diff -r 000000000000 -r 6474c204b198 gfx/2d/convolver.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gfx/2d/convolver.cpp Wed Dec 31 06:09:35 2014 +0100 @@ -0,0 +1,909 @@ +// Copyright (c) 2006-2011 The Chromium Authors. All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions +// are met: +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above copyright +// notice, this list of conditions and the following disclaimer in +// the documentation and/or other materials provided with the +// distribution. +// * Neither the name of Google, Inc. nor the names of its contributors +// may be used to endorse or promote products derived from this +// software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS +// OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED +// AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT +// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +// SUCH DAMAGE. + +#include "convolver.h" + +#include + +#include "skia/SkTypes.h" + +// note: SIMD_SSE2 is not enabled because of bugs, apparently + +#if defined(SIMD_SSE2) +#include // ARCH_CPU_X86_FAMILY was defined in build/config.h +#endif + +#if defined(SK_CPU_LENDIAN) +#define R_OFFSET_IDX 0 +#define G_OFFSET_IDX 1 +#define B_OFFSET_IDX 2 +#define A_OFFSET_IDX 3 +#else +#define R_OFFSET_IDX 3 +#define G_OFFSET_IDX 2 +#define B_OFFSET_IDX 1 +#define A_OFFSET_IDX 0 +#endif + +namespace skia { + +namespace { + +// Converts the argument to an 8-bit unsigned value by clamping to the range +// 0-255. +inline unsigned char ClampTo8(int a) { + if (static_cast(a) < 256) + return a; // Avoid the extra check in the common case. + if (a < 0) + return 0; + return 255; +} + +// Stores a list of rows in a circular buffer. The usage is you write into it +// by calling AdvanceRow. It will keep track of which row in the buffer it +// should use next, and the total number of rows added. +class CircularRowBuffer { + public: + // The number of pixels in each row is given in |source_row_pixel_width|. + // The maximum number of rows needed in the buffer is |max_y_filter_size| + // (we only need to store enough rows for the biggest filter). + // + // We use the |first_input_row| to compute the coordinates of all of the + // following rows returned by Advance(). + CircularRowBuffer(int dest_row_pixel_width, int max_y_filter_size, + int first_input_row) + : row_byte_width_(dest_row_pixel_width * 4), + num_rows_(max_y_filter_size), + next_row_(0), + next_row_coordinate_(first_input_row) { + buffer_.resize(row_byte_width_ * max_y_filter_size); + row_addresses_.resize(num_rows_); + } + + // Moves to the next row in the buffer, returning a pointer to the beginning + // of it. + unsigned char* AdvanceRow() { + unsigned char* row = &buffer_[next_row_ * row_byte_width_]; + next_row_coordinate_++; + + // Set the pointer to the next row to use, wrapping around if necessary. + next_row_++; + if (next_row_ == num_rows_) + next_row_ = 0; + return row; + } + + // Returns a pointer to an "unrolled" array of rows. These rows will start + // at the y coordinate placed into |*first_row_index| and will continue in + // order for the maximum number of rows in this circular buffer. + // + // The |first_row_index_| may be negative. This means the circular buffer + // starts before the top of the image (it hasn't been filled yet). + unsigned char* const* GetRowAddresses(int* first_row_index) { + // Example for a 4-element circular buffer holding coords 6-9. + // Row 0 Coord 8 + // Row 1 Coord 9 + // Row 2 Coord 6 <- next_row_ = 2, next_row_coordinate_ = 10. + // Row 3 Coord 7 + // + // The "next" row is also the first (lowest) coordinate. This computation + // may yield a negative value, but that's OK, the math will work out + // since the user of this buffer will compute the offset relative + // to the first_row_index and the negative rows will never be used. + *first_row_index = next_row_coordinate_ - num_rows_; + + int cur_row = next_row_; + for (int i = 0; i < num_rows_; i++) { + row_addresses_[i] = &buffer_[cur_row * row_byte_width_]; + + // Advance to the next row, wrapping if necessary. + cur_row++; + if (cur_row == num_rows_) + cur_row = 0; + } + return &row_addresses_[0]; + } + + private: + // The buffer storing the