Unity3D C#调用C++ dll并且实现两者之间的图像传输

Unity3D官方下载地址
opencv环境配置教程
Dependency Walker下载地址
OpenCV for Unity package提取码：a8h5
参考书籍：Windows核心编程第五版【第19、20章】提取码：u6ps
Unity圣典

vs生成dll
将下图中的两处改为dll编译就会生成dll，改回exe则为应用程序

process.cpp

#include <opencv2\opencv.hpp>

#define DLL_API extern "C" __declspec (dllexport)

DLL_API void transferImage(int rgbInt[], int width, int height, int channel);

void transferImage(int rgbInt[], int width, int height, int channel)
{
	cv::Mat image(height, width, CV_MAKETYPE(CV_8U, channel));
	uchar* ptr = image.data;
	for (int i = 0; i < width*height*channel; i++) {
		*ptr++ = (uchar)rgbInt[i];
	}
	cv::imshow("image", image);
	cv::waitKey(10);
	
	// start process image
	image = processImage(image);
	// end process image
	
	ptr = image.data;
	for (int i = 0; i < width*height*channel; i++) {
		rgbInt[i] = int(*ptr++);
	}
}

生成process.dll，拷贝到unity工程中【yourProjectPath/Assets/Plugins】
如果没有Plugins文件夹，则自己创建

ProcessImage.cs

using UnityEngine;
using System.Collections;
using System.Runtime.InteropServices;
using OpenCVForUnity;

public class ProcessImage: MonoBehaviour {

    [DllImport("process")]
    public extern static void transferImage(int[] rgbInt, int width, int height, int channel);

    public int width = 640;
    public int height = 480;
    public VideoCapture capture = new VideoCapture();
    private int[] rgbInt;
    private Mat frame;
    private Mat gray;
    public int cntFrame = 0;

    // Use this for initialization
    void Start () {
        capture.open(0);
        rgbInt = new int[width * height * 3];
        frame = new Mat(480, 640, CvType.CV_8UC4);
        gray = new Mat();
    }

	// Update is called once per frame
	void Update () {
        capture.read(frame);
        Imgproc.cvtColor(frame, gray, Imgproc.COLOR_BGR2GRAY);

        frame.get(0, 0, rgbByte);
        for (int i = 0; i < width * height*3; i++)
        {
            rgbInt[i] = (int)rgbByte[i];
        }

        transferImage(rgbInt, width, height, 3);

        for (int i = 0; i < width * height * 3; i++)
        {
            rgbByte[i] = (byte)rgbInt[i];
        }

        byte[] bb = new byte[3];

        int cnt = 0;
        for(int i = 0; i < height; i++)
        {
            for(int j = 0; j < width; j++)
            {
                bb[2] = rgbByte[cnt];
                cnt += 1;
                bb[1] = rgbByte[cnt];
                cnt += 1;
                bb[0] = rgbByte[cnt];
                cnt += 1;
                frame.put(i, j, bb);
            }
        }
    
        Texture2D texture = new Texture2D(width, height, TextureFormat.RGB24, false, false);
        Utils.matToTexture2D(frame, texture);
        gameObject.GetComponent<Renderer>().material.mainTexture = texture;

        cntFrame++;
    }
}

如果unity运行时找不到process.dll，可能是process.dll调用了其他dll,可以用Dependency Walker查看，将缺少的dll的路径添加到系统环境变量中，unity就可以找到dll了