shell/gpu/gpu_surface_vulkan_impeller.cc

// 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 "flutter/shell/gpu/gpu_surface_vulkan_impeller.h"

#include "flow/surface_frame.h"
#include "flutter/fml/make_copyable.h"
#include "impeller/display_list/dl_dispatcher.h"
#include "impeller/renderer/backend/vulkan/surface_context_vk.h"
#include "impeller/renderer/surface.h"
#include "impeller/typographer/backends/skia/typographer_context_skia.h"

namespace flutter {

GPUSurfaceVulkanImpeller::GPUSurfaceVulkanImpeller(
    std::shared_ptr<impeller::Context> context) {
  if (!context || !context->IsValid()) {
    return;
  }

  auto aiks_context = std::make_shared<impeller::AiksContext>(
      context, impeller::TypographerContextSkia::Make());
  if (!aiks_context->IsValid()) {
    return;
  }

  impeller_context_ = std::move(context);
  aiks_context_ = std::move(aiks_context);
  is_valid_ = true;
}

// |Surface|
GPUSurfaceVulkanImpeller::~GPUSurfaceVulkanImpeller() = default;

// |Surface|
bool GPUSurfaceVulkanImpeller::IsValid() {
  return is_valid_;
}

// |Surface|
std::unique_ptr<SurfaceFrame> GPUSurfaceVulkanImpeller::AcquireFrame(
    const SkISize& size) {
  if (!IsValid()) {
    FML_LOG(ERROR) << "Vulkan surface was invalid.";
    return nullptr;
  }

  if (size.isEmpty()) {
    FML_LOG(ERROR) << "Vulkan surface was asked for an empty frame.";
    return nullptr;
  }

  auto& context_vk = impeller::SurfaceContextVK::Cast(*impeller_context_);
  std::unique_ptr<impeller::Surface> surface = context_vk.AcquireNextSurface();

  if (!surface) {
    FML_LOG(ERROR) << "No surface available.";
    return nullptr;
  }

  auto cull_rect = surface->GetRenderTarget().GetRenderTargetSize();

  impeller::RenderTarget render_target = surface->GetRenderTarget();

  SurfaceFrame::EncodeCallback encode_callback = [aiks_context =
                                                      aiks_context_,  //
                                                  render_target,
                                                  cull_rect  //
  ](SurfaceFrame& surface_frame, DlCanvas* canvas) mutable -> bool {
    if (!aiks_context) {
      return false;
    }

    auto display_list = surface_frame.BuildDisplayList();
    if (!display_list) {
      FML_LOG(ERROR) << "Could not build display list for surface frame.";
      return false;
    }

    SkIRect sk_cull_rect = SkIRect::MakeWH(cull_rect.width, cull_rect.height);
    return impeller::RenderToOnscreen(aiks_context->GetContentContext(),  //
                                      render_target,                      //
                                      display_list,                       //
                                      sk_cull_rect,                       //
                                      /*reset_host_buffer=*/true          //
    );
  };

  return std::make_unique<SurfaceFrame>(
      nullptr,                          // surface
      SurfaceFrame::FramebufferInfo{},  // framebuffer info
      encode_callback,                  // encode callback
      fml::MakeCopyable([surface = std::move(surface)](const SurfaceFrame&) {
        return surface->Present();
      }),       // submit callback
      size,     // frame size
      nullptr,  // context result
      true      // display list fallback
  );
}

// |Surface|
SkMatrix GPUSurfaceVulkanImpeller::GetRootTransformation() const {
  // This backend does not currently support root surface transformations. Just
  // return identity.
  return {};
}

// |Surface|
GrDirectContext* GPUSurfaceVulkanImpeller::GetContext() {
  // Impeller != Skia.
  return nullptr;
}

// |Surface|
std::unique_ptr<GLContextResult>
GPUSurfaceVulkanImpeller::MakeRenderContextCurrent() {
  // This backend has no such concept.
  return std::make_unique<GLContextDefaultResult>(true);
}

// |Surface|
bool GPUSurfaceVulkanImpeller::EnableRasterCache() const {
  return false;
}

// |Surface|
std::shared_ptr<impeller::AiksContext>
GPUSurfaceVulkanImpeller::GetAiksContext() const {
  return aiks_context_;
}

}  // namespace flutter