quite. ----------------------------------- rcbhs Thu Jan 03, 2008 5:01 am Re: [Tutorial] How to Jump ----------------------------------- Oh and thx for this though. Working nicely but now every time I go in one direction I don't stop, i can turn directions and sich but cant stop. I also cant go up with the up arrows key anymore (jump is TAB btw) which I need for ladder climbing. Still trying to figure it out. ----------------------------------- Mazer Thu Jan 03, 2008 12:15 pm RE:[Tutorial] How to Jump ----------------------------------- That's kind of confusing. You'll have to explain your problem better or post some code. ----------------------------------- thrivey Fri Jan 11, 2008 4:01 pm Re: [Tutorial] How to Jump ----------------------------------- I am trying to make my character jump onto a platform. Can some one please tell me what an if statement would look like if there are 2 conditions because if my character passes the Y co-ordinate he will teleport to the platform and if he passes the X co-ordinate he teleports to the platform aswell. I need a code that needs both co-ordinates of the platform before it teleports to the platform.. Which wouldn't look like it teleported there cause the co-ordinates would be the same. This is what i got. if placex = 70 and placey = 70 then placex := 70 placey := 70 end if Edit: Or I just need any code that allows my character to jump on a specific like say 60, 60, 60, 60,red ----------------------------------- Clayton Fri Jan 11, 2008 6:54 pm RE:[Tutorial] How to Jump ----------------------------------- if placex = 70 and placey = 70 then placex := 70 placey := 70 end if Think about that piece of code for a minute. I mean chew it over, think about what's happening. Afterwards, tell yourself what's wrong with it. ----------------------------------- thrivey Mon Jan 14, 2008 6:45 am Re: [Tutorial] How to Jump ----------------------------------- Honestly, I don't know :P. I just know what I'm learning in school which isn't very much. That was just me trying get my character to jump onto something. ----------------------------------- [Gandalf] Mon Jan 14, 2008 10:08 am RE:[Tutorial] How to Jump ----------------------------------- If an apple is worth $5 and an orange is worth $5 then adjust the price of the apple to $5 and the orange to $5. That's essentially what you're doing. Will it have any effect, except wasting time? No. Using += will probably get your further... ----------------------------------- thrivey Mon Jan 14, 2008 12:26 pm Re: [Tutorial] How to Jump ----------------------------------- I'm still pretty lost.. Isn't there a command that I can make that when my character collides with my platform it = the base of the platform and therefore stays on? Can anyone add to the above "How to Jump" code and make it so that box can jump onto something.. I think i'd be able to get it to work from there. ----------------------------------- Tony Mon Jan 14, 2008 12:50 pm RE:[Tutorial] How to Jump ----------------------------------- go back and read over the code, it's already there % simple "collision" check. just makes sure the player stays above ground if posy < GROUND_HEIGHT then posy := GROUND_HEIGHT vely := 0 end if ----------------------------------- thrivey Mon Jan 14, 2008 12:53 pm Re: [Tutorial] How to Jump ----------------------------------- I tried something like that already.. but it doesn't work.. =/ if placey = 75 and placex > 100 and placex < 200 then placey := 75 speedy := 0 end if ----------------------------------- Tony Mon Jan 14, 2008 1:04 pm RE:[Tutorial] How to Jump ----------------------------------- that's because you are skipping over the details 100 and placex < 200 then speedy := jumpspeed end if if chars (KEY_UP_ARROW) and placey = 340 then speedy := jumpspeed end if % down force (gravity) speedy -= downforce placex += round (speedx) placey += round (speedy) %making sure the character doesn't go through the platforms floor, and walls. if placey < ground then placey := ground speedy := 0 end if if placey > 95 and placex < 100 and placex < 200 and placey < 85 then placey := 90 speedy := 90 end if if placey 230 and placex < 400 then placey := 340 speedy := 0 end if if placex < 0 then placex := 0 speedx := 0 end if if placex > 770 then placex := 770 speedx := 770 end if %picture management(so the picture of the character never leaves) if not placey = ground then Pic.ScreenLoad ("mario4.jpg", placex - 2, placey + 2, 0) end if if chars (KEY_UP_ARROW) then Pic.ScreenLoad ("mario4.jpg", placex - 2, placey + 2, 0) end if if not placey = ground and chars (KEY_LEFT_ARROW) then Pic.ScreenLoad ("mario3.jpg", placex - 2, placey + 2, 0) end if if not placey = ground and chars (KEY_RIGHT_ARROW) then Pic.ScreenLoad ("mario4.jpg", placex - 2, placey + 2, 0) end if if placey = ground and chars (KEY_LEFT_ARROW) then Pic.ScreenLoad ("mario3.jpg", placex - 2, placey + 2, 0) end if if placey = ground and chars (KEY_RIGHT_ARROW) then Pic.ScreenLoad ("mario4.jpg", placex - 2, placey + 2, 0) end if if placey = ground and not chars (KEY_LEFT_ARROW) then Pic.ScreenLoad ("mario4.jpg", placex - 2, placey + 2, 0) end if %platforms and floor. drawline (0, ground, maxx, ground, blue) drawline (100, 90, 200, 90, 6) drawline (230, 340, 400, 340, 6) View.Update delay (25) cls