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[sdf -> bsdf] Added option to use squared distances. 

* src/sdf/ftbsdf.c (bsdf_is_edge): Modified the function
  to use distance map rather than the alpha values from
  the source image.

* src/sdf/ftbsdf.c (bsdf_approximate_edge): Only calculate
  approximate edges for edge pixels. Use `bsdf_is_edge' is
  to check for edge pixels. For non edge pixel assgn far
  away distances.

* src/sdf/ftbsdf.c (finalize_sdf): Handle distances in case
  of squared distances.
  And also use the macro `VECTOR_LENGTH_16D16' in the entire
  code to compute vector length. This takes care of squared
  distances.

* src/sdf/ftsdfcommon.c (VECTOR_LENGTH_16D16): Move the macro
  `VECTOR_LENGTH_16D16' from `ftsdf.c' to this file because
  it is also used by the `bsdf' renderer.
This commit is contained in:
Anuj Verma 2020-08-01 18:21:32 +05:30 committed by anujverma
parent 436f091db1
commit a62fd640f3
4 changed files with 59 additions and 29 deletions
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23
[GSoC]ChangeLog
View File

@ -1,3 +1,26 @@
2020-08-1 Anuj Verma <anujv@iitbhilai.ac.in>
[sdf -> bsdf] Added option to use squared distances.
* src/sdf/ftbsdf.c (bsdf_is_edge): Modified the function
to use distance map rather than the alpha values from
the source image.
* src/sdf/ftbsdf.c (bsdf_approximate_edge): Only calculate
approximate edges for edge pixels. Use `bsdf_is_edge' is
to check for edge pixels. For non edge pixel assgn far
away distances.
* src/sdf/ftbsdf.c (finalize_sdf): Handle distances in case
of squared distances.
And also use the macro `VECTOR_LENGTH_16D16' in the entire
code to compute vector length. This takes care of squared
distances.
* src/sdf/ftsdfcommon.c (VECTOR_LENGTH_16D16): Move the macro
`VECTOR_LENGTH_16D16' from `ftsdf.c' to this file because
it is also used by the `bsdf' renderer.
2020-08-1 Anuj Verma <anujv@iitbhilai.ac.in> 2020-08-1 Anuj Verma <anujv@iitbhilai.ac.in>
* src/sdf/ftbsdf.c (compare_neighbor): Fix bug. * src/sdf/ftbsdf.c (compare_neighbor): Fix bug.

