C is a simple language. You’re only allowed to have one function with each name. C++, on the other hand, gives you much more flexibility: You can have multiple functions with the same name (overloading). You can overload built-in operators like + and ==. You can write function templates. Namespaces ...

Flap Hero is a small game written entirely in C++ without using an existing game engine. All of its source code is available on GitHub. I think it can serve as an interesting resource for novice and intermediate game developers to study. In this post, I’ll explain how Flap Hero’s code is organized, ...

I just released a mobile game called Flap Hero. It’s a Flappy Bird clone with cartoony graphics and a couple of twists: You can go in the pipes (wow!) and it takes two collisions to end the game. Flap Hero is free, quick to download (between 3 - 5 MB) and opens instantly. Give it a try! Flap Hero is...

Consider the lowly text file. This text file can take on a surprising number of different formats. The text could be encoded as ASCII, UTF-8, UTF-16 (little or big-endian), Windows-1252, Shift JIS, or any of dozens of other encodings. The file may or may not begin with a byte order mark (BOM). Lines...

Plywood is an open-source C++ framework I released a few weeks ago. It includes, among other things, a runtime module that exposes a cross-platform API for I/O, memory, threads, process management and more. This post is about the I/O part. For those who don’t know, I/O stands for input/output, and r...

For the past little while – OK, long while – I’ve been working on a custom game engine in C++. Today, I’m releasing part of that game engine as an open source framework. It’s called the Plywood framework. View the documentation View on GitHub Please note that Plywood, by itself, is not a game engine...

In the previous post, I presented a basic system for runtime reflection in C++11. The post included a sample project that created a type descriptor using a block of macros: // Define Node's type descriptor REFLECT_STRUCT_BEGIN(Node) REFLECT_STRUCT_MEMBER(key) REFLECT_STRUCT_MEMBER(value) REFLECT_STR...

In this post, I’ll present a small, flexible system for runtime reflection using C++11 language features. This is a system to generate metadata for C++ types. The metadata takes the form of TypeDescriptor objects, created at runtime, that describe the structure of other runtime objects. I’ll call th...

Lately I’ve been writing a game engine in C++. I’m using it to make a little mobile game called Hop Out. Here’s a clip captured from my iPhone 6. (Unmute for sound!) Hop Out is the kind of game I want to play: Retro arcade gameplay with a 3D cartoon look. The goal is to change the color of every pad...

I wasn’t planning to write about lock-free programming again, but a commenter named Mike recently asked an interesting question on my Acquire and Release Semantics post from 2012. It’s a question I wondered about years ago, but could never really reconcile until (possibly) now. A quick recap: A read...

Cairo is an open source C library for drawing vector graphics. I used it to create many of the diagrams and graphs on this blog. Cairo is great, but it’s always been difficult to find a precompiled Windows DLL that’s up-to-date and that doesn’t depend on a bunch of other DLLs. I was recently unable ...

As explained in my previous post, every CMake-based project must contain a script named CMakeLists.txt. This script defines targets, but it can also do a lot of other things, such as finding third-party libraries or generating C++ header files. CMake scripts have a lot of flexibility. Every time you...

CMake is a versatile tool that helps you build C/C++ projects on just about any platform you can think of. It’s used by many popular open source projects including LLVM, Qt, KDE and Blender. All CMake-based projects contain a script named CMakeLists.txt, and this post is meant as a guide for configu...

If you want to support multiple readers for a data structure, while protecting against concurrent writes, a read-write lock might seem like the only way – but it isn’t! You can achieve the same thing without a read-write lock if you allow several copies of the data structure to exist in memory. You ...

A hash table is a data structure that stores a set of items, each of which maps a specific key to a specific value. There are many ways to implement a hash table, but they all have one thing in common: buckets. Every hash table maintains an array of buckets somewhere, and each item belongs to exactl...

In an earlier post, I showed how to implement the “world’s simplest lock-free hash table” in C++. It was so simple that you couldn’t even delete entries or resize the table. Well, a few years have passed since then, and I’ve recently written some concurrent maps without those limitations. You’ll fin...

A map is a data structure that maps a collection of keys to a collection of values. It’s a common concept in computer programming. You typically manipulate maps using functions such as find, insert and erase. A concurrent map is one that lets you call some of those functions concurrently – even in c...

Atomic read-modify-write operations – or “RMWs” – are more sophisticated than atomic loads and stores. They let you read from a variable in shared memory and simultaneously write a different value in its place. In the C++11 atomic library, all of the following functions perform an RMW: std::atomic<>...

In my cpp11-on-multicore project on GitHub, there’s a class that packs three 10-bit values into a 32-bit integer. I could have implemented it using traditional bitfields… struct Status { uint32_t readers : 10; uint32_t waitToRead : 10; uint32_t writers : 10; }; Or with some bit twiddling… uint32_t s...

In multithreaded programming, it’s important to make threads wait. They must wait for exclusive access to a resource. They must wait when there’s no work available. One way to make threads wait – and put them to sleep inside the kernel, so that they no longer take any CPU time – is with a semaphore....

C++ has changed a lot in recent years. The last two revisions, C++11 and C++14, introduce so many new features that, in the words of Bjarne Stroustrup, “It feels like a new language.” It’s true. Modern C++ lends itself to a whole new style of programming – and I couldn’t help noticing it has more of...

As I explained previously, there are two valid ways for a C++11 compiler to implement memory_order_consume: an efficient strategy and a heavy one. In the heavy strategy, the compiler simply treats memory_order_consume as an alias for memory_order_acquire. The heavy strategy is not what the designers...

GCC is not just a compiler. It’s an open source project that lets you build all kinds of compilers. Some compilers support multithreading; some support shared libraries; some support multilib. It all depends on how you configure the compiler before building it. This guide will demonstrate how to bui...

Several modern C++ features are currently missing from Visual Studio Express, and from the system GCC compiler provided with many of today’s Linux distributions. Generic lambdas – also known as polymorphic lambdas – are one such feature. This feature is, however, available in the latest versions of ...

Last month, I attended CppCon 2014 in Bellevue, Washington. It was an awesome conference, filled with the who’s who of C++ development, and loaded with interesting, relevant talks. It was a first-year conference, so I’m sure CppCon 2015 will be even better. I highly recommend it for any serious C++ ...