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These minor optimizations were probably already done by the compiler but they can't hurt.

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This commit is contained in:
Jorge Rodriguez 2014-09-09 22:07:40 -07:00
parent 41e6aad693
commit 1d5c902e2e
1 changed files with 47 additions and 32 deletions
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79
stb_image_resize.h
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@ -1225,14 +1225,13 @@ static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void
{ {
for (x=0; x < num_pixels; ++x) for (x=0; x < num_pixels; ++x)
{ {
int output_pixel_index = x*channels; int pixel_index = x*channels;
int encode_pixel_index = x*channels; float alpha = encode_buffer[pixel_index + alpha_channel];
float alpha = encode_buffer[encode_pixel_index + alpha_channel];
STBIR__DEBUG_ASSERT(alpha > 0); STBIR__DEBUG_ASSERT(alpha > 0);
float reciprocal_alpha = alpha ? 1.0f / alpha : 0; float reciprocal_alpha = alpha ? 1.0f / alpha : 0;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
if (n != alpha_channel) if (n != alpha_channel)
encode_buffer[encode_pixel_index + n] *= reciprocal_alpha; encode_buffer[pixel_index + n] *= reciprocal_alpha;
} }
} }
@ -1241,50 +1240,58 @@ static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void
case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR): case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_LINEAR):
for (x=0; x < num_pixels; ++x) for (x=0; x < num_pixels; ++x)
{ {
int output_pixel_index = x*channels; int pixel_index = x*channels;
int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned char*)output_buffer)[output_pixel_index + n] = (unsigned char)(round(stbir__saturate(encode_buffer[encode_pixel_index + n]) * 255)); {
int index = pixel_index + n;
((unsigned char*)output_buffer)[index] = (unsigned char)(round(stbir__saturate(encode_buffer[index]) * 255));
}
} }
break; break;
case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB): case STBIR__DECODE(STBIR_TYPE_UINT8, STBIR_COLORSPACE_SRGB):
for (x=0; x < num_pixels; ++x) for (x=0; x < num_pixels; ++x)
{ {
int output_pixel_index = x*channels; int pixel_index = x*channels;
int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned char*)output_buffer)[output_pixel_index + n] = stbir__linear_to_srgb_uchar(encode_buffer[encode_pixel_index + n]); {
int index = pixel_index + n;
((unsigned char*)output_buffer)[index] = stbir__linear_to_srgb_uchar(encode_buffer[index]);
}
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE)) if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((unsigned char*)output_buffer)[output_pixel_index + alpha_channel] = (unsigned char)(round(stbir__saturate(encode_buffer[encode_pixel_index + alpha_channel]) * 255)); ((unsigned char*)output_buffer)[pixel_index + alpha_channel] = (unsigned char)(round(stbir__saturate(encode_buffer[pixel_index + alpha_channel]) * 255));
} }
break; break;
case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR): case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR):
for (x=0; x < num_pixels; ++x) for (x=0; x < num_pixels; ++x)
{ {
int output_pixel_index = x*channels; int pixel_index = x*channels;
int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned short*)output_buffer)[output_pixel_index + n] = (unsigned short)(round(stbir__saturate(encode_buffer[encode_pixel_index + n]) * 65535)); {
int index = pixel_index + n;
((unsigned short*)output_buffer)[index] = (unsigned short)(round(stbir__saturate(encode_buffer[index]) * 65535));
}
} }
break; break;
case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB): case STBIR__DECODE(STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB):
for (x=0; x < num_pixels; ++x) for (x=0; x < num_pixels; ++x)
{ {
int output_pixel_index = x*channels; int pixel_index = x*channels;
int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned short*)output_buffer)[output_pixel_index + n] = (unsigned short)(round(stbir__linear_to_srgb(stbir__saturate(encode_buffer[encode_pixel_index + n])) * 65535)); {
int index = pixel_index + n;
((unsigned short*)output_buffer)[index] = (unsigned short)(round(stbir__linear_to_srgb(stbir__saturate(encode_buffer[index])) * 65535));
}
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE)) if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((unsigned short*)output_buffer)[output_pixel_index + alpha_channel] = (unsigned short)(round(stbir__saturate(encode_buffer[encode_pixel_index + alpha_channel]) * 65535)); ((unsigned short*)output_buffer)[pixel_index + alpha_channel] = (unsigned short)(round(stbir__saturate(encode_buffer[pixel_index + alpha_channel]) * 65535));
} }
break; break;
@ -1292,50 +1299,58 @@ static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void
case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR): case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_LINEAR):
for (x=0; x < num_pixels; ++x) for (x=0; x < num_pixels; ++x)
{ {
int output_pixel_index = x*channels; int pixel_index = x*channels;
int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned int*)output_buffer)[output_pixel_index + n] = (unsigned int)(round(((double)stbir__saturate(encode_buffer[encode_pixel_index + n])) * 4294967295)); {
int index = pixel_index + n;
((unsigned int*)output_buffer)[index] = (unsigned int)(round(((double)stbir__saturate(encode_buffer[index])) * 4294967295));
}
} }
break; break;
case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB): case STBIR__DECODE(STBIR_TYPE_UINT32, STBIR_COLORSPACE_SRGB):
for (x=0; x < num_pixels; ++x) for (x=0; x < num_pixels; ++x)
{ {
int output_pixel_index = x*channels; int pixel_index = x*channels;
int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned int*)output_buffer)[output_pixel_index + n] = (unsigned int)(round(((double)stbir__linear_to_srgb(stbir__saturate(encode_buffer[encode_pixel_index + n]))) * 4294967295)); {
int index = pixel_index + n;
((unsigned int*)output_buffer)[index] = (unsigned int)(round(((double)stbir__linear_to_srgb(stbir__saturate(encode_buffer[index]))) * 4294967295));
}
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE)) if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((unsigned int*)output_buffer)[output_pixel_index + alpha_channel] = (unsigned int)(round(((double)stbir__saturate(encode_buffer[encode_pixel_index + alpha_channel])) * 4294967295)); ((unsigned int*)output_buffer)[pixel_index + alpha_channel] = (unsigned int)(round(((double)stbir__saturate(encode_buffer[pixel_index + alpha_channel])) * 4294967295));
} }
break; break;
case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR): case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_LINEAR):
for (x=0; x < num_pixels; ++x) for (x=0; x < num_pixels; ++x)
{ {
int output_pixel_index = x*channels; int pixel_index = x*channels;
int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((float*)output_buffer)[output_pixel_index + n] = encode_buffer[encode_pixel_index + n]; {
int index = pixel_index + n;
((float*)output_buffer)[index] = encode_buffer[index];
}
} }
break; break;
case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB): case STBIR__DECODE(STBIR_TYPE_FLOAT, STBIR_COLORSPACE_SRGB):
for (x=0; x < num_pixels; ++x) for (x=0; x < num_pixels; ++x)
{ {
int output_pixel_index = x*channels; int pixel_index = x*channels;
int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((float*)output_buffer)[output_pixel_index + n] = stbir__linear_to_srgb(encode_buffer[encode_pixel_index + n]); {
int index = pixel_index + n;
((float*)output_buffer)[index] = stbir__linear_to_srgb(encode_buffer[index]);
}
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE)) if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((float*)output_buffer)[output_pixel_index + alpha_channel] = encode_buffer[encode_pixel_index + alpha_channel]; ((float*)output_buffer)[pixel_index + alpha_channel] = encode_buffer[pixel_index + alpha_channel];
} }
break; break;