Loading a native C++ dll generated from MATLAB(Simulink) into Unity3d - c++

Question

I am a game developer working on a serious game. I have some data simulation taking place as a result of a MATLAB (Simulink) model, that was created by someone who left the team now. All this data simulation generates useful data and allows me to query and check variables when needed. I needed to build a game using this model. So I used the Simulink Code generator to generate the code for my model in C++. This is native C++ and is procedural. The volume of code is high for me to rewrite it, hence I am refraining from doing that. I need to use this code in Unity3d, the engine I am developing the game on.
Long story short. I need to load a native C++ dll (generated by Simulink) in Unity3d.
What I tried:
I tried using the Unity3d's native plugin API. I have pro version and it doesn't seem to detect the dll, and just throws exceptions. I am using the extern keyword to make the required variables public, still no luck.
I tried following this tutorial (http://blogs.abo.fi/alexeevpetr/2011/11/18/simplified-building-simulink-generated-c-code-in-visual-studio/) , but it throws errors and doesn't build, maybe that's because of the version of MATLAB.
I also considered using a wrapper, however that would imply me rewriting most of the code again.

Answer 1

I've never used native dlls in Unity, but you could always try one of the several code bridging methods to call C++ code from C#, I guess. So how about writing a C++/CLI wrapper? It won't force you to rewrite anything. It gives managed access to your unmanaged code, and it's a useful technique to learn anyway.

Answer 2

You should be able to load your native plugin into Unity3D, even if it requires MATLAB libraries (Just make sure they're also in the plugins directory). I recently answered a similar question around this, as it can be fairly tricky to get right. I would suggest you check it out HERE, and modify your question with specific errors and problems you're having trying to loading the native code.

Answer 3

From Geomorillo on U3d forums:
Before anything,
1) install Visual C++ Studio Express 2010 we need the sdk from .NET for compiling, (NOTE:Maybe you can use visual C# express instead for compiling because it require the .NET sdk but no sure )
2)You must setup matlab with the command "mbuild - setup", and choose the compiler Microsoft Visual C++ Studio Express 2010
3) you must have a function already created and saved to a ".m" file mine is called mycos.m here is its contents:
function a=mycos(b)
a=cosd(b);
end
where "a" is the return parameter and "b" the input parameter, it is important to know how many return parameter you have in this case 1 (see step 12)
4) use the "deploytool" command, a window should open, name the project "simplelibs" any name should do, choose a location c:\matlab\simplelib, choose in type .NET Assembly, OK
5) After that new options int form of tabs should appear to the right of your window, the Build and Package Tabs.
In the Build tab you should add a class with the Add class option, it will automaticly was named Class1, but i changed it to Myclass, here you can add your functions to your class using Add files, i've added mycos.m
6) You should have noticed 3 buttons next to the project name, click the 3rd one with the shape of a nut, go to Settings a new window should appear, go to .NET tab and in the Microsoft Framework choose 3.5 to make sure you are using .net 3.5 for compiling(required for unity3d)
7) we are ready to compile, do so with the 1st button, it should take a while....
8) After compiling without errors, the files are in the distrib folder inside your project path , open unity and create a new project. copy the 2 dlls into the root inside unity.
9) Locate de directory "dotnetbuilder" inside "c/.../matlab/../toolbox" copy or drag it all its contents to your unity project.
10) We need the a dll MWArray.dll because when compiling our libraries matlab wraps our function in an Array and it use its methods to access our functions im not gonna explain this, google it please, normally it can be found inside matlab installation dotnetbuilder/bin/win32/2.0/ but since you have copied it to unity dont copy again, when using this mwarray i found a bug with monodevelop in this library so i had to decompile it and fix the bug i've to recompile it again :) you you can download this file here https://dl.dropbox.com/u/6716823/MWArray.dll and replace the one found inside unity project (do not!!! replace the original from matlab directory)
11) create a c# script and asign it to main camera or any object in scene
here is its contents
using UnityEngine;
using System.Collections;
using System;
using MathWorks.MATLAB.NET.Arrays; // import from MWArray.dll
using simplelib;
public class myMatlab : MonoBehaviour {
void Start () {
simplelib.Myclass g = new simplelib.Myclass();
Debug.Log(g.mycos(1,95).GetValue(0));
}
}
12) g.mycos(1,95); // remember when i said it wraps your function !!! the first parameter is the number of parameters returned from our matlab function in this case 1, the 95 is the parameter we want to send to our function, we get an array we can access it with .GetValue(0)
13) play and enjoy
This is an example with a simple function so i dont know if it will work with a more complex program
i hope this works for you