| Flutter Impeller |

Classes | Public Types | Public Member Functions | Static Public Member Functions | Static Public Attributes | Protected Attributes | List of all members
impeller::Tessellator Class Reference

A utility that generates triangles of the specified fill type given a polyline. This happens on the CPU. More...

`#include <tessellator.h>`

## Classes
class | ArcVertexGenerator
| The |VertexGenerator| implementation common to all shapes that are based on a polygonal representation of an ellipse. More...
class | EllipticalVertexGenerator
| The |VertexGenerator| implementation common to all shapes that are based on a polygonal representation of an ellipse. More...
class | Trigs
class | VertexGenerator
| An object which produces a list of vertices as |Point|s that tessellate a previously provided shape and delivers the vertices through a |TessellatedVertexProc| callback. More...

## Public Types
enum class | Result { kSuccess , kInputError , kTessellationError }
using | TessellatedVertexProc = std::function< void(const Point &p)>
| A callback function for a |VertexGenerator| to deliver the vertices it computes as |Point| objects. More...

## Public Member Functions
| Tessellator ()
virtual | ~Tessellator ()
VertexBuffer | TessellateConvex (const PathSource &path, HostBuffer &host_buffer, Scalar tolerance, bool supports_primitive_restart=false, bool supports_triangle_fan=false)
| Given a convex path, create a triangle fan structure. More...
EllipticalVertexGenerator | FilledCircle (const Matrix &view_transform, const Point &center, Scalar radius)
| Create a |VertexGenerator| that can produce vertices for a filled circle of the given radius around the given center with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform. More...
EllipticalVertexGenerator | StrokedCircle (const Matrix &view_transform, const Point &center, Scalar radius, Scalar half_width)
| Create a |VertexGenerator| that can produce vertices for a stroked circle of the given radius and half_width around the given shared center with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform. The outer edge of the stroked circle is generated at (radius + half_width) and the inner edge is generated at (radius - half_width). More...
ArcVertexGenerator | FilledArc (const Matrix &view_transform, const Arc &arc, bool supports_triangle_fans)
| Create a |VertexGenerator| that can produce vertices for a stroked arc inscribed within the given oval_bounds with the given stroke half_width with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform. The outer edge of the stroked arc is generated at (radius + half_width) and the inner edge is generated at (radius - half_width). More...
ArcVertexGenerator | StrokedArc (const Matrix &view_transform, const Arc &arc, Cap cap, Scalar half_width)
| Create a |VertexGenerator| that can produce vertices for a stroked arc inscribed within the given oval_bounds with the given stroke half_width with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform. The outer edge of the stroked arc is generated at (radius + half_width) and the inner edge is generated at (radius - half_width). More...
EllipticalVertexGenerator | RoundCapLine (const Matrix &view_transform, const Point &p0, const Point &p1, Scalar radius)
| Create a |VertexGenerator| that can produce vertices for a line with round end caps of the given radius with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform. More...
EllipticalVertexGenerator | FilledEllipse (const Matrix &view_transform, const Rect &bounds)
| Create a |VertexGenerator| that can produce vertices for a filled ellipse inscribed within the given bounds with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform. More...
EllipticalVertexGenerator | FilledRoundRect (const Matrix &view_transform, const Rect &bounds, const Size &radii)
| Create a |VertexGenerator| that can produce vertices for a filled round rect within the given bounds and corner radii with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform. More...
std::vector< Point > & | GetStrokePointCache ()
| Retrieve a pre-allocated arena of kPointArenaSize points. More...
Trigs | GetTrigsForDeviceRadius (Scalar pixel_radius)

## Static Public Member Functions
static void | TessellateConvexInternal (const PathSource &path, std::vector< Point > &point_buffer, std::vector< uint16_t > &index_buffer, Scalar tolerance)

## Static Public Attributes
static constexpr Scalar | kCircleTolerance = 0.1f
| The pixel tolerance used by the algorighm to determine how many divisions to create for a circle. More...

## Protected Attributes
std::unique_ptr< std::vector< Point > > | point_buffer_
| Used for polyline generation. More...
std::unique_ptr< std::vector< uint16_t > > | index_buffer_
std::vector< Point > | stroke_points_
| Used for stroke path generation. More...

