impeller::TextureContents Class Reference

#include <texture_contents.h>

Inheritance diagram for impeller::TextureContents:

Public Member Functions
	TextureContents ()
	~TextureContents () override
void	SetLabel (std::string label)
void	SetDestinationRect (Rect rect)
void	SetTexture (std::shared_ptr< Texture > texture)
std::shared_ptr< Texture >	GetTexture () const
void	SetSamplerDescriptor (SamplerDescriptor desc)
const SamplerDescriptor &	GetSamplerDescriptor () const
void	SetSourceRect (const Rect &source_rect)
const Rect &	GetSourceRect () const
void	SetStrictSourceRect (bool strict)
bool	GetStrictSourceRect () const
void	SetOpacity (Scalar opacity)
Scalar	GetOpacity () const
void	SetStencilEnabled (bool enabled)
std::optional< Rect >	GetCoverage (const Entity &entity) const override
	Get the area of the render pass that will be affected when this contents is rendered.
std::optional< Snapshot >	RenderToSnapshot (const ContentContext &renderer, const Entity &entity, std::optional< Rect > coverage_limit=std::nullopt, const std::optional< SamplerDescriptor > &sampler_descriptor=std::nullopt, bool msaa_enabled=true, int32_t mip_count=1, const std::string &label="Texture Snapshot") const override
	Render this contents to a snapshot, respecting the entity's transform, path, clip depth, and blend mode. The result texture size is always the size of GetCoverage(entity).
bool	Render (const ContentContext &renderer, const Entity &entity, RenderPass &pass) const override
bool	CanInheritOpacity (const Entity &entity) const override
	Whether or not this contents can accept the opacity peephole optimization.
void	SetInheritedOpacity (Scalar opacity) override
	Inherit the provided opacity.
void	SetDeferApplyingOpacity (bool defer_applying_opacity)
Public Member Functions inherited from impeller::Contents
	Contents ()
virtual	~Contents ()
virtual void	PopulateGlyphAtlas (const std::shared_ptr< LazyGlyphAtlas > &lazy_glyph_atlas, Scalar scale)
	Add any text data to the specified lazy atlas. The scale parameter must be used again later when drawing the text.
void	SetCoverageHint (std::optional< Rect > coverage_hint)
	Hint that specifies the coverage area of this Contents that will actually be used during rendering. This is for optimization purposes only and can not be relied on as a clip. May optionally affect the result of GetCoverage().
const std::optional< Rect > &	GetCoverageHint () const
virtual bool	IsOpaque () const
	Whether this Contents only emits opaque source colors from the fragment stage. This value does not account for any entity properties (e.g. the blend mode), clips/visibility culling, or inherited opacity.
virtual ClipCoverage	GetClipCoverage (const Entity &entity, const std::optional< Rect > &current_clip_coverage) const
	Given the current pass space bounding rectangle of the clip buffer, return the expected clip coverage after this draw call. This should only be implemented for contents that may write to the clip buffer.
virtual bool	ShouldRender (const Entity &entity, const std::optional< Rect > clip_coverage) const
std::optional< Size >	GetColorSourceSize () const
	Return the color source's intrinsic size, if available.
void	SetColorSourceSize (Size size)
virtual std::optional< Color >	AsBackgroundColor (const Entity &entity, ISize target_size) const
	Returns a color if this Contents will flood the given target_size with a color. This output color is the "Source" color that will be used for the Entity's blend operation.
virtual const FilterContents *	AsFilter () const
	Cast to a filter. Returns nullptr if this Contents is not a filter.
virtual bool	ApplyColorFilter (const ColorFilterProc &color_filter_proc)
	If possible, applies a color filter to this contents inputs on the CPU.

