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Fix non uniform scaling where out_w < in_w && out_h > in_h.

This commit is contained in:
Jorge Rodriguez 2014-07-24 23:32:25 -07:00
parent 736596ba09
commit 666c025710
1 changed files with 9 additions and 8 deletions
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17
stb_resample.h
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@ -473,7 +473,7 @@ static void stbr__resample_horizontal_upsample(stbr__info* stbr_info, int n, flo
}
}
static void stbr__resample_horizontal_downsample(stbr__info* stbr_info, int n)
static void stbr__resample_horizontal_downsample(stbr__info* stbr_info, int n, float* output_buffer)
{
int x, k, c;
int input_w = stbr_info->input_w;
@ -483,8 +483,6 @@ static void stbr__resample_horizontal_downsample(stbr__info* stbr_info, int n)
stbr__contributors* horizontal_contributors = stbr_info->horizontal_contributors;
float* horizontal_coefficients = stbr_info->horizontal_coefficients;
float* horizontal_buffer = stbr_info->horizontal_buffer;
STBR_DEBUG_ASSERT(stbr_info->output_w < stbr_info->input_w);
for (x = 0; x < input_w; x++)
@ -509,9 +507,9 @@ static void stbr__resample_horizontal_downsample(stbr__info* stbr_info, int n)
for (c = 0; c < channels; c++)
{
horizontal_buffer[out_texel_index + c] += decode_buffer[in_texel_index + c] * coefficient;
output_buffer[out_texel_index + c] += decode_buffer[in_texel_index + c] * coefficient;
STBR_DEBUG_ASSERT(horizontal_buffer[out_texel_index + c] <= 1.0); // This would indicate that the sum of kernels for this texel doesn't add to 1.
STBR_DEBUG_ASSERT(output_buffer[out_texel_index + c] <= 1.0); // This would indicate that the sum of kernels for this texel doesn't add to 1.
}
}
}
@ -529,7 +527,10 @@ static void stbr__decode_and_resample_upsample(stbr__info* stbr_info, int n)
stbr__decode_scanline(stbr_info, n);
// Now resample it into the ring buffer.
stbr__resample_horizontal_upsample(stbr_info, n, stbr__add_empty_ring_buffer_entry(stbr_info, n));
if (stbr_info->output_w > stbr_info->input_w)
stbr__resample_horizontal_upsample(stbr_info, n, stbr__add_empty_ring_buffer_entry(stbr_info, n));
else
stbr__resample_horizontal_downsample(stbr_info, n, stbr__add_empty_ring_buffer_entry(stbr_info, n));
// Now it's sitting in the ring buffer ready to be used as source for the vertical sampling.
}
@ -551,7 +552,7 @@ static void stbr__decode_and_resample_downsample(stbr__info* stbr_info, int n)
if (stbr_info->output_w > stbr_info->input_w)
stbr__resample_horizontal_upsample(stbr_info, n, stbr_info->horizontal_buffer);
else
stbr__resample_horizontal_downsample(stbr_info, n);
stbr__resample_horizontal_downsample(stbr_info, n, stbr_info->horizontal_buffer);
// Now it's sitting in the horizontal buffer ready to be distributed into the ring buffers.
}
@ -589,7 +590,7 @@ static void stbr__resample_vertical_upsample(stbr__info* stbr_info, int n, int i
int output_row_index = n * stbr_info->output_stride_bytes;
STBR_DEBUG_ASSERT(stbr_info->output_w > stbr_info->input_w);
STBR_DEBUG_ASSERT(stbr_info->output_h > stbr_info->input_h);
STBR_DEBUG_ASSERT(n0 >= in_first_scanline);
STBR_DEBUG_ASSERT(n1 <= in_last_scanline);