rows. They are packed, each one row_byte_width_. + std::vector buffer_; + + // Number of bytes per row in the |buffer_|. + int row_byte_width_; + + // The number of rows available in the buffer. + int num_rows_; + + // The next row index we should write into. This wraps around as the + // circular buffer is used. + int next_row_; + + // The y coordinate of the |next_row_|. This is incremented each time a + // new row is appended and does not wrap. + int next_row_coordinate_; + + // Buffer used by GetRowAddresses(). + std::vector row_addresses_; +}; + +// Convolves horizontally along a single row. The row data is given in +// |src_data| and continues for the num_values() of the filter. +template +// This function is miscompiled with gcc 4.5 with pgo. See bug 827946. +#if defined(__GNUC__) && defined(MOZ_GCC_VERSION_AT_LEAST) +#if MOZ_GCC_VERSION_AT_LEAST(4, 5, 0) && !MOZ_GCC_VERSION_AT_LEAST(4, 6, 0) +__attribute__((optimize("-O1"))) +#endif +#endif +void ConvolveHorizontally(const unsigned char* src_data, + const ConvolutionFilter1D& filter, + unsigned char* out_row) { + // Loop over each pixel on this row in the output image. + int num_values = filter.num_values(); + for (int out_x = 0; out_x < num_values; out_x++) { + // Get the filter that determines the current output pixel. + int filter_offset, filter_length; + const ConvolutionFilter1D::Fixed* filter_values = + filter.FilterForValue(out_x, &filter_offset, &filter_length); + + // Compute the first pixel in this row that the filter affects. It will + // touch |filter_length| pixels (4 bytes each) after this. + const unsigned char* row_to_filter = &src_data[filter_offset * 4]; + + // Apply the filter to the row to get the destination pixel in |accum|. + int accum[4] = {0}; + for (int filter_x = 0; filter_x < filter_length; filter_x++) { + ConvolutionFilter1D::Fixed cur_filter = filter_values[filter_x]; + accum[0] += cur_filter * row_to_filter[filter_x * 4 + R_OFFSET_IDX]; + accum[1] += cur_filter * row_to_filter[filter_x * 4 + G_OFFSET_IDX]; + accum[2] += cur_filter * row_to_filter[filter_x * 4 + B_OFFSET_IDX]; + if (has_alpha) + accum[3] += cur_filter * row_to_filter[filter_x * 4 + A_OFFSET_IDX]; + } + + // Bring this value back in range. All of the filter scaling factors + // are in fixed point with kShiftBits bits of fractional part. + accum[0] >>= ConvolutionFilter1D::kShiftBits; + accum[1] >>= ConvolutionFilter1D::kShiftBits; + accum[2] >>= ConvolutionFilter1D::kShiftBits; + if (has_alpha) + accum[3] >>= ConvolutionFilter1D::kShiftBits; + + // Store the new pixel. + out_row[out_x * 4 + R_OFFSET_IDX] = ClampTo8(accum[0]); + out_row[out_x * 4 + G_OFFSET_IDX] = ClampTo8(accum[1]); + out_row[out_x * 4 + B_OFFSET_IDX] = ClampTo8(accum[2]); + if (has_alpha) + out_row[out_x * 4 + A_OFFSET_IDX] = ClampTo8(accum[3]); + } +} + +// Does vertical convolution to produce one output row. The filter values and +// length are given in the first two parameters. These are applied to each +// of the rows pointed to in the |source_data_rows| array, with each row +// being |pixel_width| wide. +// +// The output must have room for |pixel_width * 4| bytes. +template +void ConvolveVertically(const ConvolutionFilter1D::Fixed* filter_values, + int filter_length, + unsigned char* const* source_data_rows, + int pixel_width, + unsigned char* out_row) { + // We go through each column in the output and do a vertical convolution, + // generating one output pixel each time. + for (int out_x = 0; out_x < pixel_width; out_x++) { + // Compute the number of bytes over in each row that the current column + // we're convolving starts at. The pixel will cover the next 4 bytes. + int byte_offset = out_x * 4; + + // Apply the filter to one column of pixels. + int accum[4] = {0}; + for (int filter_y = 0; filter_y < filter_length; filter_y++) { + ConvolutionFilter1D::Fixed cur_filter = filter_values[filter_y]; + accum[0] += cur_filter + * source_data_rows[filter_y][byte_offset + R_OFFSET_IDX]; + accum[1] += cur_filter + * source_data_rows[filter_y][byte_offset + G_OFFSET_IDX]; + accum[2] += cur_filter + * source_data_rows[filter_y][byte_offset + B_OFFSET_IDX]; + if (has_alpha) + accum[3] += cur_filter + * source_data_rows[filter_y][byte_offset + A_OFFSET_IDX]; + } + + // Bring