Porting Third Party to WebAssembly

The idea of this article is to take a more complex application (as it could exist in a C++ library) and port it to WebAssembly. In this process, the application is first compiled into native machine code and executed directly on the operating system. Then, in a second step, the same application is compiled into WebAssembly and used in a web application.

Bitmap Application

The application uses the bitmap_image.hpp by Arash Partow, which is used to work with bitmaps in C++.

#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <string>

#include "bitmap_image.hpp"

void cartesian()
{
    ...
}

void fractal()
{
    ...
}

extern "C"
void build_bitmap(int choosen)
{
   switch(choosen) {
      case 1:
         cartesian();
         break;
      case 2:
         fractal();
         break;
      default:
         break;
   }
}

int main(int argc, char **argv)
{
   int choosen = 0;
   if(argc > 1)
   {
      choosen = std::atoi(argv[1]);
   }

   build_bitmap(choosen);
   
   return 0;
}

The application consists of two functions, cartesian and fractal, which generate different bitmaps. You can choose the respective function using the 1 or 2 as a parameter in the main function.

Before you can proceed, the program needs to be compiled. To do that, the following Makefile is used:

COMPILER      = -c++
OPTIONS       = -ansi -pedantic-errors -Wall -Wall -Werror -Wextra -o
LINKER_OPT    =…