## Detailed Description

A utility that generates triangles of the specified fill type given a polyline. This happens on the CPU.

Also contains functionality for optimized generation of circles and ellipses.

This object is not thread safe, and its methods must not be called from multiple threads.

Definition at line 37 of file tessellator.h.

## Member Typedef Documentation

## ◆ TessellatedVertexProc

using impeller::Tessellator::TessellatedVertexProc = std::function<void(const Point& p)>

A callback function for a |VertexGenerator| to deliver the vertices it computes as |Point| objects.

Definition at line 97 of file tessellator.h.

## Member Enumeration Documentation

## ◆ Result

enum impeller::Tessellator::Result
| strong

Enumerator
kSuccess |
kInputError |
kTessellationError |

Definition at line 89 of file tessellator.h.

89 {
90 kSuccess,
91 kInputError,
92 kTessellationError,
93 };

## Constructor & Destructor Documentation

## ◆ Tessellator()

impeller::Tessellator::Tessellator | ( |  | ) |

Definition at line 296 of file tessellator.cc.

297 : point_buffer_(std::make_unique<std::vector<Point>>()),
298 index_buffer_(std::make_unique<std::vector<uint16_t>>()),
299 stroke_points_(kPointArenaSize) {
300 point_buffer_->reserve(2048);
301 index_buffer_->reserve(2048);
302 }
impeller::Tessellator::stroke_points_
std::vector< Point > stroke_points_
Used for stroke path generation.
Definition: tessellator.h:382
impeller::Tessellator::point_buffer_
std::unique_ptr< std::vector< Point > > point_buffer_
Used for polyline generation.
Definition: tessellator.h:379
impeller::Tessellator::index_buffer_
std::unique_ptr< std::vector< uint16_t > > index_buffer_
Definition: tessellator.h:380
impeller::kPointArenaSize
static constexpr size_t kPointArenaSize
The size of the point arena buffer stored on the tessellator.
Definition: tessellator.h:25

References index_buffer_, and point_buffer_.

## ◆ ~Tessellator()

impeller::Tessellator::~Tessellator | ( |  | ) |
| virtualdefault

## Member Function Documentation

## ◆ FilledArc()

ArcVertexGenerator impeller::Tessellator::FilledArc | ( | const Matrix & | view_transform,
|  | const Arc & | arc,
|  | bool | supports_triangle_fans
| ) |  |

Create a |VertexGenerator| that can produce vertices for a stroked arc inscribed within the given oval_bounds with the given stroke half_width with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform. The outer edge of the stroked arc is generated at (radius + half_width) and the inner edge is generated at (radius - half_width).

Note that the view transform is only used to choose the number of sample points to use per quarter circle and the returned points are not transformed by it, instead they are relative to the coordinate space of the oval bounds.

Definition at line 556 of file tessellator.cc.

558 {
559 size_t divisions = ComputeQuadrantDivisions(
560 view_transform.GetMaxBasisLengthXY() * arc.GetOvalSize().MaxDimension());
561
562 return ArcVertexGenerator(
563 arc.ComputeIterations(divisions), GetTrigsForDivisions(divisions),
564 arc.GetOvalBounds(), arc.IncludeCenter(), supports_triangle_fans);
565 };
impeller::ArcVertexGenerator
Tessellator::ArcVertexGenerator ArcVertexGenerator
Definition: tessellator.cc:439

References impeller::Arc::ComputeIterations(), impeller::Matrix::GetMaxBasisLengthXY(), impeller::Arc::GetOvalBounds(), impeller::Arc::GetOvalSize(), impeller::Arc::IncludeCenter(), and impeller::TSize< T >::MaxDimension().

## ◆ FilledCircle()

EllipticalVertexGenerator impeller::Tessellator::FilledCircle | ( | const Matrix & | view_transform,
|  | const Point & | center,
|  | Scalar | radius
| ) |  |

Create a |VertexGenerator| that can produce vertices for a filled circle of the given radius around the given center with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform.

Note that the view transform is only used to choose the number of sample points to use per quarter circle and the returned points are not transformed by it, instead they are relative to the coordinate space of the center point.

Definition at line 452 of file tessellator.cc.

