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cogl/matrix: Project and transpose using graphene matrices

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Use dot products to simplify calculations. Because the 'w' column of
the matrix is always summed, use 1.f in the 'w' component of the point
vector.

Because CoglMatrix is column-major and graphene_matrix_t is row-major,
it is necessary to transpose the matrix before retrieving the rows.
When we switch CoglMatrix to be row-major, this transposition will
go away.

https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1439
This commit is contained in:
Georges Basile Stavracas Neto 2020-09-10 13:57:41 -03:00
parent 5d84f73aa0
commit b1472a6015
1 changed files with 74 additions and 34 deletions
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108
cogl/cogl/cogl-matrix.c
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@ -1675,12 +1675,18 @@ cogl_matrix_transform_point (const CoglMatrix *matrix,
float *z,
float *w)
{
float _x = *x, _y = *y, _z = *z, _w = *w;
graphene_matrix_t m;
graphene_vec4_t p;
*x = matrix->xx * _x + matrix->xy * _y + matrix->xz * _z + matrix->xw * _w;
*y = matrix->yx * _x + matrix->yy * _y + matrix->yz * _z + matrix->yw * _w;
*z = matrix->zx * _x + matrix->zy * _y + matrix->zz * _z + matrix->zw * _w;
*w = matrix->wx * _x + matrix->wy * _y + matrix->wz * _z + matrix->ww * _w;
graphene_vec4_init (&p, *x, *y, *z, *w);
cogl_matrix_to_graphene_matrix (matrix, &m);
graphene_matrix_transform_vec4 (&m, &p, &p);
*x = graphene_vec4_get_x (&p);
*y = graphene_vec4_get_y (&p);
*z = graphene_vec4_get_z (&p);
*w = graphene_vec4_get_w (&p);
}
typedef struct _Point2f
@ -1704,6 +1710,21 @@ typedef struct _Point4f
float w;
} Point4f;
static void
init_matrix_rows (const CoglMatrix *matrix,
unsigned int n_rows,
graphene_vec4_t *rows)
{
graphene_matrix_t m;
unsigned int i;
cogl_matrix_to_graphene_matrix (matrix, &m);
graphene_matrix_transpose (&m, &m);
for (i = 0; i < n_rows; i++)
graphene_matrix_get_row (&m, i, &rows[i]);
}
static void
_cogl_matrix_transform_points_f2 (const CoglMatrix *matrix,
size_t stride_in,
@ -1712,16 +1733,22 @@ _cogl_matrix_transform_points_f2 (const CoglMatrix *matrix,
void *points_out,
int n_points)
{
graphene_vec4_t rows[3];
int i;
init_matrix_rows (matrix, G_N_ELEMENTS (rows), rows);
for (i = 0; i < n_points; i++)
{
Point2f p = *(Point2f *)((uint8_t *)points_in + i * stride_in);
Point3f *o = (Point3f *)((uint8_t *)points_out + i * stride_out);
graphene_vec4_t point;
o->x = matrix->xx * p.x + matrix->xy * p.y + matrix->xw;
o->y = matrix->yx * p.x + matrix->yy * p.y + matrix->yw;
o->z = matrix->zx * p.x + matrix->zy * p.y + matrix->zw;
graphene_vec4_init (&point, p.x, p.y, 0.f, 1.f);
o->x = graphene_vec4_dot (&rows[0], &point);
o->y = graphene_vec4_dot (&rows[1], &point);
o->z = graphene_vec4_dot (&rows[2], &point);
}
}
@ -1733,17 +1760,23 @@ _cogl_matrix_project_points_f2 (const CoglMatrix *matrix,
void *points_out,
int n_points)
{
graphene_vec4_t rows[4];
int i;
init_matrix_rows (matrix, G_N_ELEMENTS (rows), rows);
for (i = 0; i < n_points; i++)
{
Point2f p = *(Point2f *)((uint8_t *)points_in + i * stride_in);
