surface_mtl.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 <QuartzCore/CAMetalLayer.h>
#include <memory>
 
#include "flutter/fml/macros.h"
#include "impeller/geometry/rect.h"
#include "impeller/renderer/context.h"
#include "impeller/renderer/surface.h"
 
namespace impeller {
 
class SurfaceMTL final : public Surface {
 public:
#pragma GCC diagnostic push
  // Disable the diagnostic for iOS Simulators. Metal without emulation isn't
  // available prior to iOS 13 and that's what the simulator headers say when
  // support for CAMetalLayer begins. CAMetalLayer is available on iOS 8.0 and
  // above which is well below Flutters support level.
#pragma GCC diagnostic ignored "-Wunguarded-availability-new"
  //----------------------------------------------------------------------------
  /// @brief      Wraps the current drawable of the given Metal layer to create
  ///             a surface Impeller can render to. The surface must be created
  ///             as late as possible and discarded immediately after rendering
  ///             to it.
  ///
  /// @param[in]  context  The context
  /// @param[in]    layer  The layer whose current drawable to wrap to create a
  ///                      surface.
  ///
  /// @return     A pointer to the wrapped surface or null.
  ///
  static id<CAMetalDrawable> GetMetalDrawableAndValidate(
      const std::shared_ptr<Context>& context,
      CAMetalLayer* layer);
 
  static std::unique_ptr<SurfaceMTL> MakeFromMetalLayerDrawable(
      const std::shared_ptr<Context>& context,
      id<CAMetalDrawable> drawable,
      std::optional<IRect> clip_rect = std::nullopt);
 
  static std::unique_ptr<SurfaceMTL> MakeFromTexture(
      const std::shared_ptr<Context>& context,
      id<MTLTexture> texture,
      std::optional<IRect> clip_rect,
      id<CAMetalDrawable> drawable = nil);
#pragma GCC diagnostic pop
 
  // |Surface|
  ~SurfaceMTL() override;
 
  id<MTLDrawable> drawable() const { return drawable_; }
 
  // Returns a Rect defining the area of the surface in device pixels
  IRect coverage() const;
 
  // |Surface|
  bool Present() const override;
 
 private:
  std::weak_ptr<Context> context_;
  std::shared_ptr<Texture> resolve_texture_;
  id<CAMetalDrawable> drawable_ = nil;
  std::shared_ptr<Texture> source_texture_;
  std::shared_ptr<Texture> destination_texture_;
  bool requires_blit_ = false;
  std::optional<IRect> clip_rect_;
 
  static bool ShouldPerformPartialRepaint(std::optional<IRect> damage_rect);
 
  SurfaceMTL(const std::weak_ptr<Context>& context,
             const RenderTarget& target,
             std::shared_ptr<Texture> resolve_texture,
             id<CAMetalDrawable> drawable,
             std::shared_ptr<Texture> source_texture,
             std::shared_ptr<Texture> destination_texture,
             bool requires_blit,
             std::optional<IRect> clip_rect);
 
  FML_DISALLOW_COPY_AND_ASSIGN(SurfaceMTL);
};
 
}  // namespace impeller