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move x loop inside switch in horizontal_downsample

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Sean Barrett 2014-09-13 07:46:09 -07:00
parent 7a8c9196d1
commit adbbe8dabd
1 changed files with 64 additions and 20 deletions
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52
stb_image_resize.h
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@ -1430,18 +1430,18 @@ static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, int n
STBIR__DEBUG_ASSERT(!stbir__use_width_upsampling(stbir_info)); STBIR__DEBUG_ASSERT(!stbir__use_width_upsampling(stbir_info));
switch (channels) {
case 1:
for (x = 0; x < max_x; x++) for (x = 0; x < max_x; x++)
{ {
int n0 = horizontal_contributors[x].n0; int n0 = horizontal_contributors[x].n0;
int n1 = horizontal_contributors[x].n1; int n1 = horizontal_contributors[x].n1;
int in_x = x - filter_pixel_margin; int in_x = x - filter_pixel_margin;
int in_pixel_index = in_x * channels; int in_pixel_index = in_x * 1;
int max_n = n1; int max_n = n1;
int coefficient_group = coefficient_width * x; int coefficient_group = coefficient_width * x;
switch (channels) {
case 1:
for (k = n0; k <= max_n; k++) for (k = n0; k <= max_n; k++)
{ {
int out_pixel_index = k * 1; int out_pixel_index = k * 1;
@ -1449,9 +1449,20 @@ static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, int n
STBIR__DEBUG_ASSERT(coefficient != 0); STBIR__DEBUG_ASSERT(coefficient != 0);
output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient; output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
} }
}
break; break;
case 2: case 2:
for (x = 0; x < max_x; x++)
{
int n0 = horizontal_contributors[x].n0;
int n1 = horizontal_contributors[x].n1;
int in_x = x - filter_pixel_margin;
int in_pixel_index = in_x * 2;
int max_n = n1;
int coefficient_group = coefficient_width * x;
for (k = n0; k <= max_n; k++) for (k = n0; k <= max_n; k++)
{ {
int out_pixel_index = k * 2; int out_pixel_index = k * 2;
@ -1460,9 +1471,20 @@ static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, int n
output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient; output_buffer[out_pixel_index + 0] += decode_buffer[in_pixel_index + 0] * coefficient;
output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient; output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
} }
}
break; break;
case 3: case 3:
for (x = 0; x < max_x; x++)
{
int n0 = horizontal_contributors[x].n0;
int n1 = horizontal_contributors[x].n1;
int in_x = x - filter_pixel_margin;
int in_pixel_index = in_x * 3;
int max_n = n1;
int coefficient_group = coefficient_width * x;
for (k = n0; k <= max_n; k++) for (k = n0; k <= max_n; k++)
{ {
int out_pixel_index = k * 3; int out_pixel_index = k * 3;
@ -1472,9 +1494,20 @@ static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, int n
output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient; output_buffer[out_pixel_index + 1] += decode_buffer[in_pixel_index + 1] * coefficient;
output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient; output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
} }
}
break; break;
case 4: case 4:
for (x = 0; x < max_x; x++)
{
int n0 = horizontal_contributors[x].n0;
int n1 = horizontal_contributors[x].n1;
int in_x = x - filter_pixel_margin;
int in_pixel_index = in_x * 4;
int max_n = n1;
int coefficient_group = coefficient_width * x;
for (k = n0; k <= max_n; k++) for (k = n0; k <= max_n; k++)
{ {
int out_pixel_index = k * 4; int out_pixel_index = k * 4;
@ -1485,9 +1518,20 @@ static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, int n
output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient; output_buffer[out_pixel_index + 2] += decode_buffer[in_pixel_index + 2] * coefficient;
output_buffer[out_pixel_index + 3] += decode_buffer[in_pixel_index + 3] * coefficient; output_buffer[out_pixel_index + 3] += decode_buffer[in_pixel_index + 3] * coefficient;
} }
}
break; break;
default: default:
for (x = 0; x < max_x; x++)
{
int n0 = horizontal_contributors[x].n0;
int n1 = horizontal_contributors[x].n1;
int in_x = x - filter_pixel_margin;
int in_pixel_index = in_x * channels;
int max_n = n1;
int coefficient_group = coefficient_width * x;
for (k = n0; k <= max_n; k++) for (k = n0; k <= max_n; k++)
{ {
int c; int c;
@ -1497,8 +1541,8 @@ static void stbir__resample_horizontal_downsample(stbir__info* stbir_info, int n
for (c = 0; c < channels; c++) for (c = 0; c < channels; c++)
output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient; output_buffer[out_pixel_index + c] += decode_buffer[in_pixel_index + c] * coefficient;
} }
break;
} }
break;
} }
} }