dec_group_border.cc (8284B)
1 // Copyright (c) the JPEG XL Project Authors. All rights reserved. 2 // 3 // Use of this source code is governed by a BSD-style 4 // license that can be found in the LICENSE file. 5 6 #include "lib/jxl/dec_group_border.h" 7 8 #include <atomic> 9 10 namespace jxl { 11 12 void GroupBorderAssigner::Init(const FrameDimensions& frame_dim) { 13 frame_dim_ = frame_dim; 14 size_t num_corners = 15 (frame_dim_.xsize_groups + 1) * (frame_dim_.ysize_groups + 1); 16 counters_.reset(new std::atomic<uint8_t>[num_corners]); 17 // Initialize counters. 18 for (size_t y = 0; y < frame_dim_.ysize_groups + 1; y++) { 19 for (size_t x = 0; x < frame_dim_.xsize_groups + 1; x++) { 20 // Counters at image borders don't have anything on the other side, we 21 // pre-fill their value to have more uniform handling afterwards. 22 uint8_t init_value = 0; 23 if (x == 0) { 24 init_value |= kTopLeft | kBottomLeft; 25 } 26 if (x == frame_dim_.xsize_groups) { 27 init_value |= kTopRight | kBottomRight; 28 } 29 if (y == 0) { 30 init_value |= kTopLeft | kTopRight; 31 } 32 if (y == frame_dim_.ysize_groups) { 33 init_value |= kBottomLeft | kBottomRight; 34 } 35 counters_[y * (frame_dim_.xsize_groups + 1) + x] = init_value; 36 } 37 } 38 } 39 40 void GroupBorderAssigner::ClearDone(size_t group_id) { 41 size_t x = group_id % frame_dim_.xsize_groups; 42 size_t y = group_id / frame_dim_.xsize_groups; 43 size_t top_left_idx = y * (frame_dim_.xsize_groups + 1) + x; 44 size_t top_right_idx = y * (frame_dim_.xsize_groups + 1) + x + 1; 45 size_t bottom_right_idx = (y + 1) * (frame_dim_.xsize_groups + 1) + x + 1; 46 size_t bottom_left_idx = (y + 1) * (frame_dim_.xsize_groups + 1) + x; 47 counters_[top_left_idx].fetch_and(~kBottomRight); 48 counters_[top_right_idx].fetch_and(~kBottomLeft); 49 counters_[bottom_left_idx].fetch_and(~kTopRight); 50 counters_[bottom_right_idx].fetch_and(~kTopLeft); 51 } 52 53 // Looking at each corner between groups, we can guarantee that the four 54 // involved groups will agree between each other regarding the order in which 55 // each of the four groups terminated. Thus, the last of the four groups 56 // gets the responsibility of handling the corner. For borders, every border 57 // is assigned to its top corner (for vertical borders) or to its left corner 58 // (for horizontal borders): the order as seen on those corners will decide who 59 // handles that border. 60 61 void GroupBorderAssigner::GroupDone(size_t group_id, size_t padx, size_t pady, 62 Rect* rects_to_finalize, 63 size_t* num_to_finalize) { 64 size_t x = group_id % frame_dim_.xsize_groups; 65 size_t y = group_id / frame_dim_.xsize_groups; 66 Rect block_rect(x * frame_dim_.group_dim / kBlockDim, 67 y * frame_dim_.group_dim / kBlockDim, 68 frame_dim_.group_dim / kBlockDim, 69 frame_dim_.group_dim / kBlockDim, frame_dim_.xsize_blocks, 70 frame_dim_.ysize_blocks); 71 72 size_t top_left_idx = y * (frame_dim_.xsize_groups + 1) + x; 73 size_t top_right_idx = y * (frame_dim_.xsize_groups + 1) + x + 1; 74 size_t bottom_right_idx = (y + 1) * (frame_dim_.xsize_groups + 1) + x + 1; 75 size_t bottom_left_idx = (y + 1) * (frame_dim_.xsize_groups + 1) + x; 76 77 auto fetch_status = [this](size_t idx, uint8_t bit) { 78 // Note that the acq-rel semantics of this fetch are actually needed to 79 // ensure that the pixel data of the group is already written to memory. 80 size_t status = counters_[idx].fetch_or(bit); 81 JXL_DASSERT((bit & status) == 0); 82 return bit | status; 83 }; 84 85 size_t top_left_status = fetch_status(top_left_idx, kBottomRight); 86 size_t top_right_status = fetch_status(top_right_idx, kBottomLeft); 87 size_t bottom_right_status = fetch_status(bottom_right_idx, kTopLeft); 88 size_t bottom_left_status = fetch_status(bottom_left_idx, kTopRight); 89 90 size_t x1 = block_rect.x0() + block_rect.xsize(); 91 size_t y1 = block_rect.y0() + block_rect.ysize(); 92 93 bool is_last_group_x = frame_dim_.xsize_groups == x + 1; 94 bool is_last_group_y = frame_dim_.ysize_groups == y + 1; 95 96 // Start of border of neighbouring group, end of border of this group, start 97 // of border of this group (on the other side), end of border of next group. 