openGL画直线、圆、椭圆(4)

} glBegin(GL_POINTS); glVertex3f(x,y,0); for(int k=1;k<=steps;k++) { x+=delta_x; y+=delta_y; glBegin(GL_POINTS); glVertex3f(x,y,0); glEnd(); }

/* the display callback: */

void display1() //画圆

{

glClear(GL_COLOR_BUFFER_BIT); /*clear the window */

/*----------------------------------------*/

/* viewport stuff */

/*----------------------------------------*/

/* set up a viewport in the screen window */ /* args to glViewport are left, bottom, width, height */ glViewport(0, 0, 500, 500); /* NB: default viewport has same coords as in myinit, */

/* so this could be omitted: */

dda_line(20,20,420,350);

/* and flush that buffer to the screen */

glFlush();

}

void display2() //画圆

{

glClear(GL_COLOR_BUFFER_BIT); /*clear the window */

/*----------------------------------------*/

/* viewport stuff */

/*----------------------------------------*/

/* set up a viewport in the screen window */

/* args to glViewport are left, bottom, width, height */

glViewport(0, 0, 500, 500);

/* NB: default viewport has same coords as in myinit, */