impeller::Entity Class Reference

#include <entity.h>

Public Types
enum class	RenderingMode { kDirect , kSubpassAppendSnapshotTransform , kSubpassPrependSnapshotTransform }
enum class	TileMode { kClamp , kRepeat , kMirror , kDecal }
enum class	ClipOperation { kDifference , kIntersect }

Public Member Functions
	Entity ()
	~Entity ()
	Entity (Entity &&)
const Matrix &	GetTransform () const
	Get the global transform matrix for this Entity. More...
Matrix	GetShaderTransform (const RenderPass &pass) const
	Get the vertex shader transform used for drawing this Entity. More...
void	SetTransform (const Matrix &transform)
	Set the global transform matrix for this Entity. More...
std::optional< Rect >	GetCoverage () const
Contents::ClipCoverage	GetClipCoverage (const std::optional< Rect > &current_clip_coverage) const
bool	ShouldRender (const std::optional< Rect > &clip_coverage) const
void	SetContents (std::shared_ptr< Contents > contents)
const std::shared_ptr< Contents > &	GetContents () const
void	SetClipDepth (uint32_t clip_depth)
uint32_t	GetClipDepth () const
float	GetShaderClipDepth () const
void	SetBlendMode (BlendMode blend_mode)
BlendMode	GetBlendMode () const
bool	Render (const ContentContext &renderer, RenderPass &parent_pass) const
bool	CanInheritOpacity () const
bool	SetInheritedOpacity (Scalar alpha)
std::optional< Color >	AsBackgroundColor (ISize target_size) const
Scalar	DeriveTextScale () const
Entity	Clone () const

Static Public Member Functions
static Entity	FromSnapshot (const Snapshot &snapshot, BlendMode blend_mode=BlendMode::kSourceOver)
	Create an entity that can be used to render a given snapshot. More...
static Matrix	GetShaderTransform (Scalar clip_depth, const RenderPass &pass, const Matrix &transform)
	Static utility that computes the vertex shader transform used for drawing an Entity with a given the clip depth and RenderPass size. More...
static float	GetShaderClipDepth (uint32_t clip_depth)
static bool	IsBlendModeDestructive (BlendMode blend_mode)
	Returns true if the blend mode is "destructive", meaning that even fully transparent source colors would result in the destination getting changed. More...

Static Public Attributes
static constexpr BlendMode	kLastPipelineBlendMode = BlendMode::kModulate
static constexpr BlendMode	kLastAdvancedBlendMode = BlendMode::kLuminosity
static constexpr Scalar	kDepthEpsilon = 1.0f / 262144.0

Detailed Description

Definition at line 20 of file entity.h.

Member Enumeration Documentation

ClipOperation

enum class impeller::Entity::ClipOperation

strong

Enumerator
kDifference
kIntersect

Definition at line 61 of file entity.h.

                           {
    kDifference,
    kIntersect,
  };

RenderingMode

enum class impeller::Entity::RenderingMode

strong

Enumerator
kDirect	In direct mode, the Entity's transform is used as the current local-to-screen transform matrix.
kSubpassAppendSnapshotTransform	In subpass mode, the Entity passed through the filter is in screen space rather than local space, and so some filters (namely, MatrixFilterContents) need to interpret the given EffectTransform as the current transform matrix.
kSubpassPrependSnapshotTransform

Definition at line 27 of file entity.h.

                           {
    /// In direct mode, the Entity's transform is used as the current
    /// local-to-screen transform matrix.
    kDirect,
    /// In subpass mode, the Entity passed through the filter is in screen space
    /// rather than local space, and so some filters (namely,
    /// MatrixFilterContents) need to interpret the given EffectTransform as the
    /// current transform matrix.
    kSubpassAppendSnapshotTransform,
    kSubpassPrependSnapshotTransform,
  };

TileMode

enum class impeller::Entity::TileMode

strong

An enum to define how to repeat, fold, or omit colors outside of the typically defined range of the source of the colors (such as the bounds of an image or the defining geometry of a gradient).

Enumerator
kClamp	Replicate the edge color if the shader draws outside of its original bounds.
kRepeat	Repeat the shader's image horizontally and vertically (or both along and perpendicular to a gradient's geometry).
kMirror	Repeat the shader's image horizontally and vertically, seamlessly alternating mirrored images.
kDecal	Render the shader's image pixels only within its original bounds. If the shader draws outside of its original bounds, transparent black is drawn instead.

Definition at line 42 of file entity.h.

