util: add a couple of 3x3 matrix helper functions

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
This commit is contained in:
Peter Hutterer 2014-08-26 09:37:29 +10:00
parent 24c03646a9
commit 748d094c9c
2 changed files with 178 additions and 0 deletions

View file

@ -25,6 +25,7 @@
#include <unistd.h>
#include <math.h>
#include <string.h>
#include "libinput.h"
@ -179,4 +180,103 @@ long_set_bit_state(unsigned long *array, int bit, int state)
long_clear_bit(array, bit);
}
struct matrix {
float val[3][3]; /* [row][col] */
};
static inline void
matrix_init_identity(struct matrix *m)
{
memset(m, 0, sizeof(*m));
m->val[0][0] = 1;
m->val[1][1] = 1;
m->val[2][2] = 1;
}
static inline void
matrix_from_farray6(struct matrix *m, const float values[6])
{
matrix_init_identity(m);
m->val[0][0] = values[0];
m->val[0][1] = values[1];
m->val[0][2] = values[2];
m->val[1][0] = values[3];
m->val[1][1] = values[4];
m->val[1][2] = values[5];
}
static inline void
matrix_init_scale(struct matrix *m, float sx, float sy)
{
matrix_init_identity(m);
m->val[0][0] = sx;
m->val[1][1] = sy;
}
static inline void
matrix_init_translate(struct matrix *m, float x, float y)
{
matrix_init_identity(m);
m->val[0][2] = x;
m->val[1][2] = y;
}
static inline int
matrix_is_identity(struct matrix *m)
{
return (m->val[0][0] == 1 &&
m->val[0][1] == 0 &&
m->val[0][2] == 0 &&
m->val[1][0] == 0 &&
m->val[1][1] == 1 &&
m->val[1][2] == 0 &&
m->val[2][0] == 0 &&
m->val[2][1] == 0 &&
m->val[2][2] == 1);
}
static inline void
matrix_mult(struct matrix *dest,
const struct matrix *m1,
const struct matrix *m2)
{
struct matrix m; /* allow for dest == m1 or dest == m2 */
int row, col, i;
for (row = 0; row < 3; row++) {
for (col = 0; col < 3; col++) {
double v = 0;
for (i = 0; i < 3; i++) {
v += m1->val[row][i] * m2->val[i][col];
}
m.val[row][col] = v;
}
}
memcpy(dest, &m, sizeof(m));
}
static inline void
matrix_mult_vec(struct matrix *m, int *x, int *y)
{
int tx, ty;
tx = *x * m->val[0][0] + *y * m->val[0][1] + m->val[0][2];
ty = *x * m->val[1][0] + *y * m->val[1][1] + m->val[1][2];
*x = tx;
*y = ty;
}
static inline void
matrix_to_farray6(const struct matrix *m, float out[6])
{
out[0] = m->val[0][0];
out[1] = m->val[0][1];
out[2] = m->val[0][2];
out[3] = m->val[1][0];
out[4] = m->val[1][1];
out[5] = m->val[1][2];
}
#endif /* LIBINPUT_UTIL_H */

View file

@ -431,6 +431,83 @@ START_TEST(config_status_string)
}
END_TEST
START_TEST(matrix_helpers)
{
struct matrix m1, m2, m3;
float f[6] = { 1, 2, 3, 4, 5, 6 };
int x, y;
int row, col;
matrix_init_identity(&m1);
for (row = 0; row < 3; row++) {
for (col = 0; col < 3; col++) {
ck_assert_int_eq(m1.val[row][col],
(row == col) ? 1 : 0);
}
}
ck_assert(matrix_is_identity(&m1));
matrix_from_farray6(&m2, f);
ck_assert_int_eq(m2.val[0][0], 1);
ck_assert_int_eq(m2.val[0][1], 2);
ck_assert_int_eq(m2.val[0][2], 3);
ck_assert_int_eq(m2.val[1][0], 4);
ck_assert_int_eq(m2.val[1][1], 5);
ck_assert_int_eq(m2.val[1][2], 6);
ck_assert_int_eq(m2.val[2][0], 0);
ck_assert_int_eq(m2.val[2][1], 0);
ck_assert_int_eq(m2.val[2][2], 1);
x = 100;
y = 5;
matrix_mult_vec(&m1, &x, &y);
ck_assert_int_eq(x, 100);
ck_assert_int_eq(y, 5);
matrix_mult(&m3, &m1, &m1);
ck_assert(matrix_is_identity(&m3));
matrix_init_scale(&m2, 2, 4);
ck_assert_int_eq(m2.val[0][0], 2);
ck_assert_int_eq(m2.val[0][1], 0);
ck_assert_int_eq(m2.val[0][2], 0);
ck_assert_int_eq(m2.val[1][0], 0);
ck_assert_int_eq(m2.val[1][1], 4);
ck_assert_int_eq(m2.val[1][2], 0);
ck_assert_int_eq(m2.val[2][0], 0);
ck_assert_int_eq(m2.val[2][1], 0);
ck_assert_int_eq(m2.val[2][2], 1);
matrix_mult_vec(&m2, &x, &y);
ck_assert_int_eq(x, 200);
ck_assert_int_eq(y, 20);
matrix_init_translate(&m2, 10, 100);
ck_assert_int_eq(m2.val[0][0], 1);
ck_assert_int_eq(m2.val[0][1], 0);
ck_assert_int_eq(m2.val[0][2], 10);
ck_assert_int_eq(m2.val[1][0], 0);
ck_assert_int_eq(m2.val[1][1], 1);
ck_assert_int_eq(m2.val[1][2], 100);
ck_assert_int_eq(m2.val[2][0], 0);
ck_assert_int_eq(m2.val[2][1], 0);
ck_assert_int_eq(m2.val[2][2], 1);
matrix_mult_vec(&m2, &x, &y);
ck_assert_int_eq(x, 210);
ck_assert_int_eq(y, 120);
matrix_to_farray6(&m2, f);
ck_assert_int_eq(f[0], 1);
ck_assert_int_eq(f[1], 0);
ck_assert_int_eq(f[2], 10);
ck_assert_int_eq(f[3], 0);
ck_assert_int_eq(f[4], 1);
ck_assert_int_eq(f[5], 100);
}
END_TEST
int main (int argc, char **argv) {
litest_add_no_device("events:conversion", event_conversion_device_notify);
litest_add_no_device("events:conversion", event_conversion_pointer);
@ -441,5 +518,6 @@ int main (int argc, char **argv) {
litest_add("device:id", device_ids, LITEST_ANY, LITEST_ANY);
litest_add_no_device("config:status string", config_status_string);
litest_add_no_device("misc:matrix", matrix_helpers);
return litest_run(argc, argv);
}