Category: Construct

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Automating the import of hundreds of sprites to Construct

I’m making a game where an area of ground is broken piece by piece. I managed to create a python script that uses a voronoi pattern to shatter my image into several small irregular pieces. Here’s how that looked:

I then needed to import those 200 pieces into Construct. I figured out that if I set the position of each piece to 0,0, they would form the full image perfectly. After that I can just crop the pieces to their actual pixels and things work really nicely: the voronoi jigsaw puzzle comes together like it should.

The only pain point I had left was importing 200 sprites one by one into Construct. I knew that I could drag them all at the same time on top of Construct, which would create an animation. But I needed to create several individual sprites instead of animation frames.

The real life saver in this situation turned out to be the Project Folder feature in Construct (works best in Chrome), since it gives direct access to the project file structure. So here are the steps I performed and the scripts I used:

Please don’t attempt this with your production code, instead start a new empty Construct project and save it as a Project Folder on your local hard disk

1. Use a Python script to loop through all the image files in a folder and have it generate the JSON files Construct expects to have in the objectTypes folder. Here is the script for that (zipped due to security considerations). To run that, just unzip, place it in the same folder with the images, open a terminal there and type: python generateProjectJSON.py and hit enter. A bunch of JSON files should appear which you should copy to your Project Folder’s objectTypes folder.

2. Next the project.c3proj file needed to have the files listed in the items array in this manner:

“objectTypes”: {
“items”: [
“myImage_0”,
“myImage_1”,
“myImage_2”
],

So made a script to generate the array. Note that this is a very simple script and could be improved to support more files name conventions. At the moment it is just adding an incrementing number at the end of each image name. This script will output a simple array in a file called names.txt. Copy the array to your project.c3proj file.

3. The images needed to be renamed with -default-000.png appended to their file name. Time for another script, run this similarly in the folder with the images. After that I copied the images into the images folder inside the Project Folder.

4. That’s basically it but I also wanted the sprites already placed in the layout at coordinates 0,0 so I wrote one more script to do that. Run this script where you have your JSON files (that we generated earlier) and it will give you a new file called new_layout.json. Take the “instances” array from the generated file and merge it with your Layout 1.json file (which can be found in the layouts folder).

Now just reload the project and something magical happens: all your images will appear in the project and in the layout! Even if it’s hundreds or even thousands of images.

So there we have it. This workflow is obviously not useful if you just need to import a small number of sprites. But if you needs hundreds, then this can definitely save you some frustrating manual labor.

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Gamepad not working on a Mac?

Many people are reporting issues with various gamepads/game controllers and Macs. I was able to get a USB gamepad to work on my MacBook Pro (running MacOS Monterey) by installing (from the App store) a tool called Gamepad Mapper. Then I simply mapped the x-axis (which didn’t work at first) to keyboard keys (which my game also supports). I also had to allow this software in the security settings (accessibility submenu).

Now my Retro-bit NES USB controller works just fine with my Construct 3 video game. Check out the game King David RPG here:

https://ecation.itch.io/king-david-rpg

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Basics of working with timelines in Scirra Construct 3

Construct 3 has received a long-awaited feature when the Timelines got introduce a few years back. They have been built to be incredibly powerful, but getting started with timeline animation in Construct can feel confusing even for professional animators who are very familiar with concepts like keyframes and eases.

Here are the basic steps you should perform when you want to use the Timeline to create a rotation for an object:

-Right click somewhere in the layout editor and choose Timeline -new timeline

-Drag and drop an instance to the timeline

-Turn on editing (the pen icon)

-Select the instance and change it’s angle value in the properties bar

-Record this change as a keyframe by clicking on the + button to set keyframes

Here’s a few other tips:

-If you want to open the Timeline properties like the name of the Timeline, you need to click on the headers for things like the timeline name or a specific track. Then they will open up in the properties bar. Simply clicking on the Timeline bar itself is not enough.

-If you want to access the Timeline with events, you need to add the global timeline object to the project.

-You can zoom the timeline by scrolling while holding down ctrl

-To change the value of an existing keyframe, you don’t click “set keyframe” as in many other animation programs, but instead change the value, right click on the keyframe and choose “update”.

You can set any instance to play with the timeline using the “Set instance” action. Very handy for giving different objects the same animation.

One way of uniquely identifying a timeline is to give them a unique tag, possibly based on the UID of the instance involved.

If you want to do something with the instance you play with a timeline, one easy option for that is using the “system –> wait for previous actions to complete” action, which will wait for the timeline to finish and allow you to operate on the instance right after that.

