准备一张图片投影VR全景中正常显示,使用C++实现

要在VR全景中显示图片，您需要将其转换为全景图像（例如equirectangular projection）。以下是使用OpenCV和OpenGL的C++代码示例：

#include <opencv2/opencv.hpp>
#include <GL/glut.h>

// Load image and convert to equirectangular projection
cv::Mat loadAndConvertImage(std::string filename) {
    cv::Mat image = cv::imread(filename);
    cv::Mat sphere(image.rows, image.cols * 2, CV_8UC3);
    cv::Mat left(sphere, cv::Rect(0, 0, image.cols, image.rows));
    image.copyTo(left);
    cv::Mat right(sphere, cv::Rect(image.cols, 0, image.cols, image.rows));
    cv::flip(image, right, 1);
    cv::cvtColor(sphere, sphere, cv::COLOR_BGR2RGB);
    return sphere;
}

// OpenGL display function
void display() {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glPushMatrix();
    glRotatef(90, 0, 1, 0);
    glRotatef(-90, 1, 0, 0);
    glBegin(GL_QUADS);
    glTexCoord2f(0.0, 0.0); glVertex3f(-1.0f, -1.0f, 0.0f);
    glTexCoord2f(1.0, 0.0); glVertex3f(1.0f, -1.0f, 0.0f);
    glTexCoord2f(1.0, 1.0); glVertex3f(1.0f, 1.0f, 0.0f);
    glTexCoord2f(0.0, 1.0); glVertex3f(-1.0f, 1.0f, 0.0f);
    glEnd();
    glPopMatrix();
    glutSwapBuffers();
}

int main(int argc, char** argv) {
    // Initialize glut
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(800, 600);
    glutCreateWindow("VR Image");

    // Load and convert image
    cv::Mat image = loadAndConvertImage("image.jpg");

    // Set up OpenGL texture
    GLuint textureID;
    glGenTextures(1, &textureID);
    glBindTexture(GL_TEXTURE_2D, textureID);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, image.cols, image.rows, 0, GL_RGB, GL_UNSIGNED_BYTE, image.data);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    // Set up OpenGL projection
    glViewport(0, 0, 800, 600);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60.0, 4.0 / 3.0, 0.1, 100.0);

    // Set up OpenGL modelview
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(0.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, 1.0, 0.0);

    // Enable OpenGL features
    glEnable(GL_TEXTURE_2D);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LEQUAL);

    // Set up display function and start main loop
    glutDisplayFunc(display);
    glutMainLoop();
    return 0;
}

这段代码使用OpenCV将图像转换为equirectangular projection。然后，它使用OpenGL将纹理贴到一个四边形上，并将其放置在相机的前面。您可以使用gluLookAt函数调整相机位置。在此示例中，相机位于原点，朝向负Z轴。