使用OpenGL3.0为AVFrame离屏渲染添加水印的完整代码

由于AVFrame和OpenGL在很多方面都是非常复杂的主题，因此为AVFrame添加水印的完整代码可能因情况而异，具体取决于您的环境和需求。不过，我可以提供一个基本的框架，以便您开始尝试在OpenGL 3.0中为AVFrame添加水印。以下是一个简单的例子，它使用OpenGL 3.0为AVFrame离屏渲染添加一个简单的红色矩形：

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#define WIDTH 640
#define HEIGHT 480

GLuint loadShader(const char* source, GLenum shaderType);
GLuint createProgram(const char* vertexShaderSource, const char* fragmentShaderSource);

int main() {
  GLFWwindow* window;

  if (!glfwInit()) {
    std::cerr << "Failed to initialize GLFW" << std::endl;
    return -1;
  }

  glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
  glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
  glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
  glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

  window = glfwCreateWindow(WIDTH, HEIGHT, "AVFrame Watermarking", NULL, NULL);
  if (!window) {
    std::cerr << "Failed to create GLFW window" << std::endl;
    glfwTerminate();
    return -1;
  }

  glfwMakeContextCurrent(window);

  if (glewInit() != GLEW_OK) {
    std::cerr << "Failed to initialize GLEW" << std::endl;
    return -1;
  }

  const GLfloat vertices[] = {
    -1.0f, -1.0f,
    1.0f, -1.0f,
    1.0f, 1.0f,
    -1.0f, 1.0f,
  };

  const GLushort indices[] = { 0, 1, 2, 0, 2, 3 };

  GLuint vao, vbo, ebo;
  glGenVertexArrays(1, &vao);
  glBindVertexArray(vao);

  glGenBuffers(1, &vbo);
  glBindBuffer(GL_ARRAY_BUFFER, vbo);
  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

  glGenBuffers(1, &ebo);
  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
  glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

  glEnableVertexAttribArray(0);
  glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, 0);

  const char* vertexShaderSource = R"glsl(
    #version 300 es

    in vec2 position;

    void main() {
      gl_Position = vec4(position, 0.0, 1.0);
    }
  )glsl";

  const char* fragmentShaderSource = R"glsl(
    #version 300 es

    precision mediump float;

    out vec4 fragColor;

    void main() {
      fragColor = vec4(1.0, 0.0, 0.0, 1.0);
    }
  )glsl";

  GLuint program = createProgram(vertexShaderSource, fragment