this value back in range. All of the filter scaling factors + // are in fixed point with kShiftBits bits of precision. + accum[0] >>= ConvolutionFilter1D::kShiftBits; + accum[1] >>= ConvolutionFilter1D::kShiftBits; + accum[2] >>= ConvolutionFilter1D::kShiftBits; + if (has_alpha) + accum[3] >>= ConvolutionFilter1D::kShiftBits; + + // Store the new pixel. + out_row[byte_offset + R_OFFSET_IDX] = ClampTo8(accum[0]); + out_row[byte_offset + G_OFFSET_IDX] = ClampTo8(accum[1]); + out_row[byte_offset + B_OFFSET_IDX] = ClampTo8(accum[2]); + if (has_alpha) { + unsigned char alpha = ClampTo8(accum[3]); + + // Make sure the alpha channel doesn't come out smaller than any of the + // color channels. We use premultipled alpha channels, so this should + // never happen, but rounding errors will cause this from time to time. + // These "impossible" colors will cause overflows (and hence random pixel + // values) when the resulting bitmap is drawn to the screen. + // + // We only need to do this when generating the final output row (here). + int max_color_channel = std::max(out_row[byte_offset + R_OFFSET_IDX], + std::max(out_row[byte_offset + G_OFFSET_IDX], out_row[byte_offset + B_OFFSET_IDX])); + if (alpha < max_color_channel) + out_row[byte_offset + A_OFFSET_IDX] = max_color_channel; + else + out_row[byte_offset + A_OFFSET_IDX] = alpha; + } else { + // No alpha channel, the image is opaque. + out_row[byte_offset + A_OFFSET_IDX] = 0xff; + } + } +} + + +// Convolves horizontally along a single row. The row data is given in +// |src_data| and continues for the num_values() of the filter. +void ConvolveHorizontally_SSE2(const unsigned char* src_data, + const ConvolutionFilter1D& filter, + unsigned char* out_row) { +#if defined(SIMD_SSE2) + int num_values = filter.num_values(); + + int filter_offset, filter_length; + __m128i zero = _mm_setzero_si128(); + __m128i mask[4]; + // |mask| will be used to decimate all extra filter coefficients that are + // loaded by SIMD when |filter_length| is not divisible by 4. + // mask[0] is not used in following algorithm. + mask[1] = _mm_set_epi16(0, 0, 0, 0, 0, 0, 0, -1); + mask[2] = _mm_set_epi16(0, 0, 0, 0, 0, 0, -1, -1); + mask[3] = _mm_set_epi16(0, 0, 0, 0, 0, -1, -1, -1); + + // Output one pixel each iteration, calculating all channels (RGBA) together. + for (int out_x = 0; out_x < num_values; out_x++) { + const ConvolutionFilter1D::Fixed* filter_values = + filter.FilterForValue(out_x, &filter_offset, &filter_length); + + __m128i accum = _mm_setzero_si128(); + + // Compute the first pixel in this row that the filter affects. It will + // touch |filter_length| pixels (4 bytes each) after this. + const __m128i* row_to_filter = + reinterpret_cast(&src_data[filter_offset << 2]); + + // We will load and accumulate with four coefficients per iteration. + for (int filter_x = 0; filter_x < filter_length >> 2; filter_x++) { + + // Load 4 coefficients => duplicate 1st and 2nd of them for all channels. + __m128i coeff, coeff16; + // [16] xx xx xx xx c3 c2 c1 c0 + coeff = _mm_loadl_epi64(reinterpret_cast(filter_values)); + // [16] xx xx xx xx c1 c1 c0 c0 + coeff16 = _mm_shufflelo_epi16(coeff, _MM_SHUFFLE(1, 1, 0, 0)); + // [16] c1 c1 c1 c1 c0 c0 c0 c0 + coeff16 = _mm_unpacklo_epi16(coeff16, coeff16); + + // Load four pixels => unpack the first two pixels to 16 bits => + // multiply with coefficients => accumulate the convolution result. + // [8] a3 b3 g3 r3 a2 b2 g2 r2 a1 b1 g1 r1 a0 b0 g0 r0 + __m128i src8 = _mm_loadu_si128(row_to_filter); + // [16] a1 b1 g1 r1 a0 b0 g0 r0 + __m128i src16 = _mm_unpacklo_epi8(src8, zero); + __m128i mul_hi = _mm_mulhi_epi16(src16, coeff16); + __m128i mul_lo = _mm_mullo_epi16(src16, coeff16); + // [32] a0*c0 b0*c0 g0*c0 r0*c0 + __m128i t = _mm_unpacklo_epi16(mul_lo, mul_hi); + accum = _mm_add_epi32(accum, t); + // [32] a1*c1 b1*c1 g1*c1 r1*c1 + t = _mm_unpackhi_epi16(mul_lo, mul_hi); + accum = _mm_add_epi32(accum, t); + + // Duplicate 3rd and 4th coefficients for all channels => + // unpack the 3rd and 4th pixels to 16 bits => multiply with coefficients + // => accumulate the convolution results. + // [16] xx xx xx xx c3 c3 c2 c2 + coeff16 = _mm_shufflelo_epi16(coeff, _MM_SHUFFLE(3, 3, 2, 2)); + // [16] c3 c3 c3 c3 c2 c2 