文字映射到VR全景图片任意位置,使用C++实现示例代码

要实现文字映射到VR全景图片任意位置，需要使用以下步骤：

1. 将全景图片加载到内存中。可以使用OpenCV库加载图片。

2. 创建一个虚拟环境，例如OpenGL场景，用于展示全景图片和文字。

3. 将文本转换为纹理，并将其加载到OpenGL中。

4. 将全景图片和文字纹理映射到OpenGL场景中。可以使用OpenGL的纹理映射功能来实现。

下面是一个简单的示例代码，用于将文字映射到VR全景图片的任意位置。这里我们使用OpenGL来创建虚拟环境，并使用FreeType库将文本转换为纹理。

#include <iostream>
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <opencv2/opencv.hpp>
#include <ft2build.h>
#include FT_FREETYPE_H

using namespace std;
using namespace cv;

// 顶点着色器
const char* vertexShaderSource =
    "#version 330 core\n"
    "layout (location = 0) in vec3 aPos;\n"
    "layout (location = 1) in vec2 aTexCoord;\n"
    "out vec2 TexCoord;\n"
    "void main()\n"
    "{\n"
    "   gl_Position = vec4(aPos, 1.0);\n"
    "   TexCoord = vec2(aTexCoord.x, aTexCoord.y);\n"
    "}\0";

// 片段着色器
const char* fragmentShaderSource =
    "#version 330 core\n"
    "in vec2 TexCoord;\n"
    "out vec4 FragColor;\n"
    "uniform sampler2D ourTexture;\n"
    "void main()\n"
    "{\n"
    "   FragColor = texture(ourTexture, TexCoord);\n"
    "}\n\0";

// 文本渲染器
class TextRenderer {
public:
    TextRenderer(const char* fontPath, int fontSize) {
        FT_Init_FreeType(&ft);
        FT_New_Face(ft, fontPath, 0, &face);
        FT_Set_Pixel_Sizes(face, 0, fontSize);
        glGenTextures(1, &texId);
        glBindTexture(GL_TEXTURE_2D, texId);
        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);
    }

    void renderText(const char* text, float x, float y, float sx, float sy) {
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RED, width, height, 0, GL_RED, GL_UNSIGNED_BYTE, buffer);
        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texId);
        glUniform1i(glGetUniformLocation(shaderProgram, "ourTexture"), 0);

        GLfloat vertices[] = {
            x, y + height * sy, 0.0f, 0.0f,
            x + width * sx, y + height * sy, 1.0f, 0.0f,
            x + width * sx, y, 1.0f, 1.0f,
            x, y, 0.0f, 1.0f
        };

        unsigned int indices[] = {
            0, 1, 2,
            2, 3, 0
        };

        GLuint VAO, VBO, EBO;
        glGenVertexArrays(1, &VAO);
        glGenBuffers(1, &VBO);
        glGenBuffers(1, &EBO);

        glBindVertexArray(VAO);

        glBindBuffer(GL_ARRAY_BUFFER, VBO);
        glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
        glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

        glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (void*)0);
        glEnableVertexAttribArray(0);

        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (void*)(2 * sizeof(GLfloat)));
        glEnableVertexAttribArray(1);

        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

        glDeleteVertexArrays(1, &VAO);
        glDeleteBuffers(1, &VBO);
        glDeleteBuffers(1, &EBO);
    }

    void setText(const char* text) {
        FT_GlyphSlot g = face->glyph;

        int w = 0, h = 0;
        for (int i = 0; i < strlen(text); i++) {
            FT_Load_Char(face, text[i], FT_LOAD_RENDER);
            w += g->bitmap.width;
            h = max(h, g->bitmap.rows);
        }

        width = w;
        height = h;

        buffer = new unsigned char[width * height];

        int x = 0;
        for (int i = 0; i < strlen(text); i++) {
            FT_Load_Char(face, text[i], FT_LOAD_RENDER);
            for (int j = 0; j < g->bitmap.width; j++) {
                for (int k = 0; k < g->bitmap.rows; k++) {
                    buffer[(k + g->bitmap_top) * width + (x + j)] = g->bitmap.buffer[k * g->bitmap.width + j];
                }
            }
            x += g->bitmap.width;
        }
    }

private:
    FT_Library ft;
    FT_Face face;
    unsigned char* buffer;
    GLuint texId;
    int width, height;
};

int main()
{
    // 初始化OpenGL
    glfwInit();
    GLFWwindow* window = glfwCreateWindow(800, 600, "Text on VR panorama", NULL, NULL);
    glfwMakeContextCurrent(window);
    glewExperimental = GL_TRUE;
    glewInit();

    // 加载全景图片
    Mat img = imread("panorama.jpg");
    if (img.empty()) {
        cout << "Failed to load image!" << endl;
        return -1;
    }

    // 创建文本渲染器
    TextRenderer renderer("arial.ttf", 48);

    // 创建着色器程序
    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
    glCompileShader(vertexShader);

    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
    glCompileShader(fragmentShader);

    GLuint shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    // 加载图片到OpenGL中
    GLuint textureId;
    glGenTextures(1, &textureId);
    glBindTexture(GL_TEXTURE_2D, textureId);

    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);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img.cols, img.rows, 0, GL_BGR_EXT, GL_UNSIGNED_BYTE, img.ptr());

    // 渲染循环
    while (!glfwWindowShouldClose(window)) {
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        glUseProgram(shaderProgram);

        GLfloat vertices[] = {
            // 顶点坐标  纹理坐标
            -1.0f,  1.0f,  0.0f, 1.0f,
             1.0f,  1.0f,  1.0f, 1.0f,
             1.0f, -1.0f,  1.0f, 0.0f,
            -1.0f, -1.0f,  0.0f, 0.0f,
        };

        unsigned int indices[] = {
            0, 1, 2,
            2, 3, 0
        };

        GLuint VAO, VBO, EBO;
        glGenVertexArrays(1, &VAO);
        glGenBuffers(1, &VBO);
        glGenBuffers(1, &EBO);

        glBindVertexArray(VAO);

        glBindBuffer(GL_ARRAY_BUFFER, VBO);
        glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
        glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

        glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (void*)0);
        glEnableVertexAttribArray(0);

        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (void*)(2 * sizeof(GLfloat)));
        glEnableVertexAttribArray(1);

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, textureId);
        glUniform1i(glGetUniformLocation(shaderProgram, "ourTexture"), 0);

        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

        // 渲染文本
        renderer.setText("Hello, world!");
        renderer.renderText("Hello, world!", 400, 300, 0.5, 0.5);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glfwTerminate();

    return 0;
}

这是一个简单的示例代码，演示了如何将文本映射到VR全景图片的任意位置。您可以根据自己的需求进行修改和扩展。