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Reland [Impeller] new blur: refactored math and fixed expanded padding size (flutter/engine#49302)

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https://github.com/flutter/engine/pull/49206 had to reland because it had integration failures.  The changes are in a separate commit below.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
This commit is contained in:
gaaclarke
2023-12-20 17:16:23 -08:00
committed by GitHub
parent e986324f93
commit 53c07de30c
4 changed files with 45 additions and 65 deletions
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1
engine/src/flutter/impeller/aiks/aiks_unittests.cc
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@@ -3976,6 +3976,5 @@ TEST_P(AiksTest, SubpassWithClearColorOptimization) {
// will be filled with NaNs and may produce a magenta texture on macOS or iOS.
ASSERT_TRUE(OpenPlaygroundHere(canvas.EndRecordingAsPicture()));
}
} // namespace testing
} // namespace impeller

99
engine/src/flutter/impeller/entity/contents/filters/gaussian_blur_filter_contents.cc
View File

@@ -19,16 +19,6 @@ using GaussianBlurFragmentShader = GaussianBlurPipeline::FragmentShader;
namespace {
std::optional<Rect> ExpandCoverageHint(const std::optional<Rect>& coverage_hint,
const Matrix& source_to_local_transform,
const Vector2& padding) {
if (!coverage_hint.has_value()) {
return std::nullopt;
}
Vector2 transformed_padding = (source_to_local_transform * padding).Abs();
return coverage_hint->Expand(transformed_padding);
}
SamplerDescriptor MakeSamplerDescriptor(MinMagFilter filter,
SamplerAddressMode address_mode) {
SamplerDescriptor sampler_desc;
@@ -48,12 +38,6 @@ void BindVertices(Command& cmd,
cmd.BindVertices(vtx_builder.CreateVertexBuffer(host_buffer));
}
Matrix MakeAnchorScale(const Point& anchor, Vector2 scale) {
return Matrix::MakeTranslation({anchor.x, anchor.y, 0}) *
Matrix::MakeScale(scale) *
Matrix::MakeTranslation({-anchor.x, -anchor.y, 0});
}
void SetTileMode(SamplerDescriptor* descriptor,
const ContentContext& renderer,
Entity::TileMode tile_mode) {
@@ -87,7 +71,6 @@ std::shared_ptr<Texture> MakeDownsampleSubpass(
const SamplerDescriptor& sampler_descriptor,
const Quad& uvs,
const ISize& subpass_size,
const Vector2 padding,
Entity::TileMode tile_mode) {
ContentContext::SubpassCallback subpass_callback =
[&](const ContentContext& renderer, RenderPass& pass) {
@@ -104,23 +87,13 @@ std::shared_ptr<Texture> MakeDownsampleSubpass(
frame_info.texture_sampler_y_coord_scale = 1.0;
frame_info.alpha = 1.0;
// Insert transparent gutter around the downsampled image so the blur
// creates a halo effect. This compensates for when the expanded clip
// region can't give us the full gutter we want.
Vector2 texture_size = Vector2(input_texture->GetSize());
Quad guttered_uvs =
MakeAnchorScale({0.5, 0.5},
(texture_size + padding * 2) / texture_size)
.Transform(uvs);
BindVertices<TextureFillVertexShader>(
cmd, host_buffer,
{
{Point(0, 0), guttered_uvs[0]},
{Point(1, 0), guttered_uvs[1]},
{Point(0, 1), guttered_uvs[2]},
{Point(1, 1), guttered_uvs[3]},
});
BindVertices<TextureFillVertexShader>(cmd, host_buffer,
{
{Point(0, 0), uvs[0]},
{Point(1, 0), uvs[1]},
{Point(0, 1), uvs[2]},
{Point(1, 1), uvs[3]},
});
SamplerDescriptor linear_sampler_descriptor = sampler_descriptor;
SetTileMode(&linear_sampler_descriptor, renderer, tile_mode);
@@ -270,17 +243,17 @@ std::optional<Entity> GaussianBlurFilterContents::RenderFilter(
Vector2 blur_radius = {CalculateBlurRadius(scaled_sigma.x),
CalculateBlurRadius(scaled_sigma.y)};
Vector2 padding(ceil(blur_radius.x), ceil(blur_radius.y));
Vector2 local_padding =
(entity.GetTransform().Basis() * effect_transform.Basis() * padding)
.Abs();
// Apply as much of the desired padding as possible from the source. This may
// be ignored so must be accounted for in the downsample pass by adding a
// transparent gutter.
std::optional<Rect> expanded_coverage_hint = ExpandCoverageHint(
coverage_hint, entity.GetTransform() * effect_transform, padding);
// TODO(gaaclarke): How much of the gutter is thrown away can be used to
// adjust the padding that is added in the downsample pass.
// For example, if we get all the padding we requested from
// the expanded_coverage_hint, there is no need to add a
// transparent gutter.
std::optional<Rect> expanded_coverage_hint;
if (coverage_hint.has_value()) {
expanded_coverage_hint = coverage_hint->Expand(local_padding);
}
std::optional<Snapshot> input_snapshot =
inputs[0]->GetSnapshot("GaussianBlur", renderer, entity,
@@ -300,21 +273,29 @@ std::optional<Entity> GaussianBlurFilterContents::RenderFilter(
// gutter from the expanded_coverage_hint, we can skip the downsample pass.
// pass.
Vector2 downsample_scalar(desired_scalar, desired_scalar);
Vector2 padded_size =
Vector2(input_snapshot->texture->GetSize()) + 2.0 * padding;
Vector2 downsampled_size = padded_size * downsample_scalar;
// TODO(gaaclarke): I don't think we are correctly handling this fractional
// amount we are throwing away.
Rect source_rect = Rect::MakeSize(input_snapshot->texture->GetSize());
Rect source_rect_padded = source_rect.Expand(padding);
Matrix padding_snapshot_adjustment = Matrix::MakeTranslation(-padding);
// TODO(gaaclarke): The padding could be removed if we know it's not needed or
// resized to account for the expanded_clip_coverage. There doesn't appear
// to be the math to make those calculations though. The following
// optimization works, but causes a shimmer as a result of
// https://github.com/flutter/flutter/issues/140193 so it isn't applied.
//
// !input_snapshot->GetCoverage()->Expand(-local_padding)
// .Contains(coverage_hint.value()))
Vector2 downsampled_size = source_rect_padded.GetSize() * downsample_scalar;
ISize subpass_size =
ISize(round(downsampled_size.x), round(downsampled_size.y));
Vector2 effective_scalar = subpass_size / padded_size;
Vector2 effective_scalar =
Vector2(subpass_size) / source_rect_padded.GetSize();
Quad uvs =
CalculateUVs(inputs[0], entity, input_snapshot->texture->GetSize());
Quad uvs = CalculateUVs(inputs[0], entity, source_rect_padded,
input_snapshot->texture->GetSize());
std::shared_ptr<Texture> pass1_out_texture = MakeDownsampleSubpass(
renderer, input_snapshot->texture, input_snapshot->sampler_descriptor,
uvs, subpass_size, padding, tile_mode_);
uvs, subpass_size, tile_mode_);
Vector2 pass1_pixel_size = 1.0 / Vector2(pass1_out_texture->GetSize());
@@ -343,13 +324,12 @@ std::optional<Entity> GaussianBlurFilterContents::RenderFilter(
MinMagFilter::kLinear, SamplerAddressMode::kClampToEdge);
return Entity::FromSnapshot(
Snapshot{
.texture = pass3_out_texture,
.transform = input_snapshot->transform *
Matrix::MakeTranslation({-padding.x, -padding.y, 0}) *
Matrix::MakeScale(1 / effective_scalar),
.sampler_descriptor = sampler_desc,
.opacity = input_snapshot->opacity},
Snapshot{.texture = pass3_out_texture,
.transform = input_snapshot->transform *
padding_snapshot_adjustment *
Matrix::MakeScale(1 / effective_scalar),
.sampler_descriptor = sampler_desc,
.opacity = input_snapshot->opacity},
entity.GetBlendMode(), entity.GetClipDepth());
}
@@ -360,11 +340,10 @@ Scalar GaussianBlurFilterContents::CalculateBlurRadius(Scalar sigma) {
Quad GaussianBlurFilterContents::CalculateUVs(
const std::shared_ptr<FilterInput>& filter_input,
const Entity& entity,
const Rect& source_rect,
const ISize& texture_size) {
Matrix input_transform = filter_input->GetLocalTransform(entity);
Rect snapshot_rect =
Rect::MakeXYWH(0, 0, texture_size.width, texture_size.height);
Quad coverage_quad = snapshot_rect.GetTransformedPoints(input_transform);
Quad coverage_quad = source_rect.GetTransformedPoints(input_transform);
Matrix uv_transform = Matrix::MakeScale(
{1.0f / texture_size.width, 1.0f / texture_size.height, 1.0f});