end loop ----------------------------------- thrivey Thu Jan 17, 2008 11:55 am Re: [Tutorial] How to Jump ----------------------------------- Any suggestions? ----------------------------------- TopBypass Sat Jan 19, 2008 11:53 am RE:[Tutorial] How to Jump ----------------------------------- Is it possible to change the object from a box to an image? ----------------------------------- Clayton Sat Jan 19, 2008 12:38 pm RE:[Tutorial] How to Jump ----------------------------------- Yes, instead of drawing your box, draw the image in it's place... ----------------------------------- TopBypass Sat Jan 19, 2008 12:51 pm RE:[Tutorial] How to Jump ----------------------------------- i mean inserting an image. ----------------------------------- Clayton Sat Jan 19, 2008 2:24 pm RE:[Tutorial] How to Jump ----------------------------------- It's the exact same thing. However, this really deserves it's own topic in [Turing Help], ask your question there. ----------------------------------- Michael516 Fri Mar 14, 2008 2:18 pm Re: [Tutorial] How to Jump ----------------------------------- thrivey if you still cant figure out how to put platforms in i have edited the how to jump program so that is has a platform in it here it is... ----------------------------------- A.J Sun Mar 16, 2008 4:21 pm Re: [Tutorial] How to Jump ----------------------------------- just to add to this tutorial, the example Michael516 gave is good, but make sure you can't jump up through the line (it shouldn't be accessible up or down) and make sure you can't go out of the screen (a couple more if statements) ----------------------------------- Doug101 Wed Mar 26, 2008 7:11 pm Re: [Tutorial] How to Jump ----------------------------------- Hey Micheal its Doug its a coll game but wat do these stand for "var velx, vely : real" im really confused? :? ----------------------------------- Mackie Wed Mar 26, 2008 7:17 pm RE:[Tutorial] How to Jump ----------------------------------- They stand for X Velocity and Y Velocity. Which is the speed the character is moving at for both x, and y axis. ----------------------------------- Doug101 Wed Mar 26, 2008 7:22 pm Re: [Tutorial] How to Jump ----------------------------------- Thanks Mackie that explains alot :D ----------------------------------- Jujeff Mon May 12, 2008 12:08 pm Re: [Tutorial] How to Jump ----------------------------------- I've already posted this to collision detection, but I don't know where to really put it, so I put it here too. I'm new to here, and Turing (sort of) so I'm sorry if I appear a noob. I wanted to make a platformer for a school project, so I realized I needed to make my character jump. I found the highly-helpful Mazer Jump Tutorial, copied and pasted (there are some numbers I couldn't figure out the use of), and tweaked it to my needs. After putting in a platform, I discovered that this messed everything up (the character cannot jump once on a platform), I tried to fix it as best as I could, and added in a boolean variable by recommendation of a friend, however as it is not clear to me the use of this, I will paste the code that I had before the boolean variable. (The problem of the jumping of the platform, as far as I can see, is that the Yvelocity must be 0 to be able to jump, but the character can only be on the platform if Yvelocity is above the value of "gravity".) Code: setscreen ("graphics:1011;699;nobuttonbar;offscreenonly") % VARIABLES! var keystroke : array char of boolean var height : int := 1 var LeftWall : int := 1 var RightWall : int := 1011 var movespeed : int := 10 var jumpspeed : int := 30 var gravity : int := 2 var Xposition, Yposition : int var Xvelocity, Yvelocity : real Xposition := 20 Yposition := 400 Xvelocity := 0 Yvelocity := 0 % game loop loop Input.KeyDown (keystroke) % horizontal movement if keystroke ('a') then Xvelocity := -movespeed elsif keystroke ('d') then Xvelocity := movespeed else Xvelocity := 0 end if % jump movement if keystroke ('w') and Yposition = height then Yvelocity := jumpspeed end if % world (lines and where you can walk and such) drawline (0, height, maxx, height, blue) drawline (245, 146, 384, 146, blue) % line (if you're on the middle line, stay on it) if Xposition >= 245 and Xposition = 140 then Yposition := 140 Yvelocity := 10 end if % reinstate gravity every loop Yvelocity -= gravity Xposition += round (Xvelocity) Yposition += round (Yvelocity) % don't fall through the ground or go past the edges if Yposition RightWall then Xposition := 1010 end if % character (square for now) drawfillbox (Xposition - 10, Yposition, Xposition + 10, Yposition + 20, green) drawfillbox (Xposition - 10, Yposition, Xposition + 10, Yposition + 20, red) % animation View.Update delay (25) cls end loop ----------------------------------- Jujeff Mon May 12, 2008 7:47 pm Re: [Tutorial] How to Jump ----------------------------------- EDIT::: no need, answer is found ----------------------------------- DaveAngus Tue May 20, 2008 12:35 pm RE:[Tutorial] How to Jump ----------------------------------- This tutorial is great and has helped me out a lot! Thanks Mazer! ----------------------------------- SAMZ Mon May 26, 2008 9:17 am Re: [Tutorial] How to Jump ----------------------------------- What about a wall? How would I jump over and back with a wall?