fill_path_geometry.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/geometry/fill_path_geometry.h"
 
#include "fml/logging.h"
#include "impeller/core/formats.h"
#include "impeller/core/vertex_buffer.h"
#include "impeller/entity/contents/content_context.h"
#include "impeller/entity/geometry/geometry.h"
 
namespace impeller {
 
FillPathGeometry::FillPathGeometry(const Path& path,
                                   std::optional<Rect> inner_rect)
    : path_(path), inner_rect_(inner_rect) {}
 
GeometryResult FillPathGeometry::GetPositionBuffer(
    const ContentContext& renderer,
    const Entity& entity,
    RenderPass& pass) const {
  auto& host_buffer = renderer.GetTransientsBuffer();
 
  const auto& bounding_box = path_.GetBoundingBox();
  if (bounding_box.has_value() && bounding_box->IsEmpty()) {
    return GeometryResult{
        .type = PrimitiveType::kTriangle,
        .vertex_buffer =
            VertexBuffer{
                .vertex_buffer = {},
                .vertex_count = 0,
                .index_type = IndexType::k16bit,
            },
        .transform = pass.GetOrthographicTransform() * entity.GetTransform(),
    };
  }
 
  VertexBuffer vertex_buffer;
 
  auto points = renderer.GetTessellator()->TessellateConvex(
      path_, entity.GetTransform().GetMaxBasisLength());
 
  vertex_buffer.vertex_buffer = host_buffer.Emplace(
      points.data(), points.size() * sizeof(Point), alignof(Point));
  vertex_buffer.index_buffer = {}, vertex_buffer.vertex_count = points.size();
  vertex_buffer.index_type = IndexType::kNone;
 
  return GeometryResult{
      .type = PrimitiveType::kTriangleStrip,
      .vertex_buffer = vertex_buffer,
      .transform = entity.GetShaderTransform(pass),
      .mode = GetResultMode(),
  };
}
 
GeometryResult::Mode FillPathGeometry::GetResultMode() const {
  const auto& bounding_box = path_.GetBoundingBox();
  if (path_.IsConvex() ||
      (bounding_box.has_value() && bounding_box->IsEmpty())) {
    return GeometryResult::Mode::kNormal;
  }
 
  switch (path_.GetFillType()) {
    case FillType::kNonZero:
      return GeometryResult::Mode::kNonZero;
    case FillType::kOdd:
      return GeometryResult::Mode::kEvenOdd;
  }
 
  FML_UNREACHABLE();
}
 
std::optional<Rect> FillPathGeometry::GetCoverage(
    const Matrix& transform) const {
  return path_.GetTransformedBoundingBox(transform);
}
 
bool FillPathGeometry::CoversArea(const Matrix& transform,
                                  const Rect& rect) const {
  if (!inner_rect_.has_value()) {
    return false;
  }
  if (!transform.IsTranslationScaleOnly()) {
    return false;
  }
  Rect coverage = inner_rect_->TransformBounds(transform);
  return coverage.Contains(rect);
}
 
}  // namespace impeller