Create HTML5 Vertical Endless Runner cross platform games

Using Phaser framework and other FREE software
Endless runner games are gaining more and more popularity and they are really easy to code.
I will take you by hand through the creation of a complete HTML5 vertical endless runner cross platform game with a lot of features and room for customization.
100 pages + 31 source code examples with a free update to come in a few days.

Creation of a platform game with Flash – step 1

Emanuele Feronato Flash

November 3rd update: part 2 released.

Back from my holidays, here I come with a brand new tutorial serial.

This time I will talk about platform games.

“Platform game, or platformer, is a video game genre characterized by jumping to and from suspended platforms or over obstacles. It must be possible to control these jumps and to fall from platforms or miss jumps. The most common unifying element to these games is a jump button.”

This is the beginning of a very interesting article taken from Wikipedia.

I strongly recommend you to read it… all in all it’s a piece of our history.

I think we can develop interesting Flash platform games.

The very first step is introducing the level. I decided to code the level as a tile-based level, so you should read How to load levels in a Flash tile based game tutorial before all.

Level creation

In this example I am going to use the array method.

In the first frame write the actionscript:

Line 1: Defining a new array called level that will contain the level data

Line 2: Creating a new empty movie clip that will contain the level

Lines 3-17: Populating the array with more arrays to design the level. We will have a zero for an empty spot or a one for a platform/wall

Lines 18-19: Loops that scan the entire array and sub-arrays

Lines 20-23: If the array at position (y,x) is different than zero (in this case it can only be one but this will be useful when we will introduce different types of platforms) then attach a movie previously created and linkaged as “block” in the right position according to y and x array position. The gotoAndStop instruction will be useful when we will have more platform tiles, one per frame in the same movieclip.

Now the level is complete, time to add the hero.

The Player

I linkaged another movieclip as player. In this first example, you should design your hero smaller than any other platform. We’ll see in further tutorials how this won’t be so important once the game engine will be finished, but at the moment it’s very important.

The new actionscript is:

Line 1: Initializing yspeed variable at zero. This is the vertical speed of the player

Line 2: Initializing max_yspeed variable at 16. This is the maximum vertical speed of the player. You will know what I mean in a minute or two.

Line 3: Initializing gravity variable at 1. This represents the gravity of the game.

Here I have to make a consideration: there should be two types of platforms: one with a so called “gravity” and one without it.
If you make a platform game with gravity, when the player steps off a platform, he will start falling down at increasing speed, just like in the real world. If you make the game without gravity, when the player steps off a platform, he will simply “move down” at a constant speed.

If you want the player to fall down at an increasing speed, use a low gravity value and a high max_yspeed value, like in my example. You will have to put a limit to yspeed anyway for a playability reason.

If you want the player to fall down at a constant speed, use a mid gravity value, such as 4 or 5 and do the same for the max_yspeed value. In this case, I suggest to set both values equals to the walking speed you will learn later.

Line 29: Putting the player on the stage, in a high place. You may need to reload the page to watch him fall.

Line 30: Routine to be executed at every frame

Line 31: yspeed variable is increased by gravity value

Lines 32-34: Checking if yspeed value exceeds max_yspeed value and if true, set yspeed value to max_yspeed value

Lines 35-37: These are the core lines for gravity management. Look: I perform an hit test between the platforms and the “feet” of the player plus yspeed value. In other words, I forecast next player’s position as if there was no walls. Then, I check if there is a wall in that position. If there is a wall, I decrease yspeed value and repeat the whole operation.

This picture will explain how does it work.


Line 38: Adding yspeed to _y position. As explained, yspeed can be zero if the player is already on a platform

Now we have a static player on the stage. Time to move him!

The moving player

We want now the player to move left and right

Line 1: Defining xspeed in the same way yspeed was defined

Line 5: Initalizing walk_speed variable. This is the speed of the player when walking (later he will be able to run!)

Lines 37-39: If the left arrow key is pressed, then set xspeed to -walk_speed (the player will move to the left)

Lines 40-42: Same thing with the right key

Lines 46-51: Apllying the same principle seen when the player was falling to x and y movements. This time the “hot spot”, the point where the collision is checked, is on the left (or right) side of the player in the middle of his height. This will work fine now, but will require some adjustments when we will have a “real” player on the stage instead of a red box.

Line 53: Updating player x position according to xspeed

Line 54: Set xspeed to zero. If you don’t do that, the player won’t stop walking when you release the arrow key.

Now we have a player running! Time to make him jump

The jumping player

When we want to make a player jump, we need to know two things:

1) The player can jump only when he has his feet on the ground

2) The player has a head so he cannot jump through platforms (he will be able to jump through some special platforms, called “clouds”, in next tutorial)

We need too to decide if the player can change direction while in the air or not. This is your decision and will affect gameplay.

Line 6: Initializing can_jump variable to false. This variable determines if the player can jump or not.

