• openCV打开摄像头,用openGL实现纹理贴图和视频预览


    由于项目需要,在windows平台需要实现openGL预览摄像头。于是想到将openCV和openGL结合起来,而openCV恰好支持openGL。

    首先感谢https://www.cnblogs.com/feifanrensheng/p/9201629.html链接中作者的无私奉献,本文在TA基础上加工而成,希望能够帮助到有需要的朋友。需要安装openGL库glew,以及openCV库。

      1 #include <iostream>
      2 #include <GL/glew.h>
      3 #include <opencv2/opencv.hpp>
      4 #include <windows.h>
      5 using namespace cv;
      6 using namespace std;
      7 
      8 
      9 cv::VideoCapture capture = cv::VideoCapture(0);
     10 GLuint m_backgroundTextureId;
     11 Mat m_backgroundImage;
     12 
     13 
     14 void drawCameraFrame()
     15 {
     16     glGenTextures(1, &m_backgroundTextureId);
     17     glBindTexture(GL_TEXTURE_2D, m_backgroundTextureId);
     18 
     19     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
     20     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     21     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
     22     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
     23     glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
     24 
     25 
     26     int w = m_backgroundImage.cols;
     27     int h = m_backgroundImage.rows;
     28 
     29     glPixelStorei(GL_PACK_ALIGNMENT, 1);
     30     glBindTexture(GL_TEXTURE_2D, m_backgroundTextureId);
     31 
     32     // Upload new texture data:
     33     glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
     34     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_BGR_EXT, GL_UNSIGNED_BYTE, m_backgroundImage.data);
     35 
     36     //glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_BGRA_EXT, GL_UNSIGNED_BYTE, m_backgroundImage.data);
     37 
     38     //glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, m_backgroundImage.data);
     39 
     40     const GLfloat bgTextureVertices[] = { 0, 0, w, 0, 0, h, w, h };
     41     const GLfloat bgTextureCoords[] = { 1, 0, 1, 1, 0, 0, 0, 1 };
     42     const GLfloat proj[] = { 0, -2.f / w, 0, 0, -2.f / h, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1 };
     43 
     44     glMatrixMode(GL_PROJECTION);
     45     glLoadMatrixf(proj);
     46 
     47     glMatrixMode(GL_MODELVIEW);
     48     glLoadIdentity();
     49 
     50     glEnable(GL_TEXTURE_2D);
     51     glBindTexture(GL_TEXTURE_2D, m_backgroundTextureId);
     52 
     53     // Update attribute values.
     54     glEnableClientState(GL_VERTEX_ARRAY);
     55     glEnableClientState(GL_TEXTURE_COORD_ARRAY);
     56 
     57     glVertexPointer(2, GL_FLOAT, 0, bgTextureVertices);
     58     glTexCoordPointer(2, GL_FLOAT, 0, bgTextureCoords);
     59 
     60     glColor4f(1, 1, 1, 1);
     61     glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
     62 
     63     glDisableClientState(GL_VERTEX_ARRAY);
     64     glDisableClientState(GL_TEXTURE_COORD_ARRAY);
     65     glDisable(GL_TEXTURE_2D);
     66 }
     67 void draw(void* param)
     68 {
     69     glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
     70     drawCameraFrame();
     71     glFlush();
     72 }
     73 
     74 const int g_nMaxAlphaValue = 100;
     75 double g_dAlphaValue;
     76 double g_dBetaValue;
     77 int initTrackVal = 0;//滑块的初始位置
     78 void onTracker(int nVal, void*pVal)
     79 {    
     80     g_dAlphaValue = (double)nVal/g_nMaxAlphaValue;
     81     g_dBetaValue = (1.0) - g_dAlphaValue;     
     82     updateWindow("windowName");
     83 
     84 }
     85 
     86 int main( int argc, char** argv)
     87 {
     88     if (!capture.isOpened())
     89     {
     90         printf("[%s][%d]could not load video data...
    ", __FUNCTION__, __LINE__);
     91         return -1;
     92     }
     93     
     94     while (capture.read(m_backgroundImage))
     95     {
     96         namedWindow("windowName", cv::WINDOW_OPENGL);
     97         resizeWindow("windowName", m_backgroundImage.cols, m_backgroundImage.rows);
     98         setOpenGlContext("windowName");
     99         setOpenGlDrawCallback("windowName", draw, NULL);
    100         updateWindow("windowName");
    101         char szTrackName[100];
    102         sprintf(szTrackName, "参数 %d", g_nMaxAlphaValue);
    103         //滑块
    104         createTrackbar(szTrackName, "windowName", &initTrackVal, g_nMaxAlphaValue, onTracker);
    105         onTracker(initTrackVal, 0);
    106         char c = waitKey(10);
    107         if (c == 27)//Esc键
    108         {
    109             break;
    110         }
    111     }
    112     return 0;
    113 }
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  • 原文地址:https://www.cnblogs.com/2014-august/p/13255708.html
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