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This is definitely faster than the function pointer solution.

pull/32/head
Jorge Rodriguez 2014-07-29 12:11:03 -07:00
parent 9bd5abb52d
commit 3a3e06029e
1 changed files with 12 additions and 67 deletions
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79
stb_resample.h
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@ -699,62 +699,6 @@ static float* stbr__add_empty_ring_buffer_entry(stbr__info* stbr_info, int n)
return ring_buffer;
}
typedef void(*stbr__output_decode_coefficients)(float* output_buffer, int out_texel_index, float* decode_buffer, int decode_texel_index, int channels, float coefficient);
static void stbr__output_decode_coefficients_1(float* output_buffer, int out_texel_index, float* input_buffer, int input_texel_index, int channels, float coefficient)
{
STBR_DEBUG_ASSERT(channels == 1);
output_buffer[out_texel_index] += input_buffer[input_texel_index] * coefficient;
}
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)
{
STBR_DEBUG_ASSERT(channels == 2);
output_buffer[out_texel_index ] += input_buffer[input_texel_index ] * coefficient;
output_buffer[out_texel_index + 1] += input_buffer[input_texel_index + 1] * coefficient;
}
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)
{
STBR_DEBUG_ASSERT(channels == 3);
output_buffer[out_texel_index ] += input_buffer[input_texel_index ] * coefficient;
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;
}
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)
{
STBR_DEBUG_ASSERT(channels == 4);
output_buffer[out_texel_index ] += input_buffer[input_texel_index ] * coefficient;
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;
output_buffer[out_texel_index + 3] += input_buffer[input_texel_index + 3] * coefficient;
}
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)
{
int c;
for (c = 0; c < channels; c++)
output_buffer[out_texel_index + c] += input_buffer[input_texel_index + c] * coefficient;
}
static stbr__output_decode_coefficients stbr__get_output_decode_coefficients_function(int channels)
{
if (channels == 1)
return &stbr__output_decode_coefficients_1;
else if (channels == 2)
return &stbr__output_decode_coefficients_2;
else if (channels == 3)
return &stbr__output_decode_coefficients_3;
else if (channels == 4)
return &stbr__output_decode_coefficients_4;
return &stbr__output_decode_coefficients_n;
}
static void stbr__resample_horizontal_upsample(stbr__info* stbr_info, int n, float* output_buffer)
{
@ -766,8 +710,6 @@ static void stbr__resample_horizontal_upsample(stbr__info* stbr_info, int n, flo
stbr__contributors* horizontal_contributors = stbr_info->horizontal_contributors;
float* horizontal_coefficients = stbr_info->horizontal_coefficients;
stbr__output_decode_coefficients output_decode_coefficients_fn = stbr__get_output_decode_coefficients_function(channels);
for (x = 0; x < output_w; x++)
{
int n0 = horizontal_contributors[x].n0;
@ -789,7 +731,9 @@ static void stbr__resample_horizontal_upsample(stbr__info* stbr_info, int n, flo
int in_texel_index = k * channels;
float coefficient = horizontal_coefficients[coefficient_index];
output_decode_coefficients_fn(output_buffer, out_texel_index, decode_buffer, in_texel_index, channels, coefficient);
int c;
for (c = 0; c < channels; c++)
output_buffer[out_texel_index + c] += decode_buffer[in_texel_index + c] * coefficient;
}
}
}
@ -807,8 +751,6 @@ static void stbr__resample_horizontal_downsample(stbr__info* stbr_info, int n, f
int filter_texel_margin = stbr__get_filter_texel_margin(stbr_info->filter);
int max_x = input_w + filter_texel_margin * 2;
stbr__output_decode_coefficients output_decode_coefficients_fn = stbr__get_output_decode_coefficients_function(channels);
STBR_DEBUG_ASSERT(!stbr__use_width_upsampling(stbr_info));
for (x = 0; x < max_x; x++)
@ -830,7 +772,9 @@ static void stbr__resample_horizontal_downsample(stbr__info* stbr_info, int n, f
int out_texel_index = k * channels;
float coefficient = horizontal_coefficients[coefficient_index];
output_decode_coefficients_fn(output_buffer, out_texel_index, decode_buffer, in_texel_index, channels, coefficient);
int c;
for (c = 0; c < channels; c++)
output_buffer[out_texel_index + c] += decode_buffer[in_texel_index + c] * coefficient;
}
}
}
@ -1039,7 +983,6 @@ 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__output_decode_coefficients output_decode_coefficients_fn = stbr__get_output_decode_coefficients_function(channels);
stbr__encode_scanline_channels encode_channels_fn = stbr__get_encode_channels_function(channels);
stbr__encode_scanline_type_colorspace encode_type_colorspace_fn = stbr__get_encode_type_colorspace_function(stbr_info->type, stbr_info->colorspace);
@ -1063,7 +1006,9 @@ static void stbr__resample_vertical_upsample(stbr__info* stbr_info, int n, int i
float* ring_buffer_entry = stbr__get_ring_buffer_scanline(k, ring_buffer, ring_buffer_begin_index, ring_buffer_first_scanline, kernel_texel_width, ring_buffer_length);
float coefficient = vertical_coefficients[coefficient_index];
output_decode_coefficients_fn(encode_buffer, 0, ring_buffer_entry, in_texel_index, channels, coefficient);
int c;
for (c = 0; c < channels; c++)
encode_buffer[c] += ring_buffer_entry[in_texel_index + c] * coefficient;
}
encode_channels_fn(output_data, out_texel_index, encode_buffer, 0, channels, encode_type_colorspace_fn);
@ -1094,8 +1039,6 @@ static void stbr__resample_vertical_downsample(stbr__info* stbr_info, int n, int
int n1 = vertical_contributors->n1;
int max_n = stbr__min(n1, output_h - 1);
stbr__output_decode_coefficients output_decode_coefficients_fn = stbr__get_output_decode_coefficients_function(channels);
STBR_DEBUG_ASSERT(!stbr__use_height_upsampling(stbr_info));
STBR_DEBUG_ASSERT(n0 >= in_first_scanline);
STBR_DEBUG_ASSERT(n1 <= in_last_scanline);
@ -1113,7 +1056,9 @@ static void stbr__resample_vertical_downsample(stbr__info* stbr_info, int n, int
{
int in_texel_index = x * channels;
output_decode_coefficients_fn(ring_buffer_entry, in_texel_index, horizontal_buffer, in_texel_index, channels, coefficient);
int c;
for (c = 0; c < channels; c++)
ring_buffer_entry[in_texel_index + c] += horizontal_buffer[in_texel_index + c] * coefficient;
}
}
}