Static Public Member Functions
static std::shared_ptr< TextureContents >	MakeRect (Rect destination)
	A common case factory that marks the texture contents as having a destination rectangle. In this situation, a subpass can be avoided when image filters are applied.
Static Public Member Functions inherited from impeller::Contents
static std::shared_ptr< Contents >	MakeAnonymous (RenderProc render_proc, CoverageProc coverage_proc)

Additional Inherited Members
Public Types inherited from impeller::Contents
using	ColorFilterProc = std::function< Color(Color)>
using	RenderProc = std::function< bool(const ContentContext &renderer, const Entity &entity, RenderPass &pass)>
using	CoverageProc = std::function< std::optional< Rect >(const Entity &entity)>

Detailed Description

Definition at line 21 of file texture_contents.h.

Constructor & Destructor Documentation

TextureContents()

impeller::TextureContents::TextureContents ( )

default

~TextureContents()

impeller::TextureContents::~TextureContents ( )

overridedefault

Member Function Documentation

CanInheritOpacity()

bool impeller::TextureContents::CanInheritOpacity ( const Entity &  entity ) const

overridevirtual

Whether or not this contents can accept the opacity peephole optimization.

By default all contents return false. Contents are responsible for determining whether or not their own geometries intersect in a way that makes accepting opacity impossible. It is always safe to return false, especially if computing overlap would be computationally expensive.

Reimplemented from impeller::Contents.

Definition at line 57 of file texture_contents.cc.

                                                                  {
  return true;
}

GetCoverage()

std::optional< Rect > impeller::TextureContents::GetCoverage ( const Entity &  entity ) const

overridevirtual

Get the area of the render pass that will be affected when this contents is rendered.

During rendering, coverage coordinates count pixels from the top left corner of the framebuffer.

Returns

The coverage rectangle. An std::nullopt result means that rendering this contents has no effect on the output color.

Implements impeller::Contents.

Definition at line 69 of file texture_contents.cc.

                                                                         {
  if (GetOpacity() == 0) {
    return std::nullopt;
  }
  return destination_rect_.TransformBounds(entity.GetTransform());
};

GetOpacity()

Scalar impeller::TextureContents::GetOpacity

(

)

const

Definition at line 65 of file texture_contents.cc.

                                         {
  return opacity_ * inherited_opacity_;
}

GetSamplerDescriptor()

const SamplerDescriptor & impeller::TextureContents::GetSamplerDescriptor

(

)

const

Definition at line 215 of file texture_contents.cc.

                                                                     {
  return sampler_descriptor_;
}

GetSourceRect()

const Rect & impeller::TextureContents::GetSourceRect

(

)

const

Definition at line 199 of file texture_contents.cc.

                                                 {
  return source_rect_;
}

GetStrictSourceRect()

bool impeller::TextureContents::GetStrictSourceRect

(

)

const

Definition at line 207 of file texture_contents.cc.

                                                {
  return strict_source_rect_enabled_;
}

GetTexture()

std::shared_ptr< Texture > impeller::TextureContents::GetTexture

(

)

const

Definition at line 45 of file texture_contents.cc.

                                                         {
  return texture_;
}

MakeRect()

std::shared_ptr< TextureContents > impeller::TextureContents::MakeRect ( Rect  destination )

static

A common case factory that marks the texture contents as having a destination rectangle. In this situation, a subpass can be avoided when image filters are applied.

Definition at line 27 of file texture_contents.cc.

                                                                         {
  auto contents = std::make_shared<TextureContents>();
  contents->destination_rect_ = destination;
  return contents;
}

Render()

bool impeller::TextureContents::Render ( const ContentContext &  renderer, const Entity &  entity, RenderPass &  pass  ) const

overridevirtual

Implements impeller::Contents.

Definition at line 109 of file texture_contents.cc.

