How To Create A Scrolling Background In Scratch

This article covers a step-by-step process nigh how to make a Scrolling Platformer. A scrolling platformer is a type of platformer where the camera follows the player as they move through the level(s).

Coding the Histrion

To code the movement of the thespian, the following scripts need to be made. All scripts in this section are to go in the 'Role player' sprite.

Note:

Variables in caps (eastward.g. "SCROLL X" and "SCROLL Y") are global variables, and those lowercase (e.g. "ten" and "y") are made with the "For this sprite only" choice selected.

When green flag clicked broadcast (Green Flag v) and expect//A way to simply need 1 flag block. Flag blocks create lag, then the fewer the better. broadcast (Play Game v) and wait//Broadcasts to the other sprites that the game has started  When I receive [Play game 5] forever broadcast (Reset 5) and wait     broadcast (Ready Upward five) and wait     Game On::custom//sets up the variables     repeat until <(EXIT)>()>//means the actor has either died or won         broadcast (Tick v)     stop     if <(Go out)=(win)> and so         Win::custom     else         Die::custom//if the role player had not won, they would've had to have died     finish  define Position get to x:((x)-(SCROLL X)) y: ((y) - (Curlicue Y)  define Game On//Run without screen refresh bespeak in management (90) set size to (100)% clear graphic effects set [in air five] to (0) set rotation fashion [left-right v] gear up [sy 5] to (0) set [x v] to (0) set [y 5] to (0) set [EXIT v] to () // Nothing set [SCROLLL X 5] to (0) set [SCROLLL Y v] to (0) show  When I receive [Tick v] broadcast (Ready five) Tick <fundamental (Right arrow five) pressed?> <key (Up arrow five) pressed?> <central (Left arrow v) pressed?>::custom//checks if a key has been pressed  ascertain Tick <right> <up> <left> if <left> and so//If the left fundamental was pressed, it moves the player left     Change player X by [-viii]::custom end if <correct> and so//If the correct key was pressed, it moves the player right     Change histrion X by [eight]::custom end if <<upward> and <(in air)< (4)>> then//If the up primal was pressed, it checks if they are in the air still, if they are not, information technology makes the player leap     set [sy v] to (16) end change [sy v] by (-1)//Gravity,prepare it to any negative number Change player Y by (sy)::custom//Really moves the role player's Y position Exam dying::custom//Checks if the player has hit a danger sprite if <(Scroll X)<(0)> then     prepare [Curl X v] to (0) end if <(SCROLL Y)<(0)> then     set [Roll Y v] to (0) end modify [SCROLL Y 5] by (round(((y)-(SCROLL Y))/(10))) modify [SCROLL Ten v] by (round(((x)-(SCROLL X))/(five))) Position::custom//Positions the player'south location correctly if <(y position) < (-180)> then//If the player has fallen into the abyss     gear up [EXIT 5] to [die] end  ascertain Change player Ten by (sx)//Moves the player's X axis if <(sx::custom)<(0)> then//If the thespian is moving left     indicate in management (-ninety)//They indicate left else     betoken in direction (90)//They point right end modify [ten 5] by (sx::csutom)//Changes the X variable by the amount of movement needed (sx) Position::custom//Positions the player if <touching (platforms v) ?> then//Will check if the player has hit a wall, or a slope     echo (12)//Will check if the wall/slope in question is 12 pixels steep or not         change [y v] by (1)//Moves the role player up 1 pixel         Position::custom//Positions the histrion         if <not<touching (platforms 5) ?>> then//Then, that ways it was a gradient, and then we tin can finish trying             stop [this script v]         end     end     modify [y v] by (-12)//Corrects for the 12 that was used above     echo until <not<touching (platforms 5)?>> //Repeatedly  checks is the role player has ran into a wall         if <(sx)>(0)> and so //To come across if the histrion is moving left of right             alter [x v] by (-i) //The player is trying to move right, and then we need to move left to non go into the wall         else             alter [x v] past (one) //The actor is trying to move left, so we need to motion right to stay out of the wall         cease         Position::custom //Reposistions the role player on the scrolling airplane     cease cease  define Change player Y by (sy) change [y v] past (sy::custom) //Changes the y variable by an corporeality (sy) change [in air v] by (ane) //This is and so that we know if we are in the air, or on the ground. Without this, you would be able to hold leap and just fly. Position::custom //Reposistions the player repeat until <not<touching (platforms v)?>>     if <(sy::custom)>(0)> and then         change [y 5] by (-1)     else         change [y v] by (one)         ready [in air v] to (0)     stop     set [sy five] to (0)     Position::custom end  define Test dying if <touching (Danger v)?> so     ready [EXIT v] to [die] finish  define Die prepare [Leave v] to ()//nothing echo (iv)     hibernate     wait (0.one) seconds     show stop wait (0.5) seconds  define Win set rotation style [don't rotate v] repeat (50)     indicate towards (Portal v)     turn cw (65) degrees     move ((distance to (Portal v))/(2)) steps     change size by (-1)     modify [ghost v] result by (2) terminate hide change [LEVEL v] by (i) wait (1) seconds clear graphic furnishings fix rotation way [left-correct v]