c2 c2 + coeff16 = _mm_unpacklo_epi16(coeff16, coeff16); + // [16] a3 g3 b3 r3 a2 g2 b2 r2 + src16 = _mm_unpackhi_epi8(src8, zero); + mul_hi = _mm_mulhi_epi16(src16, coeff16); + mul_lo = _mm_mullo_epi16(src16, coeff16); + // [32] a2*c2 b2*c2 g2*c2 r2*c2 + t = _mm_unpacklo_epi16(mul_lo, mul_hi); + accum = _mm_add_epi32(accum, t); + // [32] a3*c3 b3*c3 g3*c3 r3*c3 + t = _mm_unpackhi_epi16(mul_lo, mul_hi); + accum = _mm_add_epi32(accum, t); + + // Advance the pixel and coefficients pointers. + row_to_filter += 1; + filter_values += 4; + } + + // When |filter_length| is not divisible by 4, we need to decimate some of + // the filter coefficient that was loaded incorrectly to zero; Other than + // that the algorithm is same with above, exceot that the 4th pixel will be + // always absent. + int r = filter_length&3; + if (r) { + // Note: filter_values must be padded to align_up(filter_offset, 8). + __m128i coeff, coeff16; + coeff = _mm_loadl_epi64(reinterpret_cast(filter_values)); + // Mask out extra filter taps. + coeff = _mm_and_si128(coeff, mask[r]); + coeff16 = _mm_shufflelo_epi16(coeff, _MM_SHUFFLE(1, 1, 0, 0)); + coeff16 = _mm_unpacklo_epi16(coeff16, coeff16); + + // Note: line buffer must be padded to align_up(filter_offset, 16). + // We resolve this by use C-version for the last horizontal line. + __m128i src8 = _mm_loadu_si128(row_to_filter); + __m128i src16 = _mm_unpacklo_epi8(src8, zero); + __m128i mul_hi = _mm_mulhi_epi16(src16, coeff16); + __m128i mul_lo = _mm_mullo_epi16(src16, coeff16); + __m128i t = _mm_unpacklo_epi16(mul_lo, mul_hi); + accum = _mm_add_epi32(accum, t); + t = _mm_unpackhi_epi16(mul_lo, mul_hi); + accum = _mm_add_epi32(accum, t); + + src16 = _mm_unpackhi_epi8(src8, zero); + coeff16 = _mm_shufflelo_epi16(coeff, _MM_SHUFFLE(3, 3, 2, 2)); + coeff16 = _mm_unpacklo_epi16(coeff16, coeff16); + mul_hi = _mm_mulhi_epi16(src16, coeff16); + mul_lo = _mm_mullo_epi16(src16, coeff16); + t = _mm_unpacklo_epi16(mul_lo, mul_hi); + accum = _mm_add_epi32(accum, t); + } + + // Shift right for fixed point implementation. + accum = _mm_srai_epi32(accum, ConvolutionFilter1D::kShiftBits); + + // Packing 32 bits |accum| to 16 bits per channel (signed saturation). + accum = _mm_packs_epi32(accum, zero); + // Packing 16 bits |accum| to 8 bits per channel (unsigned saturation). + accum = _mm_packus_epi16(accum, zero); + + // Store the pixel value of 32 bits. + *(reinterpret_cast(out_row)) = _mm_cvtsi128_si32(accum); + out_row += 4; + } +#endif +} + +// Convolves horizontally along four rows. The row data is given in +// |src_data| and continues for the num_values() of the filter. +// The algorithm is almost same as |ConvolveHorizontally_SSE2|. Please +// refer to that function for detailed comments. +void ConvolveHorizontally4_SSE2(const unsigned char* src_data[4], + const ConvolutionFilter1D& filter, + unsigned char* out_row[4]) { +#if defined(SIMD_SSE2) + int num_values = filter.num_values(); + + int filter_offset, filter_length; + __m128i zero = _mm_setzero_si128(); + __m128i mask[4]; + // |mask| will be used to decimate all extra filter coefficients that are + // loaded by SIMD when |filter_length| is not divisible by 4. + // mask[0] is not used in following algorithm. + mask[1] = _mm_set_epi16(0, 0, 0, 0, 0, 0, 0, -1); + mask[2] = _mm_set_epi16(0, 0, 0, 0, 0, 0, -1, -1); + mask[3] = _mm_set_epi16(0, 0, 0, 0, 0, -1, -1, -1); + + // Output one pixel each iteration, calculating all channels (RGBA) together. + for (int out_x = 0; out_x < num_values; out_x++) { + const ConvolutionFilter1D::Fixed* filter_values = + filter.FilterForValue(out_x, &filter_offset, &filter_length); + + // four pixels in a column per iteration. + __m128i accum0 = _mm_setzero_si128(); + __m128i accum1 = _mm_setzero_si128(); + __m128i accum2 = _mm_setzero_si128(); + __m128i accum3 = _mm_setzero_si128(); + int start = (filter_offset<<2); + // We will load and accumulate with four coefficients per iteration. + for (int filter_x = 0; filter_x < (filter_length >> 2); filter_x++) { + __m128i coeff, coeff16lo, coeff16hi; + // [16] xx xx xx xx c3 c2 c1 c0 + coeff = _mm_loadl_epi64(reinterpret_cast(filter_values)); + // [16] xx xx xx xx c1 c1 c0 c0 + coeff16lo = _mm_shufflelo_epi16(coeff, _MM_SHUFFLE(1, 1, 0, 