455 {
456 size_t divisions =
457 ComputeQuadrantDivisions(view_transform.GetMaxBasisLengthXY() * radius);
458 return EllipticalVertexGenerator(Tessellator::GenerateFilledCircle,
459 GetTrigsForDivisions(divisions),
460 PrimitiveType::kTriangleStrip, 4,
461 {
462 .reference_centers = {center, center},
463 .radii = {radius, radius},
464 .half_width = -1.0f,
465 });
466 }
impeller::PrimitiveType::kTriangleStrip
@ kTriangleStrip
impeller::EllipticalVertexGenerator
Tessellator::EllipticalVertexGenerator EllipticalVertexGenerator
Definition: tessellator.cc:438

References impeller::Matrix::GetMaxBasisLengthXY().

Referenced by FilledEllipse(), and RoundCapLine().

## ◆ FilledEllipse()

EllipticalVertexGenerator impeller::Tessellator::FilledEllipse | ( | const Matrix & | view_transform,
|  | const Rect & | bounds
| ) |  |

Create a |VertexGenerator| that can produce vertices for a filled ellipse inscribed within the given bounds with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform.

Note that the view transform is only used to choose the number of sample points to use per quarter circle and the returned points are not transformed by it, instead they are relative to the coordinate space of the bounds.

Definition at line 606 of file tessellator.cc.

608 {
609 if (bounds.IsSquare()) {
610 return FilledCircle(view_transform, bounds.GetCenter(),
611 bounds.GetWidth() * 0.5f);
612 }
613 auto max_radius = bounds.GetSize().MaxDimension();
614 auto divisions = ComputeQuadrantDivisions(
615 view_transform.GetMaxBasisLengthXY() * max_radius);
616 auto center = bounds.GetCenter();
617 return EllipticalVertexGenerator(Tessellator::GenerateFilledEllipse,
618 GetTrigsForDivisions(divisions),
619 PrimitiveType::kTriangleStrip, 4,
620 {
621 .reference_centers = {center, center},
622 .radii = bounds.GetSize() * 0.5f,
623 .half_width = -1.0f,
624 });
625 }
impeller::Tessellator::FilledCircle
EllipticalVertexGenerator FilledCircle(const Matrix &view_transform, const Point &center, Scalar radius)
Create a |VertexGenerator| that can produce vertices for a filled circle of the given radius around t...
Definition: tessellator.cc:452

References FilledCircle(), impeller::TRect< T >::GetCenter(), impeller::Matrix::GetMaxBasisLengthXY(), impeller::TRect< T >::GetSize(), impeller::TRect< T >::GetWidth(), impeller::TRect< T >::IsSquare(), and impeller::kTriangleStrip.

Referenced by FilledRoundRect().

## ◆ FilledRoundRect()

EllipticalVertexGenerator impeller::Tessellator::FilledRoundRect | ( | const Matrix & | view_transform,
|  | const Rect & | bounds,
|  | const Size & | radii
| ) |  |

Create a |VertexGenerator| that can produce vertices for a filled round rect within the given bounds and corner radii with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform.

Note that the view transform is only used to choose the number of sample points to use per quarter circle and the returned points are not transformed by it, instead they are relative to the coordinate space of the bounds.

Definition at line 627 of file tessellator.cc.

630 {
631 if (radii.width * 2 < bounds.GetWidth() ||
632 radii.height * 2 < bounds.GetHeight()) {
633 auto max_radius = radii.MaxDimension();
634 auto divisions = ComputeQuadrantDivisions(
635 view_transform.GetMaxBasisLengthXY() * max_radius);
636 auto upper_left = bounds.GetLeftTop() + radii;
637 auto lower_right = bounds.GetRightBottom() - radii;
638 return EllipticalVertexGenerator(Tessellator::GenerateFilledRoundRect,
639 GetTrigsForDivisions(divisions),
640 PrimitiveType::kTriangleStrip, 4,
641 {
642 .reference_centers =
643 {
644 upper_left,
645 lower_right,
646 },
647 .radii = radii,
648 .half_width = -1.0f,
649 });
650 } else {
651 return FilledEllipse(view_transform, bounds);
652 }
653 }
impeller::Tessellator::FilledEllipse
EllipticalVertexGenerator FilledEllipse(const Matrix &view_transform, const Rect &bounds)
Create a |VertexGenerator| that can produce vertices for a filled ellipse inscribed within the given ...
Definition: tessellator.cc:606

References FilledEllipse(), impeller::TRect< T >::GetHeight(), impeller::TRect< T >::GetLeftTop(), impeller::Matrix::GetMaxBasisLengthXY(), impeller::TRect< T >::GetRightBottom(), impeller::TRect< T >::GetWidth(), impeller::TSize< T >::height, impeller::kTriangleStrip, impeller::TSize< T >::MaxDimension(), and impeller::TSize< T >::width.

