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https://gitlab.freedesktop.org/wayland/weston
synced 2024-07-22 19:24:27 +00:00
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>
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Pekka Paalanen
parent
1ef94c8742
commit
d1f0ab6343
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@ -545,7 +545,7 @@ static void
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weston_surface_update_transform(struct weston_surface *surface)
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{
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struct weston_matrix *matrix = &surface->transform.matrix;
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struct weston_inverse_matrix *inverse = &surface->transform.inverse;
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struct weston_matrix *inverse = &surface->transform.inverse;
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struct weston_transform *tform;
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if (!surface->transform.dirty)
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@ -230,7 +230,7 @@ struct weston_surface {
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/* derived state, set up by weston_surface_update_transform */
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struct weston_matrix matrix;
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struct weston_inverse_matrix inverse;
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struct weston_matrix inverse;
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int enabled;
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} transform;
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61
src/matrix.c
61
src/matrix.c
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@ -29,6 +29,7 @@
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#include "matrix.h"
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/*
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* Matrices are stored in column-major order, that is the array indices are:
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* 0 4 8 12
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@ -116,6 +117,16 @@ swap_rows(double *a, double *b)
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}
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}
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static inline void
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swap_unsigned(unsigned *a, unsigned *b)
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{
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unsigned tmp;
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tmp = *a;
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*a = *b;
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*b = tmp;
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}
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static inline unsigned
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find_pivot(double *column, unsigned k)
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{
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@ -133,16 +144,15 @@ find_pivot(double *column, unsigned k)
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* LU decomposition, forward and back substitution: Chapter 3.
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*/
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WL_EXPORT int
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weston_matrix_invert(struct weston_inverse_matrix *inverse,
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const struct weston_matrix *matrix)
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MATRIX_TEST_EXPORT inline int
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matrix_invert(double *A, unsigned *p, const struct weston_matrix *matrix)
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{
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double A[16];
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unsigned p[4] = { 0, 1, 2, 3 };
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unsigned i, j, k;
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unsigned pivot;
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double pv;
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for (i = 0; i < 4; ++i)
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p[i] = i;
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for (i = 16; i--; )
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A[i] = matrix->d[i];
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@ -150,9 +160,7 @@ weston_matrix_invert(struct weston_inverse_matrix *inverse,
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for (k = 0; k < 4; ++k) {
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pivot = find_pivot(&A[k * 4], k);
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if (pivot != k) {
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unsigned tmp = p[k];
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p[k] = p[pivot];
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p[pivot] = tmp;
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swap_unsigned(&p[k], &p[pivot]);
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swap_rows(&A[k], &A[pivot]);
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}
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@ -168,30 +176,25 @@ weston_matrix_invert(struct weston_inverse_matrix *inverse,
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}
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}
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memcpy(inverse->LU, A, sizeof(A));
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memcpy(inverse->p, p, sizeof(p));
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return 0;
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}
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WL_EXPORT void
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weston_matrix_inverse_transform(struct weston_inverse_matrix *inverse,
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struct weston_vector *v)
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MATRIX_TEST_EXPORT inline void
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inverse_transform(const double *LU, const unsigned *p, GLfloat *v)
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{
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/* Solve A * x = v, when we have P * A = L * U.
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* P * A * x = P * v => L * U * x = P * v
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* Let U * x = b, then L * b = P * v.
