OpenGL生成指定的直线DDA算法和Bresenham算法

1. 实验目的：（1）学会使用OpenGL生成指定的直线。（2）掌握生成直线的DDA算法和Bresenham算法。2. 实验内容： 运用DDA和Bresenham算法画出一条直线，3. 实验算法分析：DDA算法：利用两点确定斜率，及在8个象限中的坐标增量的规律生成直线；Bresenham算法：1、将直线光栅化，计算误差初值Pi=2dy-dx，求出下一点的位置； 2、如果Pi0，则y（i+1）=yi+1，否则y（i+1）=yi； 3、画出点，继而迭代求出各点，最终生成直线。4. 程序源代码：DDA算法：#include void init(void) glClearColor(1.0,1.0,1.0,1.0); gluOrtho2D(0.0,50.0,0.0,50.0); int abs(int x) int y; if(xabs(dy) steps=abs(dx); else steps=abs(dy); delta_x=(float)dx/(float)steps; delta_y=(float)dy/(float)steps; x=xa; y=ya; set_pixel(x,y); for(k=1;k=steps;k+) x+=delta_x; y+=delta_y; set_pixel(x,y); void display(void) glClear(GL_COLOR_BUFFER_BIT); glColor3f(0.5,1.0,0.5); dda_line(25,25,5,45); glPointSize(6.0); glBegin(GL_POINTS); glVertex2f(1.0,1.0); glEnd(); glFlush(); int main(int argc, char* argv) glutInit(&argc,argv); glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB); glutInitWindowSize(250,250); glutInitWindowPosition(500,250); glutCreateWindow(OpenGL框架之直线与点); init(); glutDisplayFunc(display); glutMainLoop(); return 0; Bresenham算法：#include void init(void) glClearColor(1.0,1.0,1.0,1.0); gluOrtho2D(0.0,50.0,0.0,50.0); int abs(int x) int y; if(x=0) inc=1;else inc=-1; if (abs(dx)abs(dy) if(dx0) tmp=x1; x1=x2; x2=tmp; tmp=y1; y1=y2; y2=tmp; dx=-dx; dy=-dy; p=2*dy-dx;const1=2*dy;const2=2*(dy-dx);x=x1;y=y1;set_pixel(x,y);while(xx2) x+; if(p0) p+=const1; else y+=inc; p+=const2; set_pixel(x,y); else if(dy0) tmp=x1; x1=x2; x2=tmp; tmp=y1; y1=y2; y2=tmp; dx=-dx; dy=-dy; p=2*dx-dy; const1=2*dx; const2=2*(dx-dy); x=x1; y=y1; set_pixel(x,y); while(yy2) y+; if(p0) p+=const1; else x+=inc; p+=const2; set_pixel(x,y); void display(void) glClear(GL_COLOR_BUFFER_BIT); glColor3f(0.5,1.0,0.5); voidline(25,5,45,45); glPointSize(6.0); glFlush(); int main(int argc, char* argv) glutInit(&argc,argv); glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB); glutInitWindowSize(250,250); glutInitWindowPosition(500,250); glutCreateWindow(OpenGL框架之