Line 7: Initializing the jump power. The higher the value, the higher the jump

Line 8: Variable that determines if the player can change direction while jumping

Line 37: Additional control when the player presses the left key. Before changing the xspeed I check that the player can walk while jumping or can jump = is not jumping

Line 43: Same thing with the right key

Lines 46-49: If the player presses the jump button (in this case the spacebar) then subtract jump_speed to yspeed and, since the player now is jumping, set can_jump to false (you can jump while jumping).

Line 56: If the player has the feet on the ground, then he can jump

Lines 64-66: Collision test as explained before with the “head” of the player

Lines 69-71: xspeed is resetted to zero only if the player can walk while jumping or can jump = is not jumping

And this is the very primitive first result. It has some glitches because player hot spots aren’t fully defined. In next tutorial we will learn how to insert a real player and everything will work fine.

Download the source codes of this tutorial, experiment and give me feedback

Then, move to part 2.

From null to full HTML5 cross platform game

I will take you by hand from the bare bones of JavaScript programming through the creation of a full cross platform HTML5 game, with detailed explainations and source code.

If you don't know where to start, then From null to full HTML5 cross platform game is the book for you.

Comments 63

  1. eblup

    hey did you already do this?

    o well still good and helped me find an error in my codeing of my style of jumping.

    ares are veary simmilar.

  2. And Mar

    If I jump while I’m just under the right edge of the first platform, and I hold down space, the player flies off the screen because of continous jumping.

  3. eblup

    hey wooow nice error you found

    And Mar

    i think it may be caused by the xspeed– and xspeed
    mixed with he has if not on ground grav increese.

    so if you move under it while gumping at the right position it will send you to the other side of the block and durring that it keeps him in the block while aadding jump power and makes him fly up

  4. sam

    or it could be because if hes on the ground, he can jump again and since hes going threw the platform, hes continuously hitting it, causing him to continuously jump…. keep up the good work…

  5. Jamie

    awesome tutorial emanuele!

    some suggestions for next time:
    sloping tiles
    pick-ups (coins, health, etc)
    doors – to switch from screen to screen (like the zelda games)


  6. squeenburg

    i have been looking for something just like this.
    ill constaantly be checking for your next tutorial,
    but until then, im going to try to do stuff by guess and check.
    i think i know how, but i have never been good at doing things right,so at least ill try.

  7. Pingback: games » Creation of a platform game with Flash - step 1 : Emanuele Feronato - blog of an italian geek

  8. Hello!

    Hello, I am new at making flash games and your website has helped me a lot at making games, TY!!!!!!!!
    I really like this concept of platform gaming.
    Can you make the next tut soon, plz?

  9. Pingback: Creation of a platform game with Flash - step 2 : Emanuele Feronato - italian geek and PROgrammer

  10. Post
    Emanuele Feronato

    It’s already out, but I forgot to put the link.
    Now you’ll find the link at the beginning and the end of this post

  11. Pingback: Creation of a platform game with Flash - step 3 : Emanuele Feronato - italian geek and PROgrammer

  12. Tommy

    I was just trying to do a vry simple thing using the hittesting code and I came across a problem when I try to attachMovie. It just doesn’t appear, I checked my code against your source code and I can’t see what is wrong with it.

  13. Tommy

    I just found that right clicking on the movieclip and doing the linkage thing makes them appear. Should that be necessary?

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  16. marc0

    im on the first example, but i cant get mine going… what is attached to “lev” on line 2? this might be my problem.

    thanks in advance.

  17. Pingback: New tile based platform engine - part 1 : Emanuele Feronato

  18. Blake

    i keep getting an error at the beginning that says “the class or interface brick cannot be loaded” and it points to my stop(); command in my brick movie clip. any ideas why this happens?

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  23. Alexandra

    Do you know how to make it so the platforms are solid so you can jump up onto them as this is exactly how I want me game to be although I don’t get how to make any of it Please can you explain exactly how to do it to me
    Please reply as soon as possible

  24. hazzasnake

    can someone help me because when I try making the level I only get 2 blocks appear on my screen and it doesn’t make the layout typed in the array

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  26. niyarbro789

    im tryin to get this code for the player. when i put the code in for the movie clip ‘player’ an error pops up saying: “Statement must appear within on handler.” what is that? im using ‘Sothink SWF Quicker’. the level code works with ‘Sothink SWF Quicker’, but not the player code.

  27. Chris Kimmel

    Excellent tutorial. However, the character can have a corner in a wall and the engine won’t notice. Perhaps it could be solved by using 8 point to check instead of one:

    Points = +
    Else = .


    That would really minimize the problems.

  28. Chris Kimmel


    My textart got screwed up. Here: If the character is a rectangle from the coordinates 1,1 to 10,20, there would be a point for hit testing at 2,1 & 1,2 & 9,1 & 10,2 & 1,19 & 2, 20 * 9,20 & 10,19.

    I’ll leave the visual up to you. :P

  29. Packapunch

    It’s nice, but how do you animate the player, so that when he walks, the player has a walking animation while moving?

  30. Pingback: Small updates and AS3 experiments « Mothership Games

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