| Flutter Impeller |

draw_order_resolver.cc
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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 << "Attemped to pop the first draw order clip layer. This "
31 "may be a bug in `EntityPass`.";
32 return;
33 }
34
35 DrawOrderLayer& layer = draw_order_layers_.back();
36 DrawOrderLayer& parent_layer =
37 draw_order_layers_[draw_order_layers_.size() - 2];
38
39 layer.WriteCombinedDraws(parent_layer.dependent_elements, 0, 0);
40
41 draw_order_layers_.pop_back();
42 }
43
44 void DrawOrderResolver::Flush() {
45 FML_DCHECK(draw_order_layers_.size() >= 1u);
46
47 size_t layer_count = draw_order_layers_.size();
48
49 // Pop all clip layers.
50 while (draw_order_layers_.size() > 1u) {
51 PopClip();
52 }
53
54 // Move the root layer items into the sorted list.
55 DrawOrderLayer& layer = draw_order_layers_.back();
56 if (!first_root_flush_.has_value()) {
57 // Record the first flush.
58 first_root_flush_ = std::move(layer);
59 layer = {};
60 } else {
61 // Write subsequent flushes into the sorted root list.
62 layer.WriteCombinedDraws(sorted_elements_, 0, 0);
63 layer.opaque_elements.clear();
64 layer.dependent_elements.clear();
65 }
66
67 // Refill with empty layers.
68 draw_order_layers_.resize(layer_count);
69 }
70
71 DrawOrderResolver::ElementRefs DrawOrderResolver::GetSortedDraws(
72 size_t opaque_skip_count,
73 size_t translucent_skip_count) const {
74 FML_DCHECK(draw_order_layers_.size() == 1u)
75 << "Attempted to get sorted draws before all clips were popped.";
76
77 ElementRefs sorted_elements;
78 sorted_elements.reserve(
79 (first_root_flush_.has_value()
80 ? first_root_flush_->opaque_elements.size() +
81 first_root_flush_->dependent_elements.size()
82 : 0u) +
83 sorted_elements_.size() +
84 draw_order_layers_.back().opaque_elements.size() +
85 draw_order_layers_.back().dependent_elements.size());
86
87 // Write all flushed items.
88 if (first_root_flush_.has_value()) {
89 first_root_flush_->WriteCombinedDraws(sorted_elements, opaque_skip_count,
90 translucent_skip_count);
91 }
92 sorted_elements.insert(sorted_elements.end(), sorted_elements_.begin(),
93 sorted_elements_.end());
94
95 // Write any remaining non-flushed items.
96 draw_order_layers_.back().WriteCombinedDraws(
97 sorted_elements, first_root_flush_.has_value() ? 0 : opaque_skip_count,
98 first_root_flush_.has_value() ? 0 : translucent_skip_count);
99
100 return sorted_elements;
101 }
102
103 void DrawOrderResolver::DrawOrderLayer::WriteCombinedDraws(
104 ElementRefs& destination,
105 size_t opaque_skip_count,
106 size_t translucent_skip_count) const {
107 FML_DCHECK(opaque_skip_count <= opaque_elements.size());
108 FML_DCHECK(translucent_skip_count <= dependent_elements.size());
109
110 destination.reserve(destination.size() + //
111 opaque_elements.size() - opaque_skip_count + //
112 dependent_elements.size() - translucent_skip_count);
113
114 // Draw backdrop-independent elements in reverse order first.
115 destination.insert(destination.end(), opaque_elements.rbegin(),
116 opaque_elements.rend() - opaque_skip_count);
117 // Then, draw backdrop-dependent elements in their original order.
118 destination.insert(destination.end(),
119 dependent_elements.begin() + translucent_skip_count,
120 dependent_elements.end());
121 }
122
123 } // namespace impeller
impeller::DrawOrderResolver::Flush
void Flush()
Definition: draw_order_resolver.cc:44
impeller::DrawOrderResolver::PushClip
void PushClip(size_t element_index)
Definition: draw_order_resolver.cc:22
impeller::DrawOrderResolver::GetSortedDraws
ElementRefs GetSortedDraws(size_t opaque_skip_count, size_t translucent_skip_count) const
Returns the sorted draws for the current draw order layer. This should only be called after all recor...
Definition: draw_order_resolver.cc:71
impeller::DrawOrderResolver::ElementRefs
std::vector< size_t > ElementRefs
Definition: draw_order_resolver.h:17
impeller::DrawOrderResolver::AddElement
void AddElement(size_t element_index, bool is_opaque)
Definition: draw_order_resolver.cc:14
impeller::DrawOrderResolver::DrawOrderResolver
DrawOrderResolver()
Definition: draw_order_resolver.cc:12
impeller::DrawOrderResolver::PopClip
void PopClip()
Definition: draw_order_resolver.cc:27
draw_order_resolver.h
impeller
Definition: allocation.cc:12
validation.h
VALIDATION_LOG
#define VALIDATION_LOG
Definition: validation.h:91