Cfrgtkky

I was wondering if anyone could help me with binding for a C++ class, which takes an std::vector<T> as a constructor, in Emscripten. I would like something along the lines of the following:

EMSCRIPTEN_BINDINGS(my_class) {



    emscripten::class_<test_class>("test_class")

        .constructor<std::vector<float>>()

        .property("x", &test_class::get_x, &test_class::set_x)

        ;

}

I read up on this post, and implemented a proxy function to take my JS float array created by var inputArray = new Float32Array([1,2,3], to an std::vector<float>.

However, when I use the inputArray as a parameter to the class constructor I get the following warning:

5258048 - Exception catching is disabled, this exception cannot be caught. Compile with -s DISABLE_EXCEPTION_CATCHING=0 or DISABLE_EXCEPTION_CATCHING=2 to catch.

I have added the DISABLE_EXCEPTION_CATCHING=2 flag to the emcc step, however, this doesn't produce any different output.

Has anyone else come up with a solution?

The key thing is to ensure that you've defined a mapping for std::vector using register_vector so you can pass the vector your copy function has created back to JavaScript and then back into C++.

This code seems to work for me, if I understand your problem correctly:

#include <vector>



#include <emscripten.h>

#include <emscripten/bind.h>



class test_class {

    float x;



public:

    test_class(std::vector<float> arr);

    float get_x() const;

    void set_x(float val);

};



test_class::test_class(std::vector<float> arr) {

    x = 0;

    for (size_t i = 0; i < arr.size(); i++) {

        x += arr[i];

    }

    x = x / arr.size();

}



float test_class::get_x() const {

    return x;

}



void test_class::set_x(float val) {

    x = val;

}



EMSCRIPTEN_BINDINGS(my_class) {



    emscripten::register_vector<float>("VectorFloat");



    emscripten::class_<test_class>("test_class")

        .constructor<std::vector<float>>()

        .property("x", &test_class::get_x, &test_class::set_x)

        ;

}



int main() {

    EM_ASM(

        var arr = new Float32Array([1.0, 2.0, 0.5]);

        var vec = new Module.VectorFloat();

        for (var i = 0; i < arr.length; i++) {

            vec.push_back(arr[i]);

        }

        var obj = new Module.test_class(vec);

        console.log('obj.x is ' + obj.x);

    );

}

This sample code does an inefficient copy from the Float32Array to the std::vector (represented as the VectorFloat proxy object in JS), assuming you've got that part working, and concentrates on passing the vector into the constructor.