I'm new to OpenGL and trying to run some classic sample code from Edward Angel's famous book Interactive Computer Graphics. However, I've encountered a problem which puzzles me a lot but is probably very obvious to many others. The sample code is "Gasket.c" which can be downloaded from http://www.cs.unm.edu/~angel/BOOK/INTERACTIVE_COMPUTER_GRAPHICS/FIFTH_EDITION/PROGRAMS/CHAPTER02/
I've run this code with VS2010 Express on my Lenovo X60 (windows 7) and it has successfully drawn Sierspinski Gasket. However, it did not draw anything and only showed a blank (white) window when I was trying to run the same code on my desktop (Intel HD Graphics card) with same software systems. The file was complied/built with no problems and there were no errors/warnings.
Gasket.c is as follows
/* Two-Dimensional Sierpinski Gasket */
/* Generated Using Randomly Selected Vertices */
/* And Bisection */
#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
void myinit()
{
/* attributes */
glClearColor(1.0, 1.0, 1.0, 1.0); /* white background */
glColor3f(1.0, 0.0, 0.0); /* draw in red */
/* set up viewing */
/* 500 x 500 window with origin lower left */
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0.0, 50.0, 0.0, 50.0);
glMatrixMode(GL_MODELVIEW);
}
void display( void )
{
GLfloat vertices[3][2]={{0.0,0.0},{25.0,50.0},{50.0,0.0}}; /* A triangle */
int j, k;
int rand(); /* standard random number generator */
GLfloat p[2] ={7.5,5.0}; /* An arbitrary initial point inside traingle */
glClear(GL_COLOR_BUFFER_BIT); /*clear the window */
/* compute and plots 5000 new points */
glBegin(GL_POINTS);
for( k=0; k<5000; k++)
{
j=rand()%3; /* pick a vertex at random */
/* Compute point halfway between selected vertex and old point */
p[0] = (p[0]+vertices[j][0])/2.0;
p[1] = (p[1]+vertices[j][1])/2.0;
/* plot new point */
glVertex2fv(p);
}
glEnd();
glFlush(); /* clear buffers */
}
void main(int argc, char** argv)
{
/* Standard GLUT initialization */
glutInit(&argc,argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); /* default, not needed */
glutInitWindowSize(500,500); /* 500 x 500 pixel window */
glutInitWindowPosition(0,0); /* place window top left on display */
glutCreateWindow("Sierpinski Gasket"); /* window title */
glutDisplayFunc(display); /* display callback invoked when window opened */
myinit(); /* set attributes */
glutMainLoop(); /* enter event loop */
}