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bresehams.cpp
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bresehams.cpp
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#include<stdio.h>
#include<math.h>
#include<GL/glut.h>
void setPixel(int x, int y)
{
glColor3f(1, 0, 0);
glBegin(GL_POINTS);
glVertex2f(x, y);
glEnd();
}
void myinit()
{
glMatrixMode(GL_PROJECTION_MATRIX);
glLoadIdentity();
gluOrtho2D(-500, 500, -500, 500);
glMatrixMode(GL_MODELVIEW);
}
void breshnans(int x0, int y0, int xend, int yend)
{
int dx = abs(xend - x0);
int dy = abs(yend - y0);
int p = 2 * dy - dx;
int twody = 2 * dy, twoDyminusdx = 2 * (dy - dx);
int twodx = 2 * dx, twoDxminusdy = 2 * (dx - dy);
int x, y;
if (x0 > xend)
{
x = xend;
y = yend;
xend = x0;
yend = y0;
}
else
{
x = x0;
y = y0;
}
//glColor3f(1, 0, 0);
setPixel(x, y);
if (dx > dy)
{
while (x < xend)
{
x++;
if (p < 0)
{
p += twody;
}
else
{
y++;
p += twoDyminusdx;
}
setPixel(x, y);
}
}
else
{
p = 2 * dx - dy;
while (y < yend)
{
y++;
if (p < 0)
{
p += twodx;
}
else
{
x++;
p += twoDxminusdy;
}
setPixel(x, y);
}
}
}
void display()
{
glClearColor(1, 1, 1, 1);
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1, 0, 0);
breshnans(-200, -200, 200, 200);
glFlush();
}
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
glutInitWindowPosition(500, 500);
glutInitWindowSize(500, 500);
glutCreateWindow("Breshnans");
myinit();
glutDisplayFunc(display);
glutMainLoop();
}