impeller::Tessellator::ArcVertexGenerator Class Reference

The |VertexGenerator| implementation common to all shapes that are based on a polygonal representation of an ellipse. More...

#include <tessellator.h>

Inheritance diagram for impeller::Tessellator::ArcVertexGenerator:

Public Member Functions
PrimitiveType	GetTriangleType () const override
	|VertexGenerator| More...
size_t	GetVertexCount () const override
	|VertexGenerator| More...
void	GenerateVertices (const TessellatedVertexProc &proc) const override
	|VertexGenerator| More...

Static Public Member Functions
static ArcVertexGenerator	MakeFilled (const Arc::Iteration &iteration, Trigs &&trigs, const Rect &oval_bounds, bool use_center, bool supports_triangle_fans)
static ArcVertexGenerator	MakeStroked (const Arc::Iteration &iteration, Trigs &&trigs, const Rect &oval_bounds, Scalar half_width, Cap cap, std::unique_ptr< Trigs > round_cap_trigs)

Friends
class	Tessellator

Detailed Description

The |VertexGenerator| implementation common to all shapes that are based on a polygonal representation of an ellipse.

Definition at line 191 of file tessellator.h.

Member Function Documentation

GenerateVertices()

void impeller::ArcVertexGenerator::GenerateVertices ( const TessellatedVertexProc &  proc ) const

overridevirtual

|VertexGenerator|

Implements impeller::Tessellator::VertexGenerator.

Definition at line 597 of file tessellator.cc.

                                             {
  if (half_width_ > 0) {
    FML_DCHECK(!use_center_);
    Tessellator::GenerateStrokedArc(trigs_, iteration_, oval_bounds_,
                                    half_width_, cap_, round_cap_trigs_, proc);
  } else if (supports_triangle_fans_) {
    Tessellator::GenerateFilledArcFan(trigs_, iteration_, oval_bounds_,
                                      use_center_, proc);
  } else {
    Tessellator::GenerateFilledArcStrip(trigs_, iteration_, oval_bounds_,
                                        use_center_, proc);
  }
}

GetTriangleType()

PrimitiveType impeller::ArcVertexGenerator::GetTriangleType ( ) const

overridevirtual

|VertexGenerator|

Implements impeller::Tessellator::VertexGenerator.

Definition at line 564 of file tessellator.cc.

                                                        {
  return (half_width_ < 0 && supports_triangle_fans_)
             ? PrimitiveType::kTriangleFan
             : PrimitiveType::kTriangleStrip;
}

References impeller::kTriangleFan, and impeller::kTriangleStrip.

GetVertexCount()

size_t impeller::ArcVertexGenerator::GetVertexCount ( ) const

overridevirtual

|VertexGenerator|

Implements impeller::Tessellator::VertexGenerator.

Definition at line 570 of file tessellator.cc.

                                                {
  size_t count = iteration_.GetPointCount();
  if (half_width_ > 0) {
    // Stroked arc
    FML_DCHECK(!use_center_);
    count *= 2;
    if (cap_ == Cap::kSquare) {
      count += 4;
    } else if (cap_ == Cap::kRound) {
      FML_DCHECK(round_cap_trigs_);
      // 4 vertices for each Trig in round_cap_trigs_: 2 vertices for each in
      // the start cap and 2 for each in the end cap. Subtract 4 because the cap
      // vertices elide the beginning and end vertices of the arc.
      count += round_cap_trigs_->size() * 4 - 4;
    }
  } else if (supports_triangle_fans_) {
    // Filled arc using a triangle fan
    if (use_center_) {
      count++;
    }
  } else {
    // Filled arc using a triangle strip
    count = (2 * count) - 1;
  }
  return count;
}

References impeller::Arc::Iteration::GetPointCount(), impeller::kRound, and impeller::kSquare.

MakeFilled()

ArcVertexGenerator impeller::ArcVertexGenerator::MakeFilled ( const Arc::Iteration &  iteration, Trigs &&  trigs, const Rect &  oval_bounds, bool  use_center, bool  supports_triangle_fans  )

static

Definition at line 525 of file tessellator.cc.

                                 {
  return ArcVertexGenerator(iteration, std::move(trigs), oval_bounds,
                            use_center, supports_triangle_fans, -1.0f,
                            Cap::kSquare, nullptr);
}

References use_center.

Referenced by impeller::Tessellator::FilledArc().

MakeStroked()

ArcVertexGenerator impeller::ArcVertexGenerator::MakeStroked ( const Arc::Iteration &  iteration, Trigs &&  trigs, const Rect &  oval_bounds, Scalar  half_width, Cap  cap, std::unique_ptr< Trigs >  round_cap_trigs  )

static

Definition at line 536 of file tessellator.cc.

                                          {
  return ArcVertexGenerator(iteration, std::move(trigs), oval_bounds, false,
                            false, half_width, cap, std::move(round_cap_trigs));
}

Referenced by impeller::Tessellator::StrokedArc().

Friends And Related Function Documentation

Tessellator

friend class Tessellator

friend

Definition at line 217 of file tessellator.h.

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

• impeller/tessellator/tessellator.h
• impeller/tessellator/tessellator.cc