Point4f *o = (Point4f *)((uint8_t *)points_out + i * stride_out);
graphene_vec4_t point;
o->x = matrix->xx * p.x + matrix->xy * p.y + matrix->xw;
o->y = matrix->yx * p.x + matrix->yy * p.y + matrix->yw;
o->z = matrix->zx * p.x + matrix->zy * p.y + matrix->zw;
o->w = matrix->wx * p.x + matrix->wy * p.y + matrix->ww;
graphene_vec4_init (&point, p.x, p.y, 0.f, 1.f);
o->x = graphene_vec4_dot (&rows[0], &point);
o->y = graphene_vec4_dot (&rows[1], &point);
o->z = graphene_vec4_dot (&rows[2], &point);
o->w = graphene_vec4_dot (&rows[3], &point);
}
}
@ -1755,19 +1788,22 @@ _cogl_matrix_transform_points_f3 (const CoglMatrix *matrix,
void *points_out,
int n_points)
{
graphene_vec4_t rows[3];
int i;
init_matrix_rows (matrix, G_N_ELEMENTS (rows), rows);
for (i = 0; i < n_points; i++)
{
Point3f p = *(Point3f *)((uint8_t *)points_in + i * stride_in);
Point3f *o = (Point3f *)((uint8_t *)points_out + i * stride_out);
graphene_vec4_t point;
o->x = matrix->xx * p.x + matrix->xy * p.y +
matrix->xz * p.z + matrix->xw;
o->y = matrix->yx * p.x + matrix->yy * p.y +
matrix->yz * p.z + matrix->yw;
o->z = matrix->zx * p.x + matrix->zy * p.y +
matrix->zz * p.z + matrix->zw;
graphene_vec4_init (&point, p.x, p.y, p.z, 1.f);
o->x = graphene_vec4_dot (&rows[0], &point);
o->y = graphene_vec4_dot (&rows[1], &point);
o->z = graphene_vec4_dot (&rows[2], &point);
}
}
@ -1779,21 +1815,23 @@ _cogl_matrix_project_points_f3 (const CoglMatrix *matrix,
void *points_out,
int n_points)
{
graphene_vec4_t rows[4];
int i;
init_matrix_rows (matrix, G_N_ELEMENTS (rows), rows);
for (i = 0; i < n_points; i++)
{
Point3f p = *(Point3f *)((uint8_t *)points_in + i * stride_in);
Point4f *o = (Point4f *)((uint8_t *)points_out + i * stride_out);
graphene_vec4_t point;
o->x = matrix->xx * p.x + matrix->xy * p.y +
matrix->xz * p.z + matrix->xw;
o->y = matrix->yx * p.x + matrix->yy * p.y +
matrix->yz * p.z + matrix->yw;
o->z = matrix->zx * p.x + matrix->zy * p.y +
matrix->zz * p.z + matrix->zw;
o->w = matrix->wx * p.x + matrix->wy * p.y +
matrix->wz * p.z + matrix->ww;
graphene_vec4_init (&point, p.x, p.y, p.z, 1.f);
o->x = graphene_vec4_dot (&rows[0], &point);
o->y = graphene_vec4_dot (&rows[1], &point);
o->z = graphene_vec4_dot (&rows[2], &point);
o->w = graphene_vec4_dot (&rows[3], &point);
}
}
@ -1805,21 +1843,23 @@ _cogl_matrix_project_points_f4 (const CoglMatrix *matrix,
void *points_out,
int n_points)
{
graphene_vec4_t rows[4];
int i;
init_matrix_rows (matrix, G_N_ELEMENTS (rows), rows);
for (i = 0; i < n_points; i++)
{
Point4f p = *(Point4f *)((uint8_t *)points_in + i * stride_in);
Point4f *o = (Point4f *)((uint8_t *)points_out + i * stride_out);
graphene_vec4_t point;
o->x = matrix->xx * p.x + matrix->xy * p.y +
matrix->xz * p.z + matrix->xw * p.w;
o->y = matrix->yx * p.x + matrix->yy * p.y +
matrix->yz * p.z + matrix->yw * p.w;
o->z = matrix->zx * p.x + matrix->zy * p.y +
matrix->zz * p.z + matrix->zw * p.w;
o->w = matrix->wx * p.x + matrix->wy * p.y +
matrix->wz * p.z + matrix->ww * p.w;
graphene_vec4_init (&point, p.x, p.y, p.z, p.w);
o->x = graphene_vec4_dot (&rows[0], &point);
o->y = graphene_vec4_dot (&rows[1], &point);
o->z = graphene_vec4_dot (&rows[2], &point);
o->w = graphene_vec4_dot (&rows[3], &point);
}
}