nim-4k-intro-sample

4k intro sample code written with Nim programming language. This sample is written for MS Windows.

Build tools

• Nim
  • Works in version 1.2.0
  • Current sample requires devel version. You can download it from nim-lang/nightlies
• Visual Studio 2015
• Crinkler

Nim use C compiler in Visual Studio as backend. Crinkler works as linker and compress your code and data. Output executable file from crinkler decompress code at runtime.

Required libraries

• winlean4k
• with
  • Used in openGL4kGen
• OpenGL Extension Header Files
  • Optional. This header file is used when building samples in csrc directory that uses OpenGL.
  • Create the directory GL in somewhere and download glext.h and wglext.h to it.
  • Create the directory KHR in same place and download khrplatform.h to it.

How to build Nim sampels

Make sure parent directories of nim and crinker are in PATH environment variable and you can run them from command prompt.

1. Set LIB environment variable to the directory containing *.lib files to use Windows API.
   • For example:

     set lib=c:\Program Files (x86)\Windows Kits\8.1\Lib\winv6.3\um\x86

   • Do not use double quote in LIB environment variable. Otherwise crinkler doesn't recognize it.

2. Build

   git clone https://github.com/demotomohiro/nim-4k-intro-sample.git
   cd nim-4k-intro-sample\src

   • Release build:

     nim c -d:danger minimum.nim

   • Debug build:

     nim c minimum.nim

How to build C samples

Make sure parent directories of nim and crinker are in PATH environment variable and you can run them from command prompt.

1. Run VS2015 x86 Native Tools command prompt
2. Set INCLUDE environment variable to the directory containing OpenGL Extension Header Files(GL/glext.h, GL/wglext.h and KHR/khrplatform.h).
   • For example:

     set INCLUDE=c:\path\to\include;%INCLUDE%

3. Build

   git clone https://github.com/demotomohiro/nim-4k-intro-sample.git
   cd nim-4k-intro-sample\csrc
   minimum_build.bat

   • Each *_build.bat files builds each samples.

Directory structure

• csrc
  • C language code same to source code in src directory so that you can see whether Nim code can be compiled as small as C
• shaders
  • GLSL shader langage code used by samples that use shader
• src
  • Nim language sample code
• tools
  • Tools used for making 4k intros with Nim

openGL4kGen

It downloads and reads the OpenGL Registry XML file and generates a OpenGL wrapper optimized for 4k-intro. It imports OpenGL 1.0 and 1.1 functions with header pragma. Like Official OpenGL interface, it uses undocumented 'dynlib' feature and Nim generate a procedure that load only OpenGL extension functions used in user code. So loadExtensions() must be called after the creation of an OpenGL context and before any OpenGL extension procs are used. It only generates procedures and enums in OpenGL core profile.

How to use openGL4kGen

Following code build openGL4kGen and generate OpenGL wrapper.

cd nim-4k-intro-sample\tools\openGL4kGen
nim c -d:ssl openGL4kGen.nim
openGL4kGen.exe > ..\..\src\openGL4k2.nim

If you want to use OpenGL with Nim not for 4k-intro, use one of them:

• Official OpenGL interface All OpenGL functions and constants are hard coded. It uses undocumented Nim feature that allow only load OpenGL functions used in your code. Don't forget to call loadExtensions after initialized OpenGL context and before calling any OpenGL functions.

• glad GL/GLES/EGL/GLX/WGL Loader-Generator based on the official specs written in Python lanuage. You can specify OpenGL API version or which extension to be generated. It doesn't use undocumented Nim feature and it loads all OpenGL functions in your specified OpenGL version.

• Nim Game Library NimGL (Nim Game Library) is a collection of bindings for popular libraries, mostly used in computer graphics. A library of libraries.