compositor: simplify the matrix inversion API

The compositor will likely do an order of magnitude less matrix
inversions than point transformations with an inverse, hence we do not
really need the optimised path for single-shot invert-and-transform.

Expose only the computing of the explicit inverse matrix in the API.

However, the matrix inversion tests need access to the internal
functions. Designate a unit test build by #defining UNIT_TEST, and
export the internal functions in that case.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
dev
Pekka Paalanen 13 years ago
parent 1ef94c8742
commit d1f0ab6343
  1. 2
      src/compositor.c
  2. 2
      src/compositor.h
  3. 61
      src/matrix.c
  4. 21
      src/matrix.h
  5. 2
      tests/Makefile.am
  6. 60
      tests/matrix-test.c

@ -545,7 +545,7 @@ static void
weston_surface_update_transform(struct weston_surface *surface)
{
struct weston_matrix *matrix = &surface->transform.matrix;
struct weston_inverse_matrix *inverse = &surface->transform.inverse;
struct weston_matrix *inverse = &surface->transform.inverse;
struct weston_transform *tform;
if (!surface->transform.dirty)

@ -230,7 +230,7 @@ struct weston_surface {
/* derived state, set up by weston_surface_update_transform */
struct weston_matrix matrix;
struct weston_inverse_matrix inverse;
struct weston_matrix inverse;
int enabled;
} transform;

@ -29,6 +29,7 @@
#include "matrix.h"
/*
* Matrices are stored in column-major order, that is the array indices are:
* 0 4 8 12
@ -116,6 +117,16 @@ swap_rows(double *a, double *b)
}
}
static inline void
swap_unsigned(unsigned *a, unsigned *b)
{
unsigned tmp;
tmp = *a;
*a = *b;
*b = tmp;
}
static inline unsigned
find_pivot(double *column, unsigned k)
{
@ -133,16 +144,15 @@ find_pivot(double *column, unsigned k)
* LU decomposition, forward and back substitution: Chapter 3.
*/
WL_EXPORT int
weston_matrix_invert(struct weston_inverse_matrix *inverse,
const struct weston_matrix *matrix)
MATRIX_TEST_EXPORT inline int
matrix_invert(double *A, unsigned *p, const struct weston_matrix *matrix)
{
double A[16];
unsigned p[4] = { 0, 1, 2, 3 };
unsigned i, j, k;
unsigned pivot;
double pv;
for (i = 0; i < 4; ++i)
p[i] = i;
for (i = 16; i--; )
A[i] = matrix->d[i];
@ -150,9 +160,7 @@ weston_matrix_invert(struct weston_inverse_matrix *inverse,
for (k = 0; k < 4; ++k) {
pivot = find_pivot(&A[k * 4], k);
if (pivot != k) {
unsigned tmp = p[k];
p[k] = p[pivot];
p[pivot] = tmp;
swap_unsigned(&p[k], &p[pivot]);
swap_rows(&A[k], &A[pivot]);
}
@ -168,30 +176,25 @@ weston_matrix_invert(struct weston_inverse_matrix *inverse,
}
}
memcpy(inverse->LU, A, sizeof(A));
memcpy(inverse->p, p, sizeof(p));
return 0;
}
WL_EXPORT void
weston_matrix_inverse_transform(struct weston_inverse_matrix *inverse,
struct weston_vector *v)
MATRIX_TEST_EXPORT inline void
inverse_transform(const double *LU, const unsigned *p, GLfloat *v)
{
/* Solve A * x = v, when we have P * A = L * U.
* P * A * x = P * v => L * U * x = P * v
* Let U * x = b, then L * b = P * v.
*/
unsigned *p = inverse->p;
double *LU = inverse->LU;
double b[4];
unsigned j;
/* Forward substitution, column version, solves L * b = P * v */
/* The diagonal of L is all ones, and not explicitly stored. */
b[0] = v->f[p[0]];
b[1] = (double)v->f[p[1]] - b[0] * LU[1 + 0 * 4];
b[2] = (double)v->f[p[2]] - b[0] * LU[2 + 0 * 4];
b[3] = (double)v->f[p[3]] - b[0] * LU[3 + 0 * 4];
b[0] = v[p[0]];
b[1] = (double)v[p[1]] - b[0] * LU[1 + 0 * 4];
b[2] = (double)v[p[2]] - b[0] * LU[2 + 0 * 4];
b[3] = (double)v[p[3]] - b[0] * LU[3 + 0 * 4];
b[2] -= b[1] * LU[2 + 1 * 4];
b[3] -= b[1] * LU[3 + 1 * 4];
b[3] -= b[2] * LU[3 + 2 * 4];
@ -225,5 +228,23 @@ weston_matrix_inverse_transform(struct weston_inverse_matrix *inverse,
/* the result */
for (j = 0; j < 4; ++j)
v->f[j] = b[j];
v[j] = b[j];
}
WL_EXPORT int
weston_matrix_invert(struct weston_matrix *inverse,
const struct weston_matrix *matrix)
{
double LU[16]; /* column-major */
unsigned perm[4]; /* permutation */
unsigned c;
if (matrix_invert(LU, perm, matrix) < 0)
return -1;
weston_matrix_init(inverse);
for (c = 0; c < 4; ++c)
inverse_transform(LU, perm, &inverse->d[c * 4]);
return 0;
}

