opengl图形填充、正余弦曲线绘制、字符输出(C++)

实验五1、实验目的和要求了解且掌握图形填充、曲线绘制和字符输出等技术。2、实验内容1)用OpenGL实现用黑白相间的棋盘图案填充多边形2)用OpenGL分别用点和折线模式实现正弦和余弦的绘制3)用OpenGL在屏幕上输出”OpenGL”字样3、实验步骤1）相关算法及原理描述①图案填充多边形多边形模式设置函数为：voidglPolygonMode(GLenumface,GLenummode);控制多边形指定面的绘制模式。参数face为GL_FRONT、GL_BACK或GL_FRONT_AND_BACK；参数mode为GL_POINT、GL_LINE或GL_FILL，分别表示绘制轮廓点式多边形、轮廓线式多边形或全填充式多边形。缺省时，绘制的是正反面全填充式多边形。设置图案填充式多边形函数为：voidglPolygonStipple(constGLubyte*mask);为当前多边形定义填充图案模式。参数mask是一个指向32x32位图的指针。与虚点线绘制的道理一样，某位为1时绘制，为0时什么也不绘。注意，在调用这个函数前，必须先启动一下，即用glEnable(GL_POLYGON_STIPPLE)；不用时用glDisable(GL_POLYGON_STIPPLE)关闭。②正弦和余弦曲线的绘制线的绘制需要用到GL_LINES模式，它指定在glBegin/glEnd函数对中，从第一个点开始，两两构成一条直线段。绘制正余弦曲线的话，只需要编写一段循环语句，指定绘制路线，设置不同线型。③在屏幕上显示字符在OpenGL实用程序工具包中包含了一些预定义的字符库，用来显示点阵和矢量字符。函数voidglutBitmapCharacter(void*font,intcharacter);显示一个GLUT位图字符。其中font是GLUT符号常数，指定点阵字库。参数character采用ASCII编码的形式指定要显示的字符。用函数glutBitmapCharacter显示字符时，是将当前的光栅位置作为字符的左下角点，函数执行后，点阵字符装入刷新缓冲存储器，当前的光栅位置会在x坐标方向上获得一个字符宽度的增量，这样可以较轻易的生成一个水平方向的字符串。2）程序调试、测试与运行结果分析①图案填充多边形②正余弦曲线的绘制③在屏幕上显示字符4、实验总结这次的实验有三个，其中显示字符比较简单，只需要调用一个函数就可以完成，各字母对应的ASCII码查找也简单，所以完成的很快很顺利。再就是正余弦曲线的绘制，之前都有做过直线的绘制，基本都是大同小异，稍有难处的就是曲线坐标的确定。在函数中我用一段循环语句来确定曲线点的坐标。最难做的就是棋盘填充多边形了。这个实验的代码也很简单，遇到困难的是数组定义位图。其实数组的编写现在也没有搞太明白，感觉设计起来很难，有在网上查资料，才最终解决了。对知识了解，但编写还是有些困难。这次的实验也是一样的有趣，吸引人，以后会更加努力的。5、附录1）棋盘填充多边形#includegl/glut.hvoidInitial(void){glClearColor(1.0f,1.0f,1.0f,1.0f);glMatrixMode(GL_PROJECTION);gluOrtho2D(0.0,200.0,0.0,150.0);}GLubytetianchong[]={/*填充模式定义（32x32）*/0x00,0x01,0x80,0x00,0x00,0x03,0xc0,0x00,0x00,0x07,0xe0,0x00,0x00,0x0f,0xf0,0x00,0x00,0x1f,0xf8,0x00,0x00,0x3f,0xfc,0x00,0x00,0x7f,0xfe,0x00,0x00,0xff,0xff,0x00,0x01,0xff,0xff,0x80,0x03,0xff,0xff,0xc0,0x07,0xff,0xff,0xe0,0x0f,0xff,0xff,0xf0,0x1f,0xff,0xff,0xf8,0x3f,0xff,0xff,0xfc,0x7f,0xff,0xff,0xfe,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0x7f,0xff,0xff,0xfe,0x3f,0xff,0xff,0xfc,0x1f,0xff,0xff,0xf8,0x0f,0xff,0xff,0xf0,0x07,0xff,0xff,0xe0,0x03,0xff,0xff,0xc0,0x01,0xff,0xff,0x80,0x00,0xff,0xff,0x00,0x00,0x7f,0xfe,0x00,0x00,0x3f,0xfc,0x00,0x00,0x1f,0xf8,0x00,0x00,0x0f,0xf0,0x00,0x00,0x07,0xe0,0x00,0x00,0x03,0xc0,0x00,0x00,0x01,0x80,0x00};voidDisplay(void){glClear(GL_COLOR_BUFFER_BIT);///*绘制一个指定图案填充的矩形*/glColor3f(0.1,0.8,0.7);glEnable(GL_POLYGON_STIPPLE);glPolygonStipple(tianchong);glRectf(50.0f,100.