0)); + // [16] c1 c1 c1 c1 c0 c0 c0 c0 + coeff16lo = _mm_unpacklo_epi16(coeff16lo, coeff16lo); + // [16] xx xx xx xx c3 c3 c2 c2 + coeff16hi = _mm_shufflelo_epi16(coeff, _MM_SHUFFLE(3, 3, 2, 2)); + // [16] c3 c3 c3 c3 c2 c2 c2 c2 + coeff16hi = _mm_unpacklo_epi16(coeff16hi, coeff16hi); + + __m128i src8, src16, mul_hi, mul_lo, t; + +#define ITERATION(src, accum) \ + src8 = _mm_loadu_si128(reinterpret_cast(src)); \ + src16 = _mm_unpacklo_epi8(src8, zero); \ + mul_hi = _mm_mulhi_epi16(src16, coeff16lo); \ + mul_lo = _mm_mullo_epi16(src16, coeff16lo); \ + t = _mm_unpacklo_epi16(mul_lo, mul_hi); \ + accum = _mm_add_epi32(accum, t); \ + t = _mm_unpackhi_epi16(mul_lo, mul_hi); \ + accum = _mm_add_epi32(accum, t); \ + src16 = _mm_unpackhi_epi8(src8, zero); \ + mul_hi = _mm_mulhi_epi16(src16, coeff16hi); \ + mul_lo = _mm_mullo_epi16(src16, coeff16hi); \ + t = _mm_unpacklo_epi16(mul_lo, mul_hi); \ + accum = _mm_add_epi32(accum, t); \ + t = _mm_unpackhi_epi16(mul_lo, mul_hi); \ + accum = _mm_add_epi32(accum, t) + + ITERATION(src_data[0] + start, accum0); + ITERATION(src_data[1] + start, accum1); + ITERATION(src_data[2] + start, accum2); + ITERATION(src_data[3] + start, accum3); + + start += 16; + filter_values += 4; + } + + int r = filter_length & 3; + if (r) { + // Note: filter_values must be padded to align_up(filter_offset, 8); + __m128i coeff; + coeff = _mm_loadl_epi64(reinterpret_cast(filter_values)); + // Mask out extra filter taps. + coeff = _mm_and_si128(coeff, mask[r]); + + __m128i coeff16lo = _mm_shufflelo_epi16(coeff, _MM_SHUFFLE(1, 1, 0, 0)); + /* c1 c1 c1 c1 c0 c0 c0 c0 */ + coeff16lo = _mm_unpacklo_epi16(coeff16lo, coeff16lo); + __m128i coeff16hi = _mm_shufflelo_epi16(coeff, _MM_SHUFFLE(3, 3, 2, 2)); + coeff16hi = _mm_unpacklo_epi16(coeff16hi, coeff16hi); + + __m128i src8, src16, mul_hi, mul_lo, t; + + ITERATION(src_data[0] + start, accum0); + ITERATION(src_data[1] + start, accum1); + ITERATION(src_data[2] + start, accum2); + ITERATION(src_data[3] + start, accum3); + } + + accum0 = _mm_srai_epi32(accum0, ConvolutionFilter1D::kShiftBits); + accum0 = _mm_packs_epi32(accum0, zero); + accum0 = _mm_packus_epi16(accum0, zero); + accum1 = _mm_srai_epi32(accum1, ConvolutionFilter1D::kShiftBits); + accum1 = _mm_packs_epi32(accum1, zero); + accum1 = _mm_packus_epi16(accum1, zero); + accum2 = _mm_srai_epi32(accum2, ConvolutionFilter1D::kShiftBits); + accum2 = _mm_packs_epi32(accum2, zero); + accum2 = _mm_packus_epi16(accum2, zero); + accum3 = _mm_srai_epi32(accum3, ConvolutionFilter1D::kShiftBits); + accum3 = _mm_packs_epi32(accum3, zero); + accum3 = _mm_packus_epi16(accum3, zero); + + *(reinterpret_cast(out_row[0])) = _mm_cvtsi128_si32(accum0); + *(reinterpret_cast(out_row[1])) = _mm_cvtsi128_si32(accum1); + *(reinterpret_cast(out_row[2])) = _mm_cvtsi128_si32(accum2); + *(reinterpret_cast(out_row[3])) = _mm_cvtsi128_si32(accum3); + + out_row[0] += 4; + out_row[1] += 4; + out_row[2] += 4; + out_row[3] += 4; + } +#endif +} + +// Does vertical convolution to produce one output row. The filter values and +// length are given in the first two parameters. These are applied to each +// of the rows pointed to in the |source_data_rows| array, with each row +// being |pixel_width| wide. +// +// The output must have room for |pixel_width * 4| bytes. +template +void ConvolveVertically_SSE2(const ConvolutionFilter1D::Fixed* filter_values, + int filter_length, + unsigned char* const* source_data_rows, + int pixel_width, + unsigned char* out_row) { +#if defined(SIMD_SSE2) + int width = pixel_width & ~3; + + __m128i zero = _mm_setzero_si128(); + __m128i accum0, accum1, accum2, accum3, coeff16; + const __m128i* src; + // Output four pixels per iteration (16 bytes). + for (int out_x = 0; out_x < width; out_x += 4) { + + // Accumulated result for each pixel. 