39
src/sdf/ftbsdf.c
View File

@ -74,8 +74,8 @@
y + y_offset >= 0 && y + y_offset < r ) \ y + y_offset >= 0 && y + y_offset < r ) \
{ \ { \
num_neighbour++; \ num_neighbour++; \
to_check = s + y_offset * w + x_offset; \ to_check = dm + y_offset * w + x_offset; \
if ( *to_check == 0 ) \ if ( to_check->alpha == 0 ) \
{ \ { \
is_edge = 1; \ is_edge = 1; \
goto Done; \ goto Done; \
@ -97,21 +97,21 @@
* [TODO] * [TODO]
*/ */
static FT_Bool static FT_Bool
bsdf_is_edge( FT_Byte* s, /* source bitmap */ bsdf_is_edge( ED* dm, /* distance map */
FT_Int x, /* x index of point to check */ FT_Int x, /* x index of point to check */
FT_Int y, /* y index of point to check */ FT_Int y, /* y index of point to check */
FT_Int w, /* width */ FT_Int w, /* width */
FT_Int r ) /* rows */ FT_Int r ) /* rows */
{ {
FT_Bool is_edge = 0; FT_Bool is_edge = 0;
FT_Byte* to_check = NULL; ED* to_check = NULL;
FT_Int num_neighbour = 0; FT_Int num_neighbour = 0;
if ( *s == 0 ) if ( dm->alpha == 0 )
goto Done; goto Done;
if ( *s > 0 && *s < 255 ) if ( dm->alpha > 0 && dm->alpha < 255 )
{ {
is_edge = 1; is_edge = 1;
goto Done; goto Done;
@ -340,19 +340,20 @@
{ {
index = j * worker->width + i; index = j * worker->width + i;
/* [TODO]: Check if the current pixel is edge. */ if ( bsdf_is_edge( worker->distance_map + index,
if ( ed[index].alpha != 0 ) i, j, worker->width, worker->rows ) )
{ {
/* approximate the edge distance */ /* for edge pixels approximate the edge distance */
ed[index].near = compute_edge_distance( ed + index, i, j, ed[index].near = compute_edge_distance( ed + index, i, j,
worker->width, worker->rows ); worker->width, worker->rows );
ed[index].dist = FT_Vector_Length( &ed[index].near ); ed[index].dist = VECTOR_LENGTH_16D16( ed[index].near );
} }
else else
{ {
ed[index].dist = 200 * ONE; /* for non edge pixels assign far away distances */
ed[index].near.x = 100 * ONE; ed[index].dist = 400 * ONE;
ed[index].near.y = 100 * ONE; ed[index].near.x = 200 * ONE;
ed[index].near.y = 200 * ONE;
} }
} }
} }
@ -554,7 +555,7 @@
dist_vec = to_check->near; dist_vec = to_check->near;
dist_vec.x += x_offset * ONE; dist_vec.x += x_offset * ONE;
dist_vec.y += y_offset * ONE; dist_vec.y += y_offset * ONE;
dist = FT_Vector_Length( &dist_vec ); dist = VECTOR_LENGTH_16D16( dist_vec );
if ( dist < current->dist ) if ( dist < current->dist )
{ {
current->dist = dist; current->dist = dist;
@ -798,12 +799,18 @@
index = j * w + i; index = j * w + i;
dist = worker->distance_map[index].dist; dist = worker->distance_map[index].dist;
#if USE_SQUARED_DISTANCES
if ( dist < 0 )
dist = FT_INT_16D16( worker->params.spread );
else
dist = square_root( dist );
#endif
/* convert from 16.16 to 6.10 */ /* convert from 16.16 to 6.10 */
dist /= 64; dist /= 64;
final_dist = (FT_6D10)(dist & 0x0000FFFF); final_dist = (FT_6D10)(dist & 0x0000FFFF);
/* [TODO]: Assing the sign properly. */
if ( final_dist > worker->params.spread * 1024 ) if ( final_dist > worker->params.spread * 1024 )
final_dist = worker->params.spread * 1024; final_dist = worker->params.spread * 1024;

13
src/sdf/ftsdf.c
View File

@ -155,19 +155,6 @@
#define VEC_26D6_DOT( p, q ) ( MUL_26D6( p.x, q.x ) + \ #define VEC_26D6_DOT( p, q ) ( MUL_26D6( p.x, q.x ) + \
MUL_26D6( p.y, q.y ) ) MUL_26D6( p.y, q.y ) )
/* [IMPORTANT]: The macro `VECTOR_LENGTH_16D16' is not always the same */
/* and must not be used anywhere except a few places. This macro is */
/* controlled by the `USE_SQUARED_DISTANCES' macro. It compute squared */
/* distance or actual distance based on `USE_SQUARED_DISTANCES' value. */
/* By using squared distances the performance can be greatly improved */
/* but there is a risk of overflow. Use it wisely. */
#if USE_SQUARED_DISTANCES
# define VECTOR_LENGTH_16D16( v ) ( FT_MulFix( v.x, v.x ) + \
FT_MulFix( v.y, v.y ) )
#else
# define VECTOR_LENGTH_16D16( v ) FT_Vector_Length( &v )
#endif
/************************************************************************** /**************************************************************************
* *
* structures and enums * structures and enums

13
src/sdf/ftsdfcommon.h
View File

@ -68,6 +68,19 @@ FT_BEGIN_HEADER
goto Exit; \ goto Exit; \
} while ( 0 ) } while ( 0 )
/* [IMPORTANT]: The macro `VECTOR_LENGTH_16D16' is not always the same */
/* and must not be used anywhere except a few places. This macro is */
/* controlled by the `USE_SQUARED_DISTANCES' macro. It compute squared */
/* distance or actual distance based on `USE_SQUARED_DISTANCES' value. */
/* By using squared distances the performance can be greatly improved */
/* but there is a risk of overflow. Use it wisely. */
#if USE_SQUARED_DISTANCES
# define VECTOR_LENGTH_16D16( v ) ( FT_MulFix( v.x, v.x ) + \
FT_MulFix( v.y, v.y ) )
#else
# define VECTOR_LENGTH_16D16( v ) FT_Vector_Length( &v )
#endif
/************************************************************************** /**************************************************************************
* *
* common typedefs * common typedefs