ÈÓã Çááå ÇáÑÍãä ÇáÑÍíã
ÇáÓáÇã Úáíßã æ ÑÍãÉ Çááå.

Ýí åÐÇ ÇáãæÖæÚ ÓäÓÊÎÏã freeglut ßãÇ ÊÍÏËäÇ Ýí ÇáãæÖæÚ ÇáÓÇÈÞ, æ ÇáÃÝÖá ÞÑÇÁÉ ÇáãæÇÖíÚ ÇáÓÇÈÞÉ ÞÈá ÞÑÇÁÉ åÐÇ ÇáãæÖæÚ.
ÇáÑÓã Úáì ÇáÔÇÔÉ æ opengl
ÍÌÑ ÇáÃÓÇÓ Ýí ÈÑãÌÉ ÇáÃáÚÇÈ: ÇáÜ Game Loop
freeglut

ãÇ ÇÑíÏ ÇáÊÍÏË Úäå Çáíæã åæ ÊÍÑíß ÇáßÇÆäÇÊ Ýí ÇááÚÈÉ ..
áäÍáá ÇáãÓÃáÉ ÞÈá ÇáÔÑæÚ Ýí ÇáÚãá:
æ áäÃÎÐ ÃÈÓØ ÍÇáÉ: áÏíäÇ ßÇÆä æÇÍÏ, äÑÓãå Úáì Ôßá ãÑÈÚ, æ äÖÚå Ýí ÈÏÇíÉ ÇááÚÈÉ Ýí ãßÇä ãÇ Úáì ÇáÔÇÔÉ.
(åäÇ Ãäæå Çäß áÇ ÈÏ Çä Êßæä ÝÇåãÇ ÌíÏÇ áãÓÃáÉ Çä ÇáÔÇÔÉ åí ÚÈÇÑÉ Úä ÓØÍ ËäÇÆí ÇáÃÈÚÇÏ, ãßæä ãä ãÌãæÚÉ ßÈíÑÉ ãä ÇáäÞÇØ ÇáãÊÑÇÕÉ, æ áäÑÓã ÔíÆÇ Úáì ÇáÔÇÔÉ ÚáíäÇ Çä äÍÏÏ ãæÞÚå.)
ÇáÓÄÇá åæ, ßíÝ äÍÑß åÐÇ ÇáßÇÆä¿
ÍÓäÇ, áäÝÑÖ ÇääÇ ßÈÏÇíÉ, ÑÓãäÇ ÇáßÇÆä åÐÇ Ýí ãæÞÚ x,y = 100,80
æ äÑíÏ ÊÍÑíßå Çáì Çáíãíä, ßíÝ¿
áÇ ÈÏ Çä äÚÑÝ ÃæáÇ ÇáÜ coordinate system ÇáãÓÊÎÏã Ýí äÙÇã ÇáÑÓã .. Ýí ÇáÜ opengl ÚÇÏÉ Êßæä äÞØÉ ÇáÕÝÑ åí ÇáäÞØÉ ÇáÓÝáíÉ ÇáíÓÑì .. ÈäÇÁÇ Úáì Ðáß, ßáãÇ ÇÒÏÇÏÊ ÞíãÉ x ÓäÊÍÑß ÈÇÊÌÇå Çáíãíä, æ ßáãÇ äÞÕÊ ÞíãÉ x ÓäÊÍÑß ÈÇÊÌÇå ÇáíÓÇÑ.
æ ÈäÝÓ ÇáãäØÞ, ßáãÇ ÒÇÏÊ ÞíãÉ ÇáÜ y ÊÍÑßäÇ Çáì ÇáÃÚáì, æ ßáãÇ äÞÕÊ ÞíãÉ ÇáÜ y ÊÍÑßäÇ Çáì ÇáÃÓÝá.

ÅÐÇ, áæ ÇÑÏäÇ ÊÍÑíß åÐÇ ÇáßÇÆä ÎØæÉ æÇÍÏÉ Çáì Çáíãíä, íÌÈ Çä äãÓÍå ãä ãæÞÚå ÇáÞÏíã æ äÑÓãå Ýí ÇáãæÞÚ ÇáÌÏíÏ æ åæ x,y = 101,80
ÞÏ íßæä åÐÇ ÇáãÞÏÇÑ ÖÆíáÇ ÌÏÇ ÈÍíË Çä ÇáãÓÊÎÏã ÞÏ áÇ íáÇÍÙ ÝÑÞ .. áÐáß íãßä ÒíÇÏÉ ÇáÇÒÇÍÉ ÍÓÈ ÇáÑÛÈÉ.

ãä ÃÌá Çä äÞæã ÈÐáß Ýí ÇáÈÑäÇãÌ, íÌÈ ÚáíäÇ Çä "äÊÐßÑ" ÇáãæÞÚ ÇáÍÇáí ááßÇÆä, ÈÍíË ßáãÇ äÍÑßå äãÓÍå ãä ãæÞÚå ÇáÞÏíã, äÛíÑ Þíã x,y ÍÓÈ ÇáãØáæÈ, Ëã äÑÓãå ãä ÌÏíÏ Úáì ÇáãæÞÚ x,y ÈÚÏ Çä ÊÛíÑ áíÚßÓ ÇáãæÞÚ ÇáÌÏíÏ ÇáãÝÊÑÖ ááßÇÆä.

