void readConfigFile ( char *fnme )
{
FILE *fptr = fopen ( fnme, "rt" ) ;
int i ;
char inputline [ 256 ] ;
if ( fptr )
{
/* Read a header line */
checkedFGets ( inputline, sizeof ( inputline ), fptr ) ;
/* Read a comment line */
checkedFGets ( inputline, sizeof ( inputline ), fptr ) ;
/* Read the window title */
checkedFGets ( inputline, sizeof ( inputline ), fptr ) ;
/* We assume here that this line will not exceed 79 characters plus a
newline (window_title is 80 characters long). That'll cause a buffer
overflow. For a simple program like this, though, we're letting it
slide!
*/
sscanf ( inputline, "%[a-zA-Z0-9!@#$%^&*()+=/\\_-\" ]", window_title ) ;
/* Read a comment line */
checkedFGets ( inputline, sizeof ( inputline ), fptr ) ;
/* Read the number of affine transformations */
checkedFGets ( inputline, sizeof ( inputline ), fptr ) ;
sscanf ( inputline, "%d", &num_trans ) ;
affine = (AffineTrans *)malloc ( num_trans * sizeof(AffineTrans) ) ;
/* Read a comment line */
checkedFGets ( inputline, sizeof ( inputline ), fptr ) ;
for ( i = 0; i < num_trans; i++ )
{
/* Read an affine transformation definition */
checkedFGets ( inputline, sizeof ( inputline ), fptr ) ;
sscanf ( inputline, "%lf %lf %lf %lf %lf %lf", &affine[i].a00, &affine[i].a01,
&affine[i].a10, &affine[i].a11, &affine[i].b0, &affine[i].b1 ) ;
}
}
else /* No data file, set a default */
{
printf ( "ERROR opening file <%s>\n", fnme ) ;
strcpy ( window_title, "Koch Snowflake" ) ;
num_trans = 4 ;
affine = (AffineTrans *)malloc ( num_trans * sizeof(AffineTrans) ) ;
affine[0].a00 = 1/3. ; affine[0].a01 = 0.00 ; affine[0].a10 = 0.00 ; affine[0].a11 = 1/3. ;
affine[0].b0 = 0.0 ; affine[0].b1 = 0.0 ;
affine[1].a00 = 1/6. ; affine[1].a01 = -1/3.*sin(FGH_PI/3.) ; affine[1].a10 = 1/3.*sin(FGH_PI/3.) ; affine[1].a11 = 1/6. ;
affine[1].b0 = 1/3. ; affine[1].b1 = 0.0 ;
affine[2].a00 = 1/6. ; affine[2].a01 = -1/3.*sin(-FGH_PI/3.) ; affine[2].a10 = 1/3.*sin(-FGH_PI/3.) ; affine[2].a11 = 1/6. ;
affine[2].b0 = 0.5 ; affine[2].b1 = sqrt(3)/6. ;
affine[3].a00 = 1/3. ; affine[3].a01 = 0.00 ; affine[3].a10 = 0.00 ; affine[3].a11 = 1/3. ;
affine[3].b0 = 2/3. ; affine[3].b1 = 0.0 ;
}
for ( i = 0; i < num_trans; i++ )
{
double m00, m01, m10, m11 ; /* Matrix "I" minus "A" */
double determ ; /* Determinant of this matrix */
/* Calculate the stationary point */
m00 = 1.0 - affine[i].a00 ;
m01 = - affine[i].a01 ;
m10 = - affine[i].a10 ;
m11 = 1.0 - affine[i].a11 ;
determ = m00 * m11 - m01 * m10 ;
if ( fabs ( determ ) > 1.e-6 )
{
affine[i].statx = ( m11 * affine[i].b0 - m01 * affine[i].b1 ) / determ ;
affine[i].staty = ( -m10 * affine[i].b0 + m00 * affine[i].b1 ) / determ ;
}
else
affine[i].statx = affine[i].staty = 0.0 ;
}
}
void key_cb ( unsigned char key, int x, int y )
{
int i ;
char inputline [ INPUT_LINE_LENGTH ] ;
switch ( key )
{
case 'r' : case 'R' : /* Reset the simulation */
/* Reset the Lorenz parameters */
sigma = s0 ;
b = b0 ;
r = r0 ;
/* Set an initial position */
red_position[0][0] = (double)rand() / (double)RAND_MAX ;
red_position[0][1] = (double)rand() / (double)RAND_MAX ;
red_position[0][2] = (double)rand() / (double)RAND_MAX ;
grn_position[0][0] = (double)rand() / (double)RAND_MAX ;
grn_position[0][1] = (double)rand() / (double)RAND_MAX ;
grn_position[0][2] = (double)rand() / (double)RAND_MAX ;
array_index = 0 ;
/* Initialize the arrays */
for ( i = 1; i < NUM_POINTS; i++ )
{
memcpy ( red_position[i], red_position[0], 3 * sizeof(double) ) ;
memcpy ( grn_position[i], grn_position[0], 3 * sizeof(double) ) ;
}
break ;
case 'm' : case 'M' : /* Modify the Lorenz parameters */
printf ( "Please enter new value for <sigma> (default %f, currently %f): ", s0, sigma ) ;
checkedFGets ( inputline, sizeof ( inputline ), stdin ) ;
sscanf ( inputline, "%lf", &sigma ) ;
printf ( "Please enter new value for <b> (default %f, currently %f): ", b0, b ) ;
checkedFGets ( inputline, sizeof ( inputline ), stdin ) ;
sscanf ( inputline, "%lf", &b ) ;
printf ( "Please enter new value for <r> (default %f, currently %f): ", r0, r ) ;
checkedFGets ( inputline, sizeof ( inputline ), stdin ) ;
sscanf ( inputline, "%lf", &r ) ;
break ;
case 's' : case 'S' : /* Stop the animation */
animate = 0 ;
break ;
case 'g' : case 'G' : /* Start the animation */
animate = 1 ;
break ;
case ' ' : /* Spacebar: Single step */
animate = 2 ;
break ;
case 27 : /* Escape key */
glutLeaveMainLoop () ;
break ;
}
}
