atlas_contents.h

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// 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.
 
#pragma once
 
#include <functional>
#include <memory>
#include <vector>
 
#include "flutter/fml/macros.h"
#include "impeller/core/sampler_descriptor.h"
#include "impeller/entity/contents/contents.h"
#include "impeller/entity/entity.h"
 
namespace impeller {
 
struct SubAtlasResult {
  // Sub atlas values.
  std::vector<Rect> sub_texture_coords;
  std::vector<Color> sub_colors;
  std::vector<Matrix> sub_transforms;
 
  // Result atlas values.
  std::vector<Rect> result_texture_coords;
  std::vector<Matrix> result_transforms;
 
  // Size of the sub-atlass.
  ISize size;
};
 
class AtlasContents final : public Contents {
 public:
  explicit AtlasContents();
 
  ~AtlasContents() override;
 
  void SetTexture(std::shared_ptr<Texture> texture);
 
  std::shared_ptr<Texture> GetTexture() const;
 
  void SetTransforms(std::vector<Matrix> transforms);
 
  void SetBlendMode(BlendMode blend_mode);
 
  void SetTextureCoordinates(std::vector<Rect> texture_coords);
 
  void SetColors(std::vector<Color> colors);
 
  void SetCullRect(std::optional<Rect> cull_rect);
 
  void SetSamplerDescriptor(SamplerDescriptor desc);
 
  void SetAlpha(Scalar alpha);
 
  const SamplerDescriptor& GetSamplerDescriptor() const;
 
  const std::vector<Matrix>& GetTransforms() const;
 
  const std::vector<Rect>& GetTextureCoordinates() const;
 
  const std::vector<Color>& GetColors() const;
 
  /// @brief Compress a drawAtlas call with blending into a smaller sized atlas.
  ///        This atlas has no overlapping to ensure
  ///        blending behaves as if it were done in the fragment shader.
  std::shared_ptr<SubAtlasResult> GenerateSubAtlas() const;
 
  // |Contents|
  std::optional<Rect> GetCoverage(const Entity& entity) const override;
 
  // |Contents|
  bool Render(const ContentContext& renderer,
              const Entity& entity,
              RenderPass& pass) const override;
 
 private:
  Rect ComputeBoundingBox() const;
 
  std::shared_ptr<Texture> texture_;
  std::vector<Rect> texture_coords_;
  std::vector<Color> colors_;
  std::vector<Matrix> transforms_;
  BlendMode blend_mode_;
  std::optional<Rect> cull_rect_;
  Scalar alpha_ = 1.0;
  SamplerDescriptor sampler_descriptor_ = {};
  mutable std::optional<Rect> bounding_box_cache_;
 
  FML_DISALLOW_COPY_AND_ASSIGN(AtlasContents);
};
 
class AtlasTextureContents final : public Contents {
 public:
  explicit AtlasTextureContents(const AtlasContents& parent);
 
  ~AtlasTextureContents() override;
 
  // |Contents|
  std::optional<Rect> GetCoverage(const Entity& entity) const override;
 
  // |Contents|
  bool Render(const ContentContext& renderer,
              const Entity& entity,
              RenderPass& pass) const override;
 
  void SetAlpha(Scalar alpha);
 
  void SetCoverage(Rect coverage);
 
  void SetTexture(std::shared_ptr<Texture> texture);
 
  void SetUseDestination(bool value);
 
  void SetSubAtlas(const std::shared_ptr<SubAtlasResult>& subatlas);
 
 private:
  const AtlasContents& parent_;
  Scalar alpha_ = 1.0;
  Rect coverage_;
  std::shared_ptr<Texture> texture_;
  bool use_destination_ = false;
  std::shared_ptr<SubAtlasResult> subatlas_;
 
  FML_DISALLOW_COPY_AND_ASSIGN(AtlasTextureContents);
};
 
class AtlasColorContents final : public Contents {
 public:
  explicit AtlasColorContents(const AtlasContents& parent);
 
  ~AtlasColorContents() override;
 
  // |Contents|
  std::optional<Rect> GetCoverage(const Entity& entity) const override;
 
  // |Contents|
  bool Render(const ContentContext& renderer,
              const Entity& entity,
              RenderPass& pass) const override;
 
  void SetAlpha(Scalar alpha);
 
  void SetCoverage(Rect coverage);
 
  void SetSubAtlas(const std::shared_ptr<SubAtlasResult>& subatlas);
 
 private:
  const AtlasContents& parent_;
  Scalar alpha_ = 1.0;
  Rect coverage_;
  std::shared_ptr<SubAtlasResult> subatlas_;
 
  FML_DISALLOW_COPY_AND_ASSIGN(AtlasColorContents);
};
 
}  // namespace impeller