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| 1 | +// Copyright 2013 The Flutter Authors. All rights reserved. |
| 2 | +// Use of this source code is governed by a BSD-style license that can be |
| 3 | +// found in the LICENSE file. |
| 4 | + |
| 5 | +#include "impeller/entity/draw_order_resolver.h" |
| 6 | + |
| 7 | +#include "flutter/fml/logging.h" |
| 8 | +#include "impeller/base/validation.h" |
| 9 | + |
| 10 | +namespace impeller { |
| 11 | + |
| 12 | +DrawOrderResolver::DrawOrderResolver() : draw_order_layers_({{}}){}; |
| 13 | + |
| 14 | +void DrawOrderResolver::AddElement(size_t element_index, bool is_opaque) { |
| 15 | + DrawOrderLayer& layer = draw_order_layers_.back(); |
| 16 | + if (is_opaque) { |
| 17 | + layer.opaque_elements.push_back(element_index); |
| 18 | + } else { |
| 19 | + layer.dependent_elements.push_back(element_index); |
| 20 | + } |
| 21 | +} |
| 22 | +void DrawOrderResolver::PushClip(size_t element_index) { |
| 23 | + draw_order_layers_.back().dependent_elements.push_back(element_index); |
| 24 | + draw_order_layers_.push_back({}); |
| 25 | +}; |
| 26 | + |
| 27 | +void DrawOrderResolver::PopClip() { |
| 28 | + if (draw_order_layers_.size() == 1u) { |
| 29 | + // This is likely recoverable, so don't assert. |
| 30 | + VALIDATION_LOG |
| 31 | + << "Attemped to pop the first draw order clip layer. This is a bug in " |
| 32 | + "`EntityPass`."; |
| 33 | + return; |
| 34 | + } |
| 35 | + |
| 36 | + DrawOrderLayer& layer = draw_order_layers_.back(); |
| 37 | + DrawOrderLayer& parent_layer = |
| 38 | + draw_order_layers_[draw_order_layers_.size() - 2]; |
| 39 | + |
| 40 | + layer.WriteCombinedDraws(parent_layer.dependent_elements, 0, 0); |
| 41 | + |
| 42 | + draw_order_layers_.pop_back(); |
| 43 | +} |
| 44 | + |
| 45 | +void DrawOrderResolver::Flush() { |
| 46 | + FML_DCHECK(draw_order_layers_.size() >= 1u); |
| 47 | + |
| 48 | + size_t layer_count = draw_order_layers_.size(); |
| 49 | + |
| 50 | + // Pop all clip layers. |
| 51 | + while (draw_order_layers_.size() > 1u) { |
| 52 | + PopClip(); |
| 53 | + } |
| 54 | + |
| 55 | + // Move the root layer items into the sorted list. |
| 56 | + DrawOrderLayer& layer = draw_order_layers_.back(); |
| 57 | + if (!first_root_flush_.has_value()) { |
| 58 | + // Record the first flush. |
| 59 | + first_root_flush_ = std::move(layer); |
| 60 | + layer = {}; |
| 61 | + } else { |
| 62 | + // Write subsequent flushes into the sorted root list. |
| 63 | + layer.WriteCombinedDraws(sorted_elements_, 0, 0); |
| 64 | + layer.opaque_elements.clear(); |
| 65 | + layer.dependent_elements.clear(); |
| 66 | + } |
| 67 | + |
| 68 | + // Refill with empty layers. |
| 69 | + draw_order_layers_.resize(layer_count); |
| 70 | +} |
| 71 | + |
| 72 | +DrawOrderResolver::ElementRefs DrawOrderResolver::GetSortedDraws( |
| 73 | + size_t opaque_skip_count, |
| 74 | + size_t translucent_skip_count) const { |
| 75 | + FML_DCHECK(draw_order_layers_.size() == 1u) |
| 76 | + << "Attempted to get sorted draws before all clips were popped."; |
| 77 | + |
| 78 | + ElementRefs sorted_elements; |
| 79 | + sorted_elements.reserve( |
| 80 | + (first_root_flush_.has_value() |
| 81 | + ? first_root_flush_->opaque_elements.size() + |
| 82 | + first_root_flush_->dependent_elements.size() |
| 83 | + : 0u) + |
| 84 | + sorted_elements_.size() + |
| 85 | + draw_order_layers_.back().opaque_elements.size() + |
| 86 | + draw_order_layers_.back().dependent_elements.size()); |
| 87 | + |
| 88 | + // Write all flushed items. |
| 89 | + if (first_root_flush_.has_value()) { |
| 90 | + first_root_flush_->WriteCombinedDraws(sorted_elements, opaque_skip_count, |
| 91 | + translucent_skip_count); |
| 92 | + } |
| 93 | + sorted_elements.insert(sorted_elements.end(), sorted_elements_.begin(), |
| 94 | + sorted_elements_.end()); |
| 95 | + |
| 96 | + // Write any remaining non-flushed items. |
| 97 | + draw_order_layers_.back().WriteCombinedDraws( |
| 98 | + sorted_elements, first_root_flush_.has_value() ? 0 : opaque_skip_count, |
| 99 | + first_root_flush_.has_value() ? 0 : translucent_skip_count); |
| 100 | + |
| 101 | + return sorted_elements; |
| 102 | +} |
| 103 | + |
| 104 | +void DrawOrderResolver::DrawOrderLayer::WriteCombinedDraws( |
| 105 | + ElementRefs& destination, |
| 106 | + size_t opaque_skip_count, |
| 107 | + size_t translucent_skip_count) const { |
| 108 | + FML_DCHECK(opaque_skip_count <= opaque_elements.size()); |
| 109 | + FML_DCHECK(translucent_skip_count <= dependent_elements.size()); |
| 110 | + |
| 111 | + destination.reserve(destination.size() + // |
| 112 | + opaque_elements.size() - opaque_skip_count + // |
| 113 | + dependent_elements.size() - translucent_skip_count); |
| 114 | + |
| 115 | + // Draw backdrop-independent elements in reverse order first. |
| 116 | + destination.insert(destination.end(), opaque_elements.rbegin(), |
| 117 | + opaque_elements.rend() - opaque_skip_count); |
| 118 | + // Then, draw backdrop-dependent elements in their original order. |
| 119 | + destination.insert(destination.end(), |
| 120 | + dependent_elements.begin() + translucent_skip_count, |
| 121 | + dependent_elements.end()); |
| 122 | +} |
| 123 | + |
| 124 | +} // namespace impeller |
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