                      {
    /// Replicate the edge color if the shader draws outside of its original
    /// bounds.
    kClamp,
 
    /// Repeat the shader's image horizontally and vertically (or both along and
    /// perpendicular to a gradient's geometry).
    kRepeat,
 
    /// Repeat the shader's image horizontally and vertically, seamlessly
    /// alternating mirrored images.
    kMirror,
 
    /// Render the shader's image pixels only within its original bounds. If the
    /// shader draws outside of its original bounds, transparent black is drawn
    /// instead.
    kDecal,
  };

Constructor & Destructor Documentation

Entity() [1/2]

impeller::Entity::Entity ( )

default

~Entity()

impeller::Entity::~Entity ( )

default

Entity() [2/2]

impeller::Entity::Entity ( Entity &&  )

default

Member Function Documentation

AsBackgroundColor()

std::optional< Color > impeller::Entity::AsBackgroundColor

(

ISize

target_size

)

const

Definition at line 145 of file entity.cc.

                                                                    {
  return contents_->AsBackgroundColor(*this, target_size);
}

CanInheritOpacity()

bool impeller::Entity::CanInheritOpacity

(

)

const

Definition at line 123 of file entity.cc.

                                     {
  if (!contents_) {
    return false;
  }
  if (!((blend_mode_ == BlendMode::kSource && contents_->IsOpaque()) ||
        blend_mode_ == BlendMode::kSourceOver)) {
    return false;
  }
  return contents_->CanInheritOpacity(*this);
}

Clone()

Entity impeller::Entity::Clone

(

)

const

Definition at line 191 of file entity.cc.

                           {
  return Entity(*this);
}

DeriveTextScale()

Scalar impeller::Entity::DeriveTextScale

(

)

const

Definition at line 187 of file entity.cc.

                                     {
  return GetTransform().GetMaxBasisLengthXY();
}

FromSnapshot()

Entity impeller::Entity::FromSnapshot ( const Snapshot &  snapshot, BlendMode  blend_mode = BlendMode::kSourceOver  )

static

Create an entity that can be used to render a given snapshot.

Definition at line 22 of file entity.cc.

                                                                          {
  auto texture_rect = Rect::MakeSize(snapshot.texture->GetSize());
 
  auto contents = TextureContents::MakeRect(texture_rect);
  contents->SetTexture(snapshot.texture);
  contents->SetSamplerDescriptor(snapshot.sampler_descriptor);
  contents->SetSourceRect(texture_rect);
  contents->SetOpacity(snapshot.opacity);
 
  Entity entity;
  entity.SetBlendMode(blend_mode);
  entity.SetTransform(snapshot.transform);
  entity.SetContents(contents);
  return entity;
}

GetBlendMode()

BlendMode impeller::Entity::GetBlendMode

(

)

const

Definition at line 119 of file entity.cc.

                                     {
  return blend_mode_;
}

GetClipCoverage()

Contents::ClipCoverage impeller::Entity::GetClipCoverage

(

const std::optional< Rect > &

current_clip_coverage

)

const

Definition at line 74 of file entity.cc.

                                                          {
  if (!contents_) {
    return {};
  }
  return contents_->GetClipCoverage(*this, current_clip_coverage);
}

GetClipDepth()

uint32_t impeller::Entity::GetClipDepth

(

)

const

Definition at line 102 of file entity.cc.

                                    {
  return clip_depth_;
}

GetContents()

const std::shared_ptr< Contents > & impeller::Entity::GetContents

(

)

const

Definition at line 94 of file entity.cc.

                                                         {
  return contents_;
}

GetCoverage()

std::optional< Rect > impeller::Entity::GetCoverage

(

)

const

Definition at line 66 of file entity.cc.

                                            {
  if (!contents_) {
    return std::nullopt;
  }
 
  return contents_->GetCoverage(*this);
}

GetShaderClipDepth() [1/2]

Scalar impeller::Entity::GetShaderClipDepth

(

)

const

Definition at line 106 of file entity.cc.

                                        {
  return Entity::GetShaderClipDepth(clip_depth_);
}

GetShaderClipDepth() [2/2]

Scalar impeller::Entity::GetShaderClipDepth ( uint32_t  clip_depth )

static

Definition at line 110 of file entity.cc.

                                                     {
  Scalar result = std::clamp(clip_depth * kDepthEpsilon, 0.0f, 1.0f);
  return std::min(result, 1.0f - kDepthEpsilon);
}

GetShaderTransform() [1/2]

Matrix impeller::Entity::GetShaderTransform

(

const RenderPass &

pass

)

const

Get the vertex shader transform used for drawing this Entity.

Definition at line 50 of file entity.cc.

