OpenGL untuk membuat 2 garis berjajar.

Berikut ini adalah program OpenGL untuk membuat 2 garis berjajar.

Praktikum grafika 4.

/* 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  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 = 100;

GLint y0 = 100;

GLint xEnd = 200;

GLint yEnd = 200;

lineBres(x0,y0,xEnd, yEnd);

glPointSize(4.0);

glColor3f(0.0,0.1,0.0);

GLint x1 = 200;

GLint y1 = 200;

GLint x2 = 100;

GLint y2 = 100;

lineBres(x1,y1,x2, y2);

glPointSize(4.0);

glColor3f(1.0,0.0,1.0);

GLint x3 = 150;

GLint y3 = 150;

GLint x4 = 200;

GLint y4 = 200;

lineBres(x3, y3, x4, y4);

}

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(drawMyLine1);

//display everything and wait

glutMainLoop();

return 0;

}