6
engine/src/flutter/impeller/entity/contents/filters/gaussian_blur_filter_contents.h
View File

@@ -41,10 +41,12 @@ class GaussianBlurFilterContents final : public FilterContents {
/// Calculate the UV coordinates for rendering the filter_input.
/// @param filter_input The FilterInput that should be rendered.
/// @param entity The associated entity for the filter_input.
/// @param texture_size The size of the texture_size the uvs will be used for.
/// @param source_rect The rect in source coordinates to convert to uvs.
/// @param texture_size The rect to convert in source coordinates.
static Quad CalculateUVs(const std::shared_ptr<FilterInput>& filter_input,
const Entity& entity,
const ISize& pass_size);
const Rect& source_rect,
const ISize& texture_size);
/// Calculate the scale factor for the downsample pass given a sigma value.
///

4
engine/src/flutter/impeller/entity/contents/filters/gaussian_blur_filter_contents_unittests.cc
View File

@@ -285,8 +285,8 @@ TEST_P(GaussianBlurFilterContentsTest, CalculateUVsSimple) {
std::shared_ptr<Texture> texture = MakeTexture(desc);
auto filter_input = FilterInput::Make(texture);
Entity entity;
Quad uvs = GaussianBlurFilterContents::CalculateUVs(filter_input, entity,
ISize(100, 100));
Quad uvs = GaussianBlurFilterContents::CalculateUVs(
filter_input, entity, Rect::MakeSize(ISize(100, 100)), ISize(100, 100));
std::optional<Rect> uvs_bounds = Rect::MakePointBounds(uvs);
EXPECT_TRUE(uvs_bounds.has_value());
if (uvs_bounds.has_value()) {