OpenGL绘制旋转风车

以下是OpenGL绘制旋转风车的示例代码：

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

// 定义旋转角度、风车半径和叶片长度
GLfloat angle = 0.0f;
GLfloat radius = 0.5f;
GLfloat bladeLength = 1.0f;

void init(void) {
   glClearColor(0.0, 0.0, 0.0, 0.0);
   glShadeModel(GL_FLAT);
}

void drawWindmill() {
   // 绘制风车柱
   glPushMatrix();
   glColor3f(0.5f, 0.5f, 0.5f);
   glTranslatef(0.0f, -0.5f, 0.0f);
   glScalef(0.1f, 1.0f, 0.1f);
   glutSolidCube(1.0f);
   glPopMatrix();

   // 绘制风车叶片
   glColor3f(0.0f, 0.0f, 1.0f);
   glPushMatrix();
   glTranslatef(0.0f, bladeLength / 2.0f, 0.0f);
   glRotatef(angle, 0.0f, 0.0f, 1.0f);
   glTranslatef(0.0f, bladeLength / 2.0f, 0.0f);
   glBegin(GL_TRIANGLES);
      glVertex3f(0.0f, 0.0f, 0.0f);
      glVertex3f(-bladeLength / 8.0f, bladeLength, 0.0f);
      glVertex3f(bladeLength / 8.0f, bladeLength, 0.0f);
   glEnd();
   glPopMatrix();
}

void display(void) {
   glClear(GL_COLOR_BUFFER_BIT);
   glPushMatrix();
   glTranslatef(0.0f, 0.0f, -2.0f);
   glRotatef(angle, 0.0f, 1.0f, 0.0f);
   glTranslatef(radius, 0.0f, 0.0f);
   drawWindmill();
   glPopMatrix();
   glutSwapBuffers();
}

void reshape(int w, int h) {
   glViewport(0, 0, (GLsizei) w, (GLsizei) h);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
   glTranslatef(0.0, 0.0, -5.0);
}

void idle(void) {
   angle += 0.5f;
   if (angle > 360.0f) {
      angle -= 360.0f;
   }
   glutPostRedisplay();
}

int main(int argc, char** argv) {
   glutInit(&argc, argv);
   glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
   glutInitWindowSize(500, 500);
   glutInitWindowPosition(100, 100);
   glutCreateWindow("Windmill");
   init();
   glutDisplayFunc(display);
   glutReshapeFunc(reshape);
   glutIdleFunc(idle);
   glutMainLoop();
   return 0;
}

这段代码使用了OpenGL的基本绘图函数和变换函数来绘制旋转的风车。其中，绘制风车柱使用了`glutSolidCube()`函数，绘制风车叶片使用了`glBegin()`和`glEnd()`函数。在`display()`函数中，使用了`glPushMatrix()`和`glPopMatrix()`函数对变换进行了保存和恢复。在`idle()`函数中，使用了`glutPostRedisplay()`函数来触发画面更新。