My game more or less works now. I added an additional enemy type, a “hill” that the player can crash into. I also added a quick HUD that shows a score which increments as the game progresses. None of the things I’m showing right now look nice. The hill is just placeholdered with the “capsule” in Unity and looks pretty weird, like an old Mario World hill in silhouette. The HUD is just black text. And my startup and end screen that I’m about to show are even worse… but the time for makepretties will be later; now I just want to get things working.

The code I wrote just does a “break” when the player dies. This obviously won’t work, so I need to add some additional scenes to my project.

I have two additional scenes: Splash, and GameOver. Splash will be the scene the player sees when the game first loads up. GameOver is after the player dies.

To make sure my game sees these scenes, I have to to go File-> Build Settings, and add each new scene to the build with the Add Current button. I should see a list of three scenes.

Notice I am working in Windows Phone mode right now. So here’s this very ugly loading screen…

Ha ha, I’m sorry, I still don’t even have a proper title for the game. But this is just a single sprite, so later, when I have a very pretty loading screen, all I will do is replace this placeholder with my pretty screen and we’ll be good to go! A small script advances the scene. I add this script to the sprite and set “scene” to be SunScene (the primary scene for the game). Then when the screen is clicked, the scene loads and the game starts. The updated script to kill the player uses Application.LoadLevel to load up the game over screen, and the game over screen also uses a click to return to the home screen.

Stuff to do:  make prettier splash screens, make a prettier score HUD and keep track of the player’s score, maybe with leaderboards? Playtest and work on feel and hitboxes, then add some Windows Phone features and publish. When HUD and score tracking are complete I’ll upload a couple web builds. Maybe you can test for me?

This part of the Sun Run project is the part that has taken me like, forever. Hopefully in this post I will be able to condense what took a lot of trial and error for me into some quick useful help for you.

What I would like in this game is the feeling that the player drives the horses, but needs to protect the chariot. Basically, ropy physics to make the avatar feel snake-like, so the control over the chariot is slightly indirect. Here’s the little most primitive diagram of what I’m talking about:

I started out with keyboard controls, but then added some mouse controls as well, so the player can use either tapping the top and bottom of the screen to move the chariot up and down, or use the arrow keys on the keyboard to move it up and down. I decided to try uploading the codes (it’s just the code for now, not the assets) to my very quiet GitHub, so if you want to follow along you can check them out there. I’ll update the commit periodically. Here’s the current version of the runner script. I’ll end up updating the code later to be sure it has proper touch control listening too. But what’s key here is that I put the code module on the front horse, and not on the chariot itself.

To make a chain in Unity you can use Unity’s 2D physics Hinge Joint. Each horse has a RigidBody2D and a HingeJoint2D, and they’re connected in a line, then parented to each other to allow the chariot to drag behind each horse. These are the settings currently on, which will probably be tweaked later (but this is already a result of a lot of tweaking…)

RunHorse1 (the front horse) is connected to RunHorse2, and so on, all the way to the chariot itself in the back. With four horses connected this way to a final chariot sprite, the control feels pretty tight, with just a little bit of slack behind. The -.75 on the chain anchor means that the horse connects to the horse behind it with a little slack instead of directly. The setting between the last horse and the chariot is at -1. I experimented with angle limits, but I didn’t like the result, so they are off for now. Notice there’s no gravity on my front horse and very little mass. If I use gravity, the horse will just fall, so away it goes! The light mass also means it’s very easy to control. Each horse has the smallest possible mass and the chariot itself is set to 0.003. Right now I’m keeping everything very light so the control feels tight, but if I want to make things harder to control, increasing the chariot’s mass makes it drag the whole chain down and is one way of doing it.

I’ve done a little playtesting with these controls and they feel “okay,” but maybe a little easier than I’d like for things to be. Some early feedback I got was that the primitive chariot sprite has a pretty unclear hit box. I’m actually using a particle system to make the chariot burst into flames… it’s so pretty, but I fear it hurts the clarity of the game, so it may have to go. Also, I’ll need a better chariot sprite and to make sure the enemy hit boxes are clear as well. Work for next time…

For most of these dev blogs, I’ll assume some basic Unity familiarity, like someone who has attended one of my Unity Getting Started talks. But I’ll explain some specific stuff about my progress. If it’s a little too basic, or if I go too fast, let me know by giving me feedback in comments or on Twitter. (Don’t be alarmed if your comment doesn’t appear right away; I moderate.)