## ◆ GetStrokePointCache()

std::vector< Point > & impeller::Tessellator::GetStrokePointCache | ( |  | ) |

Retrieve a pre-allocated arena of kPointArenaSize points.

Definition at line 306 of file tessellator.cc.

306 {
307 return stroke_points_;
308 }

References stroke_points_.

## ◆ GetTrigsForDeviceRadius()

Tessellator::Trigs impeller::Tessellator::GetTrigsForDeviceRadius | ( | Scalar | pixel_radius | ) |

Return a vector of Trig (cos, sin pairs) structs for a 90 degree circle quadrant of the specified pixel radius

Definition at line 310 of file tessellator.cc.

310 {
311 return GetTrigsForDivisions(ComputeQuadrantDivisions(pixel_radius));
312 }

Referenced by impeller::ArcStrokeGeometry::Dispatch(), impeller::StrokeRectGeometry::GetPositionBuffer(), impeller::StrokePathSegmentReceiver::RecordArc(), and impeller::testing::TEST().

## ◆ RoundCapLine()

EllipticalVertexGenerator impeller::Tessellator::RoundCapLine | ( | const Matrix & | view_transform,
|  | const Point & | p0,
|  | const Point & | p1,
|  | Scalar | radius
| ) |  |

Create a |VertexGenerator| that can produce vertices for a line with round end caps of the given radius with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform.

Note that the view transform is only used to choose the number of sample points to use per quarter circle and the returned points are not transformed by it, instead they are relative to the coordinate space of the two points.

Definition at line 583 of file tessellator.cc.

587 {
588 auto along = p1 - p0;
589 auto length = along.GetLength();
590 if (length > kEhCloseEnough) {
591 auto divisions =
592 ComputeQuadrantDivisions(view_transform.GetMaxBasisLengthXY() * radius);
593 return EllipticalVertexGenerator(Tessellator::GenerateRoundCapLine,
594 GetTrigsForDivisions(divisions),
595 PrimitiveType::kTriangleStrip, 4,
596 {
597 .reference_centers = {p0, p1},
598 .radii = {radius, radius},
599 .half_width = -1.0f,
600 });
601 } else {
602 return FilledCircle(view_transform, p0, radius);
603 }
604 }
impeller::kEhCloseEnough
constexpr float kEhCloseEnough
Definition: constants.h:57

References FilledCircle(), impeller::TPoint< T >::GetLength(), impeller::Matrix::GetMaxBasisLengthXY(), impeller::kEhCloseEnough, and impeller::kTriangleStrip.

## ◆ StrokedArc()

ArcVertexGenerator impeller::Tessellator::StrokedArc | ( | const Matrix & | view_transform,
|  | const Arc & | arc,
|  | Cap | cap,
|  | Scalar | half_width
| ) |  |

Create a |VertexGenerator| that can produce vertices for a stroked arc inscribed within the given oval_bounds with the given stroke half_width with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform. The outer edge of the stroked arc is generated at (radius + half_width) and the inner edge is generated at (radius - half_width).

Note that the arc may not include the center and its bounds must be a perfect circle (width == height)

Note that the view transform is only used to choose the number of sample points to use per quarter circle and the returned points are not transformed by it, instead they are relative to the coordinate space of the oval bounds.

Definition at line 567 of file tessellator.cc.