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*/
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unsigned *p = inverse->p;
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double *LU = inverse->LU;
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double b[4];
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unsigned j;
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/* Forward substitution, column version, solves L * b = P * v */
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/* The diagonal of L is all ones, and not explicitly stored. */
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b[0] = v->f[p[0]];
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b[1] = (double)v->f[p[1]] - b[0] * LU[1 + 0 * 4];
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b[2] = (double)v->f[p[2]] - b[0] * LU[2 + 0 * 4];
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b[3] = (double)v->f[p[3]] - b[0] * LU[3 + 0 * 4];
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b[0] = v[p[0]];
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b[1] = (double)v[p[1]] - b[0] * LU[1 + 0 * 4];
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b[2] = (double)v[p[2]] - b[0] * LU[2 + 0 * 4];
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b[3] = (double)v[p[3]] - b[0] * LU[3 + 0 * 4];
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b[2] -= b[1] * LU[2 + 1 * 4];
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b[3] -= b[1] * LU[3 + 1 * 4];
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b[3] -= b[2] * LU[3 + 2 * 4];
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@ -225,5 +228,23 @@ weston_matrix_inverse_transform(struct weston_inverse_matrix *inverse,
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/* the result */
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for (j = 0; j < 4; ++j)
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v->f[j] = b[j];
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v[j] = b[j];
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}
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WL_EXPORT int
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weston_matrix_invert(struct weston_matrix *inverse,
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const struct weston_matrix *matrix)
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{
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double LU[16]; /* column-major */
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unsigned perm[4]; /* permutation */
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unsigned c;
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if (matrix_invert(LU, perm, matrix) < 0)
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return -1;
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weston_matrix_init(inverse);
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for (c = 0; c < 4; ++c)
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inverse_transform(LU, perm, &inverse->d[c * 4]);
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return 0;
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}
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21
src/matrix.h
21
src/matrix.h
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@ -28,11 +28,6 @@ struct weston_matrix {
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GLfloat d[16];
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};
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struct weston_inverse_matrix {
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double LU[16]; /* column-major */
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unsigned p[4]; /* permutation */
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};
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struct weston_vector {
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GLfloat f[4];
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};
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@ -50,10 +45,20 @@ void
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weston_matrix_transform(struct weston_matrix *matrix, struct weston_vector *v);
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int
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weston_matrix_invert(struct weston_inverse_matrix *inverse,
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weston_matrix_invert(struct weston_matrix *inverse,
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const struct weston_matrix *matrix);
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#ifdef UNIT_TEST
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# define MATRIX_TEST_EXPORT WL_EXPORT
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int
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matrix_invert(double *A, unsigned *p, const struct weston_matrix *matrix);
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void
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weston_matrix_inverse_transform(struct weston_inverse_matrix *inverse,
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struct weston_vector *v);
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inverse_transform(const double *LU, const unsigned *p, GLfloat *v);
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#else
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# define MATRIX_TEST_EXPORT static
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#endif
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#endif /* WESTON_MATRIX_H */
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@ -6,7 +6,7 @@ endif
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AM_CFLAGS = $(GCC_CFLAGS)
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AM_CPPFLAGS = -I../src
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AM_CPPFLAGS = -I../src -DUNIT_TEST
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matrix_test_SOURCES = \
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matrix-test.c \
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@ -30,6 +30,11 @@
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#include "matrix.h"
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struct inverse_matrix {
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double LU[16]; /* column-major */
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unsigned perm[4]; /* permutation */
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};
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static struct timespec begin_time;
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static void
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@ -81,9 +86,9 @@ determinant(const struct weston_matrix *m)
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}
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static void
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print_permutation_matrix(const struct weston_inverse_matrix *m)
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print_permutation_matrix(const struct inverse_matrix *m)
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{
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const unsigned *p = m->p;
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const unsigned *p = m->perm;
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const char *row[4] = {
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"1 0 0 0\n",
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"0 1 0 0\n",
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@ -95,7 +100,7 @@ print_permutation_matrix(const struct weston_inverse_matrix *m)
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}
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static void
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print_LU_decomposition(const struct weston_inverse_matrix *m)
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print_LU_decomposition(const struct inverse_matrix *m)
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{
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unsigned r, c;
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@ -128,7 +133,7 @@ print_LU_decomposition(const struct weston_inverse_matrix *m)
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}
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static void
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print_inverse_data_matrix(const struct weston_inverse_matrix *m)
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print_inverse_data_matrix(const struct inverse_matrix *m)
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{
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unsigned r, c;
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@ -140,7 +145,7 @@ print_inverse_data_matrix(const struct weston_inverse_matrix *m)
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printf("permutation: ");
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for (r = 0; r < 4; ++r)
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printf(" %u", m->p[r]);
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printf(" %u", m->perm[r]);
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printf("\n");
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}
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@ -175,22 +180,6 @@ randomize_matrix(struct weston_matrix *m)
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#endif
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}
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static void
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invert_matrix(struct weston_matrix *m)
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{
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struct weston_inverse_matrix q;
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unsigned i;
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if (weston_matrix_invert(&q, m) != 0) {
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m->d[0] = NAN;
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return;
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}
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for (i = 0; i < 4; ++i)
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weston_matrix_inverse_transform(&q,
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(struct weston_vector *)&m->d[i * 4]);
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}
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/* Take a matrix, compute inverse, multiply together
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* and subtract the identity matrix to get the error matrix.
