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When downsampling start the buffer loop at -filter_texel_margin to make sure that all contributors get their taps in at the ring buffer.

pull/32/head
Jorge Rodriguez 2014-07-26 13:56:23 -07:00
parent 155c71fb90
commit 12acf87eec
1 changed files with 21 additions and 20 deletions
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41
stb_resample.h
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@ -516,7 +516,7 @@ static void stbr__output_decode_coefficients_1(float* output_buffer, int out_tex
output_buffer[out_texel_index] += input_buffer[input_texel_index] * coefficient;
STBR_DEBUG_ASSERT(output_buffer[out_texel_index] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index] <= 1.001f);
}
static void stbr__output_decode_coefficients_2(float* output_buffer, int out_texel_index, float* input_buffer, int input_texel_index, int channels, float coefficient)
@ -526,8 +526,8 @@ static void stbr__output_decode_coefficients_2(float* output_buffer, int out_tex
output_buffer[out_texel_index ] += input_buffer[input_texel_index ] * coefficient;
output_buffer[out_texel_index + 1] += input_buffer[input_texel_index + 1] * coefficient;
STBR_DEBUG_ASSERT(output_buffer[out_texel_index ] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index+1] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index ] <= 1.001f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 1] <= 1.001f);
}
static void stbr__output_decode_coefficients_3(float* output_buffer, int out_texel_index, float* input_buffer, int input_texel_index, int channels, float coefficient)
@ -538,9 +538,9 @@ static void stbr__output_decode_coefficients_3(float* output_buffer, int out_tex
output_buffer[out_texel_index + 1] += input_buffer[input_texel_index + 1] * coefficient;
output_buffer[out_texel_index + 2] += input_buffer[input_texel_index + 2] * coefficient;
STBR_DEBUG_ASSERT(output_buffer[out_texel_index ] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 1] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 2] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index ] <= 1.001f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 1] <= 1.001f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 2] <= 1.001f);
}
static void stbr__output_decode_coefficients_4(float* output_buffer, int out_texel_index, float* input_buffer, int input_texel_index, int channels, float coefficient)
@ -552,10 +552,10 @@ static void stbr__output_decode_coefficients_4(float* output_buffer, int out_tex
output_buffer[out_texel_index + 2] += input_buffer[input_texel_index + 2] * coefficient;
output_buffer[out_texel_index + 3] += input_buffer[input_texel_index + 3] * coefficient;
STBR_DEBUG_ASSERT(output_buffer[out_texel_index ] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 1] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 2] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 3] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index ] <= 1.001f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 1] <= 1.001f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 2] <= 1.001f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + 3] <= 1.001f);
}
static void stbr__output_decode_coefficients_n(float* output_buffer, int out_texel_index, float* input_buffer, int input_texel_index, int channels, float coefficient)
@ -565,7 +565,7 @@ static void stbr__output_decode_coefficients_n(float* output_buffer, int out_tex
{
output_buffer[out_texel_index + c] += input_buffer[input_texel_index + c] * coefficient;
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + c] <= 1.0f);
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + c] <= 1.001f);
}
}
@ -869,16 +869,16 @@ static void stbr__empty_ring_buffer(stbr__info* stbr_info, int first_necessary_s
if (stbr_info->ring_buffer_begin_index >= 0)
{
// Get rid of whatever we don't need anymore.
while (first_necessary_scanline > stbr_info->ring_buffer_first_scanline || first_necessary_scanline < 0)
while (first_necessary_scanline > stbr_info->ring_buffer_first_scanline)
{
int x, c;
int output_row = stbr_info->ring_buffer_first_scanline * output_stride_bytes;
float* ring_buffer_entry = stbr__get_ring_buffer_entry(ring_buffer, stbr_info->ring_buffer_begin_index, ring_buffer_length);
STBR_UNIMPLEMENTED(stbr_info->type != STBR_TYPE_UINT8);
if (stbr_info->ring_buffer_first_scanline >= 0 && stbr_info->ring_buffer_first_scanline < stbr_info->output_h)
{
int x, c;
int output_row = stbr_info->ring_buffer_first_scanline * output_stride_bytes;
float* ring_buffer_entry = stbr__get_ring_buffer_entry(ring_buffer, stbr_info->ring_buffer_begin_index, ring_buffer_length);
for (x = 0; x < output_w; x++)
{
int texel_index = x * channels;
@ -912,10 +912,11 @@ static void stbr__buffer_loop_downsample(stbr__info* stbr_info)
int y;
float scale_ratio = (float)stbr_info->output_h / stbr_info->input_h;
float in_pixels_radius = stbr__filter_info_table[stbr_info->filter].support / scale_ratio;
int max_y = stbr_info->input_h + stbr__get_filter_texel_margin(stbr_info->filter);
STBR_DEBUG_ASSERT(!stbr__use_height_upsampling(stbr_info));
for (y = 0; y < stbr_info->input_h; y++)
for (y = -stbr__get_filter_texel_margin(stbr_info->filter); y < max_y; y++)
{
float out_center_of_in; // Center of the current out scanline in the in scanline space
int out_first_scanline, out_last_scanline;
@ -923,8 +924,8 @@ static void stbr__buffer_loop_downsample(stbr__info* stbr_info)
stbr__calculate_sample_range_downsample(y, in_pixels_radius, scale_ratio, &out_first_scanline, &out_last_scanline, &out_center_of_in);
STBR_DEBUG_ASSERT(out_last_scanline - out_first_scanline <= stbr__get_filter_texel_width(stbr_info->filter));
STBR_DEBUG_ASSERT(out_first_scanline >= -stbr__get_filter_texel_margin(stbr_info->filter));
STBR_DEBUG_ASSERT(out_last_scanline < stbr_info->input_w + stbr__get_filter_texel_margin(stbr_info->filter));
STBR_DEBUG_ASSERT(out_first_scanline >= -2*stbr__get_filter_texel_margin(stbr_info->filter));
STBR_DEBUG_ASSERT(out_last_scanline < stbr_info->input_w + 2*stbr__get_filter_texel_margin(stbr_info->filter));
stbr__empty_ring_buffer(stbr_info, out_first_scanline);
@ -941,7 +942,7 @@ static void stbr__buffer_loop_downsample(stbr__info* stbr_info)
stbr__resample_vertical_downsample(stbr_info, y, out_first_scanline, out_last_scanline, out_center_of_in);
}
stbr__empty_ring_buffer(stbr_info, -1);
stbr__empty_ring_buffer(stbr_info, stbr_info->output_h);
}
STBRDEF int stbr_resize_arbitrary(const void* input_data, int input_w, int input_h, int input_stride_in_bytes,