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#include <string.h>
#include <stdio.h>
#include <GL/glut.h>
#include <GL/gl.h>
/* Windows parameters */
#define WIDTH 600
#define HEIGHT 600
#define TITLE "GLUT Demo: Using Subwindows"
int winIdMain;
/* Animation State Vriables */
#define SMALL_ANGLE 5.0
#define TIME_STEP 0.1
static double time = 0.0;
static double spin = 0.0;
/* This function renders a character string onto the current position */
static char label[100];
void
drawString (char *s)
{
unsigned int i;
for (i = 0; i < strlen (s); i++)
glutBitmapCharacter (GLUT_BITMAP_HELVETICA_10, s[i]);
};
void
drawStringBig (char *s)
{
unsigned int i;
for (i = 0; i < strlen (s); i++)
glutBitmapCharacter (GLUT_BITMAP_HELVETICA_18, s[i]);
};
/* Here is a display fucntion that updates the main graphic window */
void
mainDisplay (void)
{
/* Clean drawing board */
glutSetWindow (winIdMain);
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity ();
/* Write Footnote */
glColor3f (1.0F, 1.0F, 1.0F);
sprintf (label, "(c) Miguel Angel Sepulveda 1998");
glRasterPos2f (-0.80F, -0.80F);
drawString (label);
/* Draw rotating triangle */
glPushMatrix ();
glRotatef (spin, 0.0, 0.0, 1.0);
glBegin (GL_POLYGON);
glColor3f (1.0F, 0.0F, 0.0F);
glVertex2f (0.0F, 0.5F);
glColor3f (0.0F, 1.0F, 0.0F);
glVertex2f (-0.4330F, -0.25F);
glColor3f (0.0F, 0.0F, 1.0F);
glVertex2f (0.433F, -0.25F);
glEnd ();
glPopMatrix ();
glutSwapBuffers ();
};
/* Callback function for reshaping the main window */
void
mainReshape (int w, int h)
{
glViewport (0, 0, 640, 480); /* Force to 3Dfx resolution 640x480 */
glMatrixMode (GL_PROJECTION);
glLoadIdentity ();
gluOrtho2D (-1.0F, 1.0F, -1.0F, 1.0F);
glMatrixMode (GL_MODELVIEW);
glLoadIdentity ();
};
/* Now comes a function that processes keyboard events */
void
keyboard (unsigned char key, int x, int y)
{
switch (key)
{
case 'q':
case 'Q':
exit (0);
break;
};
};
/* There can be only one idle() callback function. In an
animation, this idle() function must update not only the
main window but also all derived subwindows */
void
idle (void)
{
/* Update state variables */
spin += SMALL_ANGLE;
time += TIME_STEP;
/* Update main and sub window */
glutSetWindow (winIdMain);
glutPostRedisplay ();
};
int
main (int argc, char **argv)
{
/* Glut initializations */
glutInit (&argc, argv);
glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);
glutInitWindowPosition (5, 5);
glutInitWindowSize (WIDTH, HEIGHT);
/* Main window creation and setup */
winIdMain = glutCreateWindow (TITLE);
glutFullScreen (); /* Force window to fullscreen so it cant lose focus */
glutDisplayFunc (mainDisplay);
glutReshapeFunc (mainReshape);
glutKeyboardFunc (keyboard);
glutIdleFunc (idle);
glutMainLoop ();
return 0;
};
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