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ZOOM AND ENHANCE!

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This commit is contained in:
Jorge Rodriguez 2014-07-31 15:16:36 -07:00
parent 1b2d104e00
commit aae1c7ca41
2 changed files with 18 additions and 22 deletions
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36
stb_resample.h
View File

@ -404,19 +404,19 @@ static stbr__filter_info stbr__filter_info_table[] = {
{ stbr__filter_mitchell, 2.0f },
};
stbr_inline static int stbr__use_upsampling(int output_w, int input_w)
stbr_inline static int stbr__use_upsampling(float ratio)
{
return output_w > input_w;
return ratio > 1;
}
stbr_inline static int stbr__use_width_upsampling(stbr__info* stbr_info)
{
return stbr__use_upsampling(stbr_info->output_w, stbr_info->input_w);
return stbr__use_upsampling(stbr_info->horizontal_scale);
}
stbr_inline static int stbr__use_height_upsampling(stbr__info* stbr_info)
{
return stbr__use_upsampling(stbr_info->output_h, stbr_info->input_h);
return stbr__use_upsampling(stbr_info->vertical_scale);
}
// This is the maximum number of input samples that can affect an output sample
@ -426,7 +426,7 @@ stbr_inline static int stbr__get_filter_texel_width(stbr_filter filter, int inpu
STBR_ASSERT(filter != 0);
STBR_ASSERT(filter < STBR_ARRAY_SIZE(stbr__filter_info_table));
if (stbr__use_upsampling(output_w, input_w))
if (stbr__use_upsampling(scale))
return (int)ceil(stbr__filter_info_table[filter].support * 2);
else
return (int)ceil(stbr__filter_info_table[filter].support * 2 / scale);
@ -461,7 +461,7 @@ stbr_inline static int stbr__get_filter_texel_margin_vertical(stbr__info* stbr_i
stbr_inline static int stbr__get_horizontal_contributors_noinfo(stbr_filter filter, int input_w, int output_w, float horizontal_scale)
{
if (stbr__use_upsampling(output_w, input_w))
if (stbr__use_upsampling(horizontal_scale))
return output_w;
else
return (input_w + stbr__get_filter_texel_margin(filter, input_w, output_w, horizontal_scale) * 2);
@ -548,16 +548,16 @@ stbr_inline static int stbr__edge_wrap(stbr_edge edge, int n, int max)
}
// What input texels contribute to this output texel?
static void stbr__calculate_sample_range_upsample(int n, float out_filter_radius, float scale_ratio, int* in_first_texel, int* in_last_texel, float* in_center_of_out)
static void stbr__calculate_sample_range_upsample(int n, float out_filter_radius, float scale_ratio, float out_shift, int* in_first_texel, int* in_last_texel, float* in_center_of_out)
{
float out_texel_center = (float)n + 0.5f;
float out_texel_influence_lowerbound = out_texel_center - out_filter_radius;
float out_texel_influence_upperbound = out_texel_center + out_filter_radius;
float in_texel_influence_lowerbound = out_texel_influence_lowerbound / scale_ratio;
float in_texel_influence_upperbound = out_texel_influence_upperbound / scale_ratio;
float in_texel_influence_lowerbound = (out_texel_influence_lowerbound + out_shift) / scale_ratio;
float in_texel_influence_upperbound = (out_texel_influence_upperbound + out_shift) / scale_ratio;
*in_center_of_out = out_texel_center / scale_ratio;
*in_center_of_out = (out_texel_center + out_shift) / scale_ratio;
*in_first_texel = (int)(floor(in_texel_influence_lowerbound + 0.5));
*in_last_texel = (int)(floor(in_texel_influence_upperbound - 0.5));
}
@ -585,7 +585,6 @@ static void stbr__calculate_coefficients_upsample(stbr__info* stbr_info, int in_
stbr_filter filter = stbr_info->filter;
STBR_DEBUG_ASSERT(in_last_texel - in_first_texel <= stbr__get_filter_texel_width_horizontal(stbr_info));
STBR_DEBUG_ASSERT(in_last_texel < stbr__get_horizontal_contributors(stbr_info));
contributor->n0 = in_first_texel;
