(→‎Making Levels)
m (→‎Creating the platformer sprite: Corrected error in example script, which caused the sprite to float upwards because of gravity(!))
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==Creating the platformer sprite==
 
==Creating the platformer sprite==
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To start off, one first needs to create the platformer [[sprite]]: the sprite that one controls and plays as in the game. The appearance of the sprite can affect the gameplay slightly, depending on the angles and size of it. Implementing an animating sprite which switches among [[costume]]s of different dimensions can prove difficulties within the [[project]]. After designing the artwork for the sprite, create two new [[variable]]s called "x velocity" and "gravity"; select the option "for this sprite only" in the creation menu. That setting makes the variable only changeable by the sprite it is created within, and is used often in a [[Physics Engines|physics]] situation because they represent personal properties of an individual sprite. Once the variables are created, add the following script to the sprite. Note that the Gravity variable can be anything you want.:
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The platformer [[Sprite]] is the [https://en.wikipedia.org/wiki/Avatar_(computing) avatar] controlled by the player. Its appearance can affect gameplay slightly, depending on the angles and size of its [[Costume|costume(s)]]. For example, a character saved from a deadly fall because the brim of her hat snagged on a ledge may lessen the realism of a game. Sprites which are animated by dint of costume changes can be even more tricky.
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Below is an example of a simple script for a platformer sprite. It uses two [[Variable|variables]]:
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#"X velocity" stores a value representing the sprite's horizontal speed. It was set as a local variable by checking the option "For this sprite only" in the creation [[Dialog|dialog]]. This means (i) the variable can only be changed by scripts in the same sprite, (ii) the variable name does not needlessly clutter the variable pane of other sprites, and (iii) the same variable name may be used in other sprites without causing conflicts.
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#"Gravity" stores a value reflecting the strength of the sprite's tendency to fall. In this example it is set as a negative number because moving a sprite ''downwards'' requires making the value of its [[Y position]] smaller. "Gravity" need not be set as a local variable; a realistic game would subject all its characters to the same gravitational force.<ref>https://en.wikipedia.org/wiki/Galileo's_Leaning_Tower_of_Pisa_experiment</ref>
 
<scratchblocks>
 
<scratchblocks>
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when gf clicked
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when green flag clicked
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set [Gravity v] to [5]
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set [Gravity v] to [-5]
 
forever
 
forever
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  if <key [left arrow v] pressed?> then
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  if <key [left arrow v] pressed?> then// Using "else" saves processing later If's unnecessarily.
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    set [XVel v] to [-4]
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    set [X velocity v] to [-4]
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  else 
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    if <key [right arrow v] pressed?> then
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      set [X velocity v] to [4]
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    else
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      set [X velocity v] to [0]
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    end
 
   end
 
   end
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   if <key [right arrow v] pressed?> then
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   if <not <touching [Ground Sprite v] ?>> then
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    set [XVel v] to [4]
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    change y by (Gravity)
 
   end
 
   end
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   if <<not <key [left arrow v] pressed?>> and <not <key [right arrow v] pressed?>>> then
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   change x by (X velocity)
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    set [XVel v] to [0]
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end
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  end
 
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  if <not <touching [ground sprite v]>> then
 
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    change y by (Gravity)
 
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  end
 
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  change x by (XVel)
 
 
</scratchblocks>
 
</scratchblocks>
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This script has been tested.<ref>https://scratch.mit.edu/projects/139773849/</ref>
  
 
==Making Levels==
 
==Making Levels==

Revision as of 19:30, 12 January 2017

A platformer is a simulation of actual physics that take place in real life. Objects fall, move, slide, jump, and bounce, and a platformer associates those properties into a game in which one controls a character to typically move toward some form of a goal.

Creating the platformer sprite

The platformer Sprite is the avatar controlled by the player. Its appearance can affect gameplay slightly, depending on the angles and size of its costume(s). For example, a character saved from a deadly fall because the brim of her hat snagged on a ledge may lessen the realism of a game. Sprites which are animated by dint of costume changes can be even more tricky.


Below is an example of a simple script for a platformer sprite. It uses two variables:

  1. "X velocity" stores a value representing the sprite's horizontal speed. It was set as a local variable by checking the option "For this sprite only" in the creation dialog. This means (i) the variable can only be changed by scripts in the same sprite, (ii) the variable name does not needlessly clutter the variable pane of other sprites, and (iii) the same variable name may be used in other sprites without causing conflicts.
  2. "Gravity" stores a value reflecting the strength of the sprite's tendency to fall. In this example it is set as a negative number because moving a sprite downwards requires making the value of its Y position smaller. "Gravity" need not be set as a local variable; a realistic game would subject all its characters to the same gravitational force.[1]
when green flag clicked
set [Gravity v] to [-5]
forever
   if <key [left arrow v] pressed?> then// Using "else" saves processing later If's unnecessarily.
     set [X velocity v] to [-4]
  else  
     if <key [right arrow v] pressed?> then
       set [X velocity v] to [4]
    else
       set [X velocity v] to [0]
    end
  end
  if <not <touching [Ground Sprite v] ?>> then
     change y by (Gravity)
  end
  change x by (X velocity)
end

This script has been tested.[2]

Making Levels

Colors can be used in a platform for detection of the end of a level or an object which sends one back to the beginning of the level. For this tutorial, assume the following:

  • the character sprite performing the physics is named "Player"
  • black is the color of the platform, or ground and walls, in which the character cannot pass through
  • red is the color that sends one back to the beginning of the level he or she is on
  • yellow is the color which must be reached to move on to the next level
  • backgrounds are used as levels instead of sprites
  • scrolling is not incorporated

Level.png

The shapes do not need to be geometric, but can be organic, meaning an unordinary, inconsistent structure. There can be curvature to the various colors and platforms, which can be used to create diverse, numerous levels. The following image displays an example of some organic shapes being used:

Alt Level.png

When you finish designing the levels as backdrops in the Stage, add the following script to the "Player" sprite: 

when gf clicked
forever
if <touching color [#FF0000]?> then //if in contact with the color red
go to x:(-180) y:(-47) //relocate to the start
end
if <touching color [#FFFF00]?> then //if at the end of a level
go to x:(-180) y:(-47) //relocate to the start
switch backdrop to [next backdrop v] //next level
end

The scripts within the "forever" loop can be merged with the larger physics script shown farther above. Merging the scripts reduces the amount of conditions being checked at once and can possibly make the project more uniform and orderly, meaning the "Player" makes each movement and then checks for the conditions instead of the conditions possibly being checked during the sprite's movement.

Note Note: A condition is a statement that is checked for a true/false response. In the example above, when the sprite checks if it's touching a color, it's checking a condition.

Then add the following script to any sprite: 

when gf clicked
switch backdrop to [Level 1 v] //begin with the first level

Lastly, add the following script to the "Player" sprite: 

when gf clicked
show
wait until <([backdrop # v] of [Stage v]) = (amount of backdrops)> //wait until the last level is reached
stop [all v]

Making the Win Background

Last of all, comes the win background. After finishing all the levels in the platformer, something would come up that says something like "You Win!". Put it as the last costume in the sprite/background. It can be some text in a basic white background saying "You win" or the art can be complex.

  • A basic You Win background with just some black text and a white background

  • A You Win background with complex art

See also

External Links

  • ↑ https://en.wikipedia.org/wiki/Galileo's_Leaning_Tower_of_Pisa_experiment
  • ↑ https://scratch.mit.edu/projects/139773849/
    • Retrieved from "https://en.scratch-wiki.info/w/index.php?title=How_to_Make_a_Basic_Platformer&oldid=158146"