framebuffer_blend_contents.cc

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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.
 
#include "framebuffer_blend_contents.h"
 
#include "impeller/entity/contents/content_context.h"
#include "impeller/renderer/render_pass.h"
 
namespace impeller {
 
FramebufferBlendContents::FramebufferBlendContents() = default;
 
FramebufferBlendContents::~FramebufferBlendContents() = default;
 
void FramebufferBlendContents::SetBlendMode(BlendMode blend_mode) {
  blend_mode_ = blend_mode;
}
 
void FramebufferBlendContents::SetChildContents(
    std::shared_ptr<Contents> child_contents) {
  child_contents_ = std::move(child_contents);
}
 
// |Contents|
std::optional<Rect> FramebufferBlendContents::GetCoverage(
    const Entity& entity) const {
  return child_contents_->GetCoverage(entity);
}
 
bool FramebufferBlendContents::Render(const ContentContext& renderer,
                                      const Entity& entity,
                                      RenderPass& pass) const {
  if (!renderer.GetDeviceCapabilities().SupportsFramebufferFetch()) {
    return false;
  }
 
  using VS = FramebufferBlendScreenPipeline::VertexShader;
  using FS = FramebufferBlendScreenPipeline::FragmentShader;
 
  auto& host_buffer = pass.GetTransientsBuffer();
 
  auto src_snapshot = child_contents_->RenderToSnapshot(
      renderer,                                    // renderer
      entity,                                      // entity
      Rect::MakeSize(pass.GetRenderTargetSize()),  // coverage_limit
      std::nullopt,                                // sampler_descriptor
      true,                                        // msaa_enabled
      "FramebufferBlendContents Snapshot");        // label
 
  if (!src_snapshot.has_value()) {
    return true;
  }
  auto coverage = src_snapshot->GetCoverage();
  if (!coverage.has_value()) {
    return true;
  }
  Rect src_coverage = coverage.value();
 
  auto size = src_coverage.GetSize();
  VertexBufferBuilder<VS::PerVertexData> vtx_builder;
  vtx_builder.AddVertices({
      {Point(0, 0), Point(0, 0)},
      {Point(size.width, 0), Point(1, 0)},
      {Point(0, size.height), Point(0, 1)},
      {Point(size.width, size.height), Point(1, 1)},
  });
 
  auto options = OptionsFromPass(pass);
  options.blend_mode = BlendMode::kSource;
  options.primitive_type = PrimitiveType::kTriangleStrip;
 
  Command cmd;
  DEBUG_COMMAND_INFO(cmd, "Framebuffer Advanced Blend Filter");
  cmd.BindVertices(vtx_builder.CreateVertexBuffer(host_buffer));
  cmd.stencil_reference = entity.GetClipDepth();
 
  switch (blend_mode_) {
    case BlendMode::kScreen:
      cmd.pipeline = renderer.GetFramebufferBlendScreenPipeline(options);
      break;
    case BlendMode::kOverlay:
      cmd.pipeline = renderer.GetFramebufferBlendOverlayPipeline(options);
      break;
    case BlendMode::kDarken:
      cmd.pipeline = renderer.GetFramebufferBlendDarkenPipeline(options);
      break;
    case BlendMode::kLighten:
      cmd.pipeline = renderer.GetFramebufferBlendLightenPipeline(options);
      break;
    case BlendMode::kColorDodge:
      cmd.pipeline = renderer.GetFramebufferBlendColorDodgePipeline(options);
      break;
    case BlendMode::kColorBurn:
      cmd.pipeline = renderer.GetFramebufferBlendColorBurnPipeline(options);
      break;
    case BlendMode::kHardLight:
      cmd.pipeline = renderer.GetFramebufferBlendHardLightPipeline(options);
      break;
    case BlendMode::kSoftLight:
      cmd.pipeline = renderer.GetFramebufferBlendSoftLightPipeline(options);
      break;
    case BlendMode::kDifference:
      cmd.pipeline = renderer.GetFramebufferBlendDifferencePipeline(options);
      break;
    case BlendMode::kExclusion:
      cmd.pipeline = renderer.GetFramebufferBlendExclusionPipeline(options);
      break;
    case BlendMode::kMultiply:
      cmd.pipeline = renderer.GetFramebufferBlendMultiplyPipeline(options);
      break;
    case BlendMode::kHue:
      cmd.pipeline = renderer.GetFramebufferBlendHuePipeline(options);
      break;
    case BlendMode::kSaturation:
      cmd.pipeline = renderer.GetFramebufferBlendSaturationPipeline(options);
      break;
    case BlendMode::kColor:
      cmd.pipeline = renderer.GetFramebufferBlendColorPipeline(options);
      break;
    case BlendMode::kLuminosity:
      cmd.pipeline = renderer.GetFramebufferBlendLuminosityPipeline(options);
      break;
    default:
      return false;
  }
 
  VS::FrameInfo frame_info;
  FS::FragInfo frag_info;
 
  auto src_sampler_descriptor = src_snapshot->sampler_descriptor;
  if (renderer.GetDeviceCapabilities().SupportsDecalSamplerAddressMode()) {
    src_sampler_descriptor.width_address_mode = SamplerAddressMode::kDecal;
    src_sampler_descriptor.height_address_mode = SamplerAddressMode::kDecal;
  }
  auto src_sampler = renderer.GetContext()->GetSamplerLibrary()->GetSampler(
      src_sampler_descriptor);
  FS::BindTextureSamplerSrc(cmd, src_snapshot->texture, src_sampler);
 
  frame_info.mvp = pass.GetOrthographicTransform() * src_snapshot->transform;
  frame_info.src_y_coord_scale = src_snapshot->texture->GetYCoordScale();
  VS::BindFrameInfo(cmd, host_buffer.EmplaceUniform(frame_info));
 
  frag_info.src_input_alpha = src_snapshot->opacity;
  FS::BindFragInfo(cmd, host_buffer.EmplaceUniform(frag_info));
 
  return pass.AddCommand(std::move(cmd));
}
 
}  // namespace impeller