WebAssembly js 调用c++ 高性能传参

DSLMing2024-09-11 9:44

WebAssembly js 调用c++ 高性能传参

通过 Emscripten，你可以直接使用 JavaScript 的 TypedArray 与 C++ 共享内存，

从而避免频繁的数据拷贝操作。TypedArray 是一种高效的二进制数据表示形式，非常适合处理大规模数值数据。

js 调用：

cpp 复制代码

 function processDataPointer(inputArray) {
    // Create a Float32Array in JavaScript
    const data = new Float32Array(inputArray);
    const length = data.length;

    console.time("processDataPointer");
    // Allocate memory in WebAssembly
    const dataPtr = Module._malloc(data.byteLength);
    // Copy data from JavaScript to WebAssembly memory
    Module.HEAPF32.set(data, dataPtr / data.BYTES_PER_ELEMENT);
    console.timeEnd("parper data");
    Module._processDataPointer(dataPtr, length);
    // Free the allocated memory
    Module._free(dataPtr);
    console.timeEnd("processDataPointer");
  }

c++

cpp 复制代码

#include <iostream>
#include <vector>
#include <cmath>
#include <limits>

#include <emscripten/emscripten.h>


int main()
{
  std::cout << "hello" << std::endl;
  return 0;
}

extern "C"
{
  EMSCRIPTEN_KEEPALIVE
  void processDataPointer(float *data, int length)
  {
    double x{};
    double y{};
    double z{};

    // 假设输入的长度总是 3 的倍数
    for (int i = 0; i < length; i += 3)
    {
      x += data[i + 0];
      y += data[i + 1];
      z += data[i + 2];
    }
  }
}

cmakeList:

sh 复制代码

cmake_minimum_required(VERSION 3.19)
project(obb)

# 默认是Release，如果需要Debug环境，可以在生成时指定 -DCMAKE_BUILD_TYPE=Debug
if(NOT CMAKE_BUILD_TYPE)
  set(CMAKE_BUILD_TYPE Release)
endif()
message(STATUS "Build type: ${CMAKE_BUILD_TYPE}")

set(CMAKE_CXX_STANDARD 11)

# include_directories(./include/)

file(GLOB SOURCE_FILES src/main.cpp)
file(GLOB HEADER_FILES src/*.h)


add_executable(${CMAKE_PROJECT_NAME} ${SOURCE_FILES} ${HEADER_FILES})

target_link_libraries(${CMAKE_PROJECT_NAME})


if(CMAKE_SYSTEM_NAME STREQUAL "Emscripten")
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O0")  # 关闭优化
    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -s WASM=1 -g -s MODULARIZE=1 -s EXPORT_NAME=createModule -s EXPORTED_FUNCTIONS=_processDataPointer,_malloc,_free -s INITIAL_MEMORY=128MB")
endif()