以DDA算法为例实现线宽函数及虚线

#include<iostream.h>#include<GL/glut.h>#include <math.h>#define ROUND(a) (int)(a + 0.5)void setPixel(GLint x, GLint y) // 画点函数{glBegin(GL_POINTS);glVertex2i(x, y);glEnd();}void setPixelWidth(int x,int y,int width,int flagWidth){if(flagWidth==0){switch(width){case 4: {setPixel( x, y-2);//break;}case 3:{setPixel( x, y+1);//break;}case 2:{setPixel(x,y-1);//break;}case 1:{setPixel(x,y);break;}}}if(flagWidth==1){switch(width){case 4: {setPixel(x-2,y);//break;}case 3: {setPixel(x+1,y);//break;}case 2: {setPixel(x-1,y);//break;}case 1:{setPixel(x,y); break;}}}}void lineDDA (int x0, int y0, int xEnd, int yEnd,int width) // DDA算法线宽函数{int dx = xEnd - x0, dy = yEnd - y0, steps, k, flagWidth;float xIncrement, yIncrement, x = x0, y = y0;if (fabs (dx) > fabs (dy)){steps = fabs (dx);flagWidth = 0;}else{steps = fabs (dy);flagWidth = 1;}xIncrement = float (dx) / float (steps);yIncrement = float (dy) / float (steps);setPixelWidth (ROUND (x), ROUND (y),width, flagWidth);for (k = 0; k < steps; k++){x += xIncrement;y += yIncrement;if(k%2==0)//要画虚线需加这条判断语句setPixelWidth(ROUND (x), ROUND (y),width, flagWidth);}}void init (void) {glClearColor (1.0, 1.0, 1.0, 0.0);glMatrixMode (GL_PROJECTION);glLoadIdentity ();gluOrtho2D (0.0, 200.0, 0.0, 150.0);}void lineDDA (void) {glClear (GL_COLOR_BUFFER_BIT);glColor3f (1.0, 0.0, 0.0);lineDDA (10, 140, 160, 15,1);//这里设置线宽可增加线宽度glFlush ( );}void main(int argc,char **argv){glutInit(&argc,argv);glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);glutInitWindowPosition(50,100);glutInitWindowSize(400,300);glutCreateWindow("An Example OpenGL Program");init();glutDisplayFunc(lineDDA);glutMainLoop();}