98 size_t xpos[4] = { 99 block_rect.x0() == 0 ? 0 : block_rect.x0() * kBlockDim - padx, 100 block_rect.x0() == 0 101 ? 0 102 : std::min(frame_dim_.xsize, block_rect.x0() * kBlockDim + padx), 103 is_last_group_x ? frame_dim_.xsize : x1 * kBlockDim - padx, 104 std::min(frame_dim_.xsize, x1 * kBlockDim + padx)}; 105 size_t ypos[4] = { 106 block_rect.y0() == 0 ? 0 : block_rect.y0() * kBlockDim - pady, 107 block_rect.y0() == 0 108 ? 0 109 : std::min(frame_dim_.ysize, block_rect.y0() * kBlockDim + pady), 110 is_last_group_y ? frame_dim_.ysize : y1 * kBlockDim - pady, 111 std::min(frame_dim_.ysize, y1 * kBlockDim + pady)}; 112 113 *num_to_finalize = 0; 114 auto append_rect = [&](size_t x0, size_t x1, size_t y0, size_t y1) { 115 Rect rect(xpos[x0], ypos[y0], xpos[x1] - xpos[x0], ypos[y1] - ypos[y0]); 116 if (rect.xsize() == 0 || rect.ysize() == 0) return; 117 JXL_DASSERT(*num_to_finalize < kMaxToFinalize); 118 rects_to_finalize[(*num_to_finalize)++] = rect; 119 }; 120 121 // Because of how group borders are assigned, it is impossible that we need to 122 // process the left and right side of some area but not the center area. Thus, 123 // we compute the first/last part to process in every horizontal strip and 124 // merge them together. We first collect a mask of what parts should be 125 // processed. 126 // We do this horizontally rather than vertically because horizontal borders 127 // are larger. 128 bool available_parts_mask[3][3] = {}; // [x][y] 129 // Center 130 available_parts_mask[1][1] = true; 131 // Corners 132 if (top_left_status == 0xF) available_parts_mask[0][0] = true; 133 if (top_right_status == 0xF) available_parts_mask[2][0] = true; 134 if (bottom_right_status == 0xF) available_parts_mask[2][2] = true; 135 if (bottom_left_status == 0xF) available_parts_mask[0][2] = true; 136 // Other borders 137 if (top_left_status & kTopRight) available_parts_mask[1][0] = true; 138 if (top_left_status & kBottomLeft) available_parts_mask[0][1] = true; 139 if (top_right_status & kBottomRight) available_parts_mask[2][1] = true; 140 if (bottom_left_status & kBottomRight) available_parts_mask[1][2] = true; 141 142 // Collect horizontal ranges. 143 constexpr size_t kNoSegment = 3; 144 std::pair<size_t, size_t> horizontal_segments[3] = {{kNoSegment, kNoSegment}, 145 {kNoSegment, kNoSegment}, 146 {kNoSegment, kNoSegment}}; 147 for (size_t y = 0; y < 3; y++) { 148 for (size_t x = 0; x < 3; x++) { 149 if (!available_parts_mask[x][y]) continue; 150 JXL_DASSERT(horizontal_segments[y].second == kNoSegment || 151 horizontal_segments[y].second == x); 152 JXL_DASSERT((horizontal_segments[y].first == kNoSegment) == 153 (horizontal_segments[y].second == kNoSegment)); 154 if (horizontal_segments[y].first == kNoSegment) { 155 horizontal_segments[y].first = x; 156 } 157 horizontal_segments[y].second = x + 1; 158 } 159 } 160 if (horizontal_segments[0] == horizontal_segments[1] && 161 horizontal_segments[0] == horizontal_segments[2]) { 162 append_rect(horizontal_segments[0].first, horizontal_segments[0].second, 0, 163 3); 164 } else if (horizontal_segments[0] == horizontal_segments[1]) { 165 append_rect(horizontal_segments[0].first, horizontal_segments[0].second, 0, 166 2); 167 append_rect(horizontal_segments[2].first, horizontal_segments[2].second, 2, 168 3); 169 } else if (horizontal_segments[1] == horizontal_segments[2]) { 170 append_rect(horizontal_segments[0].first, horizontal_segments[0].second, 0, 171 1); 172 append_rect(horizontal_segments[1].first, horizontal_segments[1].second, 1, 173 3); 174 } else { 175 append_rect(horizontal_segments[0].first, horizontal_segments[0].second, 0, 176 1); 177 append_rect(horizontal_segments[1].first, horizontal_segments[1].second, 1, 178 2); 179 append_rect(horizontal_segments[2].first, horizontal_segments[2].second, 2, 180 3); 181 } 182 } 183 184 } // namespace jxl