/*
* Calibration algorithm:
*
* The equation we want to apply at event time where x' and y' are the
* calibrated co-ordinates.
*
* x' = Ax + By + C
* y' = Dx + Ey + F
*
* For example "zero calibration" would be A=1.0 B=0.0 C=0.0, D=0.0, E=1.0,
* and F=0.0.
*
* With 6 unknowns we need 6 equations to find the constants:
*
* x1' = Ax1 + By1 + C
* y1' = Dx1 + Ey1 + F
* ...
* x3' = Ax3 + By3 + C
* y3' = Dx3 + Ey3 + F
*
* In matrix form:
*
* x1' x1 y1 1 A
* x2' = x2 y2 1 x B
* x3' x3 y3 1 C
*
* So making the matrix M we can find the constants with:
*
* A x1'
* B = M^-1 x x2'
* C x3'
*
* (and similarly for D, E and F)
*
* For the calibration the desired values x, y are the same values at which
* we've drawn at.
*
*/
static void
finish_calibration (struct calibrator *calibrator)
{
struct weston_matrix m;
struct weston_matrix inverse;
struct weston_vector x_calib, y_calib;
int i;
/*
* x1 y1 1 0
* x2 y2 1 0
* x3 y3 1 0
* 0 0 0 1
*/
memset(&m, 0, sizeof(m));
for (i = 0; i < (int)ARRAY_LENGTH(test_ratios); i++) {
m.d[i] = calibrator->tests[i].clicked_x;
m.d[i + 4] = calibrator->tests[i].clicked_y;
m.d[i + 8] = 1;
}
m.d[15] = 1;
weston_matrix_invert(&inverse, &m);
memset(&x_calib, 0, sizeof(x_calib));
memset(&y_calib, 0, sizeof(y_calib));
for (i = 0; i < (int)ARRAY_LENGTH(test_ratios); i++) {
x_calib.f[i] = calibrator->tests[i].drawn_x;
y_calib.f[i] = calibrator->tests[i].drawn_y;
}
/* Multiples into the vector */
weston_matrix_transform(&inverse, &x_calib);
weston_matrix_transform(&inverse, &y_calib);
printf ("Calibration values: %f %f %f %f %f %f\n",
x_calib.f[0], x_calib.f[1], x_calib.f[2],
y_calib.f[0], y_calib.f[1], y_calib.f[2]);
exit(0);
}
test_loop_speed_matrixvector(void)
{
struct weston_matrix m;
struct weston_vector v = { { 0.5, 0.5, 0.5, 1.0 } };
unsigned long count = 0;
double t;
printf("\nRunning 3 s test on weston_matrix_transform()...\n");
weston_matrix_init(&m);
running = 1;
alarm(3);
reset_timer();
while (running) {
weston_matrix_transform(&m, &v);
count++;
}
t = read_timer();
printf("%lu iterations in %f seconds, avg. %.1f ns/iter.\n",
count, t, 1e9 * t / count);
}
