EQS in UE4 comes with a good set of generators of query items but there might be cases where you prefer to create generators tailored on your needs. I decided to write my own generator because I had to write a query to find the best position around the querier but not too close to it. I knew that I could just add a distance tests to increment score with distance but I didn’t even want to consider items within a certain range from the querier so I ended up with a custom generator that produces a hole around the querier location. Here is a comparison between the Simple Grid Genrator available in ..read more

I’m still working at the AI system for The Mirror’s End and I decided to move the entire AI core from Behavior Tree to Utility AI. Environment Query System (EQS) is very well integrated with Behavior Trees and I really didn’t want to loose the ability to run EQS from my custom AI system. Luckily enough Unreal Engine lets us use EQS outside Behavior Trees in a very easy way. With this quick tutorial I’d like to show you how to do it with C++. LET’S CODE The data types we are interested in are UEnvQuery and FEnvQueryRequest. The UEnvQuery class inherits from UDataAsset that, as the UE4 documenta ..read more

In this article I’ll go down the rabbit hole, showing how to setup and use the AI perception system. The official documentation about this topic is good but I had to scrape other needed information from various forum threads, Unreal-Answers posts and a lot of try-fail attempts. This article will condense my experience and findings into a single place QUICK INTRO ABOUT PERCEPTION AI If this is the first time you heard about Perception AI System you might be pleased to know that UE4 has a set of ready-to-use functionalities that let you easily extend your AI with senses like sight and hearing ..read more

Hello Guys! how are you all doing? I’ve recently received emails asking about the blog and its future, so I decided it was time to explain here what I’m working on and why I’m no longer writing on ThinkAndBuild.it. It’s been a long time since the last article — 2 years! — and to me this has been a clear indication that I’m not interested in maintaining this blog anymore. It’s not that I’m no longer passionate about iOS in general: it is still my day job! In the meantime though a new interest has grown on me since the day I released my first video-game for iOS, Linia. “Coding your own video gam ..read more

It the previous two articles we saw how to setup and implement VIPER-S. In the third and last of the series we will be focusing on sharing information between modules and testing. Sharing data between modules Passing information between modules is a crucial task, and our architecture should be able to take care of it in a clear way. The first flow we’ll discuss is required when a module needs to send information to the following module, like when we select an item from the ItemsList. In this case we want to show the ItemsDetails module for the selected item. The solution that I’ve implemented ..read more

In the previous article we introduced VIPER-S, with an overview of its Domains and Roles, we organized our modules with folders and we started writing the contract for the “ItemsList” module. With this new article we’ll complete the architecture by implementing the Actors. An Actor is the entity responsible for the implementation of all the Roles for a specific Domain that, as you may remember from the previous article, are defined by the protocols in the Contract file. That being said, we are going to implement each Actor using those protocols and connecting Actors to each other in order to a ..read more

After some months using VIPER for my apps, I started working on my own architecture: I wanted to create something better for my own needs. I then started sharing thoughts with my colleague Marco. He is on the Android side of things, but we needed to discuss to find common ground and both get to a consistent result. We “kind of” failed and ended up with something really similar to VIPER, but! This revisited version of VIPER is what I’m currently using in my applications, so I wouldn’t consider it a failed attempt. More like a custom version of VIPER. Along this path I learned so many things abo ..read more

3D touch is the ability to track user’s touch pressure level and, in my opinion, is one of the most interesting and unexploited feature of iOS touch handling system. With this tutorial we are going to build a custom button that leverages on 3D touch to ask user to confirm button action and, if 3D touch is not available on user device, it just fallback to a different behaviour. Here is a quick video to show you how this control works: 1. When user’s touch begins, a circular progress bar keeps track of user touch pressure. The circle will be filled in relation to user pressure, the harder the b ..read more

After using Twitter’s iOS App for a while, I started looking at it with the developer’s eye and noticed that some of the subtle movements and component interactions are extremely interesting. This sparked my curiosity: how did you guys at Twitter do it? More specifically, let’s talk about the profile view: isn’t it elegant? It looks like a default view, but if you look closely you’ll notice there’s much more. Layers overlap, scale and move in unison with the scrollview offset, creating an harmonic and smooth ensemble of transitions… I got carried away, but yes you guessed it, I love it. So, le ..read more

With iOS 10 came a bunch of new interesting features, like the UIViewPropertyAnimator, a brand new class that improves animation handling. The view property animator completely changes the flow that we are used to, adding a finer control over the animations logic. A simple animation Let’s see how to build a simple animation to change the center property of a view. let animator = UIViewPropertyAnimator(duration: 1.0, curve: .easeOut){ AView.center = finalPoint } animator.startAnimation() There are at least 3 interesting things to note: 1) The animation is defined through a closure, r ..read more