ClanLibW
ClanLib

ClanLib is a video game SDK, supporting Microsoft Windows, macOS, and Linux, with partial support for mobile platforms. It has full hardware accelerated graphics support through OpenGL, and also a software renderer. ClanLib also helps in playing sound, using the Vorbis or MikMod libraries, and has classes for collision detection, GUIs, XML, networking, and other things that may be helpful to a game programmer.

Core AudioW
Core Audio

Core Audio is a low-level API for dealing with sound in Apple's macOS and iOS operating systems. It includes an implementation of the cross-platform OpenAL.

LADSPAW
LADSPA

LADSPA is an acronym for Linux Audio Developer's Simple Plugin API. It is an application programming interface (API) standard for handling audio filters and audio signal processing effects, licensed under the GNU Lesser General Public License (LGPL). It was originally designed for Linux through consensus on the Linux Audio Developers Mailing List, but works on a variety of other platforms. It is used in many free audio software projects and there is a wide range of LADSPA plug-ins available.

Open Sound SystemW
Open Sound System

The Open Sound System (OSS) is an interface for making and capturing sound in Unix and Unix-like operating systems. It is based on standard Unix devices system calls. The term also sometimes refers to the software in a Unix kernel that provides the OSS interface; it can be thought of as a device driver for sound controller hardware. The goal of OSS is to allow the writing of sound-based applications that are agnostic of the underlying sound hardware.

OpenALW
OpenAL

OpenAL is a cross-platform audio application programming interface (API). It is designed for efficient rendering of multichannel three-dimensional positional audio. Its API style and conventions deliberately resemble those of OpenGL. OpenAL is an environmental 3D audio library, which can add realism to a game by simulating attenuation, the Doppler effect, and material densities. OpenAL aimed to originally be an open standard and open-source replacement for proprietary 3D audio APIs such as DirectSound and Core Audio, though in practice has largely been implemented on various platforms as a wrapper around said proprietary APIs or as a proprietary and vendor-specific fork. While the reference implementation later became proprietary, there are open source implementations such as OpenAL Soft available.

RaylibW
Raylib

Raylib is a cross-platform open-source software development library. The library is meant to create graphical applications and games. The official website introduces it as "a simple and easy-to-use library to enjoy video games programming."

Simple and Fast Multimedia LibraryW
Simple and Fast Multimedia Library

Simple and Fast Multimedia Library (SFML) is a cross-platform software development library designed to provide a simple application programming interface (API) to various multimedia components in computers. It is written in C++ with bindings available for C, Crystal, D, Euphoria, Go, Java, Julia, .NET, Nim, OCaml, Python, Ruby, and Rust. Experimental mobile ports were made available for Android and iOS with the release of SFML 2.2.

Simple DirectMedia LayerW
Simple DirectMedia Layer

Simple DirectMedia Layer (SDL) is a cross-platform software development library designed to provide a hardware abstraction layer for computer multimedia hardware components. Software developers can use it to write high-performance computer games and other multimedia applications that can run on many operating systems such as Android, iOS, Linux, macOS, and Windows.