Realistic Movement & Player Control

[Zasalamel]

Most People know how to create moveable characters on the screen but may not know how to make it more realistic.
But if you do not know how to create a movable character then that is here too.

[Zasalamel]

Here is how the tutorial will be posted:
- Below will be step by step code with comments in between the blocks of code
- At the end i will add attachments of uncommented and commented completed code files
- Also if you have any semblance of coding knowledge bear with me I go into some detail
- If you have any questions please post them...

First the screen...

Turing:

setscreen ("screen:max;max,offscreenonly")              /* OR */ View.Set("graphics:500;500,offscreenonly")             /* OR */ var win:= Window.Open ("graphics:max;max,offscreenonly")

These are the three most common window customizing commands
View.Set and setscreen are basically the same but will not let you control the window
var win := Window.Open will allow you to open and close the window
screen is setting the screen in inches ( screen:10;20 )
graphics sets the screen in pixels
max will automayically set the screen or graphics to fit the size of the monitor used.

Next you will need your variables

More Posted Later on the subject...

Turing:

var chars : array char of boolean var x1 : int := 1 var x2 : int := x1 + 10 var y1 : int := 1 var y2 : int := y1 + 10 var xv : real := 0 var yv : real := 0 var g : real := 1 var ground : boolean := false

[size=16]
chars is the variable that will store the keys pressed
the x's are the x positions of your player ( we will be using a box as the player)
the y's are the y position of the player
the xv and yv are the velocities (speeds) of you player
g is the gravity this is just for convenience so you can change it at the top of the screen
ground is a boolean (true or false) that will be used to indicate that the player is touching a platform (this will be used only for multi-platform games)

Next is the main loop:

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loop     Input.KeyDown (chars)

This gives a value of the keys being pressed to chars

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if chars ('w') and y2 < maxy and ground = true then

this basically says if keys being pressed equals (w key on keyboard) and and the player is on the screen and touching the ground then do this:

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yv += 15

this will make the player jump by adding to the y velocity

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elsif chars ('a') and x1 > 0 then

else if key being pressed equals (a key on keyboard) and the box is on the screen then do this:

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xv -= 1

This subtracts 1 from the players y velocity (which will make the player move left)

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elsif chars ('d') and x2 < maxx then

if key pressed equals (d on keyboard) then

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xv += 1

add 1 to x velocity to move the player right

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end if     if y1 > 0 then

if the bottom of the box not touching the ground then

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yv -= g

subtract gravity from the velocity until the player moves down and touches the ground

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elsif y1 < 0 then

if the bottom of the box is below the screen then

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yv := 0

stop the box

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y1 := 0

move the box to the bottom of the screen

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end if     if xv > 0 then

if the box is moving then

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xv -= 0.5     elsif xv < 0 then

slow it down

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xv += 0.5     end if     if x1 < 0 then

if the box has gone off the left side of the screen then

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x1 := 0

move the box to the edge of the screen

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xv := 0

stop the box

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elsif x2 > maxx then

if the box has passed the right side of the screen then

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x1 := maxx - 10

move the box to the edge of the screen

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xv := 0

and stop the box

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end if     if y2 > maxy then

if the box has passed the top of the screen then

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y1 := maxy - 10

move it to the top of the screen

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yv := 0

stop the box

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end if     if y1 = 0 then

if the box is touching the bottom of the screen

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ground := true

ground = true (thus allowing the player to jump

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else

otherwise

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ground := false

box cannot jump

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end if

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x1 += round (xv)

adds the velocity to the x position to create movement
*side note - xv needs to be rounded because it is not an integer but a real( or a decimal) round will convert xv to integer

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y1 += round (yv)

adds the velocity to the y position to create movement
*side note - yv needs to be rounded because it is not an integer but a real( or a decimal) round will convert yv to integer

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x2 := x1 + 10

the right side of the box = the left side plus 10 pixels
This keeps the box the same size

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y2 := y1 + 10

the top of the box = the bottom of the box plus 10 pixels
*keeps the box the same size

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Draw.FillBox (x1 - 1, y1 - 1, x2 + 1, y2 + 1, grey)     Draw.FillBox (x1, y1, x2, y2, black)

This Draws our player

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View.Update

brings the drawn images to the screen

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delay (10)

makes the controls less responsive and easier to control

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cls

erases everything on the screen
* so only the currently drawn box will show

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end loop

More will be posted on the subject later

Zasalamel

[SNIPERDUDE]

