计算机图形学c实验指导五

1、实验五课程名称：计算机图形学实验名称：裁剪和曲线 实验日期：xx xx xx班级：xxxxxx姓名：xxxx 学号xxxx仪器编号：xx一、实验目的和要求1、掌握直线段的裁剪算法；2、掌握hermite |w线生成算法；二、实验内容1、下面的程序段在windows控制台下实现按住鼠标右键绘制一个矩形，按住鼠标左键，绘制直线段，并 利用cohen-sutherland算法实现肓线裁剪。要求理解掌握下面程序的执行过程。同时把该程序修改成mfc 框架形式。#include <gl7glut.h>#include <cmath>#include <vector>us

2、ing std:vector;class pt2dpublic:glfloat x, y;pt2d()(;pt2d( glfloat xx, glfloat yy )x = xx；y = yy;vector< pt2d > vector 1; vector< pt2d > vector2; int min = 0;int max = 600;pt2d startp;pt2d prep;pt2d box a;pt2d boxb;pt2d temp 1;pt2d temp2;bool buttonflag = true;以下是cohen-sutherland线段裁剪算法的实

3、现const glint winleftbitcode = 0x1;const glint winrightbitcode = 0x2;const glint winbottombitcode = 0x4;const glint wintopbitcodc = 0x& /区域码inline glint round( const glfloat a ) return glint( a + 0.5 ); inline glint inside( glint code ) return glint( !code ); inline glint reject( glint codel, gli

4、nt code2 ) return glint( code 1 & codc2 ); inline glint accept( glint codel, glint code2 ) return glint( !( codel i code2 ); 各种按位运算glubytc cncodc( pt2d pt) 获得外部码glubytc code = 0x00;if( pt.x < boxa.x )code = code i winleftbitcode;if( pt.x > boxb.x )code = code i winrightbitcode;if( pt.y <

5、; boxa.y )code = code i winbottombitcode;if( pt.y > boxb.y )code = code i wintopbitcode;return code;template< class type > void swap( type* x, type* y ) 交换数值的模板函数type temp; temp = *x;*x = *y;*y = temp;void lineclip( pt2d pl, pod p2 )裁剪算法 glubyte codel, code2;bool done = false, plotline = fa

6、lse;glfloat m;while( !done)code 1 = cncodc( pl );code2 = encode( p2 );glint qq = accept( code 1, code2 );if( accept( code 1, code2 )done = true;plotline = true;else if( reject( code 1, code2 )done = true;elseif( inside( codel )swap( &pl, &p2);swap( &codcl, &codc2);if( p2.x != pl.x )m

7、 = ( p2.y - pl.y ) / ( p2.x - pl.x );if( codel & winleftbitcode )pl.y += ( boxa.x - pl.x ) * m;pl.x = boxa.x;else if( codel & winrightbitcode )pl.y += ( boxb.x - pl.x ) * m;pl.x = boxb.x;else if( codel & winbottombitcode )if( p2.x != pl.x )pl.x += ( boxa.y pl.y ) / m;pl.y = boxa.y;else i

8、f( code 1 & wintopbitcodc )if( p2.x != pl.x )pl.x += ( boxb.y pl.y ) / m;pl.y = boxb.y;if( plotlinc)vector 1 .push_back( p 1 );vector2.push_back( p2 ); 裁剪后保存线段void drawlines() /绘制所有裁剪过后的线段for (int i = 0; i < vector2.size(); +i)glcolor3f( 0.0, 0.0, 1.0);glbegin( gl_l1nes );glvertex2i( vector 1

9、 i j.x, vector 1 i j.y );glvertex2i( vector2f i .x, vector2 i .y ); glend();void drawline( glint xl, glint yl, glint x2, glint y2 )glbegin( gl_lines );glvcrtcx2i( xl, yl );glvertex2i( x2, y2);glend();void drawbox()glcolor3f( 1.0, 0.0, 0.0);glpolygonmode( gl_front_and_back, gl.line); glrecti( boxa.x,

10、 boxa.y, boxb.x, boxb.y );void drawrcctanglc( glint xl, glint yl, glint x2, glint y2 ) glpolygonmode( gl_front_and_back, gl.line); glrecti( xl, yl, x2, y2 );void display( void )glclear( gl_color_buffer_b1t);glflush();void clickmousc( int btn, int state, int xn, int yn )if( btn = glut_left_button &am

11、p;& state = glut_down )/左键按下：记录线段buttonflag = true;startp.x = xn;startp.y = glutget( glut_window_height) yn;temp l.x = startp.x;templ.y = startp.y;else if( btn = glut_left_button && state = glut_up)左键释放：绘制线段startp.x = xn;startp.y = glutget( glut_window_height) - yn;temp2.x = startp.x;tem

12、p2.y = startp.y;lineclip( temp 1, temp2 );glclear( gl_color_buffer_bit);drawlincs();drawbox();else if( btn = glut_right.button && state = glut_down )右键按下：记录裁剪框glclcar( gl_color_buffer_bit);vectorl.clear();vector2.clear();buttonflag = false;startp.x = xn;startp.y = glutgct( glut_window_height

13、) - yn;boxa.x = startp.x;boxa.y = startp.y;else if( btn = glut_right_button && state = glut_up)/右键释放：裁剪框startp.x = xn;startp.y = glutget( glut_w1ndow_he1ght) yn;if( startp.x < boxa.x )boxb.x = boxa.x;boxa.x = startp.x;elseboxb.x = startp.x;if( startp.y < boxa.y ) boxb.y = boxa.y;boxa.y

14、 = startp.y;elseboxb.y = startp.y;drawbox();glflush();void movemouse( int xn, int yn ) 鼠标按卜移动时动态更新当前线段和裁剪框if( buttonflag)glcolor3f( 1.0, 1.0, 1.0);drawline( startp.x, startp.y, prep.x, prep.y );drawlines();draw b ox();prep.x = xn;prep.y = glutget( glut_window_height) yn;glcolor3f( 0.0, 1.0, 0.0);dra

15、wline( startp.x, startp.y, prep.x, prep.y );else glcolor3f( 1.0, 1.0, 1.0);drawrectangle( startp.x, startp.y, prep.x, prep.y ); drawlincs();prep.x = xn;prep.y = glutget( glut_window_height) yn; glcolor3f( 0.0, 1.0, 0.0);drawrectangle( startp.x, startp.y, prep.x, prep.y );glflush();void myinit()glmat

16、rixmodc( gl_projection); gluortho2d( min, max, min, max ); glclearcolor( 1.0, 1.0, 1.0, 1.0);int main( int argc, char *argv ) glutlnit( &argc, argv ); glutinitdisplaymodc( glut_single i glut_rgb );glutinitwindowsize( max, max );glutcreatewindow( "line clip");glutdisplayfunc( display);glutmousefunc( clickmouse );glutmotionfunc( movcmousc );myinit();glutmainloopo;return 0;2、假设窗口的宽高分別是600, 600个像素单位，定义的裁剪窗口由函数gluortho2d(-50.0,5