在OpenGL中围绕XZ平面上的点旋转相机

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

// 相机位置
GLfloat cameraX = 0.0f;
GLfloat cameraY = 0.0f;
GLfloat cameraZ = 5.0f;

// 围绕的点位置
GLfloat targetX = 0.0f;
GLfloat targetY = 0.0f;
GLfloat targetZ = 0.0f;

// 旋转角度
GLfloat angle = 0.0f;

void display() {
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    glLoadIdentity();
    
    // 设置相机位置
    gluLookAt(cameraX, cameraY, cameraZ, targetX, targetY, targetZ, 0.0f, 1.0f, 0.0f);
    
    // 绘制场景
    // ...
    
    glutSwapBuffers();
}

void reshape(int width, int height) {
    glViewport(0, 0, width, height);
    
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45.0f, (GLfloat)width / (GLfloat)height, 0.1f, 100.0f);
    
    glMatrixMode(GL_MODELVIEW);
}

void idle() {
    // 计算旋转后的相机位置
    cameraX = targetX + sin(angle) * 5.0f;
    cameraZ = targetZ + cos(angle) * 5.0f;
    
    angle += 0.01f; // 每次增加的旋转角度
    
    glutPostRedisplay();
}

int main(int argc, char** argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(800, 600);
    glutCreateWindow("Camera Rotation");
    
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutIdleFunc(idle);
    
    glEnable(GL_DEPTH_TEST);
    
    glutMainLoop();
    
    return 0;
}