實驗一OpenGL直線、圓的繪制

實驗一、OpenGL直線、圓的繪制1、實驗目的1〕了解OpenGL圖形庫的功能和結構；2〕學習了解OpenGL程序的根本結構，及常用函數(shù)；3〕學習使用OpenGL繪制根本圖形〔線、圓〕；2、實驗內容1〕使用OpenGL編寫一個簡單的C++程序，使該程序能夠繪制出直線。2〕使用OpenGL編寫一個簡單的C++程序，使該程序能夠繪制出圓。3、實驗過程1〕在系統(tǒng)上配置好OpenGL的環(huán)境〔頭文件，庫文件，和鏈接庫文件〕；2〕使用VisualV++6.0新建一個C++文檔，并創(chuàng)立相應的工程；3〕在文檔中引入OpenGL的頭文件，編輯代碼實現(xiàn)鼠標拖動畫直線，畫圓。4、實驗結果可單擊鼠標左鍵，然后拖動鼠標畫出兩條直線，并同時畫出圓；可單擊鼠標右鍵，然后拖動鼠標畫出兩個圓，并同時畫出直線。結果截圖：鼠標左鍵主要控制繪制的直線:鼠標右鍵主要控制繪制的圓：5、實驗代碼#include<gl/glut.h>#include<math.h>//GLintpNum=0;GLintpx1,py1,px2,py2,cx,cy,r;GLintwinWidth=600,winHeight=600;//////////////////畫直線////////////voidDraw_Bresenham(intpStartx,intpStarty,intpEndx,intpEndy){//用Bresenham算法畫直線inti;if(pStartx==pEndx){//為豎線if(pStarty<=pEndy){for(i=pStarty;i<=pEndy;i++)glVertex2f(pStartx,i);}else{for(i=pEndy;i<=pStarty;i++)glVertex2f(pStartx,i);}return;}//為橫線if(pStarty==pEndy){if(pStartx<=pEndx){for(i=pStartx;i<=pEndx;i++)glVertex2f(i,pStarty);}else{for(i=pEndx;i<=pStartx;i++)glVertex2f(i,pStarty);}return;}//為斜線floatm=(pEndy-pStarty)*1.0/(pEndx-pStartx);floatp;p=2*m-1;if(m>0&&m<=1){if(pStartx<pEndx){while(pStartx<=pEndx){glVertex2f(pStartx++,pStarty);if(p>=0){p+=2*m-2;pStarty++;}elsep+=2*m;}}else{while(pEndx<=pStartx){glVertex2f(pEndx++,pEndy);if(p>=0){p+=2*m-2;pEndy++;}elsep+=2*m;}}return;}p=-2*m-1;if(m<0&&m>=-1){if(pStartx<pEndx){while(pStartx<=pEndx){glVertex2f(pStartx++,pStarty);if(p>=0){p+=-2*m-2;pStarty--;}elsep+=-2*m;}}else{while(pEndx<=pStartx){glVertex2f(pEndx++,pEndy);if(p>=0){p+=-2*m-2;pEndy--;}elsep+=-2*m;}}return;}p=2/m-1;if(m>1){if(pStarty<pEndy){while(pStarty<=pEndy){glVertex2f(pStartx,pStarty++);if(p>=0){p+=2/m-2;pStartx++;}elsep+=2/m;}}else{while(pEndy<=pStarty){glVertex2f(pEndx,pEndy++);if(p>=0){p+=2/m-2;pEndx++;}elsep+=2/m;}}return;}p=-2/m-1;if(pStarty<pEndy){while(pStarty<=pEndy){glVertex2f(pStartx,pStarty++);if(p>=0){p+=-2/m-2;pStartx--;}elsep+=-2/m;}}else{while(pEndy<=pStarty){glVertex2f(pEndx,pEndy++);if(p>=0){p+=-2/m-2;pEndx--;}elsep+=-2/m;}}}//////////////////畫圓/////////////////////其他象限繪制voidCirclePoints(intx,inty){//第1象限glVertex2f(x,y);glVertex2f(y,x);//第2象限glVertex2f(-x,y);glVertex2f(-y,x);//第3象限glVertex2f(-y,-x);glVertex2f(-x,-y);//第4象限glVertex2f(x,-y);glVertex2f(y,-x);}//////////中點算法畫圓voidDrawCircle(intcx,intcy,intradis){glPushMatrix();glTranslatef(cx,cy,0); glPointSize(1); glColor3f(0.5f,0.5f,1.0f); glBegin(GL_POINTS);intx,y;doublep;x=0;y=radis;p=1.25-radis;while(x<=y+1){CirclePoints(x,y);x++;if(p>=0){y--;p+=2.0*(x-y)+5;}elsep+=2*x+3;} glEnd(); glPopMatrix();}//////////繪制坐標軸voidDrawOx(){ glColor3f(0.95,0.7,0.8); glPointSize(1); glBegin(GL_LINES); glVertex2f(-winWidth/2,0); glVertex2f(winWidth/2,0); glVertex2f(0,winHeight/2); glVertex2f(0,-winHeight/2); glEnd();}//////////顯示函數(shù)voidDisplay(){////////GL_COLOR_BUFFER_BIT(用背景顏色填充)glClear(GL_COLOR_BUFFER_BIT); DrawOx(); glColor3f(0.0,0.0,1.0); glBegin(GL_POINTS); //BresenhamLine(px1,py1,px2,py2); Draw_Bresenham(px1,py1,px2,py2); glEnd(); glBegin(GL_POINTS); Draw_Bresenham(py1,px1,py2,px2); glEnd();//glBegin(GL_LINES); //glVertex2f(px1,py1); //glVertex2f(px2,py2); //glVertex2f(py1,px1); //glVertex2f(py2,px2); //glEnd();DrawCircle(cx,cy,r);DrawCircle(cy,cx,r);///交換緩沖區(qū) glutSwapBuffers(); //glFlush();//刷新繪圖命令 }//設置渲染狀態(tài)〔聽起來滿下人，實際上很簡單〕voidSetupRC(void){ //去除顏色〔這里為黑色，為了方便找畫的那個點〕，可以理解成背景顏色 //和glColor4f(1.0f,0.0f,0.0f，1.0f)一樣，所有參數(shù)都在0.0到1.0之間，后綴f是表示參數(shù)是浮點型的 //最后的那個1.0f是透明度，0.0f表示全透明，1.0f是完全不透明 glClearColor(1.0f,1.0f,1.0f,1.0f);}//當繪制的窗口大小改變時重新繪制，使繪制的圖形同比例變化，//幾乎所有OpenGL程序中的這個函數(shù)都是一樣的，所以，放心大膽的拷貝吧voidChangeSize(intw,inth){ winWidth=w; winHeight=h; //設置觀察視野為窗口大小〔用FLASH里面的話來說應該叫設置攝象機視野〕 glViewport(0,0,w,h); //重置坐標系統(tǒng)，指定設置投影參數(shù) glMatrixMode(GL_PROJECTION); ///////調用單位矩陣，去掉以前的投影參數(shù)設置 glLoadIdentity();//////設置投影參數(shù) gluOrtho2D(-w/2,w/2,-h/2,h/2);}/////////////////鼠標點擊voidMousePlot(GLintbutton,GLintaction,GLintxMouse,GLintyMouse){ if(button==GLUT_LEFT_BUTTON&&action==GLUT_DOWN){ px1=xMouse-winWidth/2; py1=winHeight/2-yMouse; } if(button==GLUT_LEFT_BUTTON&&action==GLUT_UP){ px2=xMouse-winWidth/2; py2=winHeight/2-yMouse; glutPostRedisplay(); } if(button==GLUT_RIGHT_BUTTON&&action==GLUT_DOWN){ cx=xMouse-winWidth/2; cy=winHeight/2-yMouse; }}////////////////鼠標移動voidMouseMove(GLintxMouse,GLintyMouse){