图形学实验报告如何写

图形学实验报告

班级：07

学号：07

姓名：李

1.编程实现直线生成算法改进的Bresenham算法画直线

（1）源代码：

include

include

include

voidputpi_el(int_,inty)/画点函数{

glColor3f(0.0f,0.0f,0.0f);

glPointSize(3);

glBegin(GL_POINTS);

glVerte_3f(_,y,0.0f);

glEnd();

voidInitial(void)

glClearColor(1.0f,1.0f,1.0f,1.0f);

glMatri_Mode(GL_PROJECTION);gluOrtho2D(0.0,200.0,0.0,150.0);

voidBresenhamLine1(int_0,inty0,int_1,inty1)/斜率0<=k<=1{

int_,y,d_,dy,e;

d_=_1-_0;

dy=y1-y0;

e=-d_;_=_0;y=y0;

while(_<=_1)

putpi_el(_,y);

_++;

e=e+2dy;

if(e>0)

y++;

e=e-2d_;

voidBresenhamLine2(int_0,inty0,int_1,inty1)/斜率1<=k{

int_,y,d_,dy,e;

d_=_1-_0;

dy=y1-y0;

e=-dy;_=_0;y=y0;

while(y<=y1)

putpi_el(_,y);

y++;

e=e+2d_;

if(e>0)

_++;

e=e-2dy;

int_,y,_1,y2;

voidDisplay()/显示直线的函数

floatk;

glClear(GL_COLOR_BUFFER_BIT);

glColor3f(0.0f,0.0f,0.0f);

k=(y2-y)/(_1-_);

if(0<=kk<=1)

BresenhamLine1(_,y,_1,y2);

elseif(k>1)

BresenhamLine2(_,y,_1,y2);

glFlush();

voidmain(intargc,charargv[])

cout<<"依次输入起始点横纵坐标，终点横纵坐标"<_>y>_1>y2;

glutInit(argc,argv);

glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);glutInitWindowSize(400,300);/设置显示频的尺寸glutInitWindowPosition(100,120);

glutCreateWindow("breswnham算法画直线");glutDisplayFunc(Display);

Initial();

glutMainLoop();

（2）运行演示：

k>=0k<=1

画出的直线如下图所示

画斜率k>1的直线

画出的直线如图所示：

2.编程实现画圆算法

中点Bresenham算法画圆

（1）源代码：

include

include

voidputpi_el(int_,inty)/画点函数

glColor3f(0.0f,0.0f,0.0f);

glPointSize(3);

glBegin(GL_POINTS);

glVerte_3f(_,y,0.0f);

glEnd();

voidInitial(void)

glClearColor(1.0f,1.0f,1.0f,1.0f);

glMatri_Mode(GL_PROJECTION);

gluOrtho2D(0.0,200.0,0.0,150.0);/投影坐标区域

voidMidBresenhamCircle(intr,ints)/终点bresenham算法画一个圆，为了能画一个完整的圆，这里加了平移量s。

/既规定了原点坐标是（s,s）

int_,y,d;

_=0;y=r;d=1-r;

while(_<=y)

putpi_el(_+s,y+s);/下面三句分别做的是该点在2，3,4象限的对称点

putpi_el(-_+s,y+s);

putpi_el(_+s,-y+s);

putpi_el(-_+s,-y+s);

putpi_el(y+s,_+s);/先做出点已经画出的点关于y=_的对称点，再画此点在2,3,4象限的对称点

putpi_el(-y+s,-_+s);

putpi_el(-y+s,_+s);

putpi_el(y+s,-_+s);

if(d<0)

d=d+2_+3;

else

d=d+2(_-y)+5;

y--;

_++;

voidDisplay(void)

glClear(GL_COLOR_BUFFER_BIT);

glColor3f(0.0f,0.0f,0.0f);

MidBresenhamCircle(50,70);/原点从（0,0）平移到（70,70），在新的坐标系下圆心坐标为（50,50），

glFlush();

intmain(intargc,charargv[])

glutInit(argc,argv);

glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);

glutInitWindowSize(550,400);/屏幕的尺寸设定

glutInitWindowPosition(100,120);/屏幕位置的设定

glutCreateWindow("中点Bresenham算法画圆）");

glutDisplayFunc(Display);

Initial();

glutMainLoop();

return0;

（2）运行演示：

为了保证可以画出一个完整的圆，程序已将原点从（0,0）平移到（70,70），在新的坐标系

下圆心坐标为（50,50）

3.（a）编程实现绘制一段三次Bezier曲线

（1）源代码：

include

include

include

classPt3D/定义二维点坐标数据结构

public:GLfloat_,y,z;

/计算多项式的系数

voidGetCnk(GLintn,GLintc)

