在VS2012下使用glut绘制一系点连接起来的直线的示例程序,绘制的是四个螺纹,效果如下图所示,按PC的UP,DOWN,LEFT,RIGHT按键可以从不同的角度查看该图形。 GL_LINE_STRIP连续点生成直线的规则如下:
// GlutLineStripDemo.cpp : 定义控制台应用程序的入口点。 // #include "stdafx.h" #include <gl/glut.h> #include <math.h> //圆周率宏 #define GL_PI 3.1415f //获取屏幕的宽度 GLint SCREEN_WIDTH=0; GLint SCREEN_HEIGHT=0; //设置程序的窗口大小 GLint windowWidth=400; GLint windowHeight=300; //绕x轴旋转角度 GLfloat xRotAngle=0.0f; //绕y轴旋转角度 GLfloat yRotAngle=0.0f; //显示回调函数 void renderScreen(void){ GLfloat x,y,z,angle; //把整个窗口清理为当前清理颜色:黑色 glClear(GL_COLOR_BUFFER_BIT); //将当前Matrix状态入栈 glPushMatrix(); //坐标系绕x轴旋转xRotAngle glRotatef(xRotAngle,1.0f,0.0f,0.0f); //坐标系绕y轴旋转yRotAngle glRotatef(yRotAngle,0.0f,1.0f,0.0f); //白色绘制坐标系 glColor3f(1.0f,1.0f,1.0f); glBegin(GL_LINES); glVertex3f(-80.0f,0.0f,0.0f); glVertex3f(80.0f,0.0f,0.0f); glVertex3f(0.0f,-80.0f,0.0f); glVertex3f(0.0f,80.0f,0.0f); glVertex3f(0.0f,0.0f,-80.0f); glVertex3f(0.0f,0.0f,80.0f); glEnd(); glPushMatrix(); glTranslatef(80.0f,0.0f,0.0f); glRotatef(90.0f,0.0f,1.0f,0.0f); glutWireCone(3,6,10,10); glPopMatrix(); glPushMatrix(); glTranslatef(0.0f,80.0f,0.0f); glRotatef(-90.0f,1.0f,0.0f,0.0f); glutWireCone(3,6,10,10); glPopMatrix(); glPushMatrix(); glTranslatef(0.0f,0.0f,80.0f); glRotatef(90.0f,0.0f,0.0f,1.0f); glutWireCone(3,6,10,10); glPopMatrix(); //进行平滑处理 glEnable(GL_LINE_SMOOTH); glHint(GL_LINE_SMOOTH,GL_NICEST); glColor3f(0.0f,1.0f,0.0f); z=0.0f; //开始一系列连接起来的线 glBegin(GL_LINE_STRIP); //绘制四个螺纹 for(angle=0.0f;angle<=((2.0f*GL_PI)*4.0f);angle+=0.01f){ x=50.0f*sin(angle); y=50.0f*cos(angle); glVertex3f(x,y,z); z+=0.02f; } //结束绘点 glEnd(); //恢复压入栈的Matrix glPopMatrix(); //交换两个缓冲区的指针 glutSwapBuffers(); } //设置Redering State void setupRederingState(void){ //设置清理颜色为黑色 glClearColor(0.0f,0.0,0.0,1.0f); //设置绘画颜色为绿色 glColor3f(0.0f,1.0f,0.0f); } //窗口大小变化回调函数 void changSize(GLint w,GLint h){ //横宽比率 GLfloat ratio; //设置坐标系为x(-100.0f,100.0f)、y(-100.0f,100.0f)、z(-100.0f,100.0f) GLfloat coordinatesize=100.0f; //窗口宽高为零直接返回 if((w==0)||(h==0)) return; //设置视口和窗口大小一致 glViewport(0,0,w,h); //对投影矩阵应用随后的矩阵操作 glMatrixMode(GL_PROJECTION); //重置当前指定的矩阵为单位矩阵 glLoadIdentity(); ratio=(GLfloat)w/(GLfloat)h; //正交投影 if(w<h) glOrtho(-coordinatesize,coordinatesize,-coordinatesize/ratio,coordinatesize/ratio,-coordinatesize,coordinatesize); else glOrtho(-coordinatesize*ratio,coordinatesize*ratio,-coordinatesize,coordinatesize,-coordinatesize,coordinatesize); //对模型视图矩阵堆栈应用随后的矩阵操作 glMatrixMode(GL_MODELVIEW); //重置当前指定的矩阵为单位矩阵 glLoadIdentity(); } void specialKey(int key,int x,int y){ if(key==GLUT_KEY_UP){ xRotAngle-=5.0f; } else if(key==GLUT_KEY_DOWN){ xRotAngle+=5.0f; } else if(key==GLUT_KEY_LEFT){ yRotAngle-=5.0f; } else if(key==GLUT_KEY_RIGHT){ yRotAngle+=5.0f; } //重新绘制 glutPostRedisplay(); } int main(int argc, char* argv[]) { //初始化glut glutInit(&argc,argv); //使用双缓冲区模式 glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGBA|GLUT_DEPTH); //获取系统的宽像素 SCREEN_WIDTH=glutGet(GLUT_SCREEN_WIDTH); //获取系统的高像素 SCREEN_HEIGHT=glutGet(GLUT_SCREEN_HEIGHT); //创建窗口,窗口名字为LineStrip Demo glutCreateWindow("LineStrip Demo"); //设置窗口大小 glutReshapeWindow(windowWidth,windowHeight); //窗口居中显示 glutPositionWindow((SCREEN_WIDTH-windowWidth)/2,(SCREEN_HEIGHT-windowHeight)/2); //设置窗口大小变化处理回调函数 glutReshapeFunc(changSize); //设置显示回调函数 glutDisplayFunc(renderScreen); //设置按键输入处理回调函数 glutSpecialFunc(specialKey); //设置全局渲染参数 setupRederingState(); glutMainLoop(); return 0; }