                                                     {
  auto capture = entity.GetCapture().CreateChild("TextureContents");
 
  using VS = TextureFillVertexShader;
  using FS = TextureFillFragmentShader;
  using FSStrict = TextureFillStrictSrcFragmentShader;
 
  if (destination_rect_.IsEmpty() || source_rect_.IsEmpty() ||
      texture_ == nullptr || texture_->GetSize().IsEmpty()) {
    return true;  // Nothing to render.
  }
 
  [[maybe_unused]] bool is_external_texture =
      texture_->GetTextureDescriptor().type == TextureType::kTextureExternalOES;
  FML_DCHECK(!is_external_texture);
 
  auto source_rect = capture.AddRect("Source rect", source_rect_);
  auto texture_coords =
      Rect::MakeSize(texture_->GetSize()).Project(source_rect);
 
  VertexBufferBuilder<VS::PerVertexData> vertex_builder;
  auto destination_rect =
      capture.AddRect("Destination rect", destination_rect_);
  vertex_builder.AddVertices({
      {destination_rect.GetLeftTop(), texture_coords.GetLeftTop()},
      {destination_rect.GetRightTop(), texture_coords.GetRightTop()},
      {destination_rect.GetLeftBottom(), texture_coords.GetLeftBottom()},
      {destination_rect.GetRightBottom(), texture_coords.GetRightBottom()},
  });
 
  auto& host_buffer = renderer.GetTransientsBuffer();
 
  VS::FrameInfo frame_info;
  frame_info.mvp = entity.GetShaderTransform(pass);
  frame_info.texture_sampler_y_coord_scale = texture_->GetYCoordScale();
 
#ifdef IMPELLER_DEBUG
  if (label_.empty()) {
    pass.SetCommandLabel("Texture Fill");
  } else {
    pass.SetCommandLabel("Texture Fill: " + label_);
  }
#endif  // IMPELLER_DEBUG
 
  auto pipeline_options = OptionsFromPassAndEntity(pass, entity);
  if (!stencil_enabled_) {
    pipeline_options.stencil_mode = ContentContextOptions::StencilMode::kIgnore;
  }
  pipeline_options.primitive_type = PrimitiveType::kTriangleStrip;
 
  pass.SetPipeline(strict_source_rect_enabled_
                       ? renderer.GetTextureStrictSrcPipeline(pipeline_options)
                       : renderer.GetTexturePipeline(pipeline_options));
 
  pass.SetVertexBuffer(vertex_builder.CreateVertexBuffer(host_buffer));
  VS::BindFrameInfo(pass, host_buffer.EmplaceUniform(frame_info));
 
  if (strict_source_rect_enabled_) {
    // For a strict source rect, shrink the texture coordinate range by half a
    // texel to ensure that linear filtering does not sample anything outside
    // the source rect bounds.
    auto strict_texture_coords =
        Rect::MakeSize(texture_->GetSize()).Project(source_rect.Expand(-0.5));
 
    FSStrict::FragInfo frag_info;
    frag_info.source_rect = Vector4(strict_texture_coords.GetLTRB());
    frag_info.alpha = capture.AddScalar("Alpha", GetOpacity());
    FSStrict::BindFragInfo(pass, host_buffer.EmplaceUniform((frag_info)));
    FSStrict::BindTextureSampler(
        pass, texture_,
        renderer.GetContext()->GetSamplerLibrary()->GetSampler(
            sampler_descriptor_));
  } else {
    FS::FragInfo frag_info;
    frag_info.alpha = capture.AddScalar("Alpha", GetOpacity());
    FS::BindFragInfo(pass, host_buffer.EmplaceUniform((frag_info)));
    FS::BindTextureSampler(
        pass, texture_,
        renderer.GetContext()->GetSamplerLibrary()->GetSampler(
            sampler_descriptor_));
  }
  return pass.Draw().ok();
}

RenderToSnapshot()

std::optional< Snapshot > impeller::TextureContents::RenderToSnapshot ( const ContentContext &  renderer, const Entity &  entity, std::optional< Rect >  coverage_limit = std::nullopt, const std::optional< SamplerDescriptor > &  sampler_descriptor = std::nullopt, bool  msaa_enabled = true, int32_t  mip_count = 1, const std::string &  label = "Texture Snapshot"  ) const

overridevirtual

Render this contents to a snapshot, respecting the entity's transform, path, clip depth, and blend mode. The result texture size is always the size of GetCoverage(entity).

