C++调用绘制天线水平方向图（在极坐标上）代码，绘制天线波长、间距、波束等

以下是一个基于 GLEW 的 C++ 示例代码，用于在极坐标上绘制天线水平方向图，并绘制天线波长、间距、波束等：

#include <iostream>
#include <cmath>
#include <GL/glew.h>
#include <GLFW/glfw3.h>

const int WIDTH = 800;
const int HEIGHT = 600;
const float PI = 3.14159265358979323846f;

float wavelength = 1.0f;    // 波长
float spacing = 0.5f;       // 天线间距
float beamwidth = PI / 4;   // 波束宽度

void error_callback(int error, const char* description)
{
    std::cerr << "Error: " << description << std::endl;
}

void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GLFW_TRUE);
}

void drawPolarLine(float r, float theta)
{
    float x = r * std::cos(theta);
    float y = r * std::sin(theta);
    glVertex2f(x, y);
}

void drawAntennaPattern()
{
    glLineWidth(2.0f);

    glColor3f(1.0f, 0.0f, 0.0f);
    glBegin(GL_LINE_STRIP);

    float r = 1.0f;
    for (float theta = 0.0f; theta <= 2 * PI; theta += PI / 180.0f) {
        float value = std::cos(2 * PI * spacing * std::cos(theta) / wavelength);
        value *= std::cos(beamwidth * std::sin(theta));
        drawPolarLine(r * value, theta);
    }

    glEnd();
}

void drawWavelength()
{
    glLineWidth(1.0f);

    glColor3f(0.0f, 1.0f, 0.0f);
    glBegin(GL_LINES);

    glVertex2f(0.0f, 0.0f);
    glVertex2f(wavelength, 0.0f);

    glEnd();
}

void drawSpacing()
{
    glLineWidth(1.0f);

    glColor3f(0.0f, 0.0f, 1.0f);
    glBegin(GL_LINES);

    glVertex2f(spacing, 0.0f);
    glVertex2f(spacing, 1.0f);

    glEnd();
}

void drawBeamwidth()
{
    glLineWidth(1.0f);

    glColor3f(1.0f, 1.0f, 0.0f);
    glBegin(GL_LINE_STRIP);

    float r = 1.0f;
    for (float theta = -beamwidth / 2; theta <= beamwidth / 2; theta += PI / 180.0f) {
        drawPolarLine(r, theta);
    }

    glEnd();
}

void render()
{
    glClear(GL_COLOR_BUFFER_BIT);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-1.2f, 1.2f, -1.2f, 1.2f, -1.0f, 1.0f);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    drawAntennaPattern();
    drawWavelength();
    drawSpacing();
    drawBeamwidth();

    glfwSwapBuffers(glfwGetCurrentContext());
}

int main()
{
    glfwSetErrorCallback(error_callback);

    if (!glfwInit())
        return EXIT_FAILURE;

    GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "Antenna Pattern", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        return EXIT_FAILURE;
    }

    glfwSetKeyCallback(window, key_callback);

    glfwMakeContextCurrent(window);

    if (glewInit() != GLEW_OK)
        return EXIT_FAILURE;

    glEnable(GL_LINE_SMOOTH);
    glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);

    while (!glfwWindowShouldClose(window))
    {
        render();
        glfwPollEvents();
    }

    glfwDestroyWindow(window);
    glfwTerminate();

    return EXIT_SUCCESS;
}

该示例代码使用 GLFW 和 GLEW 库进行窗口管理和 OpenGL 渲染，绘制了一个红色的圆形线条，表示天线的水平方向图，并绘制了天线的波长、间距、波束等。在 `drawAntennaPattern` 函数中，我们使用天线间距、波长和波束宽度计算出每个角度对应的天线增益，然后将其转换为直角坐标 `(x, y)`，并调用 `glVertex2f` 函数绘制线条。在 `drawWavelength`、`drawSpacing` 和 `drawBeamwidth` 函数中，我们分别绘制了天线的波长、间距和波束宽度。在主循环中，我们不断调用 `render` 函数进行渲染，直到用户关闭窗口。

请注意，这只是一个简单的示例，实际的天线模拟需要更复杂的计算和绘制过程。