Making a game requires design, playtesting, and lots of stuff people are confident they’d be ok at doing. But making a game also requires three things that are intimidating in various degrees: Art, Code, and Sound.

Sound is my weakest link, so I always have to Phone a Friend where it comes to that, and I’m sure this game will be no exception. But for now I’ll talk about Art and Code…

The Unity Asset Store is a good way to get both of those things, if you want to go looking. There’s lots of useful developer tools, plugins, and art there.  I just downloaded Unity-chan for kicks. But… I don’t actually like to use too many pre-built assets in my games because I like to have more control over the art and I don’t like my games to look too stock. So, custom art all the way.

My Unity project is actually set to 3D. You can organize your project folders however you want, but after some trial and error on this project, I find it easier just to group like things in like folders like this:

Sorry it’s small – click to embiggen. Other people like to group things by what they are, so I might put everything to do with the horse in one folder and everything to do with the bird in another. Shown here is my sprites folder. Normally when your Unity project is set to 2D, any texture you import will automatically become a sprite. But my project is actually still set to 3D, so all I have to do when I import something if I want it to be a sprite is change it to a sprite in the inspector:

Robot Unicorn Attack is probably my favorite endless runner. Of course the importance of the catchy theme song and the design can’t be overlooked, but I think one reason it works so well is the graphics. There’s something about a running horse that’s super graceful. It totally delights 12-year-old-me, still living in my brain clutching her Lisa Frank Trapper Keeper. Fortunately, a childhood full of drawing racing ponies in the margins of my notebook during study hall left me well-prepared to sketch out this sprite:

The background of this is actually transparent – I just dumped black in there to make it more visible on the blog. I also shrunk it down some for the post but you get the idea. Now that I look at it like this, the bottom-left frame is still feeling awkward to me, so I’ll probably fix it, and there’s a liiiittle bit of a ‘shake’ where something isn’t lined up right. But after importing a sprite into Unity, if you change it in the folder in the project, it will update in the game, so I’m not really stuck with it.

This sprite looks really intimidating to draw. Actually it’s pretty easy, though, and if you’re just getting started with frame to frame animations, it’s hard to go wrong with the run cycle on a horse. That’s because a) a horse run is pretty uniform, so you don’t have to worry too much about giving it individual character like you would with a human run cycle, and b) there’s so much useful reference available of this cycle. I really like the famous Muybridge photo series, which you can easily find with a web search, but any web search for “running horse reference” gets pretty good result pictures.

My sprites aren’t identical to this sequence but sketching it out is pretty easy. I used the pen tool in Photoshop, and simply copied the key frames of a horse run, tweaking them slightly and trying to get the horse shape to match previous frames. I used different reference photos for the tail, which I then adjusted to move up and down with the body. It’s not a hundred percent realistic, but since my horse is flying, I never moved the body at all.  I just drew the head and body on a separate layer and only redrew the legs and tail in every frame. That way the size of the body is consistent and it’s easy for a player’s eye to track. I also choose Photoshop because it’s where I’m most comfortable, but if you like free tools there’s InkScape (which is like Illustrator) or GIMP.

Drawing with the pen tool means I can set my sprite to be any size, but I’m using 1024 sprites for now and I’ll play with the resolution later. (If in doubt I find it best to start with a really high rez and then optimize down, unless I’m going for a pixel art look.) So my sprites are actually pretty huge. I also have to set the sprite tool to Multiple with a sheet like this, and then click on the Sprite Editor button to slice it up into individual sprites.

Here’s what all those sprites look like after using the Sprite Editor to break them down:

They have numbers on them, since they’re set up as frames, so if I select all the sprites (not just one) and drag them into the stage, Unity will create a new animation. I wanted to make an animated gif of it, but it would take longer to do that than it does to make the animation in Unity, so I’ll post some videos later of the whole thing in action. That’s all for now. Good luck if you want to draw cute horses!