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posts filed under: tutorials

Colliding with Slopes?!

Colliding with Slopes?!
In my last blog post I talked a little bit about how I've implemented slopes in my latest project, but I only talked about how I was actually importing them from Ogmo Editor into Flashpunk and not about how I'm actually using them for platforming. In this post I'll attempt to explain how I actually use slopes in my movement system, which means my platformer characters can walk up and down them without any problems.

The first thing to keep in mind is that all of my slope code only really works with slopes that increase or decrease by 1 pixel. I could rework some of it to make it work with a step of any size that the programmer could define, but for now 1 step is all I really need.

Pixel Sweepin'

The first thing to know is how I actually go about moving my platformer characters, and other moving objects around my game world. I use a method that I refer to as pixel sweeping. Basically whenever an object moves in my games, I move it one pixel at a time and check for collisions at each step! This might sound a little crazy to some folk, but this is the most reliable way I've been able to do stuff like platforming and other moving objects and still collide with even the tiniest pixel of a floor or wall. I've been using this technique since the very beginning of Bonesaw: The Game.

Flash Develop Pre-Build Command Line

Flash Develop Pre-Build Command Line
Last week I posted an asset generator script that will go through the contents of a folder and spit out an Actionscript class with static embeds for all of the assets. It's been pretty useful so far in my current project, but then I found a nifty feature of FlashDevelop that made it even better! Using FlashDevelop's Pre-Build Command Line option, I'm able to automatically execute my assetGenerator.py script every time I build my game, which means I don't even have to manually execute the script whenever I add content.

To hook it up in your project, just go to Project, then Properties in FlashDevelop. You should get a window with a couple of tabs across the top. Select the "Build" tab and you'll get something that looks like this:


In that screenshot I've already added the command to run the script every time I build. The first part of the line is c:\windows\system32\cmd.exe which just calls up the command prompt in Windows. The next part is the /C which is a flag that is set on cmd.exe which roughly translates to "run the following command, then terminate." The last part is $(ProjectDir)/assetGenerator.py which is basically just telling cmd.exe to run that command. $(ProjectDir) is actually a special string that FlashDevelop recognizes, and will replace with the full path to the project. In my case I had to surround the command with quotes due to having a space in the full path.

I also checked the "Always Execute" checkbox... not really sure what that means, but as far as I know I want assetGenerator.py to be run every time I hit build, so I want that checked.

Right now this makes adding level content to my game even easier. Now whenever the game builds, the assetGenerator.py will reassemble my Assets.as class, and then my "Universe" class which manages the entire game world will look at everything in my Assets class with the prefix "LEVEL_" and assemble the interconnected game world out of everything embedded with that prefix.

I absolutely hate any sort of tedious work, like adding content to a game by hand and copying pasting the same line 100 times and modifying each line slightly... so if I can spend a few hours coming up with methods to spare me of those tasks then it's totally worth it in the end.

Twitter API 1.1: User Timeline to PHP

Twitter API 1.1: User Timeline to PHP
Sometime in the past few months Twitter updated their API to make super simple tasks like fetching a user timeline pretty difficult. I started looking into the changes to see how to fix my code on my various sites but every time I started to get into I would just get frustrated and give up. So finally I attacked the new API again and this time I was able to get all the way to the finish line.

In order to fully remember what I did, and maybe even help some people out, here's a (relatively) quick guide on how to fetch a user timeline and get the data into a php script in order to spit out on your website however you want.