@ -28,11 +28,6 @@ struct weston_matrix {
GLfloat d[16];
};
struct weston_inverse_matrix {
double LU[16]; /* column-major */
unsigned p[4]; /* permutation */
};
struct weston_vector {
GLfloat f[4];
};
@ -50,10 +45,20 @@ void
weston_matrix_transform(struct weston_matrix *matrix, struct weston_vector *v);
int
weston_matrix_invert(struct weston_inverse_matrix *inverse,
weston_matrix_invert(struct weston_matrix *inverse,
const struct weston_matrix *matrix);
#ifdef UNIT_TEST
# define MATRIX_TEST_EXPORT WL_EXPORT
int
matrix_invert(double *A, unsigned *p, const struct weston_matrix *matrix);
void
weston_matrix_inverse_transform(struct weston_inverse_matrix *inverse,
struct weston_vector *v);
inverse_transform(const double *LU, const unsigned *p, GLfloat *v);
#else
# define MATRIX_TEST_EXPORT static
#endif
#endif /* WESTON_MATRIX_H */

@ -6,7 +6,7 @@ endif
AM_CFLAGS = $(GCC_CFLAGS)
AM_CPPFLAGS = -I../src
AM_CPPFLAGS = -I../src -DUNIT_TEST
matrix_test_SOURCES = \
matrix-test.c \