ÚãáíÉ ÇáãÍæ ãä ÇáãæÞÚ ÇáÞÏíã íãßä ÚãáåÇ Ýí opengl Úä ØÑíÞ ãÍæ ÇáÔÇÔÉ ÈßÇãáåÇ! ÈÇÓÊÎÏÇã glClear
ãÓÃáÉ ÇÎÐ input ãä ÇáÜ keyboard Ýí glut ãÚÞÏÉ ÔæíÉ .. áÇÒã äÓÌá callback function ááÜ event ÇááÐí íÍÏË Úä ÖÛØ ÒÑ Úáì ÇáßíÈæÑÏ .. áÇÍÙæÇ ÇáßæÏ.

ãÓÃáÉ ÑÓã ãÑÈÚ, ãÓÃáÉ ÈÓíØÉ äÓÈíÇ .. íãßä ÑÓã ãÑÈÚ Úä ØÑíÞ ÇáÈÏÁ ÈÜ glBegin æ äãÑÑ áåÇ GL_POLYGON Ëã äÍÏÏ äÞÇØ ÇáãÑÈÚ Ëã äÓÊÏÚí glEnd, ÇáäÞØÉ ÇáæÍíÏÉ ÇááÊí íÌÈ ÇáÇäÊÈÇå áåÇ åí ÊÑÊíÈ ÇáäÞÇØ .. áÇÒã äÑÓáåÇ ÈÊÑÊíÈ ãÚíä æ ÇáÇ íÊÎÑÈØ ÇáÔßá. (áæ ãÔ æÇÖÍÉ åÇáäÞØÉ ããßä äæÖÍåÇ ÃßËÑ Åä ÔÇÁ Çááå ÍÓÈ ÑÛÈÊßã).

ÇáåÏÝ åæ ÊæÕíá ÇáÝßÑÉ ÇáÃÓÇÓíÉ, åÐÇ ÇáãËÇá ÈÓíØ ÌÏÇ, ØÈÚÇ åäÇß ÊÝÇÕíá ÇÎÑì ÞÏ íäÈÛì ÇáÚäÇíÉ ÈåÇ Ýí ÇáÇáÚÇÈ ÇáÍÞíÞÉ .. æ áßä ÇáåÏÝ åæ ÊæÕíá ÇáÝßÑÉ ÇáÃÓÇÓíÉ áÊßæíä ãÝåæã ÌíÏ Úä ÇáãæÖæÚ Ýí ÇááÇæÚí

åÐÇ ÊØÈíÞ ãÚ ÈÚÖ ÇáÊÚáíÞÇÊ ÇáÈÓíØÉ.

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

int x, y; //global variables for the location of the object
void drawBox( int x, int y ); //a function to draw a small box at a certain location
void handleInput( int key, int mx, int my ); //our keyboard event handler
void init();

int main(int argc, char** argv)
{
   glutInit(&argc,argv);
   glutInitDisplayMode(GLUT_SINGLE |GLUT_RGB);
   glutInitWindowSize(400,400);
   glutInitWindowPosition(50,50);
   glutCreateWindow("Moving Box");
   glutSpecialFunc( handleInput ); //register our keyboard handler for special keys (arrows are special keys)
   init(); //initialize
   glutMainLoop(); //enter the glut main loop .. 
   return 0;
}

void drawBox( int x, int y )
{
    int x1 = x + 20;
    int y1 = y + 20;

    glBegin(GL_POLYGON);
        //note the order of sending the points, it's important
        glVertex2d( x, y );
        glVertex2d( x, y1 );
        glVertex2d( x1, y1 );
        glVertex2d( x1, y );
    glEnd();
}

void handleInput( int key, int mx, int my )
{
    //if key is an arrow key, adjust the global x,y accordingly
    switch( key )
    {
    case GLUT_KEY_LEFT:
        {
            x -= 5;
        }
        break;
    case GLUT_KEY_RIGHT:
        {
            x += 5;
        }
        break;
    case GLUT_KEY_UP:
        {
            y += 5;
        }
        break;
    case GLUT_KEY_DOWN:
        {
            y -= 5;
        }
        break;
    default:
        return; //if it's not an arrow key, we can quit the function
    }

    //clear the screen and draw the box in it's new position
    glClear(GL_COLOR_BUFFER_BIT);
    drawBox( x, y );
    glFlush();
}

//Typical initialization function .. not how ever that we initlize the object too.
void init()
{
   glClearColor(0.3f,0.3f,0.3f,0.0f);
   glColor3f(1.0,1.0,0.5);
   glPointSize(2.0);
   glMatrixMode(GL_PROJECTION);
   gluOrtho2D(0.0,768.0,0.0,1024.0);
   
   //initialize and draw the object in its initial location
   x = y = 30;
   glClear(GL_COLOR_BUFFER_BIT);   
   drawBox( x, y );
   glFlush();
}