koobas.hobune.stream
Passing Arrays as Parameters Between Functions in C# and C++ dll's within Unity
Here's the sample code where the external C++ function is declared in the C# code:
[DllImport("PhysicsEngine")]
private static extern void CalculateTrajectory(float deltaT, float muzzleVelocity, float theta, float phi, float[] origin, float[,] trajectory, int size);
And, here's where the function is called:
int size = 20;
float deltaT = 0.02f;
float muzzleVelocity = 900.0f;
float[] origin = new float[3];
origin[0] = -200.0f;
origin[1] = 1.242f;
origin[2] = 1000.0f;
float theta = 0.0f;
float phi = 0.0f;
float maxRange = 1000.0f;
float[,] trajectory = new float[size, 3];
CalculateTrajectory(deltaT, muzzleVelocity, theta, phi, origin, trajectory, size);
Here's the original C++ function definition's name and parameters:
void EXPORT_API CalculateTrajectory(float deltaT, float muzzleVelocity, float theta, float phi, float* origin, float** trajectory, int size)
The problem is that when I try to run the game in Unity or my own personal C# tester program, both programs crash. Why is that? Has anyone else successfully passed arrays as parameters between Unity and their own C++ dll's? If so, then please let me know so that I and others may benefit from your knowledge. Thank-you.
The answer I gave to your other question has some links which may be helpful.
There is a link to an MSDN page which discusses marshaling arrays. Also, there is a link to some code I use to pass arrays back and forth between Unity and a C++ plugin. (Though I haven't attempted multi-dimensional arrays.)
From experience, I strongly recommend testing all marshaling code outside Unity in an IDE. Once it is working there without any errors, then move it into Unity. You can avoid a lot of the hassle since your external IDE will usually give you better error responses than Unity can provide.