@ -30,6 +30,11 @@
#include "matrix.h"
struct inverse_matrix {
double LU[16]; /* column-major */
unsigned perm[4]; /* permutation */
};
static struct timespec begin_time;
static void
@ -81,9 +86,9 @@ determinant(const struct weston_matrix *m)
}
static void
print_permutation_matrix(const struct weston_inverse_matrix *m)
print_permutation_matrix(const struct inverse_matrix *m)
{
const unsigned *p = m->p;
const unsigned *p = m->perm;
const char *row[4] = {
"1 0 0 0\n",
"0 1 0 0\n",
@ -95,7 +100,7 @@ print_permutation_matrix(const struct weston_inverse_matrix *m)
}
static void
print_LU_decomposition(const struct weston_inverse_matrix *m)
print_LU_decomposition(const struct inverse_matrix *m)
{
unsigned r, c;
@ -128,7 +133,7 @@ print_LU_decomposition(const struct weston_inverse_matrix *m)
}
static void
print_inverse_data_matrix(const struct weston_inverse_matrix *m)
print_inverse_data_matrix(const struct inverse_matrix *m)
{
unsigned r, c;
@ -140,7 +145,7 @@ print_inverse_data_matrix(const struct weston_inverse_matrix *m)
printf("permutation: ");
for (r = 0; r < 4; ++r)
printf(" %u", m->p[r]);
printf(" %u", m->perm[r]);
printf("\n");
}
@ -175,22 +180,6 @@ randomize_matrix(struct weston_matrix *m)
#endif
}
static void
invert_matrix(struct weston_matrix *m)
{
struct weston_inverse_matrix q;
unsigned i;
if (weston_matrix_invert(&q, m) != 0) {
m->d[0] = NAN;
return;
}
for (i = 0; i < 4; ++i)
weston_matrix_inverse_transform(&q,
(struct weston_vector *)&m->d[i * 4]);
}
/* Take a matrix, compute inverse, multiply together
* and subtract the identity matrix to get the error matrix.
* Return the largest absolute value from the error matrix.
@ -199,15 +188,14 @@ static double
test_inverse(struct weston_matrix *m)
{
unsigned i;
struct weston_inverse_matrix q;
struct inverse_matrix q;
double errsup = 0.0;
if (weston_matrix_invert(&q, m) != 0)
if (matrix_invert(q.LU, q.perm, m) != 0)
return INFINITY;
for (i = 0; i < 4; ++i)
weston_matrix_inverse_transform(&q,
(struct weston_vector *)&m->d[i * 4]);
inverse_transform(q.LU, q.perm, &m->d[i * 4]);
m->d[0] -= 1.0f;
m->d[5] -= 1.0f;
@ -309,21 +297,21 @@ static void __attribute__((noinline))
test_loop_speed_inversetransform(void)
{
struct weston_matrix m;
struct weston_inverse_matrix inv;
struct inverse_matrix inv;
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_inverse_transform()...\n");
printf("\nRunning 3 s test on inverse_transform()...\n");
weston_matrix_init(&m);
weston_matrix_invert(&inv, &m);
matrix_invert(inv.LU, inv.perm, &m);
running = 1;
alarm(3);
reset_timer();
while (running) {
weston_matrix_inverse_transform(&inv, &v);
inverse_transform(inv.LU, inv.perm, v.f);
count++;
}
t = read_timer();
@ -336,11 +324,11 @@ static void __attribute__((noinline))
test_loop_speed_invert(void)
{
struct weston_matrix m;
struct weston_inverse_matrix inv;
struct inverse_matrix inv;
unsigned long count = 0;
double t;
printf("\nRunning 3 s test on weston_matrix_invert()...\n");
printf("\nRunning 3 s test on matrix_invert()...\n");
weston_matrix_init(&m);
@ -348,7 +336,7 @@ test_loop_speed_invert(void)
alarm(3);
reset_timer();
while (running) {
weston_matrix_invert(&inv, &m);
matrix_invert(inv.LU, inv.perm, &m);
count++;
}
t = read_timer();
@ -364,7 +352,7 @@ test_loop_speed_invert_explicit(void)
unsigned long count = 0;
double t;
printf("\nRunning 3 s test on computing the explicit inverse matrix...\n");
printf("\nRunning 3 s test on weston_matrix_invert()...\n");
weston_matrix_init(&m);
@ -372,7 +360,7 @@ test_loop_speed_invert_explicit(void)
alarm(3);
reset_timer();
while (running) {
invert_matrix(&m);
weston_matrix_invert(&m, &m);
count++;
}
t = read_timer();
@ -385,7 +373,7 @@ int main(void)
{
struct sigaction ding;
struct weston_matrix M;
struct weston_inverse_matrix Q;
struct inverse_matrix Q;
int ret;
double errsup;
double det;
@ -402,7 +390,7 @@ int main(void)
M.d[2] = 6.0; M.d[6] = 18.0; M.d[10] = -12; M.d[14] = 0.0;
M.d[3] = 0.0; M.d[7] = 0.0; M.d[11] = 0.0; M.d[15] = 1.0;
ret = weston_matrix_invert(&Q, &M);
ret = matrix_invert(Q.LU, Q.perm, &M);
printf("ret = %d\n", ret);
printf("det = %g\n\n", determinant(&M));

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