Coding the Platforms Sprite

One time the thespian'south lawmaking has been completed, lawmaking for the ground sprite (called 'platforms' here) needs to be added in order to create a scrolling outcome. The following scripts become in the 'platforms' sprite.

when I receive [Tick 5] Position ((x)-(Curlicue X)) ((y) - (SCROLL Y) when I receive [Dark-green flag v] testify  define Position (10) (y) go to x: (x::custom) y: (y::custom) if <<(x::custom)= (x position)> and <(y::custom) = (y position)>> then     show else     hide stop  When I receive [Setup v] ready [x v] to (0) set up [y v] to (0) if <(LEVEL)=(ane)> then     switch costume to (Level 1 1)     Clone (450) (0) // This clones a new level. This needs to be done every bit many times as the number of levels. In this case, 3 is used as an example.     Clone (450) (0)     Clone (450) (0) else     ...::grey // If there is another scene then information technology should be cloned here using another if else block. terminate  ascertain Clone (ten) (y) create clone of (myself 5) change [x v] past (x::custom) change [y v] by (y::custom) adjacent costume

Coding the Danger Sprite

To code the danger sprite only duplicate the "platforms" sprite and supervene upon all the levels with only the dangerous elements that would hurt the player.

Annotation:

Make sure to call the danger sprite "danger" because the script higher up already makes the actor sense for a sprite of that proper name.

when I receive [Tick v] position ((x)-(Coil 10))((y)-(Roll Y))::custom  when I receive [Dark-green flag 5] show  when I receive [Reset five] delete this clone  define Position (x) (y) go to x: (ten::custom) y: (y::custom) if <<(x::custom)= (x position)> and <(y::custom) = (y position)>> then     bear witness else     hibernate terminate  when I receive [Setup five] set [ten v] to (0) set [y v] to (0) if <(LEVEL)=(i)> then     switch costume to (Level i ane)     Clone (450) (0) // This clones a new level, do this as many times as the number of levels, in this case three is used as an example.     Clone (450) (0)     Clone (450) (0) else     ...::grey // If there is another scene then it should exist cloned hither using another if else block. end  define Clone (x) (y) create clone of (myself v) alter [ten five] by (ten::custom) modify [y v] by (y::custom) next costume

Coding the Portal

Now that everything is made, a way to go to the next level needs to be made.

When I receive [Tick v] Position ((x)-(Roll Ten)) (((y) - (Coil Y)) + ((([sin v] of (timer)) *(100))*(20)))::custom if <<(costume [number v]) = (two)> and <touching (player v)?>> then     ready [EXIT 5] to [win] end  When I receive [Setup v] prepare [x v] to (0) fix [y v] to (0) if <(LEVEL)=(1)> then     switch costume to (Level one 1)     Position Portal at (450) (180)::custom else     ...::grey // If there is some other scene than the portal needs to be positioned hither using some other if else cake. stop  ascertain Position Portal at (x) (y) prepare [x 5] to (10::custom) set [y v] to (y::custom)  ascertain Position (x) (y) go to ten: (x::custom) y: (y::custom) if <<(x::custom)= (ten position)> and <(y::custom) = (y position)>> then     show else     hide finish

Adding Collectibles

Collectibles can be added to the game to make information technology more interesting. They are objects that need to be collected in club to attain a sure goal. The code to make them is shown beneath:

When I receive [Tick v] Position ((10)-(SCROLL X)) (((y) - (SCROLL Y)) + ((([sin five] of (timer)) *(300))*(5)))::custom if <touching (player 5)?> and so     alter [COLLECTED five] by (1)     if <(COLLECTED)=(COLLECTED MAX)> then         broadcast (Open up portal 5)         start audio (All coins nerveless v)     else         start sound (Collect v)     end     delete this clone end  When I receive [Green flag v] prove  when [m 5] key pressed fix [MOUSE v] to (join ((mouse x) + (Scroll X))(join [,]((mouse y) + (SCROLL Y))))  When I receive [Reset v] delete this clone  define Position (10) (y) go to 10: (ten::custom) y: (y::custom) if <<(10::custom)= (x position)> and <(y::custom) = (y position)>> and then     prove else     hide stop  When I receive [Setup 5] set [x v] to (0) set up [y five] to (0) if <(LEVEL)=(1)> then     Clone (450) (180)::custom else     ...::grey // If there is another scene than coins need to exist cloned here using another if else cake. end  define Clone (ten) (y) set [x five] to (x::custom) set [y 5] to (y::custom) create clone of (myself v) modify [COLLECTED MAX v] by (i)

Transforming a Basic Platformer

Frequently, Scratchers make bones platformers earlier they make a scrolling platformer, and they may want to use their onetime script to make a scrolling platformer. To do this, the "footing" sprite would move with the player. Making a script to do this is elementary:

when greenish flag clicked//This goes in the role player sprite. forever Scroll (((0) - (x position)) * (0.8)) (((-40) - (y position)) * (0.8))//0 and -forty are the desired x and y positions of the player. ...//The basic platformer script goes hither. stop  define Coil (x) (y)//This goes in the histrion sprite. change [level x v] by (round (10))//Round the variables so the level moves correctly. alter [level y v] past (round (y)) change x by (round (x))//When the level moves, the actor must move with it. alter y by (round (y))  when light-green flag clicked//This goes in the footing sprite. forever get to x:(level x) y:(level y) end