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Do the multiply inline, it should be a tad faster and not corrupt our data.

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This commit is contained in:
Jorge Rodriguez 2014-07-31 19:00:48 -07:00
parent 13acfca829
commit d75488b0e8
2 changed files with 36 additions and 31 deletions
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63
stb_resample.h
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@ -1003,76 +1003,81 @@ static float* stbr__get_ring_buffer_scanline(int get_scanline, float* ring_buffe
static stbr_inline void stbr__encode_scanline(void* output_buffer, int output_texel_index, float* encode_buffer, int encode_texel_index, int channels, int premul_alpha_channel, int decode)
{
int n;
float divide_alpha = 1;
if (premul_alpha_channel)
{
for (n = 0; n < channels; n++)
{
if (n == premul_alpha_channel)
continue;
encode_buffer[encode_texel_index + n] /= encode_buffer[encode_texel_index + premul_alpha_channel];
}
}
divide_alpha = encode_buffer[encode_texel_index + premul_alpha_channel];
switch (decode)
{
case STBR__DECODE(STBR_TYPE_UINT8, STBR_COLORSPACE_LINEAR):
for (n = 0; n < channels; n++)
((unsigned char*)output_buffer)[output_texel_index + n] = (unsigned char)(stbr__saturate(encode_buffer[encode_texel_index + n]) * 255);
{
float divide_alpha_channel = (n == premul_alpha_channel) ? 1 : divide_alpha;
((unsigned char*)output_buffer)[output_texel_index + n] = (unsigned char)(stbr__saturate(encode_buffer[encode_texel_index + n] / divide_alpha_channel) * 255);
}
break;
case STBR__DECODE(STBR_TYPE_UINT8, STBR_COLORSPACE_SRGB):
for (n = 0; n < channels; n++)
((unsigned char*)output_buffer)[output_texel_index + n] = stbr__linear_uchar_to_srgb_uchar[(unsigned char)(stbr__saturate(encode_buffer[encode_texel_index + n]) * 255)];
{
float divide_alpha_channel = (n == premul_alpha_channel) ? 1 : divide_alpha;
((unsigned char*)output_buffer)[output_texel_index + n] = stbr__linear_uchar_to_srgb_uchar[(unsigned char)(stbr__saturate(encode_buffer[encode_texel_index + n] / divide_alpha_channel) * 255)];
}
break;
case STBR__DECODE(STBR_TYPE_UINT16, STBR_COLORSPACE_LINEAR):
for (n = 0; n < channels; n++)
((unsigned short*)output_buffer)[output_texel_index + n] = (unsigned short)(stbr__saturate(encode_buffer[encode_texel_index + n]) * 65535);
{
float divide_alpha_channel = (n == premul_alpha_channel) ? 1 : divide_alpha;
((unsigned short*)output_buffer)[output_texel_index + n] = (unsigned short)(stbr__saturate(encode_buffer[encode_texel_index + n] / divide_alpha_channel) * 65535);
}
break;
case STBR__DECODE(STBR_TYPE_UINT16, STBR_COLORSPACE_SRGB):
for (n = 0; n < channels; n++)
((unsigned short*)output_buffer)[output_texel_index + n] = (unsigned short)(stbr__linear_to_srgb(stbr__saturate(encode_buffer[encode_texel_index + n])) * 65535);
{
float divide_alpha_channel = (n == premul_alpha_channel) ? 1 : divide_alpha;
((unsigned short*)output_buffer)[output_texel_index + n] = (unsigned short)(stbr__linear_to_srgb(stbr__saturate(encode_buffer[encode_texel_index + n] / divide_alpha_channel)) * 65535);
}
break;
case STBR__DECODE(STBR_TYPE_UINT32, STBR_COLORSPACE_LINEAR):
for (n = 0; n < channels; n++)
((unsigned int*)output_buffer)[output_texel_index + n] = (unsigned int)(((double)stbr__saturate(encode_buffer[encode_texel_index + n])) * 4294967295);
{
float divide_alpha_channel = (n == premul_alpha_channel) ? 1 : divide_alpha;
((unsigned int*)output_buffer)[output_texel_index + n] = (unsigned int)(((double)stbr__saturate(encode_buffer[encode_texel_index + n] / divide_alpha_channel)) * 4294967295);
}
break;
case STBR__DECODE(STBR_TYPE_UINT32, STBR_COLORSPACE_SRGB):
for (n = 0; n < channels; n++)
((unsigned int*)output_buffer)[output_texel_index + n] = (unsigned int)(((double)stbr__linear_to_srgb(stbr__saturate(encode_buffer[encode_texel_index + n]))) * 4294967295);
{
float divide_alpha_channel = (n == premul_alpha_channel) ? 1 : divide_alpha;
((unsigned int*)output_buffer)[output_texel_index + n] = (unsigned int)(((double)stbr__linear_to_srgb(stbr__saturate(encode_buffer[encode_texel_index + n] / divide_alpha_channel))) * 4294967295);
}
break;
case STBR__DECODE(STBR_TYPE_FLOAT, STBR_COLORSPACE_LINEAR):
for (n = 0; n < channels; n++)
((float*)output_buffer)[output_texel_index + n] = stbr__saturate(encode_buffer[encode_texel_index + n]);
{
float divide_alpha_channel = (n == premul_alpha_channel) ? 1 : divide_alpha;
((float*)output_buffer)[output_texel_index + n] = stbr__saturate(encode_buffer[encode_texel_index + n] / divide_alpha_channel);
}
break;
case STBR__DECODE(STBR_TYPE_FLOAT, STBR_COLORSPACE_SRGB):
for (n = 0; n < channels; n++)
((float*)output_buffer)[output_texel_index + n] = stbr__linear_to_srgb(stbr__saturate(encode_buffer[encode_texel_index + n]));
{
float divide_alpha_channel = (n == premul_alpha_channel) ? 1 : divide_alpha;
((float*)output_buffer)[output_texel_index + n] = stbr__linear_to_srgb(stbr__saturate(encode_buffer[encode_texel_index + n] / divide_alpha_channel));
}
break;
default:
STBR_UNIMPLEMENTED("Unknown type/colorspace/channels combination.");
break;
}
// Put it back the way it was in case this is a ring buffer.
if (premul_alpha_channel)
{
for (n = 0; n < channels; n++)
{
if (n == premul_alpha_channel)
continue;
encode_buffer[encode_texel_index + n] *= encode_buffer[encode_texel_index + premul_alpha_channel];
}
}
}
static void stbr__resample_vertical_upsample(stbr__info* stbr_info, int n, int in_first_scanline, int in_last_scanline, float in_center_of_out)

4
tests/resample_test.cpp
View File

@ -295,8 +295,8 @@ void test_premul(const char* file)
stbi_write_png("test-output/premul-original.png", w, h, n, input_data, 0);
int new_w = (int)(w * .5);
int new_h = (int)(h * .5);
int new_w = (int)(w * .1);
int new_h = (int)(h * .1);
unsigned char* output_data = (unsigned char*)malloc(new_w * new_h * n * sizeof(unsigned char));