GLinti,k;

for(k=0;k<=n;k++)

c[k]=1;

for(i=n;i>=k+1;i--)

c[k]=c[k]i;

for(i=n-k;i>=2;i--)

c[k]=c[k]/i;

/计算贝兹尔曲线上点的坐标

voidGetPointPr(GLintc,GLfloatt,Pt3DPt,intControlN,Pt3DControlP)

GLintk,n=ControlN-1;

GLfloatBernstein;

Pt->_=0.0;Pt->y=0.0;Pt->z=0.0;

for(k=0;k

Bernstein=c[k]pow(t,k)pow(1-t,n-k);

Pt->_+=ControlP[k]._Bernstein;

Pt->y+=ControlP[k].yBernstein;

Pt->z+=ControlP[k].zBernstein;

/根据控制点，求取线上的m个点

voidBezierCurve(GLintm,GLintControlN,Pt3DControlP)

GLintC,i;

Pt3DCurvePt;

C=newGLint[ControlN];

GetCnk(ControlN-1,C);

glBegin(GL_POINTS);

for(i=0;i<=m;i++)

GetPointPr(C,(GLfloat)i/(GLfloat)m,CurvePt,ControlN,ControlP);

glVerte_2f(CurvePt._,CurvePt.y);

glEnd();

delete[]C;

voidinitial(void)

glClearColor(1.0,1.0,1.0,0.0);

voidDisplay(void)

glClear(GL_COLOR_BUFFER_BIT);

GLintControlN=4,m=500;/指定有四个控制点，生成的Bezier曲线由500个点组成Pt3DControlP[4]={{-80.0,-40.0,0.0},{-10.0,90.0,0.0},{10.0,-90.0,0.0},{80.0,40.0,0.0}};/控制点的坐标

glPointSize(2);/设置当前绘制点的大小

glColor3f(0.0,0.0,0.0);

BezierCurve(m,ControlN,ControlP);/绘制Bezier曲线glBegin(GL_LINE_STRIP);/绘制控制多边形for(GLinti=0;i<4;i++)

glVerte_3f(ControlP[i]._,ControlP[i].y,ControlP[i].z);glEnd();

glFlush();

voidReshape(GLintnewWidth,GLintnewHeight)

glViewport(0,0,newWidth,newHeight);

glMatri_Mode(GL_PROJECTION);

glLoadIdentity();

gluOrtho2D(-100.0,100.0,-100.0,100.0);

voidmain(void)

glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);glutInitWindowPosition(100,100);

glutInitWindowSize(400,400);

glutCreateWindow("Bezier曲线");

initial();

glutDisplayFunc(Display);

glutReshapeFunc(Reshape);

glutMainLoop();

（2）运行演示：

3.(b)实现两段三次Bezier曲线的拼接

（1）源代码：

include

include

include

include

include

include

include

classPt3D/定义二维点坐标数据结构

public:

GLfloat_,y,z;

/就算多项式系数

voidGetCnk(GLintn,GLintc)

GLinti,k;

for(k=0;k<=n;k++)/计算多项式系数

c[k]=1;

for(k=0;k<=n;k++)/计算多项式系数

c[k]=1;

for(i=n;i>=k+1;i--)

c[k]=c[k]i;

for(i=n-k;i>=2;i--)

c[k]=c[k]/i;

/计算Bezier曲线上点的坐标

voidGetPointPr(GLintc,GLfloatt,Pt3DPt,intControlN,Pt3DControlP){

GLintk,n=ControlN-1;

GLfloatBernstein;

Pt->_=0.0;

Pt->y=0.0;

Pt->z=0.0;

for(k=0;k

Bernstein=c[k]pow(t,k)pow(1-t,n-k);

Pt->_+=ControlP[k]._Bernstein;

Pt->y+=ControlP[k].yBernstein;

Pt->z+=ControlP[k].zBernstein;

/根据控制点，求曲线上的m个点

voidBezierCurve(GLintm,GLintControlN,Pt3DControlP)

GLintC,i;

Pt3DCurvePt;

C=newGLint[ControlN];

GetCnk(ControlN-1,C);

glBegin(GL_POINTS);

for(i=0;i<=m;i++)

GetPointPr(C,(GLfloat)i/(GLfloat)m,CurvePt,ControlN,ControlP);glVerte_2f(CurvePt._,CurvePt.y);

glEnd();

delete[]C;

voidinitial(void)

glClearColor(1.0,1.0,1.0,0.0);

voidDisplay(void)

glClear(GL_COLOR_BUFFER_BIT);

GLintControlN=4,m=500;/制定有4个控制点，生成的Bezier曲线由500个点组成Pt3DControlP[4]={{-100.0,-50.0,0.0},{-20.0,70.0,0.0},{20.0,-80.0,0.0},{50.0,50.0,0.0}};/控制点坐标

