计算机图形学 裁剪算法源代码,OpenGL计算机图形学梁友栋裁剪算法实验代码及运行结果.doc...

OpenGL计算机图形学梁友栋裁剪算法实验代码及运行结果

《计算机图形学实验》报告

任课教师：钱文华

2016年春季学期

实验:

实验时间：2016年11月17日

实验地点：信息学院2204

实验目的：掌握梁友栋裁剪

程序代码：#include

#include

#include

#include

class wcPt2D{

public:

GLfloat x,y;

void setCoords(GLfloat xCoord,GLfloat yCoord){x=xCoord;y=yCoord;}

GLfloat getx() const{return x;}

GLfloat gety() const{return y;}

};

inline GLint round(const GLfloat a){return GLint(a+0.5);}

void setPixel(int x,int y){

glBegin(GL_POINTS);

glVertex2i(x,y);

glEnd();

}

void init(){

glClearColor(1.0,1.0,1.0,0.0);

glMatrixMode (GL_PROJECTION);

gluOrtho2D(-200.0,200.0,-200.0,200.0);

}

void lineBres(GLfloat x0,GLfloat y0,GLfloat xEnd,GLfloat yEnd){

int dx = fabs(xEnd - x0),dy = fabs(yEnd - y0);

int p = 2*dy - dx;

int twoDy = 2*dy,twoDyMinusDx = 2*(dy - dx);

int x,y;

if(x0>xEnd){

x = xEnd;

y = yEnd;

xEnd = x0;

}

else{

x = x0;

y = y0;

}

setPixel(x,y);

while(x

x++;

if(p<0)

p+=twoDy;

else{

y++;

p+=twoDyMinusDx;

}

setPixel(x,y);

}

}

GLint clipTest(GLfloat p,GLfloat q,GLfloat *u1,GLfloat *u2){

GLfloat r;

GLint returnValue = true;

if(p<0.0){

r = q/p;

if(r>*u2)

returnValue = false;

else

if(r>*u1)

*u1 = r;

}

else

if(p>0.0){

r = q/p;

if(r

returnValue = false;

else if(r

*u2 = r;

}

else

if(q<0.0)

returnValue = false;

return(returnValue);

}

void lineClipLiangBarsk(wcPt2D winMin,wcPt2D winMax,wcPt2D p1,wcPt2D p2){

GLfloat u1 = 0.0,u2 = 1.0,dx = p2.getx()-p1.getx(),dy;

GLfloat x1 = p1.getx(),y1 = p1.gety();

GLfloat x2 = p2.getx(),y2 = p2.gety();

if(clipTest(-dx,p1.getx()-winMin.getx(),&u1,&u2))

if(clipTest(dx,winMax.getx()-p1.getx(),&u1,&u2)){

dy = p2.gety()-p1.gety();

if(clipTest(-dy,p1.gety()-winMin.gety(),&u1,&u2)){

if(clipTest(dy,winMax.gety()-p1.gety(),&u1,&u2)){

if(u2<1.0){

p2.setCoords(p1.getx()+u2*dx,p1.gety()+u2*dy);

}

if(u1>0.0){

p1.setCoords(p1.getx()+u1*dx,p1.gety()+u1*dy);

}

glColor3f(0.0,0.0,0.0);

lineBres(