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Circle_Bresenham.cpp
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Circle_Bresenham.cpp
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#include <GL/glut.h>
void initGL()
{
glClearColor(1.0f, 1.0f, 1.0f, 1.0f); //R=0,G=0,B=0, anpha=1
glOrtho(-320,320,-240,240,-1,1);
}
void draw8point(int xc, int yc, int x, int y)
{
glBegin(GL_POINTS);
glVertex2i(xc + x, yc + y);
glVertex2i(xc + y, yc + x);
glVertex2i(xc + y, yc - x);
glVertex2i(xc + x, yc - y);
glVertex2i(xc - x, yc - y);
glVertex2i(xc - y, yc - x);
glVertex2i(xc - y, yc + x);
glVertex2i(xc - x, yc + y);
glEnd();
}
void CircleBres(int xc,int yc,int R )
{
int p ;
int y = R ;
int x = 0;
p = 3 - 2*R;
draw8point(xc,yc,x,y);
while (x < y)
{
if (p <0)
p +=4*x+6;
else
{
p += 4*(x-y)+10;
y--;
}
x++;
draw8point(xc,yc,x,y);
}
}
void mydisplay()
{
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1.0, 0.0, 0.0);
CircleBres(0, 0, 200); //Tâm C(0,0) bán kính 200
glViewport(0,0,640,480);
glFlush();
}
int main(int argc, char** argv){
int mode=GLUT_SINGLE | GLUT_RGB;
glutInitDisplayMode(mode);
glutInitWindowSize(640, 480);
glutInitWindowPosition(200, 0);
glutCreateWindow("DEMO THUAT TOAN VE PARABOL");
initGL();
glutDisplayFunc(mydisplay);
glutMainLoop();
}