عندي إشكاليه في رسم الدائره في open GL

أنت تستخدم Midpoint Circle Algorithm

لقد عدلت في الكود و ستعرف أخطائك من قرائته:

#include <windows.h>
#include <GL/gl.h>
#include <GL/glut.h>

class ScreenPoint{
private:
	GLint x,y;

public:
	ScreenPoint() {
		x = y = 0;
	}

	void setCoords(GLint xCoordValue, GLint yCoordValue){
		x = xCoordValue;
		y = yCoordValue;
	}

	GLint getX() const {
		return x;
	}

	GLint getY() const {
		return y;
	}

	void incrementx() {
		x++;
	}

	void decrementy() {
		y--;
	}
};


void setPixel(GLint xCoord , GLint yCoord){
	glBegin(GL_POINTS);
		glVertex2i(xCoord ,yCoord);
	glEnd ();
}

/************************************************************/

void circelPlotPoints(GLint xc,GLint yc,ScreenPoint circpt){
	setPixel(xc + circpt.getX() , yc + circpt.getY());
	setPixel(xc - circpt.getX() , yc + circpt.getY());
	setPixel(xc + circpt.getX() , yc - circpt.getY());
	setPixel(xc - circpt.getX() , yc - circpt.getY());
	setPixel(xc + circpt.getY() , yc + circpt.getX());
	setPixel(xc - circpt.getY() , yc + circpt.getX());
	setPixel(xc - circpt.getY() , yc - circpt.getX());
	setPixel(xc + circpt.getY() , yc - circpt.getX());
}

/***************************************/

void circleMidpoint (GLint xc, GLint yc,GLint radius ){
	ScreenPoint circpt;

	GLint p = 1 - radius;

	circpt.setCoords(0,radius);

	while (circpt.getX() < circpt.getY()){
		circelPlotPoints(xc,yc,circpt);
		if (p <0)
			p +=2 * circpt.getX() +3;
		else {
			p += 2 *(circpt.getX() - circpt.getY())+5;
			circpt.decrementy();
		}
		circpt.incrementx();
	}
}
void myInit(void)
{
	glClearColor(1.0,1.0,1.0,0.0);	   // set white background color
	glColor3f(0.0f, 0.0f, 0.0f);		  // set the drawing color 
	glPointSize(4.0);			   // a ‘dot’ is 4 by 4 pixels
	glMatrixMode(GL_PROJECTION); 
	glLoadIdentity();
	gluOrtho2D(0.0, 640.0, 0.0, 480.0);
}
//<<<<<<<<<<<<<<<<<<<<<<<< myDisplay >>>>>>>>>>>>>>>>>
void myDisplay(void)
{
	glClear(GL_COLOR_BUFFER_BIT);	 // clear the screen 
	glBegin(GL_POINTS);
	circleMidpoint(320,240,100);
	glFlush();						 // send all output to display 
}

void main(int argc, char** argv){
	glutInit(&argc, argv);		  // initialize the toolkit
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // set display mode
	glutInitWindowSize(640,480);	 // set window size
	glutInitWindowPosition(100, 150); // set window position on screen
	glutCreateWindow("my first attempt"); // open the screen window
	glutDisplayFunc(myDisplay);	 // register redraw function
	myInit(); 
	glutMainLoop(); 		
}