OpenGL利用visual studio c++绘制一个实心的圆，要求圆分成若干个扇形，每个扇形颜色不同

以下是OpenGL利用visual studio c绘制一个实心的圆，圆分成若干个扇形，每个扇形颜色不同的代码实现：

#include <iostream>
#include <GL/glut.h>
#include <cmath>

using namespace std;

const int WIDTH = 640;
const int HEIGHT = 480;

void init()
{
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0, WIDTH, 0, HEIGHT);
}

void drawSector(float cx, float cy, float r, float start_angle, float end_angle, float red, float green, float blue)
{
    glColor3f(red, green, blue);
    glBegin(GL_TRIANGLE_FAN);
    glVertex2f(cx, cy);
    for (float angle = start_angle; angle <= end_angle; angle += 0.01)
    {
        float x = cx + r * cos(angle * 3.14 / 180);
        float y = cy + r * sin(angle * 3.14 / 180);
        glVertex2f(x, y);
    }
    glEnd();
}

void drawCircle(float cx, float cy, float r, int num_sectors)
{
    float angle_per_sector = 360.0 / num_sectors;
    float start_angle = 0.0;
    float end_angle = angle_per_sector;
    for (int i = 0; i < num_sectors; i++)
    {
        if (i % 2 == 0)
        {
            drawSector(cx, cy, r, start_angle, end_angle, 1.0, 0.0, 0.0);
        }
        else
        {
            drawSector(cx, cy, r, start_angle, end_angle, 0.0, 0.0, 1.0);
        }
        start_angle = end_angle;
        end_angle += angle_per_sector;
    }
}

void display()
{
    glClear(GL_COLOR_BUFFER_BIT);
    drawCircle(WIDTH / 2, HEIGHT / 2, 200, 12);
    glFlush();
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(WIDTH, HEIGHT);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("OpenGL Circle");
    init();
    glutDisplayFunc(display);
    glutMainLoop();
    return 0;
}

代码中，我们定义了一个`drawSector`函数，用于绘制一个扇形，需要指定圆心坐标、半径、起始角度、终止角度和颜色。然后定义了一个`drawCircle`函数，用于绘制一个圆，需要指定圆心坐标、半径和分成的扇形数目，每个扇形颜色不同，通过调用`drawSector`函数实现。最后在`display`函数中调用`drawCircle`函数绘制圆。