For those who want the code all in one place (for a nice copy and paste):

Turing:

var chars : array char of boolean var x1 : int := 1 var x2 : int := x1 + 10 var y1 : int := 1 var y2 : int := y1 + 10 var xv : real := 0 var yv : real := 0 var g : real := 1 var ground : boolean := true setscreen ("graphics:450;450,offscreenonly,nobuttonbar,title:Player Movement Tutorial") loop     Input.KeyDown (chars)         if chars ('w') and y2 < maxy and ground = true then         yv += 8     end if     if chars ('a') and x1 > 0 then         xv -= 1     elsif chars ('d') and x2 < maxx then         xv += 1     elsif chars (KEY_ESC) then         exit     end if         if y1 > 0 then         yv -= g     elsif y1 < 0 then         yv := 0         y1 := 0     end if         if xv > 0 then         xv -= 0.5     elsif xv < 0 then         xv += 0.5     end if         if x1 < 0 then         x1 := 0         xv := 0     elsif x2 > maxx then         x1 := maxx - 10         xv := 0     end if         if y2 > maxy then         y1 := maxy - 10         yv := 0     end if         if y1 = 0 then         ground := true     else         ground := false     end if         x1 += round(xv)     y1 += round(yv)     x2 := x1 + 10     y2 := y1 + 10         Draw.FillBox (x1, y1, x2, y2, black)     Draw.Box (x1 - 1, y1 - 1, x2 + 1, y2 + 1, grey)     locate(1, 1)         View.Update     delay (10)     cls end loop

A couple things I changed:
- There was a bug with jumping, the character kept getting stuck under 0 y, and thus couldn't jump (the velocity was automatically set back down to zero without moving the character)
- I split the if statements for 'w' and the rest so you can both jump and move at the same time
- I added an end using the ESC key.
- I minimized the jump height so it looks about average for a side-scrolling game
- I changed the setscreen and just added a title (and got rid of the buttons on top, since you can exit with the ESC key now). Also, I don't see any need to go into windows for this tutorial, just using the default will work fine for now (unless you get into multi-window games [ex: one window for gameplay, one for a map. Or two different windows for two different players {same keyboard}, one for a minimap]).

Good post, I'm sure this will be useful for some.

[Zasalamel]

Keep in mind that this was just the very basic version of the tutorial With Improvements Later On.
oh and the Window.Open is useful for the ESC key (ie:

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if chars (KEY_ESC) then exit Window.Close(win) end if

it looks neater and more professional

[Tony]

Zasalamel @ Sun Dec 20, 2009 6:17 pm wrote:

Turing:

if chars (KEY_ESC) then exit Window.Close(win) end if

Window.Close(win) will never execute.

[Zasalamel]

oops i was typing to fast i guess

[andrew.]

Here's what it should be:

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if chars (KEY_ESC) then     Window.Close(win)     exit end if

[TheGuardian001]

Zasalamel @ Sun Dec 20, 2009 4:11 pm wrote:

screen is setting the screen in inches ( screen:10;20 )

No it isn't.

screen and text modes both set the window in terms of rows and columns, based on the character sizes used by the put command.

Just thought I'd point that out.

[Zasalamel]

Thank you TheGuardian001 i was not sure. ( rows and columns do make more sense)

[livingheaven]

Great tutorial =D best so far

[blizzard4800]

How do u make more than one platform

[Turing_Gamer]

Here you would have to array the platform pictures, like so...

Turing:

var platform := Pic.FileNew ("Platform Picture.jpg") Pic.SetTransparentColor (platform, brightgreen) var xcoord, ycoord : array 1 .. 5 of int xcoord (1) := 100 xcoord (1) := 100 xcoord (2) := 100 xcoord (2) := 100 % etc... Pic.Draw (platform, xcoord (1), ycoord (1), picMerge) Pic.Draw (platform, xcoord (2), ycoord (2), picMerge) % etc...

[SNIPERDUDE]

I'm sure the question was regarding collision detection regarding platforms as opposed to drawing multiple platforms.

I'd look into the whatdotcolour and the collision detection tutorials on the Turing Walkthrough. (<- Link provided)

[evildaddy911]

looking through, I think that you should add a velocity cap, also, if you are using real variables for more realistic movement, make the x and y coords real too, the round() should be at the draw command

[Alex C.]

thats great, but if you could add wall jumping into your tutorial i feel that it would be better