One really powerful feature is the ability to add tags to master keyframes (the round ones). These tags can then be used to trigger various events in order to make things happen in sync with your animation.

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Construct 3 Rotation Angles Reference

If you have trouble remembering how Construct 3 calculates rotation angles, here is a quick chart for you. Note that movingAngles (which I believe are directional vectors) use a different coordinate system in which values can be also negative.

If you want to to make the movingAngle of the moveTo behavior change the animation of a character to left or right, one option is to do this:

  • System: (bird.MoveTo.MovingAngle+360)%360 within 88 degrees of 180
    -> bird: Set animation to “flyLeft” (play from current frame)
  • Else
    ->bird: Set animation to “flyRight” (play from current frame)

The (angle+360)%360 expression converts the values to a range of 0-360 and then we can simply check if we are within a certain degree of 180 which points left and if that’s true we set the animation to the left one.

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Finally a sprite sheet recoloring process that works

I have been searching for a good workflow for testing out different color palettes for existing video game designs.

I have finally found a relatively pain free method of testing different color palettes and applying them to entire games. I will be making a video tutorial about this in the future, but before I get to that, I thought I would already explain the basics of the workflow.

Continue reading “Finally a sprite sheet recoloring process that works”
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Construct 3 Spritefonts with Photoshop

Creating your own Spritefonts (sometimes also called bitmap fonts) for Scirra’s Construct 3 game engine using Photoshop can be surprisingly tricky. The main difficulty seems to be in creating a grid of evenly spaced characters so that the automatic Sprite font slicing mechanism in Construct can slice them up properly. A monospace font makes this much more simple since all the characters will take up the same space by default, but monospace fonts are quite limiting stylistically. What if you want to have non-monospaced fonts neatly organized in a grid for Construct?

There are helpful tools like “Give Your Fonts Mono” which can convert a regular font into a sprite font and it even generates the spacing data for Construct 3 which you paste into the Spritefont plugin settings. The spacing data looks typically something like this;

[[20,” “],[9,”l|”],[10,”Ii.,;:!'”],[16,”`”],[17,”[]”],[18,”j”],[20,”()”],[21,”t”],[22,”1-\”\/°”],[23,”r”],[25,”f”],[26,”*”],[31,”J”],[33,”u”],[34,”hkns”],[35,”Ldq”],[36,”bcgpz03789?”],[37,”Favy256+=$<>”],[38,”eox4~”],[40,”£”],[42,”BEP#€”],[44,”HNSTUZ_”],[45,”K”],[46,”D&”],[48,”R”],[49,”C”],[50,”VXY”],[51,”AG”],[52,”MO”],[53,”Q”],[54,”mw”],[58,”%”],[69,”W”],[70,”@”]]

You can’t however do any fancy stuff like giving your characters drop shadows, strokes or gradient fills etc. But there is a work around! Just save your tranparent png image from GYFM and open that in Photoshop. Then you can play with layer styles etc as long as you don’t cross the bounding box given for each character. You can increase the bounding box size in Give your fonts mono to give yourself more room. In Photoshop you might need to cut some of the rows into their separate layers for consistent gradients, but other than that this workflow should be pretty straightforward. When done in PS, simply re-save as PNG and import to Construct 3.

Unfortunately Construct doesn’t seem to support kerning at the moment so that would have to be handled with events. It’s not the easiest of programming challenges though.

Another possibility (besides custom events) might be to make a copy of the most difficult characters in the Spritefont sheet and give them special spacing rules. Then you would need to pick that special character in the situations in which your kerning looks bad. That’s also a bit hacky and tedious. So before Construct gets proper kerning support for Spritefonts, it might be best to stick to monospace Spritefonts.

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Run a simple lightweight Python server

When you are developing websites you often run into the need to test them on a server environment, because browsers block websites with certain features from running locally.

Here is a really quick way to run such a website in a server environment using Python 3 (which you probably have already installed on your machine anyways).

  1. Open the command window where your website root folder is. One easy way of doing that is simply typing “cmd” in the Windows Explorer address bar.
  2. Type this command in the command window: 
python -m http.server 8000
  1. Now simply go to http://127.0.0.1:8000/ in your browser.

If you are getting errors regarding script files with that simple version, you can also try this longer code:

python
#Use to create local host
import http.server
import socketserver

PORT = 1337

Handler = http.server.SimpleHTTPRequestHandler
Handler.extensions_map.update({
      ".js": "application/javascript",
});

httpd = socketserver.TCPServer(("", PORT), Handler)
httpd.serve_forever()

And open that with:

http://127.0.0.1:1337/