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Fix bug in coeff generation on more than 3x downsamples with width and height scale equal

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Jeff Roberts (Bellevue) 2024-02-12 22:10:02 -08:00
parent b7cf124628
commit 1828f357dc
1 changed files with 39 additions and 21 deletions
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60
stb_image_resize2.h
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@ -1,4 +1,4 @@
/* stb_image_resize2 - v2.05 - public domain image resizing /* stb_image_resize2 - v2.06 - public domain image resizing
by Jeff Roberts (v2) and Jorge L Rodriguez by Jeff Roberts (v2) and Jorge L Rodriguez
http://github.com/nothings/stb http://github.com/nothings/stb
@ -328,7 +328,9 @@
Nathan Reed: warning fixes for 1.0 Nathan Reed: warning fixes for 1.0
REVISIONS REVISIONS
2.05 (2024-02-24) fix for 2 pixel to 1 pixel resizes with wrap (thanks Aras) 2.06 (2024-02-10) fix for indentical width/height 3x or more down-scaling
undersampling a single row on rare resize ratios (about 1%)
2.05 (2024-02-07) fix for 2 pixel to 1 pixel resizes with wrap (thanks Aras)
fix for output callback (thanks Julien Koenen) fix for output callback (thanks Julien Koenen)
2.04 (2023-11-17) fix for rare AVX bug, shadowed symbol (thanks Nikola Smiljanic). 2.04 (2023-11-17) fix for rare AVX bug, shadowed symbol (thanks Nikola Smiljanic).
2.03 (2023-11-01) ASAN and TSAN warnings fixed, minor tweaks. 2.03 (2023-11-01) ASAN and TSAN warnings fixed, minor tweaks.
@ -3393,6 +3395,12 @@ static void stbir__calculate_coefficients_for_gather_downsample( int start, int
} }
} }
} }
#define STBIR_RENORMALIZE_IN_FLOAT
#ifdef STBIR_RENORMALIZE_IN_FLOAT
#define STBIR_RENORM_TYPE float
#else
#define STBIR_RENORM_TYPE double
#endif
static void stbir__cleanup_gathered_coefficients( stbir_edge edge, stbir__filter_extent_info* filter_info, stbir__scale_info * scale_info, int num_contributors, stbir__contributors* contributors, float * coefficient_group, int coefficient_width ) static void stbir__cleanup_gathered_coefficients( stbir_edge edge, stbir__filter_extent_info* filter_info, stbir__scale_info * scale_info, int num_contributors, stbir__contributors* contributors, float * coefficient_group, int coefficient_width )
{ {
@ -3415,14 +3423,14 @@ static void stbir__cleanup_gathered_coefficients( stbir_edge edge, stbir__filter
for (n = 0; n < end; n++) for (n = 0; n < end; n++)
{ {
int i; int i;
float filter_scale, total_filter = 0; STBIR_RENORM_TYPE filter_scale, total_filter = 0;
int e; int e;
// add all contribs // add all contribs
e = contribs->n1 - contribs->n0; e = contribs->n1 - contribs->n0;
for( i = 0 ; i <= e ; i++ ) for( i = 0 ; i <= e ; i++ )
{ {
total_filter += coeffs[i]; total_filter += (STBIR_RENORM_TYPE) coeffs[i];
STBIR_ASSERT( ( coeffs[i] >= -2.0f ) && ( coeffs[i] <= 2.0f ) ); // check for wonky weights STBIR_ASSERT( ( coeffs[i] >= -2.0f ) && ( coeffs[i] <= 2.0f ) ); // check for wonky weights
} }
@ -3438,10 +3446,11 @@ static void stbir__cleanup_gathered_coefficients( stbir_edge edge, stbir__filter
// if the total isn't 1.0, rescale everything // if the total isn't 1.0, rescale everything
if ( ( total_filter < (1.0f-stbir__small_float) ) || ( total_filter > (1.0f+stbir__small_float) ) ) if ( ( total_filter < (1.0f-stbir__small_float) ) || ( total_filter > (1.0f+stbir__small_float) ) )
{ {
filter_scale = 1.0f / total_filter; filter_scale = ((STBIR_RENORM_TYPE)1.0) / total_filter;
// scale them all // scale them all
for (i = 0; i <= e; i++) for (i = 0; i <= e; i++)
coeffs[i] *= filter_scale; coeffs[i] = (float) ( coeffs[i] * filter_scale );
} }
} }
++contribs; ++contribs;
@ -3562,6 +3571,8 @@ static void stbir__cleanup_gathered_coefficients( stbir_edge edge, stbir__filter
filter_info->widest = widest; filter_info->widest = widest;
} }
#undef STBIR_RENORM_TYPE
static int stbir__pack_coefficients( int num_contributors, stbir__contributors* contributors, float * coefficents, int coefficient_width, int widest, int row0, int row1 ) static int stbir__pack_coefficients( int num_contributors, stbir__contributors* contributors, float * coefficents, int coefficient_width, int widest, int row0, int row1 )
{ {
#define STBIR_MOVE_1( dest, src ) { STBIR_NO_UNROLL(dest); ((stbir_uint32*)(dest))[0] = ((stbir_uint32*)(src))[0]; } #define STBIR_MOVE_1( dest, src ) { STBIR_NO_UNROLL(dest); ((stbir_uint32*)(dest))[0] = ((stbir_uint32*)(src))[0]; }
@ -3869,26 +3880,33 @@ static void stbir__calculate_filters( stbir__sampler * samp, stbir__sampler * ot
for (k = gn0 ; k <= gn1 ; k++ ) for (k = gn0 ; k <= gn1 ; k++ )
{ {
float gc = *g_coeffs++; float gc = *g_coeffs++;
if ( ( k > highest_set ) || ( scatter_contributors->n0 > scatter_contributors->n1 ) )
// skip zero and denormals - must skip zeros to avoid adding coeffs beyond scatter_coefficient_width
// (which happens when pivoting from horizontal, which might have dummy zeros)
if ( ( ( gc >= stbir__small_float ) || ( gc <= -stbir__small_float ) ) )
{ {
if ( ( k > highest_set ) || ( scatter_contributors->n0 > scatter_contributors->n1 ) )
{ {
// if we are skipping over several contributors, we need to clear the skipped ones
stbir__contributors * clear_contributors = samp->contributors + ( highest_set + filter_pixel_margin + 1);
while ( clear_contributors < scatter_contributors )
{ {
clear_contributors->n0 = 0; // if we are skipping over several contributors, we need to clear the skipped ones
clear_contributors->n1 = -1; stbir__contributors * clear_contributors = samp->contributors + ( highest_set + filter_pixel_margin + 1);
++clear_contributors; while ( clear_contributors < scatter_contributors )
{
clear_contributors->n0 = 0;
clear_contributors->n1 = -1;
++clear_contributors;
}
} }
scatter_contributors->n0 = n;
scatter_contributors->n1 = n;
scatter_coeffs[0] = gc;
highest_set = k;
} }
scatter_contributors->n0 = n; else
scatter_contributors->n1 = n; {
scatter_coeffs[0] = gc; stbir__insert_coeff( scatter_contributors, scatter_coeffs, n, gc );
highest_set = k; }
} STBIR_ASSERT( ( scatter_contributors->n1 - scatter_contributors->n0 + 1 ) <= scatter_coefficient_width );
else
{
stbir__insert_coeff( scatter_contributors, scatter_coeffs, n, gc );
} }
++scatter_contributors; ++scatter_contributors;
scatter_coeffs += scatter_coefficient_width; scatter_coeffs += scatter_coefficient_width;