From 638267b6d5e2dde6ef5747e43fa4a27bd7927ad0 Mon Sep 17 00:00:00 2001 From: Jorge Rodriguez Date: Sun, 29 Jan 2017 12:30:38 -0800 Subject: [PATCH] Floating point rounding causes stbir__calculate_sample_range_upsample to sometimes think it needs one more scanline than it really does. This patch adds one extra entry to the ringbuffer to avoid the problem. --- stb_image_resize.h | 44 ++++++++++++++++++++++++-------------------- 1 file changed, 24 insertions(+), 20 deletions(-) diff --git a/stb_image_resize.h b/stb_image_resize.h index 5214ad6..220cce4 100644 --- a/stb_image_resize.h +++ b/stb_image_resize.h @@ -533,10 +533,11 @@ typedef struct int horizontal_num_contributors; int vertical_num_contributors; - int ring_buffer_length_bytes; // The length of an individual entry in the ring buffer. The total number of ring buffers is stbir__get_filter_pixel_width(filter) + int ring_buffer_length_bytes; // The length of an individual entry in the ring buffer. The total number of ring buffers is stbir__get_filter_pixel_width(filter) + int ring_buffer_num_entries; // Total number of entries in the ring buffer. int ring_buffer_first_scanline; int ring_buffer_last_scanline; - int ring_buffer_begin_index; + int ring_buffer_begin_index; // first_scanline is at this index in the ring buffer float* ring_buffer; float* encode_buffer; // A temporary buffer to store floats so we don't lose precision while we do multiply-adds. @@ -1411,6 +1412,8 @@ static float* stbir__add_empty_ring_buffer_entry(stbir__info* stbir_info, int n) int ring_buffer_index; float* ring_buffer; + stbir_info->ring_buffer_last_scanline = n; + if (stbir_info->ring_buffer_begin_index < 0) { ring_buffer_index = stbir_info->ring_buffer_begin_index = 0; @@ -1418,15 +1421,13 @@ static float* stbir__add_empty_ring_buffer_entry(stbir__info* stbir_info, int n) } else { - ring_buffer_index = (stbir_info->ring_buffer_begin_index + (stbir_info->ring_buffer_last_scanline - stbir_info->ring_buffer_first_scanline) + 1) % stbir_info->vertical_filter_pixel_width; + ring_buffer_index = (stbir_info->ring_buffer_begin_index + (stbir_info->ring_buffer_last_scanline - stbir_info->ring_buffer_first_scanline)) % stbir_info->ring_buffer_num_entries; STBIR_ASSERT(ring_buffer_index != stbir_info->ring_buffer_begin_index); } ring_buffer = stbir__get_ring_buffer_entry(stbir_info->ring_buffer, ring_buffer_index, stbir_info->ring_buffer_length_bytes / sizeof(float)); memset(ring_buffer, 0, stbir_info->ring_buffer_length_bytes); - stbir_info->ring_buffer_last_scanline = n; - return ring_buffer; } @@ -1678,9 +1679,9 @@ static void stbir__decode_and_resample_downsample(stbir__info* stbir_info, int n } // Get the specified scan line from the ring buffer. -static float* stbir__get_ring_buffer_scanline(int get_scanline, float* ring_buffer, int begin_index, int first_scanline, int ring_buffer_size, int ring_buffer_length) +static float* stbir__get_ring_buffer_scanline(int get_scanline, float* ring_buffer, int begin_index, int first_scanline, int ring_buffer_num_entries, int ring_buffer_length) { - int ring_buffer_index = (begin_index + (get_scanline - first_scanline)) % ring_buffer_size; + int ring_buffer_index = (begin_index + (get_scanline - first_scanline)) % ring_buffer_num_entries; return stbir__get_ring_buffer_entry(ring_buffer, ring_buffer_index, ring_buffer_length); } @@ -1865,7 +1866,7 @@ static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n, in int alpha_channel = stbir_info->alpha_channel; int type = stbir_info->type; int colorspace = stbir_info->colorspace; - int kernel_pixel_width = stbir_info->vertical_filter_pixel_width; + int ring_buffer_entries = stbir_info->ring_buffer_num_entries; void* output_data = stbir_info->output_data; float* encode_buffer = stbir_info->encode_buffer; int decode = STBIR__DECODE(type, colorspace); @@ -1900,7 +1901,7 @@ static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n, in for (k = n0; k <= n1; k++) { int coefficient_index = coefficient_counter++; - float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, kernel_pixel_width, ring_buffer_length); + float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; for (x = 0; x < output_w; ++x) { @@ -1913,7 +1914,7 @@ static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n, in for (k = n0; k <= n1; k++) { int coefficient_index = coefficient_counter++; - float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, kernel_pixel_width, ring_buffer_length); + float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; for (x = 0; x < output_w; ++x) { @@ -1927,7 +1928,7 @@ static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n, in for (k = n0; k <= n1; k++) { int coefficient_index = coefficient_counter++; - float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, kernel_pixel_width, ring_buffer_length); + float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; for (x = 0; x < output_w; ++x) { @@ -1942,7 +1943,7 @@ static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n, in for (k = n0; k <= n1; k++) { int coefficient_index = coefficient_counter++; - float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, kernel_pixel_width, ring_buffer_length); + float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; for (x = 0; x < output_w; ++x) { @@ -1958,7 +1959,7 @@ static void stbir__resample_vertical_upsample(stbir__info* stbir_info, int n, in for (k = n0; k <= n1; k++) { int coefficient_index = coefficient_counter++; - float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, kernel_pixel_width, ring_buffer_length); + float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; for (x = 0; x < output_w; ++x) { @@ -1981,7 +1982,7 @@ static void stbir__resample_vertical_downsample(stbir__info* stbir_info, int n, stbir__contributors* vertical_contributors = stbir_info->vertical_contributors; float* vertical_coefficients = stbir_info->vertical_coefficients; int channels = stbir_info->channels; - int kernel_pixel_width = stbir_info->vertical_filter_pixel_width; + int ring_buffer_entries = stbir_info->ring_buffer_num_entries; void* output_data = stbir_info->output_data; float* horizontal_buffer = stbir_info->horizontal_buffer; int coefficient_width = stbir_info->vertical_coefficient_width; @@ -2005,7 +2006,7 @@ static void stbir__resample_vertical_downsample(stbir__info* stbir_info, int n, int coefficient_group = coefficient_width * contributor; float coefficient = vertical_coefficients[coefficient_group + coefficient_index]; - float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, kernel_pixel_width, ring_buffer_length); + float* ring_buffer_entry = stbir__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, ring_buffer_entries, ring_buffer_length); switch (channels) { case 1: @@ -2071,7 +2072,7 @@ static void stbir__buffer_loop_upsample(stbir__info* stbir_info) stbir__calculate_sample_range_upsample(y, out_scanlines_radius, scale_ratio, stbir_info->vertical_shift, &in_first_scanline, &in_last_scanline, &in_center_of_out); - STBIR_ASSERT(in_last_scanline - in_first_scanline <= stbir_info->vertical_filter_pixel_width); + STBIR_ASSERT(in_last_scanline - in_first_scanline + 1 <= stbir_info->ring_buffer_num_entries); if (stbir_info->ring_buffer_begin_index >= 0) { @@ -2090,7 +2091,7 @@ static void stbir__buffer_loop_upsample(stbir__info* stbir_info) else { stbir_info->ring_buffer_first_scanline++; - stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->vertical_filter_pixel_width; + stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->ring_buffer_num_entries; } } } @@ -2148,7 +2149,7 @@ static void stbir__empty_ring_buffer(stbir__info* stbir_info, int first_necessar else { stbir_info->ring_buffer_first_scanline++; - stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->vertical_filter_pixel_width; + stbir_info->ring_buffer_begin_index = (stbir_info->ring_buffer_begin_index + 1) % stbir_info->ring_buffer_num_entries; } } } @@ -2172,7 +2173,7 @@ static void stbir__buffer_loop_downsample(stbir__info* stbir_info) stbir__calculate_sample_range_downsample(y, in_pixels_radius, scale_ratio, stbir_info->vertical_shift, &out_first_scanline, &out_last_scanline, &out_center_of_in); - STBIR_ASSERT(out_last_scanline - out_first_scanline <= stbir_info->vertical_filter_pixel_width); + STBIR_ASSERT(out_last_scanline - out_first_scanline + 1 <= stbir_info->ring_buffer_num_entries); if (out_last_scanline < 0 || out_first_scanline >= output_h) continue; @@ -2246,13 +2247,16 @@ static stbir_uint32 stbir__calculate_memory(stbir__info *info) info->horizontal_num_contributors = stbir__get_contributors(info->horizontal_scale, info->horizontal_filter, info->input_w, info->output_w); info->vertical_num_contributors = stbir__get_contributors(info->vertical_scale , info->vertical_filter , info->input_h, info->output_h); + // One extra entry because floating point precision problems sometimes cause an extra to be necessary. + info->ring_buffer_num_entries = filter_height + 1; + info->horizontal_contributors_size = info->horizontal_num_contributors * sizeof(stbir__contributors); info->horizontal_coefficients_size = stbir__get_total_horizontal_coefficients(info) * sizeof(float); info->vertical_contributors_size = info->vertical_num_contributors * sizeof(stbir__contributors); info->vertical_coefficients_size = stbir__get_total_vertical_coefficients(info) * sizeof(float); info->decode_buffer_size = (info->input_w + pixel_margin * 2) * info->channels * sizeof(float); info->horizontal_buffer_size = info->output_w * info->channels * sizeof(float); - info->ring_buffer_size = info->output_w * info->channels * filter_height * sizeof(float); + info->ring_buffer_size = info->output_w * info->channels * info->ring_buffer_num_entries * sizeof(float); info->encode_buffer_size = info->output_w * info->channels * sizeof(float); STBIR_ASSERT(info->horizontal_filter != 0);