0f,150.0f,50.0f);/*绘制一个指定图案填充的三角形*/glColor3f(0.9,0.86,0.4);glPolygonStipple(tianchong);glBegin(GL_TRIANGLES);glVertex2i(10,10);glVertex2i(90,10);glVertex2i(10,90);glEnd();glDisable(GL_POLYGON_STIPPLE);glFlush();glutSwapBuffers();}intmain(intargc,char*argv[]){glutInit(&argc,argv);glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB);glutInitWindowSize(500,300);glutInitWindowPosition(100,100);glutCreateWindow(棋盘图形填充);glutDisplayFunc(Display);Initial();glutMainLoop();return0;}2）正余弦曲线的绘制#includemath.h#includegl/glut.hvoidMyDisplay();voidInit();voidDrawSin();voidMyDisplay(){glClear(GL_COLOR_BUFFER_BIT);DrawSin();glFlush();}voidInit(){glColor3f(1.0f,0.0f,0.0f);glClearColor(1.0f,1.0f,1.0f,1.0f);}voidDrawSin(){constfloatfactor=0.1;glBegin(GL_LINES);glVertex2f(-1,0);glVertex2f(1,0);glVertex2f(0,-1);glVertex2f(0,1);glEnd();//glLineStipple(5,0x1C47);//glBegin(GL_LINES);//用虚线绘制glBegin(GL_LINE_STRIP);for(floatx=-1/factor;x1/factor;x+=0.001){glVertex2f(x*factor,sin(x)*factor);}glEnd();glBegin(GL_LINE_STRIP);for(floaty=-1/factor;y1/factor;y+=0.001){glVertex2f(y*factor,cos(y)*factor);}glEnd();glutSwapBuffers();}intmain(intargc,char*argv[]){glutInit(&argc,argv);glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);glutInitWindowSize(400,300);glutInitWindowPosition(100,150);glutCreateWindow(正余弦曲线绘制);Init();glutDisplayFunc(MyDisplay);glutMainLoop();return0;}3）在屏幕显示字符#includegl/glut.hintwinWidth=600,winHeight=300;voidInitial(void){glClearColor(1.0f,1.0f,1.0f,1.0f);}voidChangeSize(intw,inth){winWidth=w;winHeight=h;glViewport(0,0,w,h);glMatrixMode(GL_PROJECTION);glLoadIdentity();gluOrtho2D(0.0,winWidth,0.0,winHeight);}voidDisplay(void){glClear(GL_COLOR_BUFFER_BIT);glColor3f(1.0f,0.0f,0.0f);glutStrokeCharacter(GLUT_STROKE_ROMAN,79);glutStrokeCharacter(GLUT_STROKE_ROMAN,112);glutStrokeCharacter(GLUT_STROKE_ROMAN,101);glutStrokeCharacter(GLUT_STROKE_ROMAN,110);glutStrokeCharacter(GLUT_STROKE_ROMAN,71);glutStrokeCharacter(GLUT_STROKE_ROMAN,76);glutSwapBuffers();}intmain(intargc,char*argv[]){glutInit(&argc,argv);glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB);glutInitWindowSize(500,300);glutInitWindowPosition(100,100);glutCreateWindow(WriteWords);glutDisplayFunc(Display);glutReshapeFunc(ChangeSize);Initial();glutMainLoop();return0;}