                                                              {
  return Entity::GetShaderTransform(GetShaderClipDepth(), pass, transform_);
}

GetShaderTransform() [2/2]

Matrix impeller::Entity::GetShaderTransform ( Scalar  clip_depth, const RenderPass &  pass, const Matrix &  transform  )

static

Static utility that computes the vertex shader transform used for drawing an Entity with a given the clip depth and RenderPass size.

Definition at line 54 of file entity.cc.

                                                           {
  return Matrix::MakeTranslation({0, 0, shader_clip_depth}) *
         Matrix::MakeScale({1, 1, Entity::kDepthEpsilon}) *
         pass.GetOrthographicTransform() * transform;
}

GetTransform()

const Matrix & impeller::Entity::GetTransform

(

)

const

Get the global transform matrix for this Entity.

Definition at line 46 of file entity.cc.

                                         {
  return transform_;
}

IsBlendModeDestructive()

bool impeller::Entity::IsBlendModeDestructive ( BlendMode  blend_mode )

static

Returns true if the blend mode is "destructive", meaning that even fully transparent source colors would result in the destination getting changed.

This is useful for determining if EntityPass textures can be shrinkwrapped to their Entities' coverage; they can be shrinkwrapped if all of the contained Entities have non-destructive blends.

Definition at line 156 of file entity.cc.

                                                        {
  switch (blend_mode) {
    case BlendMode::kClear:
    case BlendMode::kSource:
    case BlendMode::kSourceIn:
    case BlendMode::kDestinationIn:
    case BlendMode::kSourceOut:
    case BlendMode::kDestinationOut:
    case BlendMode::kDestinationATop:
    case BlendMode::kXor:
    case BlendMode::kModulate:
      return true;
    default:
      return false;
  }
}

Render()

bool impeller::Entity::Render	(	const ContentContext &	renderer,
		RenderPass &	parent_pass
	)		const

Definition at line 173 of file entity.cc.

                                                   {
  if (!contents_) {
    return true;
  }
 
  if (!contents_->GetCoverageHint().has_value()) {
    contents_->SetCoverageHint(
        Rect::MakeSize(parent_pass.GetRenderTargetSize()));
  }
 
  return contents_->Render(renderer, *this, parent_pass);
}

SetBlendMode()

void impeller::Entity::SetBlendMode

(

BlendMode

blend_mode

)

Definition at line 115 of file entity.cc.

                                              {
  blend_mode_ = blend_mode;
}

SetClipDepth()

void impeller::Entity::SetClipDepth

(

uint32_t

clip_depth

)

Definition at line 98 of file entity.cc.

                                             {
  clip_depth_ = clip_depth;
}

SetContents()

void impeller::Entity::SetContents

(

std::shared_ptr< Contents >

contents

)

Definition at line 90 of file entity.cc.

                                                         {
  contents_ = std::move(contents);
}

SetInheritedOpacity()

bool impeller::Entity::SetInheritedOpacity

(

Scalar

alpha

)

Definition at line 134 of file entity.cc.

                                             {
  if (!CanInheritOpacity()) {
    return false;
  }
  if (blend_mode_ == BlendMode::kSource && contents_->IsOpaque()) {
    blend_mode_ = BlendMode::kSourceOver;
  }
  contents_->SetInheritedOpacity(alpha);
  return true;
}

SetTransform()

void impeller::Entity::SetTransform

(

const Matrix &

transform

)

Set the global transform matrix for this Entity.

Definition at line 62 of file entity.cc.

                                                 {
  transform_ = transform;
}

ShouldRender()

bool impeller::Entity::ShouldRender

(

const std::optional< Rect > &

clip_coverage

)

const

Definition at line 82 of file entity.cc.

                                                                      {
#ifdef IMPELLER_CONTENT_CULLING
  return contents_->ShouldRender(*this, clip_coverage);
#else
  return true;
#endif  // IMPELLER_CONTENT_CULLING
}

Member Data Documentation

kDepthEpsilon

constexpr Scalar impeller::Entity::kDepthEpsilon = 1.0f / 262144.0

staticconstexpr

Definition at line 25 of file entity.h.

kLastAdvancedBlendMode

constexpr BlendMode impeller::Entity::kLastAdvancedBlendMode = BlendMode::kLuminosity

staticconstexpr

Definition at line 23 of file entity.h.

kLastPipelineBlendMode

constexpr BlendMode impeller::Entity::kLastPipelineBlendMode = BlendMode::kModulate

staticconstexpr

Definition at line 22 of file entity.h.

---

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

• impeller/entity/entity.h
• impeller/entity/entity.cc