Reimplemented from impeller::Contents.

Definition at line 76 of file texture_contents.cc.

                                  {
  // Passthrough textures that have simple rectangle paths and complete source
  // rects.
  auto bounds = destination_rect_;
  auto opacity = GetOpacity();
  if (source_rect_ == Rect::MakeSize(texture_->GetSize()) &&
      (opacity >= 1 - kEhCloseEnough || defer_applying_opacity_)) {
    auto scale = Vector2(bounds.GetSize() / Size(texture_->GetSize()));
    return Snapshot{
        .texture = texture_,
        .transform = entity.GetTransform() *
                     Matrix::MakeTranslation(bounds.GetOrigin()) *
                     Matrix::MakeScale(scale),
        .sampler_descriptor = sampler_descriptor.value_or(sampler_descriptor_),
        .opacity = opacity};
  }
  return Contents::RenderToSnapshot(
      renderer,                                          // renderer
      entity,                                            // entity
      std::nullopt,                                      // coverage_limit
      sampler_descriptor.value_or(sampler_descriptor_),  // sampler_descriptor
      true,                                              // msaa_enabled
      /*mip_count=*/mip_count,
      label);  // label
}

SetDeferApplyingOpacity()

void impeller::TextureContents::SetDeferApplyingOpacity

(

bool

defer_applying_opacity

)

Definition at line 219 of file texture_contents.cc.

                                                                         {
  defer_applying_opacity_ = defer_applying_opacity;
}

SetDestinationRect()

void impeller::TextureContents::SetDestinationRect

(

Rect

rect

)

Definition at line 37 of file texture_contents.cc.

                                                  {
  destination_rect_ = rect;
}

SetInheritedOpacity()

void impeller::TextureContents::SetInheritedOpacity ( Scalar  opacity )

overridevirtual

Inherit the provided opacity.

   Use of this method is invalid if CanAcceptOpacity returns false.

Reimplemented from impeller::Contents.

Definition at line 61 of file texture_contents.cc.

                                                        {
  inherited_opacity_ = opacity;
}

SetLabel()

void impeller::TextureContents::SetLabel

(

std::string

label

)

Definition at line 33 of file texture_contents.cc.

                                              {
  label_ = std::move(label);
}

SetOpacity()

void impeller::TextureContents::SetOpacity

(

Scalar

opacity

)

Definition at line 49 of file texture_contents.cc.

                                               {
  opacity_ = opacity;
}

SetSamplerDescriptor()

void impeller::TextureContents::SetSamplerDescriptor

(

SamplerDescriptor

desc

)

Definition at line 211 of file texture_contents.cc.

                                                                 {
  sampler_descriptor_ = std::move(desc);
}

SetSourceRect()

void impeller::TextureContents::SetSourceRect

(

const Rect &

source_rect

)

Definition at line 195 of file texture_contents.cc.

                                                           {
  source_rect_ = source_rect;
}

SetStencilEnabled()

void impeller::TextureContents::SetStencilEnabled

(

bool

enabled

)

Definition at line 53 of file texture_contents.cc.

                                                    {
  stencil_enabled_ = enabled;
}

SetStrictSourceRect()

void impeller::TextureContents::SetStrictSourceRect

(

bool

strict

)

Definition at line 203 of file texture_contents.cc.

                                                     {
  strict_source_rect_enabled_ = strict;
}

SetTexture()

void impeller::TextureContents::SetTexture

(

std::shared_ptr< Texture >

texture

)

Definition at line 41 of file texture_contents.cc.

                                                               {
  texture_ = std::move(texture);
}

---

The documentation for this class was generated from the following files:

• impeller/entity/contents/texture_contents.h
• impeller/entity/contents/texture_contents.cc