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

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This commit is contained in:
Jorge Rodriguez 2014-07-24 23:27:29 -07:00
parent 178e301ea4
commit 736596ba09
1 changed files with 15 additions and 10 deletions
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25
stb_resample.h
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@ -432,7 +432,7 @@ static float* stbr__add_empty_ring_buffer_entry(stbr__info* stbr_info, int n)
return ring_buffer; return ring_buffer;
} }
static void stbr__resample_horizontal_upsample(stbr__info* stbr_info, int n) static void stbr__resample_horizontal_upsample(stbr__info* stbr_info, int n, float* output_buffer)
{ {
STBR_UNIMPLEMENTED(stbr_info->output_w < stbr_info->input_w); STBR_UNIMPLEMENTED(stbr_info->output_w < stbr_info->input_w);
int x, k, c; int x, k, c;
@ -443,8 +443,6 @@ static void stbr__resample_horizontal_upsample(stbr__info* stbr_info, int n)
stbr__contributors* horizontal_contributors = stbr_info->horizontal_contributors; stbr__contributors* horizontal_contributors = stbr_info->horizontal_contributors;
float* horizontal_coefficients = stbr_info->horizontal_coefficients; float* horizontal_coefficients = stbr_info->horizontal_coefficients;
float* ring_buffer = stbr__add_empty_ring_buffer_entry(stbr_info, n);
for (x = 0; x < output_w; x++) for (x = 0; x < output_w; x++)
{ {
int n0 = horizontal_contributors[x].n0; int n0 = horizontal_contributors[x].n0;
@ -466,7 +464,11 @@ static void stbr__resample_horizontal_upsample(stbr__info* stbr_info, int n)
continue; continue;
for (c = 0; c < channels; c++) for (c = 0; c < channels; c++)
ring_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(output_buffer[out_texel_index + c] <= 1.0f);
}
} }
} }
} }
@ -483,9 +485,7 @@ static void stbr__resample_horizontal_downsample(stbr__info* stbr_info, int n)
float* horizontal_buffer = stbr_info->horizontal_buffer; float* horizontal_buffer = stbr_info->horizontal_buffer;
STBR_DEBUG_ASSERT(stbr_info->output_h < stbr_info->input_h); STBR_DEBUG_ASSERT(stbr_info->output_w < stbr_info->input_w);
memset(horizontal_buffer, 0, stbr_info->output_w * channels * sizeof(float));
for (x = 0; x < input_w; x++) for (x = 0; x < input_w; x++)
{ {
@ -529,7 +529,7 @@ static void stbr__decode_and_resample_upsample(stbr__info* stbr_info, int n)
stbr__decode_scanline(stbr_info, n); stbr__decode_scanline(stbr_info, n);
// Now resample it into the ring buffer. // Now resample it into the ring buffer.
stbr__resample_horizontal_upsample(stbr_info, n); stbr__resample_horizontal_upsample(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. // Now it's sitting in the ring buffer ready to be used as source for the vertical sampling.
} }
@ -545,8 +545,13 @@ static void stbr__decode_and_resample_downsample(stbr__info* stbr_info, int n)
// Decode the nth scanline from the source image into the decode buffer. // Decode the nth scanline from the source image into the decode buffer.
stbr__decode_scanline(stbr_info, n); stbr__decode_scanline(stbr_info, n);
memset(stbr_info->horizontal_buffer, 0, stbr_info->output_w * stbr_info->channels * sizeof(float));
// Now resample it into the horizontal buffer. // Now resample it into the horizontal buffer.
stbr__resample_horizontal_downsample(stbr_info, 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);
// Now it's sitting in the horizontal buffer ready to be distributed into the ring buffers. // Now it's sitting in the horizontal buffer ready to be distributed into the ring buffers.
} }
@ -638,7 +643,7 @@ static void stbr__resample_vertical_downsample(stbr__info* stbr_info, int n, int
int n0 = vertical_contributors->n0; int n0 = vertical_contributors->n0;
int n1 = vertical_contributors->n1; int n1 = vertical_contributors->n1;
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(n0 >= in_first_scanline);
STBR_DEBUG_ASSERT(n1 <= in_last_scanline); STBR_DEBUG_ASSERT(n1 <= in_last_scanline);