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* Return the largest absolute value from the error matrix.
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@ -199,15 +188,14 @@ static double
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test_inverse(struct weston_matrix *m)
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{
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unsigned i;
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struct weston_inverse_matrix q;
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struct inverse_matrix q;
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double errsup = 0.0;
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if (weston_matrix_invert(&q, m) != 0)
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if (matrix_invert(q.LU, q.perm, m) != 0)
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return INFINITY;
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for (i = 0; i < 4; ++i)
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weston_matrix_inverse_transform(&q,
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(struct weston_vector *)&m->d[i * 4]);
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inverse_transform(q.LU, q.perm, &m->d[i * 4]);
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m->d[0] -= 1.0f;
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m->d[5] -= 1.0f;
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@ -309,21 +297,21 @@ static void __attribute__((noinline))
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test_loop_speed_inversetransform(void)
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{
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struct weston_matrix m;
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struct weston_inverse_matrix inv;
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struct inverse_matrix inv;
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struct weston_vector v = { { 0.5, 0.5, 0.5, 1.0 } };
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unsigned long count = 0;
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double t;
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printf("\nRunning 3 s test on weston_matrix_inverse_transform()...\n");
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printf("\nRunning 3 s test on inverse_transform()...\n");
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weston_matrix_init(&m);
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weston_matrix_invert(&inv, &m);
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matrix_invert(inv.LU, inv.perm, &m);
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running = 1;
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alarm(3);
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reset_timer();
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while (running) {
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weston_matrix_inverse_transform(&inv, &v);
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inverse_transform(inv.LU, inv.perm, v.f);
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count++;
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}
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t = read_timer();
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@ -336,11 +324,11 @@ static void __attribute__((noinline))
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test_loop_speed_invert(void)
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{
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struct weston_matrix m;
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struct weston_inverse_matrix inv;
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struct inverse_matrix inv;
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unsigned long count = 0;
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double t;
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printf("\nRunning 3 s test on weston_matrix_invert()...\n");
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printf("\nRunning 3 s test on matrix_invert()...\n");
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weston_matrix_init(&m);
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@ -348,7 +336,7 @@ test_loop_speed_invert(void)
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alarm(3);
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reset_timer();
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while (running) {
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weston_matrix_invert(&inv, &m);
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matrix_invert(inv.LU, inv.perm, &m);
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count++;
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}
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t = read_timer();
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@ -364,7 +352,7 @@ test_loop_speed_invert_explicit(void)
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unsigned long count = 0;
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double t;
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printf("\nRunning 3 s test on computing the explicit inverse matrix...\n");
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printf("\nRunning 3 s test on weston_matrix_invert()...\n");
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weston_matrix_init(&m);
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@ -372,7 +360,7 @@ test_loop_speed_invert_explicit(void)
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alarm(3);
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reset_timer();
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while (running) {
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invert_matrix(&m);
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weston_matrix_invert(&m, &m);
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count++;
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}
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t = read_timer();
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@ -385,7 +373,7 @@ int main(void)
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{
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struct sigaction ding;
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struct weston_matrix M;
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struct weston_inverse_matrix Q;
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struct inverse_matrix Q;
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int ret;
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double errsup;
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double det;
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@ -402,7 +390,7 @@ int main(void)
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M.d[2] = 6.0; M.d[6] = 18.0; M.d[10] = -12; M.d[14] = 0.0;
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M.d[3] = 0.0; M.d[7] = 0.0; M.d[11] = 0.0; M.d[15] = 1.0;
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ret = weston_matrix_invert(&Q, &M);
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ret = matrix_invert(Q.LU, Q.perm, &M);
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printf("ret = %d\n", ret);
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printf("det = %g\n\n", determinant(&M));
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