praktikum grafika 4 Membuat objek garis dengan DDA dan Bresenham

/* Praktikum 04
* Membuat objek garis dengan DDA dan Bresenham
*/

#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <glut.h>
#include <math.h>

void display(void)
{
//set display-window background color to white
glClearColor(1.0,1.0,1.0,0.0);
//set projection parameters
glMatrixMode(GL_PROJECTION);
gluOrtho2D(0.0, 300.0, 0.0, 300.0);
}
void setPixel(GLint xCoordinate, GLint yCoordinate)
{
glBegin(GL_POINTS);
glVertex2i(xCoordinate, yCoordinate);
glEnd();
glFlush();
}
//Procedure Bresenham line-drawing untuk |m| < 1.0
void lineBres(GLint x0, GLint y0, GLint xEnd, GLint yEnd)
{
GLint dx = (float)fabs((float) xEnd - x0);
GLint dy = (float)fabs((float) yEnd - y0);
GLint p = 2 * dy - dx;
GLint twoDy = 2 * dy;
GLint twoDyMinusDx = 2 * (dy - dx);
GLint x,y;
//determine which endpoint to use as start position
if (x0 > xEnd){
x = xEnd;
y = yEnd;
xEnd = x;
} else {
  x = x0;
  y = y0;
  }
  setPixel(x,y);
  while (x<xEnd){
  x++;
  if (p<0)
  p += twoDy;
  else {
  y++;
  p += twoDyMinusDx;
  }
  setPixel(x,y);
  }
  }
void drawMyLine1(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1.0,0.0,0.0);
glPointSize(4.0);
GLint x0 = 10;
GLint y0 = 10;
GLint xEnd = 50;
GLint yEnd = 50;
lineBres(x0,y0,xEnd, yEnd);
}
void drawMyLine(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glColor3f(1.0,0.0,0.0);
glPointSize(4.0);
GLint x0 = 50;
GLint y0 = 50;
GLint xEnd = 10;
GLint yEnd = 0;
lineBres(x0,y0,xEnd, yEnd);
}
int main(int argc, char** argv)
{
//initialize GLUT
glutInit(&argc, argv);
//initialize display mode
glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
//set display-window width & height
glutInitWindowSize(400,400);
//set display-window upper-left position
glutInitWindowPosition(0,0);
//create display-window with a title
glutCreateWindow("Digital Differential Analiyzer Algorithm");
//initialize OpenGL
display();
//call graphics to be diplayes on the window
glutDisplayFunc(drawMyLine);
glutDisplayFunc(drawMyLine1);
//display everything and wait
glutMainLoop();
return 0;
}