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내장 함수 사용에 익숙해지기 위해 한 번에 필터링 된 샘플 하나에 대해 합리적인 속도의 이중 선형 필터링 함수를 계산하려고합니다. 최대 SSE41까지 사용할 수 있습니다.SSE4.1 내장 함수가있는 이중 선형 필터
inline __m128i DivideBy255_8xUint16(const __m128i value)
{
// Blinn 16bit divide by 255 trick but across 8 packed 16bit values
const __m128i plus128 = _mm_add_epi16(value, _mm_set1_epi16(128));
const __m128i plus128ThenDivideBy256 = _mm_srli_epi16(plus128, 8); // TODO: Should this be an arithmetic or logical shift or does it matter?
const __m128i partial = _mm_add_epi16(plus128, plus128ThenDivideBy256);
const __m128i result = _mm_srli_epi16(partial, 8); // TODO: Should this be an arithmetic or logical shift or does it matter?
return result;
}
inline uint32_t BilinearSSE41(const uint8_t* data, uint32_t pitch, uint32_t width, uint32_t height, float u, float v)
{
// TODO: There are probably intrinsics I haven't found yet to avoid using these?
// 0x80 is high bit set which means zero out that component
const __m128i unpack_fraction_u_mask = _mm_set_epi8(0x80, 0, 0x80, 0, 0x80, 0, 0x80, 0, 0x80, 0, 0x80, 0, 0x80, 0, 0x80, 0);
const __m128i unpack_fraction_v_mask = _mm_set_epi8(0x80, 1, 0x80, 1, 0x80, 1, 0x80, 1, 0x80, 1, 0x80, 1, 0x80, 1, 0x80, 1);
const __m128i unpack_two_texels_mask = _mm_set_epi8(0x80, 7, 0x80, 6, 0x80, 5, 0x80, 4, 0x80, 3, 0x80, 2, 0x80, 1, 0x80, 0);
// TODO: Potentially wasting two channels of operations for now
const __m128i size = _mm_set_epi32(0, 0, height - 1, width - 1);
const __m128 uv = _mm_set_ps(0.0f, 0.0f, v, u);
const __m128 floor_uv_f = _mm_floor_ps(uv);
const __m128 fraction_uv_f = _mm_sub_ps(uv, floor_uv_f);
const __m128 fraction255_uv_f = _mm_mul_ps(fraction_uv_f, _mm_set_ps1(255.0f));
const __m128i fraction255_uv_i = _mm_cvttps_epi32(fraction255_uv_f); // TODO: Did this get rounded correctly?
const __m128i fraction255_u_i = _mm_shuffle_epi8(fraction255_uv_i, unpack_fraction_u_mask); // Splat fraction_u*255 across all 16 bit words
const __m128i fraction255_v_i = _mm_shuffle_epi8(fraction255_uv_i, unpack_fraction_v_mask); // Splat fraction_v*255 across all 16 bit words
const __m128i inverse_fraction255_u_i = _mm_sub_epi16(_mm_set1_epi16(255), fraction255_u_i);
const __m128i inverse_fraction255_v_i = _mm_sub_epi16(_mm_set1_epi16(255), fraction255_v_i);
const __m128i floor_uv_i = _mm_cvttps_epi32(floor_uv_f);
const __m128i clipped_floor_uv_i = _mm_min_epu32(floor_uv_i, size); // TODO: I haven't clamped this probably if uv was less than zero yet...
// TODO: Calculating the addresses in the SSE register set would maybe be better
int u0 = _mm_extract_epi32(floor_uv_i, 0);
int v0 = _mm_extract_epi32(floor_uv_i, 1);
const uint8_t* row = data + (u0<<2) + pitch*v0;
const __m128i row0_packed = _mm_loadl_epi64((const __m128i*)data);
const __m128i row0 = _mm_shuffle_epi8(row0_packed, unpack_two_texels_mask);
const __m128i row1_packed = _mm_loadl_epi64((const __m128i*)(data + pitch));
const __m128i row1 = _mm_shuffle_epi8(row1_packed, unpack_two_texels_mask);
// Compute (row0*fraction)/255 + row1*(255 - fraction)/255 - probably slight precision loss across addition!
const __m128i vlerp0 = DivideBy255_8xUint16(_mm_mullo_epi16(row0, fraction255_v_i));
const __m128i vlerp1 = DivideBy255_8xUint16(_mm_mullo_epi16(row1, inverse_fraction255_v_i));
const __m128i vlerp = _mm_adds_epi16(vlerp0, vlerp1);
const __m128i hlerp0 = DivideBy255_8xUint16(_mm_mullo_epi16(vlerp, fraction255_u_i));
const __m128i hlerp1 = DivideBy255_8xUint16(_mm_srli_si128(_mm_mullo_epi16(vlerp, inverse_fraction255_u_i), 16 - 2*4));
const __m128i hlerp = _mm_adds_epi16(hlerp0, hlerp1);
// Pack down to 8bit from 16bit components and return 32bit ARGB result
return _mm_extract_epi32(_mm_packus_epi16(hlerp, hlerp), 0);
}
코드는 이미지 데이터가 렌더링 ARGB8하고 분기로하지 않고 모서리 케이스를 처리하기 위해 별도의 열과 행이 가정
지금까지 나는 다음 있습니다.
나는이 글의 엉망진창의 크기를 줄이기 위해 사용할 수있는 지침에 대해 조언 한 후 물론 더 빨리 실행되도록 개선 할 수 있습니다.
고마워요 :)