playground.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.
 
#ifndef FLUTTER_IMPELLER_PLAYGROUND_PLAYGROUND_H_
#define FLUTTER_IMPELLER_PLAYGROUND_PLAYGROUND_H_
 
#include <chrono>
#include <memory>
 
#include "flutter/fml/status.h"
#include "flutter/fml/time/time_delta.h"
#include "impeller/core/runtime_types.h"
#include "impeller/core/texture.h"
#include "impeller/geometry/point.h"
#include "impeller/playground/image/compressed_image.h"
#include "impeller/playground/image/decompressed_image.h"
#include "impeller/playground/switches.h"
#include "impeller/renderer/render_pass.h"
#include "impeller/runtime_stage/runtime_stage.h"
 
namespace impeller {
 
class PlaygroundImpl;
 
enum class PlaygroundBackend {
  kMetal,
  kOpenGLES,
  kVulkan,
};
 
constexpr inline RuntimeStageBackend PlaygroundBackendToRuntimeStageBackend(
    PlaygroundBackend backend) {
  switch (backend) {
    case PlaygroundBackend::kMetal:
      return RuntimeStageBackend::kMetal;
    case PlaygroundBackend::kOpenGLES:
      return RuntimeStageBackend::kOpenGLES;
    case PlaygroundBackend::kVulkan:
      return RuntimeStageBackend::kVulkan;
  }
  FML_UNREACHABLE();
}
 
std::string PlaygroundBackendToString(PlaygroundBackend backend);
 
class Playground {
 public:
  using SinglePassCallback = std::function<bool(RenderPass& pass)>;
 
  explicit Playground(PlaygroundSwitches switches);
 
  virtual ~Playground();
 
  static bool ShouldOpenNewPlaygrounds();
 
  void SetupContext(PlaygroundBackend backend,
                    const PlaygroundSwitches& switches);
 
  void SetupWindow();
 
  void TeardownWindow();
 
  bool IsPlaygroundEnabled() const;
 
  Point GetCursorPosition() const;
 
  ISize GetWindowSize() const;
 
  Point GetContentScale() const;
 
  /// @brief Get the amount of time elapsed from the start of the playground's
  /// execution.
  Scalar GetSecondsElapsed() const;
 
  std::shared_ptr<Context> GetContext() const;
 
  std::shared_ptr<Context> MakeContext() const;
 
  using RenderCallback = std::function<bool(RenderTarget& render_target)>;
 
  bool OpenPlaygroundHere(const RenderCallback& render_callback);
 
  bool OpenPlaygroundHere(SinglePassCallback pass_callback);
 
  static std::shared_ptr<CompressedImage> LoadFixtureImageCompressed(
      std::shared_ptr<fml::Mapping> mapping);
 
  static std::optional<DecompressedImage> DecodeImageRGBA(
      const std::shared_ptr<CompressedImage>& compressed);
 
  static std::shared_ptr<Texture> CreateTextureForMapping(
      const std::shared_ptr<Context>& context,
      std::shared_ptr<fml::Mapping> mapping,
      bool enable_mipmapping = false);
 
  std::shared_ptr<Texture> CreateTextureForFixture(
      const char* fixture_name,
      bool enable_mipmapping = false) const;
 
  std::shared_ptr<Texture> CreateTextureCubeForFixture(
      std::array<const char*, 6> fixture_names) const;
 
  static bool SupportsBackend(PlaygroundBackend backend);
 
  virtual std::unique_ptr<fml::Mapping> OpenAssetAsMapping(
      std::string asset_name) const = 0;
 
  virtual std::string GetWindowTitle() const = 0;
 
  [[nodiscard]] fml::Status SetCapabilities(
      const std::shared_ptr<Capabilities>& capabilities);
 
  /// Returns true if `OpenPlaygroundHere` will actually render anything.
  bool WillRenderSomething() const;
 
  using GLProcAddressResolver = std::function<void*(const char* proc_name)>;
  GLProcAddressResolver CreateGLProcAddressResolver() const;
 
 protected:
  const PlaygroundSwitches switches_;
 
  virtual bool ShouldKeepRendering() const;
 
  void SetWindowSize(ISize size);
 
 private:
  fml::TimeDelta start_time_;
  std::unique_ptr<PlaygroundImpl> impl_;
  std::shared_ptr<Context> context_;
  Point cursor_position_;
  ISize window_size_ = ISize{1024, 768};
 
  void SetCursorPosition(Point pos);
 
  Playground(const Playground&) = delete;
 
  Playground& operator=(const Playground&) = delete;
};
 
}  // namespace impeller
 
#endif  // FLUTTER_IMPELLER_PLAYGROUND_PLAYGROUND_H_