uber_sdf_contents.cc

Go to the documentation of this file.

// 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/contents/uber_sdf_contents.h"
 
#include "impeller/entity/contents/color_source_contents.h"
#include "impeller/entity/contents/content_context.h"
#include "impeller/entity/contents/pipelines.h"
#include "impeller/entity/contents/uber_sdf_parameters.h"
#include "impeller/geometry/stroke_parameters.h"
 
namespace impeller {
 
namespace {
 
using PipelineBuilderCallback =
    std::function<PipelineRef(ContentContextOptions)>;
 
using VS = UberSDFPipeline::VertexShader;
using FS = UberSDFPipeline::FragmentShader;
 
Scalar ToShaderType(UberSDFParameters::Type type) {
  switch (type) {
    case UberSDFParameters::Type::kCircle:
      return 0.0f;
    case UberSDFParameters::Type::kRect:
      return 1.0f;
    case UberSDFParameters::Type::kOval:
      return 2.0f;
    case UberSDFParameters::Type::kRoundedRect:
      return 3.0f;
    case UberSDFParameters::Type::kRoundedSuperellipse:
      return 4.0f;
  }
}
 
Scalar ToShaderStrokeJoin(Join join) {
  switch (join) {
    case Join::kMiter:
      return 0.0f;
    case Join::kBevel:
      return 1.0f;
    case Join::kRound:
      return 2.0f;
  }
}
 
}  // namespace
 
std::unique_ptr<UberSDFContents> UberSDFContents::Make(
    const UberSDFParameters& params,
    std::unique_ptr<Geometry> geometry) {
  return std::unique_ptr<UberSDFContents>(
      new UberSDFContents(params, std::move(geometry)));
}
 
UberSDFContents::UberSDFContents(const UberSDFParameters& params,
                                 std::unique_ptr<Geometry> geometry)
    : params_(params), geometry_(std::move(geometry)) {}
 
UberSDFContents::~UberSDFContents() = default;
 
bool UberSDFContents::Render(const ContentContext& renderer,
                             const Entity& entity,
                             RenderPass& pass) const {
  auto& data_host_buffer = renderer.GetTransientsDataBuffer();
 
  VS::FrameInfo frame_info;
  FS::FragInfo frag_info;
  frag_info.type = ToShaderType(params_.type);
  frag_info.color =
      params_.color.WithAlpha(params_.color.alpha * GetOpacityFactor());
  frag_info.center = params_.center;
  frag_info.size = params_.size;
  frag_info.radii =
      Vector4(params_.radii.bottom_right.width, params_.radii.top_right.width,
              params_.radii.bottom_left.width, params_.radii.top_left.width);
  frag_info.radii_right =
      Vector4(params_.radii.bottom_right.height, params_.radii.top_right.height,
              params_.radii.bottom_left.height, params_.radii.top_left.height);
  frag_info.stroked = params_.stroke ? 1.0f : 0.0f;
  frag_info.stroke_width = params_.stroke ? params_.stroke->width : 0.0f;
  frag_info.stroke_join =
      params_.stroke ? ToShaderStrokeJoin(params_.stroke->join) : 0.0f;
  frag_info.aa_pixels = UberSDFParameters::kAntialiasPixels;
  frag_info.superellipse_degree = params_.superellipse_degree;
  frag_info.superellipse_a = params_.superellipse_a;
  frag_info.corner_angle_span = params_.corner_angle_span;
  frag_info.corner_circle_center_top = params_.corner_circle_center_top;
  frag_info.corner_circle_center_right = params_.corner_circle_center_right;
  frag_info.superellipse_c = params_.superellipse_c;
  frag_info.superellipse_scale = params_.superellipse_scale;
 
  auto geometry_result =
      GetGeometry()->GetPositionBuffer(renderer, entity, pass);
 
  PipelineBuilderCallback pipeline_callback =
      [&renderer](ContentContextOptions options) {
        return renderer.GetUberSDFPipeline(options);
      };
 
  return ColorSourceContents::DrawGeometry<VS>(
      this, GetGeometry(), renderer, entity, pass, pipeline_callback,
      frame_info,
      /*bind_fragment_callback=*/
      [&frag_info, &data_host_buffer](RenderPass& pass) {
        FS::BindFragInfo(pass, data_host_buffer.EmplaceUniform(frag_info));
        pass.SetCommandLabel("UberSDF");
        return true;
      },
      /*force_stencil=*/false,
      /*create_geom_callback=*/
      [geometry_result = std::move(geometry_result)](
          const ContentContext& renderer, const Entity& entity,
          RenderPass& pass,
          const Geometry* geometry) { return geometry_result; });
}
 
std::optional<Rect> UberSDFContents::GetCoverage(const Entity& entity) const {
  return GetGeometry()->GetCoverage(entity.GetTransform());
}
 
const Geometry* UberSDFContents::GetGeometry() const {
  return geometry_.get();
}
 
Color UberSDFContents::GetColor() const {
  return params_.color;
}
 
bool UberSDFContents::ApplyColorFilter(
    const ColorFilterProc& color_filter_proc) {
  params_.color = color_filter_proc(params_.color);
  return true;
}
 
std::optional<Color> UberSDFContents::AsBackgroundColor(
    const Entity& entity,
    ISize target_size) const {
  if (params_.type != UberSDFParameters::Type::kRect) {
    return std::nullopt;
  }
  const Geometry* geometry = GetGeometry();
  if (geometry == nullptr) {
    return std::nullopt;
  }
  IRect target_rect = IRect::MakeSize(target_size);
  return geometry->CoversArea(entity.GetTransform(), target_rect)
             ? GetColor()
             : std::optional<Color>();
}
 
}  // namespace impeller