#include <gl/glut.h>static GLsizei iMode = 1; static GLfloat sx = 1.0;static GLfloat sy = 1.0;static GLfloat tx = 0.0f;static GLfloat ty = 0.0f;void Initial(void){glClearColor(1.0f, 1.0f, 1.0f, 1.0f); //设置窗口背景颜色为白色gluOrtho2D(-30.0,30.0,-20.0,20.0);//居中显示}void ChangeSize(int w,int h){glViewport(0,0,w,h);glMatrixMode(GL_PROJECTION); //设置投影参数glLoadIdentity();gluOrtho2D(-30.0,30.0,-20.0,20.0);//居中显示}void Display(void){glClear(GL_COLOR_BUFFER_BIT); //用当前背景色填充窗口glMatrixMode(GL_PROJECTION); //设置投影参数glLoadIdentity();glTranslatef(tx, 0.0f, 0.0f); glTranslatef(0.0f, ty, 0.0f); glScalef(sx,sy,0.0f);//左键每一次点击扩大0.1glColor3f(1.0f, .0f, 0.0f); //设置当前的绘图颜色为红色switch(iMode){case 1:glColor3f(.0f, 0.0f, 0.0f); //黑break;case 2:glColor3f(1.0f, .0f, .0f); //红break;case 3:glColor3f(0.0f, .0f, 1.0f); //蓝break;case 4:glColor3f(.0f, 1.0f, 0.0f); //绿break;case 5:glColor3f(1.0f, 1.0f, 1.0f); //白break;case 6:glDisable(GL_LINE_STIPPLE);break;case 7:glEnable(GL_LINE_STIPPLE);glLineStipple(1,255);break;default :break;}//多边形的绘制glBegin(GL_LINE_LOOP);glVertex2f(-10,-10);glVertex2f(10,-10);glVertex2f(20,0);glVertex2f(0,10);glVertex2f(-20,0);glEnd();glFlush(); //处理所有的OpenGL程序}void ProcessMenu(int value){iMode = value;glutPostRedisplay();}//键盘交互调用函数void Key(unsigned char key,int x,int y){switch(key){case 'q':exit(0);break;case 'Q':exit(0);break;case 'S':sx+=0.1;sy+=0.1;glutPostRedisplay();break;case 'D':sx-=0.1;sy-=0.1;glutPostRedisplay();break;default:break;}}//如果是鼠标键控制旋转，可以参考p93void SpecialKeys(int key,int x,int y){if(key == GLUT_KEY_UP)ty += 0.1f;if(key == GLUT_KEY_DOWN) ty -= 0.1f;if(key == GLUT_KEY_LEFT) tx -= 0.1f;if(key == GLUT_KEY_RIGHT) tx += 0.1f;glutPostRedisplay();}//鼠标交互调用函数,左键缩小，右键扩大void MousePlot(GLint button,GLint action,GLint xMouse,GLint yMouse){if(button == GLUT_LEFT_BUTTON && action == GLUT_DOWN){sx+=0.1;sy+=0.1;}if(button ==GLUT_RIGHT_BUTTON && action == GLUT_DOWN){sx-=0.1;sy-=0.1;}glutPostRedisplay();}int main(int argc, char* argv[]){glutInit(&argc, argv);glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); //初始化窗口的显示模式glutInitWindowSize(800,800); //设置窗口的尺寸glutInitWindowPosition(600,120); //设置窗口的位置glutCreateWindow("矩形"); //创建一个名为矩形的窗口//创建菜单int color= glutCreateMenu(ProcessMenu);glutAddMenuEntry("黑色",1);glutAddMenuEntry("红色",2);glutAddMenuEntry("蓝色",3);glutAddMenuEntry("绿色",4);glutAddMenuEntry("白色",5);int lineStrpple = glutCreateMenu(ProcessMenu);glutAddMenuEntry("直线",6);glutAddMenuEntry("虚线",7);int nMainMenu = glutCreateMenu(ProcessMenu);glutAddSubMenu("颜色",color);glutAddSubMenu("线型",lineStrpple);glutAttachMenu(GLUT_MIDDLE_BUTTON);//与鼠标中键绑定glutKeyboardFunc(Key);//普通键输入注册函数glutSpecialFunc(SpecialKeys);glutMouseFunc(MousePlot);//注册鼠标响应函数//glutMotionFunc(MouseMove);//鼠标按下并移动时的响应函数//glutReshapeFunc(ChangeSize);glutDisplayFunc(Display); //设置当前窗口的显示回调函数Initial(); //完成窗口初始化glutMainLoop(); //启动主GLUT事件处理循环return 0;}
