opengl繪制實(shí)線、虛線、kock曲線(C++)

1、實(shí)驗(yàn)四1、實(shí)驗(yàn)?zāi)康暮鸵罄肙penGL實(shí)現(xiàn)實(shí)線，虛線，點(diǎn)劃線的繪制，及kock曲線。2、實(shí)驗(yàn)內(nèi)容用OpenGL程序繪制實(shí)現(xiàn)，虛線和點(diǎn)劃線用OpenGL程序，分別以直線和正三角形為初始生成員，實(shí)現(xiàn)迭代次數(shù)在6次以內(nèi)的kock曲線，要求用鍵盤交互控制迭代次數(shù)。3、實(shí)驗(yàn)步驟1)相關(guān)算法及原理描述直線的繪制在OpenGL中繪制直線通過(guò)指定直線段的端點(diǎn)來(lái)實(shí)現(xiàn)，用glVertex函數(shù)指定直線段端點(diǎn)的坐標(biāo)位置，用glBegin/glEnd函數(shù)對(duì)包含一系列的點(diǎn)坐標(biāo)，并利用符號(hào)常量解釋這些點(diǎn)構(gòu)成直線的方式。虛線的繪制繪制虛線需要先調(diào)用函數(shù)過(guò)了Enable(GL_LINE_STIPPLE)；打開(kāi)劃線模式。然后，

2、函數(shù)glLineStipple將建立用于劃線的模式glLineStipple(Glintfactor,GLushortpattern)；Kock曲線Kock曲線的初始生成員是一條直線，生成規(guī)則是將直線段分為三等分，首尾兩段保持不變，中間用兩段等長(zhǎng)且互成60角的直線段代替。這樣，直線段被分成四段，每段長(zhǎng)度都只有原來(lái)的1/3。Kock曲線的分形維數(shù)為D=ln4/ln31.26186假設(shè)原直線的首尾點(diǎn)是P0(xO,yO),P1(x1，y1)，則新的四段直線段的五個(gè)端點(diǎn)坐標(biāo)分別為(xO,yO)(xO+(x1-xO)/3,yO+(y1-yO)/3)(x1+x0)/2土(y0-y1)V3/6,(y1+y0

3、)/2(x1-x0)V3/6)(xO+2(x1-xO)/3,yO+2(y1-yO)/3)(x1,y1)其中，第三個(gè)點(diǎn)坐標(biāo)公式中的正負(fù)號(hào)表示中間兩條心直線段處于元直線段的哪一側(cè)。根據(jù)這一規(guī)則迭代六次。2）程序調(diào)試、測(cè)試與運(yùn)行結(jié)果分析直線的繪制結(jié)果PaintLine區(qū)1虛線的繪制結(jié)果回區(qū)IKock曲線繪制結(jié)果nxE次以內(nèi)的Knockffi線繪制問(wèn)岡5次哄內(nèi)的Knockffl繪制4、實(shí)驗(yàn)總結(jié)這次是兩個(gè)實(shí)驗(yàn)，先做的是直線、虛線的繪制，這要相對(duì)簡(jiǎn)單的多，直線、虛線的繪制只需要調(diào)用相應(yīng)的函數(shù)即可，這個(gè)程序和上次的橡皮筋技術(shù)很像，只是線的兩端點(diǎn)是自己指定的，不需要鼠標(biāo)或鍵盤的確定。而Kock曲線就比較麻煩了

4、，只是知道原理，程序的編寫(xiě)遇到些困難。我覺(jué)得其實(shí)這和直線的繪制差不多，只是各新端點(diǎn)的坐標(biāo)不好確定，所以利用了循環(huán)語(yǔ)句實(shí)現(xiàn)點(diǎn)的坐標(biāo)的賦予，最終實(shí)現(xiàn)了該算法。這次的實(shí)驗(yàn)查了資料，也思考了很多，對(duì)直線、虛線、Kock曲線的繪制有了一定的了解與掌握，在下次實(shí)驗(yàn)中會(huì)繼續(xù)認(rèn)真完成的。5、附錄1)直線的繪制#includeintwinWidth=400,winHeight=300;voidInitial(void)glClearColor(1.0f,1.0f,1.0f,1.0f);voidChangeSize(intw,inth)winWidth=w;winHeight=h;glViewport(0,0,w

5、,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);glBegin(GL_LINES);glVertex2i(50,50);glVertex2i(300,250);glEnd();glutSwapBuffers();intmain(intargc,char*argv)glutInit(&argc,argv);glutInitDis

6、playMode(GLUT_DOUBLE|GLUT_RGB);glutInitWindowSize(400,300);glutInitWindowPosition(100,100);glutCreateWindow(PaintLine);glutDisplayFunc(Display);glutReshapeFunc(ChangeSize);Initial();glutMainLoop();return0;2)虛線的繪制#includeintwinWidth=400,winHeight=300;voidInitial(void)glClearColor(1.0f,1.0f,1.0f,1.0f)

7、;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);glEnable(GL_LINE_STIPPLE);glBegin(GL_LINES);glVertex2i(50,50);glVertex2i(30

8、0,250);glEnd();glutSwapBuffers();intmain(intargc,char*argv)glutInit(&argc,argv);glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB);glutInitWindowSize(400,300);glutInitWindowPosition(100,100);glutCreateWindow(PaintLine);glLineWidth(3);glLineStipple(2,0 x0f0f);glutDisplayFunc(Display);glutReshapeFunc(ChangeSiz

