C# ETC1/ETC2 Encoding

This library enables encoding ETC1/ETC2 for use in mobile games (such as those based on Unity or cocos2d) in C# via a set of CppSharp bindings to etcpak. It is fully cross-platform (tested on Windows x64, Linux x64) and should support ARM64 with minimal modifications.

Developer Information

Ensure when you clone the repository you also clone submodules. (i.e. git clone --recurse-submodules)

Building Native Libraries

If your target platform does not support AVX2 and you are compiling using MSVC, you will need to remove the AVX2 definition from UnityImageEncoding.Native/CMakeLists.txt.

If you are compiling using MSVC, you may also need to apply MSVC_Fixes.patch to UnityImageEncoding.Native/src/lib/etcpak.

Compile for the platforms you will be using cmake and MSVC or GCC/Clang. If compiling with Clang ensure you are using a modern compiler (e.g. clang++-8 or above).

Linux:

mkdir -p UnityImageEncoding.Native/out/build/x64-linux && \
cd UnityImageEncoding.Native/out/build/x64-linux && \
cmake ../../../ && \
make -j4

Windows (from "x64 Native Tools Command Prompt for VS 2022"):

mkdir UnityImageEncoding.Native/out/build/x64-release 
cd UnityImageEncoding.Native/out/build/x64-release
cmake -G "Ninja" -DCMAKE_C_COMPILER:STRING="cl.exe" -DCMAKE_CXX_COMPILER:STRING="cl.exe" -DCMAKE_BUILD_TYPE:STRING="Release" -DCMAKE_INSTALL_PREFIX:PATH="."  -DCMAKE_MAKE_PROGRAM="C:\PROGRAM FILES\MICROSOFT VISUAL STUDIO\2022\ENTERPRISE\COMMON7\IDE\COMMONEXTENSIONS\MICROSOFT\CMAKE\Ninja\ninja.exe" "../../../"
ninja.exe

Generating Bindings

Edit BindingsGenerator/Program.cs with the name/namespace of your project, and comment out platforms you do not wish to build for. Then build and run the program. The bindings will be created in MyProgram/Native/Windows64 and MyProgram/Native/Linux64, and the native libraries will also be copied.

Use a preprocessor directive to specify at build time which bindings to use for your platform:

#if Windows
using ETCEncodingDemo.Native.Win64;
#else
using ETCEncodingDemo.Native.Linux64;
#endif

These directives can be automatically set based on build platform (see ETCEncodingDemo.csproj). If you are building on windows and running on linux, you will need to pursue an alternative solution.

Usage

An example library based on SixLabors.ImageSharp is included at ETCEncoder.cs. Image inputs into the native library must be a byte array with type Bgra32 (1 byte colours ordered Blue-green-red-alpha).

If you are supplying user input, you should ensure that the width and height are accurate, or you may run into issues.