blob: eab0565b3d38228de7c8773e4bac37e4e9ba4359 [file] [log] [blame]
// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "impeller/entity/entity_pass_clip_stack.h"
#include "impeller/entity/contents/clip_contents.h"
#include "impeller/entity/entity.h"
namespace impeller {
EntityPassClipStack::EntityPassClipStack(const Rect& initial_coverage_rect) {
subpass_state_.push_back(SubpassState{
.clip_coverage =
{
{ClipCoverageLayer{
.coverage = initial_coverage_rect,
.clip_height = 0,
}},
},
});
}
std::optional<Rect> EntityPassClipStack::CurrentClipCoverage() const {
return subpass_state_.back().clip_coverage.back().coverage;
}
bool EntityPassClipStack::HasCoverage() const {
return !subpass_state_.back().clip_coverage.empty();
}
void EntityPassClipStack::PushSubpass(std::optional<Rect> subpass_coverage,
size_t clip_height) {
subpass_state_.push_back(SubpassState{
.clip_coverage =
{
ClipCoverageLayer{.coverage = subpass_coverage,
.clip_height = clip_height},
},
});
}
void EntityPassClipStack::PopSubpass() {
subpass_state_.pop_back();
}
const std::vector<ClipCoverageLayer>
EntityPassClipStack::GetClipCoverageLayers() const {
return subpass_state_.back().clip_coverage;
}
EntityPassClipStack::ClipStateResult EntityPassClipStack::ApplyClipState(
Contents::ClipCoverage global_clip_coverage,
Entity& entity,
size_t clip_height_floor,
Point global_pass_position) {
ClipStateResult result = {.should_render = false, .clip_did_change = false};
auto& subpass_state = GetCurrentSubpassState();
switch (global_clip_coverage.type) {
case Contents::ClipCoverage::Type::kNoChange:
break;
case Contents::ClipCoverage::Type::kAppend: {
auto op = CurrentClipCoverage();
// Compute the previous clip height.
size_t previous_clip_height = 0;
if (!subpass_state.clip_coverage.empty()) {
previous_clip_height = subpass_state.clip_coverage.back().clip_height;
} else {
// If there is no clip coverage, then the previous clip height is the
// clip height floor.
previous_clip_height = clip_height_floor;
}
subpass_state.clip_coverage.push_back(
ClipCoverageLayer{.coverage = global_clip_coverage.coverage,
.clip_height = previous_clip_height + 1});
result.clip_did_change = true;
FML_DCHECK(subpass_state.clip_coverage.back().clip_height ==
subpass_state.clip_coverage.front().clip_height +
subpass_state.clip_coverage.size() - 1);
if (!op.has_value()) {
// Running this append op won't impact the clip buffer because the
// whole screen is already being clipped, so skip it.
return result;
}
} break;
case Contents::ClipCoverage::Type::kRestore: {
ClipRestoreContents* restore_contents =
reinterpret_cast<ClipRestoreContents*>(entity.GetContents().get());
size_t restore_height = restore_contents->GetRestoreHeight();
if (subpass_state.clip_coverage.back().clip_height <= restore_height) {
// Drop clip restores that will do nothing.
return result;
}
auto restoration_index =
restore_height - subpass_state.clip_coverage.front().clip_height;
FML_DCHECK(restoration_index < subpass_state.clip_coverage.size());
// We only need to restore the area that covers the coverage of the
// clip rect at target height + 1.
std::optional<Rect> restore_coverage =
(restoration_index + 1 < subpass_state.clip_coverage.size())
? subpass_state.clip_coverage[restoration_index + 1].coverage
: std::nullopt;
if (restore_coverage.has_value()) {
// Make the coverage rectangle relative to the current pass.
restore_coverage = restore_coverage->Shift(-global_pass_position);
}
subpass_state.clip_coverage.resize(restoration_index + 1);
result.clip_did_change = true;
// Skip all clip restores when stencil-then-cover is enabled.
if (subpass_state.clip_coverage.back().coverage.has_value()) {
RecordEntity(entity, global_clip_coverage.type, Rect());
}
return result;
} break;
}
RecordEntity(entity, global_clip_coverage.type,
subpass_state.clip_coverage.back().coverage);
result.should_render = true;
return result;
}
void EntityPassClipStack::RecordEntity(const Entity& entity,
Contents::ClipCoverage::Type type,
std::optional<Rect> clip_coverage) {
auto& subpass_state = GetCurrentSubpassState();
switch (type) {
case Contents::ClipCoverage::Type::kNoChange:
return;
case Contents::ClipCoverage::Type::kAppend:
subpass_state.rendered_clip_entities.push_back(
{.entity = entity.Clone(), .clip_coverage = clip_coverage});
break;
case Contents::ClipCoverage::Type::kRestore:
if (!subpass_state.rendered_clip_entities.empty()) {
subpass_state.rendered_clip_entities.pop_back();
}
break;
}
}
EntityPassClipStack::SubpassState&
EntityPassClipStack::GetCurrentSubpassState() {
return subpass_state_.back();
}
const std::vector<EntityPassClipStack::ReplayResult>&
EntityPassClipStack::GetReplayEntities() const {
return subpass_state_.back().rendered_clip_entities;
}
} // namespace impeller