9、e);Initial();glutMainLoop();return0;3)Kock曲線#include#include#include#includeusingnamespacestd;#definePI3.1415926structPointfloatx;floaty;inttype=0;staticvectorcount;/用來(lái)存放所有的點(diǎn)集合staticintm=0;/迭代次數(shù)floatline=0.0f;/線段的總長(zhǎng)度voidfirst_state(vector&count)/初始情況是只有兩個(gè)點(diǎn)Pointfirst=-0.6f,0.0f,end=0.6f,0.0f;line=sqr

10、t(pow(first.x-end.x,2)+pow(first.y-end.y,2);count.push_back(first);count.push_back(end);voidfirst_triangle(vector&count)/初始情況有三個(gè)點(diǎn)floatsqrtThree=sqrt(3.0);Pointfirst=0.2*sqrtThree,-0.2,second=-0.2*sqrtThree,-0.2,last=0,0.4;line=sqrt(pow(first.x-second.x,2)+pow(first.y-second.y,2);count.push_back(firs

11、t);count.push_back(second);count.push_back(last);voidDraw_pic(vector&count)/分別對(duì)兩種的情況進(jìn)行考慮一個(gè)是閉合的，一個(gè)開(kāi)放的if(type=1)glBegin(GL_LINE_STRIP);for(vector:size_typei=0;i!=count.size();i+)glVertex2f(counti.x,counti.y);glEnd();elseif(type=2)glBegin(GL_LINE_LOOP);for(vector:size_typei=0;i!=count.size();i+)glVerte

12、x2f(counti.x,counti.y);glEnd();voidCalculate_point(vector&count)/計(jì)算線段的時(shí)候的，沒(méi)有開(kāi)始點(diǎn)和結(jié)束點(diǎn)計(jì)算的情況vectornew_count;floatpline=line/(float)pow(float)3,(int)m);/pline為三角形的邊長(zhǎng)，通過(guò)3的迭代次數(shù)次方來(lái)實(shí)現(xiàn)的vector:size_typei;for(i=0;i!=(count.size()-1);i+)Pointp1,p2,pmid;p1.x=counti.x+(counti+1.x-counti.x)/3;p1.y=counti.y+(counti+

13、1.y-counti.y)/3;p2.x=counti.x+2*(counti+1.x-counti.x)/3;p2.y=counti.y+2*(counti+1.y-counti.y)/3;doublealpha=atan(double)(counti+1.y-counti.y)/(counti+1.x-counti.x);if(counti+1.x-counti.x=0)alpha+=PI;pmid.x=p1.x+pline*cos(alpha+PI/3);pmid.y=p1.y+pline*sin(alpha+PI/3);new_count.push_back(counti);new_c

14、ount.push_back(p1);new_count.push_back(pmid);new_count.push_back(p2);new_count.push_back(counti);count.clear();count=new_count;/之前要清空voidCalculate_triangle(vector&count)/計(jì)算是三角形的時(shí)候，要加上對(duì)開(kāi)始和結(jié)束點(diǎn)的計(jì)算vectornew_count;floatpline=line/(float)pow(float)3,(int)m);/pline為三角形的邊長(zhǎng)，通過(guò)3的迭代次數(shù)次方來(lái)實(shí)現(xiàn)的vector:size_typei;in

15、tcountSize=count.size();for(i=0;i!=countSize;i+)Pointp1,p2,pmid;intnext=i+1;if(next=countSize)next=0;p1.x=counti.x+(countnext.x-counti.x)/3;p1.y=counti.y+(countnext.y-counti.y)/3;p2.x=counti.x+2*(countnext.x-counti.x)/3;p2.y=counti.y+2*(countnext.y-counti.y)/3;doublealpha=atan(double)(countnext.y-co

16、unti.y)/(countnext.x-counti.x);if(countnext.x-counti.x=0)alpha+=PI;pmid.x=p1.x+pline*cos(alpha+PI/3);pmid.y=p1.y+pline*sin(alpha+PI/3);new_count.push_back(counti);new_count.push_back(p1);new_count.push_back(pmid);new_count.push_back(p2);/new_count.push_back(counti);count.clear();count=new_count;/之前要

17、清空voidmyDisplay()/自定義的圖形繪制函數(shù)glClear(GL_COLOR_BUFFER_BIT);glMatrixMode(GL_MODELVIEW);glLoadIdentity();glColor3f(0.0f,0.0f,1.0f);Draw_pic(count);glFlush();voidSpecialKeys(intkey,intx,inty)/鍵盤響應(yīng)函數(shù)，當(dāng)為UP的時(shí)候重繪和迭代if(key=GLUT_KEY_UP)m+;if(type=1)Calculate_point(count);elseif(type=2)Calculate_triangle(count)

18、;glutPostRedisplay();voidInitial(void)/設(shè)定初始的窗口內(nèi)容色glClearColor(1.0f,1.0f,1.0f,1.0f);voidProcessMenu(intvalue)/處理相應(yīng)菜單按鈕的函數(shù)，設(shè)定一個(gè)模式值，對(duì)效果進(jìn)行控制type=value;if(type=1)line=0.0f;m=0;count.clear();first_state(count);elseif(type=2)line=0.0f;m=0;count.clear();first_triangle(count);glutPostRedisplay();intmain(intargc,char*argv)glutInit(&argc,argv);glutInitDisplayMode(GLUT_RGB|GLUT_SINGLE);glutInitWindowPosition(100,100);glutInitWindowSize(400,400);glutCreateWindow(6次以內(nèi)的Knock曲線繪制);/創(chuàng)建菜單并定義菜單回調(diào)函數(shù)intnGlutPolyMenu=glutC