contributor->n1 = in_last_texel;
@ -614,7 +613,6 @@ static void stbr__calculate_coefficients_downsample(stbr__info* stbr_info, float
stbr_filter filter = stbr_info->filter;
STBR_DEBUG_ASSERT(out_last_texel - out_first_texel <= stbr__get_filter_texel_width_horizontal(stbr_info));
STBR_DEBUG_ASSERT(out_last_texel < stbr__get_horizontal_contributors(stbr_info));
contributor->n0 = out_first_texel;
contributor->n1 = out_last_texel;
@ -666,15 +664,13 @@ static void stbr__calculate_horizontal_filters(stbr__info* stbr_info)
{
float out_pixels_radius = stbr__filter_info_table[stbr_info->filter].support * scale_ratio;
STBR_UNIMPLEMENTED(stbr_info->horizontal_shift);
// Looping through out texels
for (n = 0; n < total_contributors; n++)
{
float in_center_of_out; // Center of the current out texel in the in texel space
int in_first_texel, in_last_texel;
stbr__calculate_sample_range_upsample(n, out_pixels_radius, scale_ratio, &in_first_texel, &in_last_texel, &in_center_of_out);
stbr__calculate_sample_range_upsample(n, out_pixels_radius, scale_ratio, stbr_info->horizontal_shift, &in_first_texel, &in_last_texel, &in_center_of_out);
stbr__calculate_coefficients_upsample(stbr_info, in_first_texel, in_last_texel, in_center_of_out, stbr__get_contributor(stbr_info, n), stbr__get_coefficient(stbr_info, n, 0));
}
@ -1084,7 +1080,7 @@ static void stbr__resample_vertical_downsample(stbr__info* stbr_info, int n, int
static void stbr__buffer_loop_upsample(stbr__info* stbr_info)
{
int y;
float scale_ratio = (float)stbr_info->output_h / stbr_info->input_h;
float scale_ratio = stbr_info->vertical_scale;
float out_scanlines_radius = stbr__filter_info_table[stbr_info->filter].support * scale_ratio;
STBR_DEBUG_ASSERT(stbr__use_height_upsampling(stbr_info));
@ -1094,7 +1090,7 @@ static void stbr__buffer_loop_upsample(stbr__info* stbr_info)
float in_center_of_out = 0; // Center of the current out scanline in the in scanline space
int in_first_scanline = 0, in_last_scanline = 0;
stbr__calculate_sample_range_upsample(y, out_scanlines_radius, scale_ratio, &in_first_scanline, &in_last_scanline, &in_center_of_out);
stbr__calculate_sample_range_upsample(y, out_scanlines_radius, scale_ratio, stbr_info->vertical_shift, &in_first_scanline, &in_last_scanline, &in_center_of_out);
STBR_DEBUG_ASSERT(in_last_scanline - in_first_scanline <= stbr__get_filter_texel_width_vertical(stbr_info));
@ -1298,8 +1294,8 @@ STBRDEF int stbr_resize_arbitrary(const void* input_data, int input_w, int input
stbr_info->horizontal_scale = ((float)output_w / input_w) / (s1 - s0);
stbr_info->vertical_scale = ((float)output_h / input_h) / (t1 - t0);
stbr_info->horizontal_shift = s0 * input_w * stbr_info->horizontal_scale;
stbr_info->vertical_shift = t0 * input_h * stbr_info->vertical_scale;
stbr_info->horizontal_shift = s0 * input_w / (s1 - s0);
stbr_info->vertical_shift = t0 * input_h / (t1 - t0);
stbr_info->channels = channels;
stbr_info->type = type;
@ -1377,7 +1373,7 @@ STBRDEF stbr_size_t stbr_calculate_memory(int input_w, int input_h, int output_w
int ring_buffer_size = output_w * channels * filter_height * sizeof(float);
int encode_buffer_size = channels * sizeof(float);
if (stbr__use_upsampling(output_h, input_h))
if (stbr__use_upsampling(horizontal_scale))
// The horizontal buffer is for when we're downsampling the height and we
// can't output the result of sampling the decode buffer directly into the
// ring buffers.

4
tests/resample_test.cpp
View File

@ -49,8 +49,8 @@ int main(int argc, char** argv)
return 1;
}
out_w = 128;
out_h = 128;
out_w = 512;
out_h = 512;
out_stride = (out_w + 10) * n;
output_data = (unsigned char*)malloc(out_stride * out_h);