Pt3DControlP1[4]={{-100.0,50.0,0.0},{10.0,50.0,0.0},{-10.0,-50.0,0.0},{50.0,50.0,0.0}};/另一个Bezier曲线的控制点坐标

glPointSize(2);/设置绘制点的大小

glColor3f(0.0,0.0,0.0);

BezierCurve(m,ControlN,ControlP);/绘制Bezier曲线1

BezierCurve(m,ControlN,ControlP1);/绘制Bezier曲线2

glBegin(GL_LINE_STRIP);/绘制控制多边形

for(GLinti=0;i<4;i++)

glVerte_3f(ControlP[i]._,ControlP[i].y,ControlP[i].z);

for(i=0;i<4;i++)

glVerte_3f(ControlP1[i]._,ControlP1[i].y,ControlP1[i].z);

glEnd();

glFlush();

voidReshape(GLintnewWidth,GLintnewHeight)

glViewport(0,0,newWidth,newHeight);

glMatri_Mode(GL_PROJECTION);

glLoadIdentity();

gluOrtho2D(-100.0,100.0,-100.0,100.0);

voidmain(void)

glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);

glutInitWindowPosition(100,100);

glutInitWindowSize(400,400);

glutCreateWindow("Bezier曲线");

initial();

glutDisplayFunc(Display);

glutReshapeFunc(Reshape);

glutMainLoop();

（2）运行演示：

4.编程实现Y-_算法（又称改进的有效边表算法）或者线段的编码裁剪算法（二选一）线段的裁剪，使用的是liang--Barsky算法

（1）源代码：

include

include

voidInitial(void)

glClearColor(1.0f,1.0f,1.0f,1.0f);

glMatri_Mode(GL_PROJECTION);

gluOrtho2D(0.0,200.0,0.0,150.0);

voidputpi_el(int_,inty)/画点函数

glPointSize(3);

glBegin(GL_POINTS);

glVerte_3f(_,y,0.0f);

glEnd();

voidDDALine(int_0,inty0,int_1,inty1)/DDA画直线函数（数值微分法）

intd_,dy,epsl,k;

float_,y,_Incre,yIncre;

d_=_1-_0;

dy=y1-y0;

_=_0;

y=y0;

if(abs(d_)>abs(dy))

epsl=abs(d_);

else

epsl=abs(dy);

_Incre=(float)d_/(float)epsl;

yIncre=(float)dy/(float)epsl;

for(k=0;k<=epsl;k++)

putpi_el(int(_+0.5),(int)(y+0.5));

_+=_Incre;

y+=yIncre;

intLBLineClipTest(floatp,floatq,floatuma_,floatumin)

/liang式线段测试函数

floatr=0.0;

if(p<0.0)/p小于0时比较最大值

r=q/p;

if(r>umin)/umin小于umin直线段才有在窗口内的部分

return0;

elseif(r>uma_)

uma_=r;

elseif(p>0.0)/p大于0时比较最小值

r=q/p;

if(r

return0;

elseif(r

umin=r;

elseif(q<0.0)/处理p=0的情况

return0;

return1;

voidLBLineClip(float_wl,float_wr,floatywb,floatywt,float_1,floaty1,float_2,floaty2)/线段裁剪函数，对线段裁剪，只保留在窗口内的部分

floatuma_,umin,delta_,deltay;

delta_=_2-_1;

deltay=y2-y1;

uma_=0.0;

umin=1.0;

if(LBLineClipTest(-delta_,_1-_wl,uma_,umin))/处理左边界交点

if(LBLineClipTest(delta_,_wr-_1,uma_,umin))/处理右边界交点{

if(LBLineClipTest(-deltay,y1-ywb,uma_,umin))/处理下边界交点{

if(LBLineClipTest(deltay,ywt-y1,uma_,umin))/处理上边界交点{

_1=int(_1+uma_delta_+0.5);

y1=int(y1+uma_delta_+0.5);

_2=int(_2+umindelta_+0.5);

y2=int(y2+umindelta_+0.5);

DDALine(_1,y1,_2,y2);

voidDisplay(void)

glClear(GL_COLOR_BUFFER_BIT);

glColor3f(0.0f,0.0f,0.0f);

LBLineClip(40.0f,160.0f,40.0f,160.0f,40.0f,10.0f,100.0f,100.0f);

glFlush();

voidmain(intargc,charargv[])

glutInit(argc,argv);

glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);

glutInitWindowSize(500,380);

glutInitWindowPosition(200,320);

glutCreateWindow("裁剪后留在窗口内的线段");

glutDisplayFunc(Display);

Initial();

glutMainLoop();

（2）运行演示：

裁减函数LBLineClip的

参数值如下

LBLineClip(40.0f,160.0f,40.0f,160.0f,40.0f,10.0f,100.0f,100.0f);直线有一部分不在窗口内被裁减掉