78 lines
2.7 KiB
C
78 lines
2.7 KiB
C
|
// Copyright 2014 Google Inc. All Rights Reserved.
|
||
|
|
//
|
||
|
|
// Use of this source code is governed by a BSD-style license
|
||
|
|
// that can be found in the COPYING file in the root of the source
|
||
|
|
// tree. An additional intellectual property rights grant can be found
|
||
|
|
// in the file PATENTS. All contributing project authors may
|
||
|
|
// be found in the AUTHORS file in the root of the source tree.
|
||
|
|
// -----------------------------------------------------------------------------
|
||
|
|
//
|
||
|
|
// Utilities for processing transparent channel.
|
||
|
|
//
|
||
|
|
// Author: Skal (pascal.massimino@gmail.com)
|
||
|
|
|
||
|
|
#include "./dsp.h"
|
||
|
|
|
||
|
|
#if defined(WEBP_USE_SSE2)
|
||
|
|
#include <emmintrin.h>
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
static int ExtractAlpha(const uint8_t* argb, int argb_stride,
|
||
|
|
int width, int height,
|
||
|
|
uint8_t* alpha, int alpha_stride) {
|
||
|
|
// alpha_and stores an 'and' operation of all the alpha[] values. The final
|
||
|
|
// value is not 0xff if any of the alpha[] is not equal to 0xff.
|
||
|
|
uint32_t alpha_and = 0xff;
|
||
|
|
int i, j;
|
||
|
|
const __m128i a_mask = _mm_set1_epi32(0xffu); // to preserve alpha
|
||
|
|
const __m128i all_0xff = _mm_set_epi32(0, 0, ~0u, ~0u);
|
||
|
|
__m128i all_alphas = all_0xff;
|
||
|
|
|
||
|
|
// We must be able to access 3 extra bytes after the last written byte
|
||
|
|
// 'src[4 * width - 4]', because we don't know if alpha is the first or the
|
||
|
|
// last byte of the quadruplet.
|
||
|
|
const int limit = (width - 1) & ~7;
|
||
|
|
|
||
|
|
for (j = 0; j < height; ++j) {
|
||
|
|
const __m128i* src = (const __m128i*)argb;
|
||
|
|
for (i = 0; i < limit; i += 8) {
|
||
|
|
// load 32 argb bytes
|
||
|
|
const __m128i a0 = _mm_loadu_si128(src + 0);
|
||
|
|
const __m128i a1 = _mm_loadu_si128(src + 1);
|
||
|
|
const __m128i b0 = _mm_and_si128(a0, a_mask);
|
||
|
|
const __m128i b1 = _mm_and_si128(a1, a_mask);
|
||
|
|
const __m128i c0 = _mm_packs_epi32(b0, b1);
|
||
|
|
const __m128i d0 = _mm_packus_epi16(c0, c0);
|
||
|
|
// store
|
||
|
|
_mm_storel_epi64((__m128i*)&alpha[i], d0);
|
||
|
|
// accumulate eight alpha 'and' in parallel
|
||
|
|
all_alphas = _mm_and_si128(all_alphas, d0);
|
||
|
|
src += 2;
|
||
|
|
}
|
||
|
|
for (; i < width; ++i) {
|
||
|
|
const uint32_t alpha_value = argb[4 * i];
|
||
|
|
alpha[i] = alpha_value;
|
||
|
|
alpha_and &= alpha_value;
|
||
|
|
}
|
||
|
|
argb += argb_stride;
|
||
|
|
alpha += alpha_stride;
|
||
|
|
}
|
||
|
|
// Combine the eight alpha 'and' into a 8-bit mask.
|
||
|
|
alpha_and &= _mm_movemask_epi8(_mm_cmpeq_epi8(all_alphas, all_0xff));
|
||
|
|
return (alpha_and == 0xff);
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif // WEBP_USE_SSE2
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
// Init function
|
||
|
|
|
||
|
|
extern void WebPInitAlphaProcessingSSE2(void);
|
||
|
|
|
||
|
|
void WebPInitAlphaProcessingSSE2(void) {
|
||
|
|
#if defined(WEBP_USE_SSE2)
|
||
|
|
WebPExtractAlpha = ExtractAlpha;
|
||
|
|
#endif
|
||
|
|
}
|