第二章图形的绘制课件.pptVIP

第二章 图形的绘制;第二章 图形的绘制;;第二章 图形的绘制;第二章 图形的绘制;第二章 图形的绘制;第二章 图形的绘制;第二章 图形的绘制;第二章 图形的绘制;第二章 图形的绘制;程序清单2.1：点的大小，直线线型和线宽的示例 //PointAndLine.c #include windows.h #include gl/glut.h #includegl/gl.h void RenderScene(void) { glClear(GL_COLOR_BUFFER_BIT); //用当前背景色填充窗口 glColor3f(0.0f, 0.0f, 0.0f); //设置当前的绘图绘图RGB颜色 GLfloat sizes[2]; //保存绘制点的尺寸范围 GLfloat step; //保存绘制点尺寸的步长 GLfloat curSize; //当前绘制的点的大小 glGetFloatv(GL_POINT_SIZE_RANGE,sizes); //获得点的尺寸范围 glGetFloatv(GL_POINT_SIZE_GRANULARITY,step); //获得点尺寸的步长;//绘制不同大小的点 curSize=sizes[0]; for (int i=0;i25;i++) { glPointSize(curSize); //设置点的大小 glBegin(GL_POINTS); glVertex3f(25.0+i*8,200.0f,0.0f); glEnd(); curSize +=step*2; } //绘制一条宽度为5的直线 glLineWidth(5); //设置线宽 glBegin(GL_LINES); glVertex3f(25.0f,160.0f,0.0f); glVertex3f(225.0f,160.0f,0.0f); glEnd();;//绘制一条虚线 glEnable(GL_LINE_STIPPLE); glLineStipple(1,0x00FF); //设置点划线模式 glBegin(GL_LINES); glVertex3f(25.0f,120.0f,0.0f); glVertex3f(225.0f,120.0f,0.0f); glEnd(); //绘制一条宽度为3的点划线 glLineWidth(3); glLineStipple(1,0xFF0C); glBegin(GL_LINES); glVertex3f(25.0f,80.0f,0.0f); glVertex3f(225.0f,80.0f,0.0f); glEnd();;//增加重复因子绘制的点划线 glLineStipple(4,0xFF0C); glBegin(GL_LINES); glVertex3f(25.0f,40.0f,0.0f); glVertex3f(225.0f,40.0f,0.0f); glEnd(); glDisable(GL_LINE_STIPPLE); glFlush();//刷新OpenGL命令队列 };void ChangeSize(GLsizei w, GLsizei h) { if(h == 0) h = 1; glViewport(0, 0, w, h); //设置视区尺寸 // 重置坐标系统 glMatrixMode(GL_PROJECTION); glLoadIdentity(); // 建立修剪空间的范围 if (w = h) glOrtho (0.0f, 250.0f, 0.0f, 250.0f*h/w, 1.0f, -1.0f); else glOrtho (0.0f, 250.0f*w/h, 0.0f, 250.0f, 1.0f, -1.0f); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); };void SetupRC(void) { glClearColor(1.0f, 1.0f, 1.0f, 1.0f); // 设置窗口的背景色 } void main(void) { glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutCreateWindow(点与线); glutDisplayFunc(RenderScene); // 设置当前窗口的显示回调函数 glutReshapeFunc(ChangeSize); // 为当前窗口设置窗口再整形回调函数 Se