"Graphics" experiment Seven: Midpoint Bresenham algorithm Draw ellipse

Development Environment:

Vc++6.0,opengl

Experimental content:

Use the midpoint Bresenham algorithm to draw an ellipse.

Experimental Results:

Code:

1#include <gl/glut.h>2 3 #defineWIDTH 5004 #defineHEIGHT 5005 #defineOFFSET 15//Offset , offset to Origin6 #defineA 67 #defineB 58 9 voidInit ()//Other InitializationTen { OneGlclearcolor (1.0f,1.0f,1.0f,1.0f);//Set background color, completely opaque AGLCOLOR3F (1.0f,0.0f,0.0f);//Set Brush Color -  - Glmatrixmode (gl_projection); the glloadidentity (); -Gluortho2d (0.0,30.0,0.0,30.0); - Glmatrixmode (gl_modelview); - } +  - voidMidbresenhamellipse (intAintb//midpoint Bresenham algorithm to draw ellipse + { A     intx, y; at     floatd1,d2; -x =0; y =b; -d1=b*b+a*a* (-b+0.25); -Glpointsize (5);//Set Brush size -  - Glbegin (gl_points); inGlvertex2i (offset+x,offset+y); -Glvertex2i (offset-x,offset-y); toGlvertex2i (offset-x,offset+y); +Glvertex2i (offset+x,offset-y); - glend (); the  *      while(B*b* (x+1) < a*a* (y0.5)){ $         if(d1<=0){Panax Notoginsengd1+=b*b* (2*x+3); -X + +; the         } +         Else{ Ad1+=b*b* (2*x+3) +a*a* (-2*y+2); theX + +; +y--; -         } $ Glbegin (gl_points); $Glvertex2i (offset+x,offset+y); -Glvertex2i (offset-x,offset-y); -Glvertex2i (offset-x,offset+y); theGlvertex2i (offset+x,offset-y); - glend ();Wuyi}//While the upper half part thed2=b*b* (x+0.5) * (x+0.5) +a*a* (y1) * (Y1)-a*a*b*b; -      while(y>0){ Wu         if(d2<=0){ -d2+=b*b* (2*x+2) +a*a* (-2*y+3); Aboutx++,y--; $         } -         Else{ -d2+=a*a* (-2*y+3); -y--; A         } + Glbegin (gl_points); theGlvertex2i (offset+x,offset+y); -Glvertex2i (offset-x,offset-y); $Glvertex2i (offset-x,offset+y); theGlvertex2i (offset+x,offset-y); the glend (); the     } the } -  in voidDisplay () the { theGlclear (Gl_color_buffer_bit);//Empty the color stack About  theMidbresenhamellipse (A, b);//draw an ellipse with a radius of 8 the  theGlflush ();//emptying buffer Directives + } -  the intMainintargcChar**argv)Bayi { theGlutinit (&argc,argv); theGlutinitdisplaymode (glut_single| GLUT_RGB);//Initialize display mode -Glutinitwindowsize (Width,height);//Initialize window size -Glutinitwindowposition ( $, -);//where the initialization window appears theGlutcreatewindow ("midpoint Bresenham Draw Ellipse");//Initialize Window caption the  theGlutdisplayfunc (Display);//Registering display functions theInit ();//Other Initialization -Glutmainloop ();//Enter program Loop the  the     return 0; the}

freecode:www.cnblogs.com/yym2013

"Graphics" experiment Seven: Midpoint Bresenham algorithm Draw ellipse