32 bits per RGBA channel. + accum0 = _mm_setzero_si128(); + accum1 = _mm_setzero_si128(); + accum2 = _mm_setzero_si128(); + accum3 = _mm_setzero_si128(); + + // Convolve with one filter coefficient per iteration. + for (int filter_y = 0; filter_y < filter_length; filter_y++) { + + // Duplicate the filter coefficient 8 times. + // [16] cj cj cj cj cj cj cj cj + coeff16 = _mm_set1_epi16(filter_values[filter_y]); + + // Load four pixels (16 bytes) together. + // [8] a3 b3 g3 r3 a2 b2 g2 r2 a1 b1 g1 r1 a0 b0 g0 r0 + src = reinterpret_cast( + &source_data_rows[filter_y][out_x << 2]); + __m128i src8 = _mm_loadu_si128(src); + + // Unpack 1st and 2nd pixels from 8 bits to 16 bits for each channels => + // multiply with current coefficient => accumulate the result. + // [16] a1 b1 g1 r1 a0 b0 g0 r0 + __m128i src16 = _mm_unpacklo_epi8(src8, zero); + __m128i mul_hi = _mm_mulhi_epi16(src16, coeff16); + __m128i mul_lo = _mm_mullo_epi16(src16, coeff16); + // [32] a0 b0 g0 r0 + __m128i t = _mm_unpacklo_epi16(mul_lo, mul_hi); + accum0 = _mm_add_epi32(accum0, t); + // [32] a1 b1 g1 r1 + t = _mm_unpackhi_epi16(mul_lo, mul_hi); + accum1 = _mm_add_epi32(accum1, t); + + // Unpack 3rd and 4th pixels from 8 bits to 16 bits for each channels => + // multiply with current coefficient => accumulate the result. + // [16] a3 b3 g3 r3 a2 b2 g2 r2 + src16 = _mm_unpackhi_epi8(src8, zero); + mul_hi = _mm_mulhi_epi16(src16, coeff16); + mul_lo = _mm_mullo_epi16(src16, coeff16); + // [32] a2 b2 g2 r2 + t = _mm_unpacklo_epi16(mul_lo, mul_hi); + accum2 = _mm_add_epi32(accum2, t); + // [32] a3 b3 g3 r3 + t = _mm_unpackhi_epi16(mul_lo, mul_hi); + accum3 = _mm_add_epi32(accum3, t); + } + + // Shift right for fixed point implementation. + accum0 = _mm_srai_epi32(accum0, ConvolutionFilter1D::kShiftBits); + accum1 = _mm_srai_epi32(accum1, ConvolutionFilter1D::kShiftBits); + accum2 = _mm_srai_epi32(accum2, ConvolutionFilter1D::kShiftBits); + accum3 = _mm_srai_epi32(accum3, ConvolutionFilter1D::kShiftBits); + + // Packing 32 bits |accum| to 16 bits per channel (signed saturation). + // [16] a1 b1 g1 r1 a0 b0 g0 r0 + accum0 = _mm_packs_epi32(accum0, accum1); + // [16] a3 b3 g3 r3 a2 b2 g2 r2 + accum2 = _mm_packs_epi32(accum2, accum3); + + // Packing 16 bits |accum| to 8 bits per channel (unsigned saturation). + // [8] a3 b3 g3 r3 a2 b2 g2 r2 a1 b1 g1 r1 a0 b0 g0 r0 + accum0 = _mm_packus_epi16(accum0, accum2); + + if (has_alpha) { + // Compute the max(ri, gi, bi) for each pixel. + // [8] xx a3 b3 g3 xx a2 b2 g2 xx a1 b1 g1 xx a0 b0 g0 + __m128i a = _mm_srli_epi32(accum0, 8); + // [8] xx xx xx max3 xx xx xx max2 xx xx xx max1 xx xx xx max0 + __m128i b = _mm_max_epu8(a, accum0); // Max of r and g. + // [8] xx xx a3 b3 xx xx a2 b2 xx xx a1 b1 xx xx a0 b0 + a = _mm_srli_epi32(accum0, 16); + // [8] xx xx xx max3 xx xx xx max2 xx xx xx max1 xx xx xx max0 + b = _mm_max_epu8(a, b); // Max of r and g and b. + // [8] max3 00 00 00 max2 00 00 00 max1 00 00 00 max0 00 00 00 + b = _mm_slli_epi32(b, 24); + + // Make sure the value of alpha channel is always larger than maximum + // value of color channels. + accum0 = _mm_max_epu8(b, accum0); + } else { + // Set value of alpha channels to 0xFF. + __m128i mask = _mm_set1_epi32(0xff000000); + accum0 = _mm_or_si128(accum0, mask); + } + + // Store the convolution result (16 bytes) and advance the pixel pointers. + _mm_storeu_si128(reinterpret_cast<__m128i*>(out_row), accum0); + out_row += 16; + } + + // When the width of the output is not divisible by 4, We need to save one + // pixel (4 bytes) each time. And also the fourth pixel is always absent. + if (pixel_width & 3) { + accum0 = _mm_setzero_si128(); + accum1 = _mm_setzero_si128(); + accum2 = _mm_setzero_si128(); + for (int filter_y = 0; filter_y < filter_length; ++filter_y) { + coeff16 = _mm_set1_epi16(filter_values[filter_y]); + // [8] a3 b3 g3 r3 a2 b2 g2 r2 a1 b1 g1 r1 a0 b0 g0 r0 + src = reinterpret_cast( + &source_data_rows[filter_y][width<<2]); + __m128i src8 = _mm_loadu_si128(src); + // [16] a1 b1 g1 r1 a0 b0 g0 r0 + __m128i src16 = _mm_unpacklo_epi8(src8, zero); + __m128i mul_hi = _mm_mulhi_epi16(src16, coeff16); + __m128i mul_lo = _mm_mullo_epi16(src16, coeff16); + // [32] a0 b0 g0 r0 + __m128i t = _mm_unpacklo_epi16(mul_lo, mul_hi); + accum0 = _mm_add_epi32(accum0, t); + // [32] a1 b1 g1 r1 + t = _mm_unpackhi_epi16(mul_lo, mul_hi); + accum1 = _mm_add_epi32(accum1, t); + // [16] a3 b3 g3 r3 a2 b2 g2 r2 + src16 = _mm_unpackhi_epi8(src8, zero); + mul_hi = _mm_mulhi_epi16(src16, coeff16); + mul_lo = _mm_mullo_epi16(src16, coeff16); + // [32] a2 b2 g2 r2 + t = _mm_unpacklo_epi16(mul_lo, mul_hi); + accum2 = _mm_add_epi32(accum2, t); + } + + accum0 = _mm_srai_epi32(accum0, ConvolutionFilter1D::kShiftBits); + accum1 = _mm_srai_epi32(accum1, ConvolutionFilter1D::kShiftBits); + accum2 = _mm_srai_epi32(accum2, ConvolutionFilter1D::kShiftBits); + // [16] a1 b1 g1 r1 a0 b0 g0 r0 + accum0 = _mm_packs_epi32(accum0, accum1); + // [16] a3 b3 g3 r3 a2 b2 g2 r2 + accum2 = _mm_packs_epi32(accum2, zero); + // [8] a3 b3 g3 r3 a2 b2 g2 r2 a1 b1 g1 r1 a0 b0 g0 r0 + accum0 = _mm_packus_epi16(accum0, accum2); + if (has_alpha) { + // [8] xx a3 b3 g3 xx a2 b2 g2 xx a1 b1 g1 xx a0 b0 g0 + __m128i a = _mm_srli_epi32(accum0, 8); + // [8] xx xx xx max3 xx xx xx max2 xx xx xx max1 xx xx xx max0 + __m128i b = _mm_max_epu8(a, accum0); // Max of r and g. + // [8] xx xx a3 b3 xx xx a2 b2 xx xx a1 b1 xx xx a0 b0 + a = _mm_srli_epi32(accum0, 16); + // [8] xx xx xx max3 xx xx xx max2 xx xx xx max1 xx xx xx max0 + b = _mm_max_epu8(a, b); // Max of r and g and b. + // [8] max3 00 00 00 max2 00 00 00 max1 00 00 00 max0 00 00 00 + b = _mm_slli_epi32(b, 24); + accum0 = _mm_max_epu8(b, accum0); + } else { + __m128i mask = _mm_set1_epi32(0xff000000); + accum0 = _mm_or_si128(accum0, mask); + } + + for (int out_x = width; out_x < pixel_width; out_x++) { + *(reinterpret_cast(out_row)) = _mm_cvtsi128_si32(accum0); + accum0 = _mm_srli_si128(accum0, 4); + out_row += 4; + } + } +#endif +} + +} // namespace + +// ConvolutionFilter1D --------------------------------------------------------- + +ConvolutionFilter1D::ConvolutionFilter1D() + : max_filter_(0) { +} + +ConvolutionFilter1D::~ConvolutionFilter1D() { +} + +void ConvolutionFilter1D::AddFilter(int filter_offset, + const float* filter_values, + int filter_length) { + SkASSERT(filter_length > 0); + + std::vector fixed_values; + fixed_values.reserve(filter_length); + + for (int i = 0; i < filter_length; ++i) + fixed_values.push_back(FloatToFixed(filter_values[i])); + + AddFilter(filter_offset, &fixed_values[0], filter_length); +} + +void ConvolutionFilter1D::AddFilter(int filter_offset, + const Fixed* filter_values, + int filter_length) { + // It is common for leading/trailing filter values to be zeros. In such + // cases it is beneficial to only store the central factors. + // For a scaling to 1/4th in each dimension using a Lanczos-2 filter on + // a 1080p image this optimization gives a ~10% speed improvement. + int first_non_zero = 0; + while (first_non_zero < filter_length && filter_values[first_non_zero] == 0) + first_non_zero++; + + if (first_non_zero < filter_length) { + // Here we have at least one non-zero factor. + int last_non_zero = filter_length - 1; + while (last_non_zero >= 0 && filter_values[last_non_zero] == 0) + last_non_zero--; + + filter_offset += first_non_zero; + filter_length = last_non_zero + 1 - first_non_zero; + SkASSERT(filter_length > 0); + + for (int i = first_non_zero; i <= last_non_zero; i++) + filter_values_.push_back(filter_values[i]); + } else { + // Here all the factors were zeroes. + filter_length = 0; + } + + FilterInstance instance; + + // We pushed filter_length elements onto filter_values_ + instance.data_location = (static_cast(filter_values_.size()) - + filter_length); + instance.offset = filter_offset; + instance.length = filter_length; + filters_.push_back(instance); + + max_filter_ = std::max(max_filter_, filter_length); +} + +void BGRAConvolve2D(const unsigned char* source_data, + int source_byte_row_stride, + bool source_has_alpha, + const ConvolutionFilter1D& filter_x, + const ConvolutionFilter1D& filter_y, + int output_byte_row_stride, + unsigned char* output, + bool use_sse2) { +#if !defined(SIMD_SSE2) + // Even we have runtime support for SSE2 instructions, since the binary + // was not built with SSE2 support, we had to fallback to C version. + use_sse2 = false; +#endif + + int max_y_filter_size = filter_y.max_filter(); + + // The next row in the input that we will generate a horizontally + // convolved row for. If the filter doesn't start at the beginning of the + // image (this is the case when we are only resizing a subset), then we + // don't want to generate any output rows before that. Compute the starting + // row for convolution as the first pixel for the first vertical filter. + int filter_offset, filter_length; + const ConvolutionFilter1D::Fixed* filter_values = + filter_y.FilterForValue(0, &filter_offset, &filter_length); + int next_x_row = filter_offset; + + // We loop over each row in the input doing a horizontal convolution. This + // will result in a horizontally convolved image. We write the results into + // a circular buffer of convolved rows and do vertical convolution as rows + // are available. This prevents us from having to store the entire + // intermediate image and helps cache coherency. + // We will need four extra rows to allow horizontal convolution could be done + // simultaneously. We also padding each row in row buffer to be aligned-up to + // 16 bytes. + // TODO(jiesun): We do not use aligned load from row buffer in vertical + // convolution pass yet. Somehow Windows does not like it. + int row_buffer_width = (filter_x.num_values() + 15) & ~0xF; + int row_buffer_height = max_y_filter_size + (use_sse2 ? 4 : 0); + CircularRowBuffer row_buffer(row_buffer_width, + row_buffer_height, + filter_offset); + + // Loop over every possible output row, processing just enough horizontal + // convolutions to run each subsequent vertical convolution. + SkASSERT(output_byte_row_stride >= filter_x.num_values() * 4); + int num_output_rows = filter_y.num_values(); + + // We need to check which is the last line to convolve before we advance 4 + // lines in one iteration. + int last_filter_offset, last_filter_length; + filter_y.FilterForValue(num_output_rows - 1, &last_filter_offset, + &last_filter_length); + + for (int out_y = 0; out_y < num_output_rows; out_y++) { + filter_values = filter_y.FilterForValue(out_y, + &filter_offset, &filter_length); + + // Generate output rows until we have enough to run the current filter. + if (use_sse2) { + while (next_x_row < filter_offset + filter_length) { + if (next_x_row + 3 < last_filter_offset + last_filter_length - 1) { + const unsigned char* src[4]; + unsigned char* out_row[4]; + for (int i = 0; i < 4; ++i) { + src[i] = &source_data[(next_x_row + i) * source_byte_row_stride]; + out_row[i] = row_buffer.AdvanceRow(); + } + ConvolveHorizontally4_SSE2(src, filter_x, out_row); + next_x_row += 4; + } else { + // For the last row, SSE2 load possibly to access data beyond the + // image area. therefore we use C version here. + if (next_x_row == last_filter_offset + last_filter_length - 1) { + if (source_has_alpha) { + ConvolveHorizontally( + &source_data[next_x_row * source_byte_row_stride], + filter_x, row_buffer.AdvanceRow()); + } else { + ConvolveHorizontally( + &source_data[next_x_row * source_byte_row_stride], + filter_x, row_buffer.AdvanceRow()); + } + } else { + ConvolveHorizontally_SSE2( + &source_data[next_x_row * source_byte_row_stride], + filter_x, row_buffer.AdvanceRow()); + } + next_x_row++; + } + } + } else { + while (next_x_row < filter_offset + filter_length) { + if (source_has_alpha) { + ConvolveHorizontally( + &source_data[next_x_row * source_byte_row_stride], + filter_x, row_buffer.AdvanceRow()); + } else { + ConvolveHorizontally( + &source_data[next_x_row * source_byte_row_stride], + filter_x, row_buffer.AdvanceRow()); + } + next_x_row++; + } + } + + // Compute where in the output image this row of final data will go. + unsigned char* cur_output_row = &output[out_y * output_byte_row_stride]; + + // Get the list of rows that the circular buffer has, in order. + int first_row_in_circular_buffer; + unsigned char* const* rows_to_convolve = + row_buffer.GetRowAddresses(&first_row_in_circular_buffer); + + // Now compute the start of the subset of those rows that the filter + // needs. + unsigned char* const* first_row_for_filter = + &rows_to_convolve[filter_offset - first_row_in_circular_buffer]; + + if (source_has_alpha) { + if (use_sse2) { + ConvolveVertically_SSE2(filter_values, filter_length, + first_row_for_filter, + filter_x.num_values(), cur_output_row); + } else { + ConvolveVertically(filter_values, filter_length, + first_row_for_filter, + filter_x.num_values(), cur_output_row); + } + } else { + if (use_sse2) { + ConvolveVertically_SSE2(filter_values, filter_length, + first_row_for_filter, + filter_x.num_values(), cur_output_row); + } else { + ConvolveVertically(filter_values, filter_length, + first_row_for_filter, + filter_x.num_values(), cur_output_row); + } + } + } +} + +} // namespace skia