jhottmaster / openql_demo

Following Tutorials for OpenGL in C++

Open GL Tutorials/Demo

Following Tutorials for OpenGL in C++ and then using that knowledge to build my own simple multi-plaform 3D engine library and demo application.

This project is split into the library (jheatt_engine_library) and demo program (jheatt_engine_demo) that demos the library's capabilities. Currently the functionality is quite limited, but does allow for loading textures, 3D models, and various types of dynamic lighting. It is currently tested running on Windows (10), Linux (Ubuntu), and OSX (Catalina).

Notes

Open GL Resources Used

• http://www.opengl-tutorial.org/beginners-tutorials/tutorial-1-opening-a-window/
• https://open.gl/introduction
• https://learnopengl.com/Introduction

Other Resources: https://thebookofshaders.com/

Ubuntu Setup

Must install necessary dev GLEW, GLFW, and GLM libraries before I could get g++ to link them:

sudo apt-get install libglew-dev
sudo apt-get install libglfw3-dev
sudo apt-get install libglm-dev
sudo apt-get install libassimp-dev

When linking, you can use the gcc -l[LIBRARY_NAME] to link the libraries. For example, -lGL for OpenGL.

Also, you'll need to download SOIL: https://www.lonesock.net/soil.html - extract that somewhere and go to ~/project/makefile directory. Edit the makefile's CXXFLAGS variable to do generate position-independent code:

CXXFLAGS = -O2 -s -Wall -fpic

You may need to uninstall and re-build, in which case you can do that by:

sudo make uninstall
sudo make clean
sudo make

Then finally run:

mkdir obj
sudo make install

This will install SOIL in Unix to allow linking. You can't use the library file that comes in /lib because it is 32-bit (unless you have a 32-bit machine)

Note: Version 5 of libassimp-dev is needed to load textures. If working on an older version of Linux, (like I was), you can forcefull install 5 by following steps here: https://stackoverflow.com/a/60584315/100875

Building

Build & run with make unix

OSX Setup

Was able to install most of the same libraries as Ubuntu using brew. (eg brew install glew, brew install assimp). Note that on OSX gcc is replaced by Clang compiler, and infact gcc actually becomes an alias to it. On OSX linking to OpenGL is also a bit different- you must use -framework OpenGL to do so. See make file for more info. We also have a -framework CoreFoundation in order to support SOIL:

As with Linux, you'll need to download SOIL: https://www.lonesock.net/soil.html - however, compiling for the latest versions of OSX is a bit different. Extract the download somewhere and go to ~/project/makefile directory, open makefile and make the following change to the CXX variable: CXX = gcc -arch i386 -arch x86_64; then run

mkdir obj
sudo make install

This architecture requires the OSX Core Foundation framework, hence the additional linker commmand specified above.

Building

Build & run with make osx

Windows

Right now this is only tested on Windows 10. To compile, you'll need to do the following:

Using Visual Studio 2019

Just open the solution file. The special configuratios is mostly in the creation of the additional_includes and additional_libs directories. GLM you can just download since it's only headers. You'll probably need to build GLEW and SOIL (SOILD Repo: https://github.com/littlstar/soil ) assemblies and place them in jheatt_engine\additional_libs\x86 if they are not already there. Likewise for Assimp, you'll need to clone the repository, built it targeting Win32, (You can do this using Cmake GUI for example) and then copy the assimp\build\lib\Release\assimp-vc142-mt.lib generated file to jheatt_engine\additional_libs\x86 as well as the assimp\build\bin\Release\assimp-vc142-mt.dll DLL to the directory where the executable will run (e.g. jheatt_engine\build\Debug)

Other (eg, using make or cmake)

I spent a few hours trying to get Windows version to compile and work with just make, MinGW, GLEW, GLFW, and soild, but alas, I couldn't manage it. If feeling adventurous, this looks like a good guide to try again: https://cis.gvsu.edu/~dulimarh/Okto/cis367/

This was the closest I got

Compiler Setup 1.) Install MinGW- download from: https://osdn.net/projects/mingw/downloads/68260/mingw-get-setup.exe/ (Good reference guide here as well: https://www.ics.uci.edu/~pattis/common/handouts/mingweclipse/mingw.html) 2.) After download, use the MinGW Installation Manager to install mingw32-base, mingw-developer-toolchain, mingw32-gcc-g++, and msys-base 3.) Wait a while for all that to finish, then add C:\MinGW\bin and C:\MinGW\msys\1.0\bin to your PATH enviornment variable.

GLEW Install Download GLEW, unzip, go to main dir and run:

mkdir lib
mkdir bin
gcc -DGLEW_NO_GLU -O2 -Wall -W -Iinclude  -DGLEW_BUILD -o src/glew.o -c src/glew.c
gcc -nostdlib -shared -Wl,-soname,libglew32.dll -Wl,--out-implib,lib/libglew32.dll.a    -o lib/glew32.dll src/glew.o -L/mingw/lib -lglu32 -lopengl32 -lgdi32 -luser32 -lkernel32
ar cr lib/libglew32.a src/glew.o

Details here: https://stackoverflow.com/questions/6005076/building-glew-on-windows-with-mingw

You should now have a glew32.dll file you can use under \lib- move that binary to the \lib\win\binaries folder.

GLFW Install 1.) Download GLFW 32-bit binaries: https://www.glfw.org/download.html 2.) Unzip, and navigate to glfw-3.3.2.bin.WIN32\lib-mingw 3.) Copy the glfw3.dll binary to \lib\win\binaries folder

SOIL Install

Download https://www.lonesock.net/soil.html

Last Steps

Add a new environment variable called CPATH that points to \lib\win\headers (but use a full path)

Other helpful resources:

• https://open.gl/introduction