570 {
571 FML_DCHECK(half_width > 0);
572 FML_DCHECK(arc.IsPerfectCircle());
573 FML_DCHECK(!arc.IncludeCenter());
574 size_t divisions =
575 ComputeQuadrantDivisions(view_transform.GetMaxBasisLengthXY() *
576 (arc.GetOvalSize().MaxDimension() + half_width));
577
578 return ArcVertexGenerator(arc.ComputeIterations(divisions),
579 GetTrigsForDivisions(divisions),
580 arc.GetOvalBounds(), half_width, cap);
581 }

References impeller::Arc::ComputeIterations(), impeller::Matrix::GetMaxBasisLengthXY(), impeller::Arc::GetOvalBounds(), impeller::Arc::GetOvalSize(), impeller::Arc::IncludeCenter(), impeller::Arc::IsPerfectCircle(), and impeller::TSize< T >::MaxDimension().

## ◆ StrokedCircle()

EllipticalVertexGenerator impeller::Tessellator::StrokedCircle | ( | const Matrix & | view_transform,
|  | const Point & | center,
|  | Scalar | radius,
|  | Scalar | half_width
| ) |  |

Create a |VertexGenerator| that can produce vertices for a stroked circle of the given radius and half_width around the given shared center with enough polygon sub-divisions to provide reasonable fidelity when viewed under the given view transform. The outer edge of the stroked circle is generated at (radius + half_width) and the inner edge is generated at (radius - half_width).

Note that the view transform is only used to choose the number of sample points to use per quarter circle and the returned points are not transformed by it, instead they are relative to the coordinate space of the center point.

Definition at line 468 of file tessellator.cc.

472 {
473 if (half_width > 0) {
474 auto divisions = ComputeQuadrantDivisions(
475 view_transform.GetMaxBasisLengthXY() * radius + half_width);
476 return EllipticalVertexGenerator(Tessellator::GenerateStrokedCircle,
477 GetTrigsForDivisions(divisions),
478 PrimitiveType::kTriangleStrip, 8,
479 {
480 .reference_centers = {center, center},
481 .radii = {radius, radius},
482 .half_width = half_width,
483 });
484 } else {
485 return FilledCircle(view_transform, center, radius);
486 }
487 }

References impeller::Matrix::GetMaxBasisLengthXY().

## ◆ TessellateConvex()

VertexBuffer impeller::Tessellator::TessellateConvex | ( | const PathSource & | path,
|  | HostBuffer & | host_buffer,
|  | Scalar | tolerance,
|  | bool | supports_primitive_restart = `false`,
|  | bool | supports_triangle_fan = `false`
| ) |  |

Given a convex path, create a triangle fan structure.

Parameters

  [in] | path | The path to tessellate.
  [in] | host_buffer | The host buffer for allocation of vertices/index data.
  [in] | tolerance | The tolerance value for conversion of the path to a polyline. This value is often derived from the Matrix::GetMaxBasisLengthXY of the CTM applied to the path for rendering.

Returns
  A vertex buffer containing all data from the provided curve.

Definition at line 314 of file tessellator.cc.

318 {
319 if (supports_primitive_restart) {
320 // Primitive Restart.
321 const auto [point_count, contour_count] =
322 PathTessellator::CountFillStorage(path, tolerance);
323 BufferView point_buffer = host_buffer.Emplace(
324 nullptr, sizeof(Point) * point_count, alignof(Point));
325 BufferView index_buffer = host_buffer.Emplace(
326 nullptr, sizeof(uint16_t) * (point_count + contour_count),
327 alignof(uint16_t));
328
329 if (supports_triangle_fan) {
330 FanPathVertexWriter writer(
331 reinterpret_cast<Point*>(point_buffer.GetBuffer()->OnGetContents() +
332 point_buffer.GetRange().offset),
333 reinterpret_cast<uint16_t*>(
334 index_buffer.GetBuffer()->OnGetContents() +
335 index_buffer.GetRange().offset));
336 PathTessellator::PathToFilledVertices(path, writer, tolerance);
337 FML_DCHECK(writer.GetPointCount() <= point_count);
338 FML_DCHECK(writer.GetIndexCount() <= (point_count + contour_count));
339 point_buffer.GetBuffer()->Flush(point_buffer.GetRange());
340 index_buffer.GetBuffer()->Flush(index_buffer.GetRange());
341
342 return VertexBuffer{
343 .vertex_buffer = std::move(point_buffer),
344 .index_buffer = std::move(index_buffer),
345 .vertex_count = writer.GetIndexCount(),
346 .index_type = IndexType::k16bit,
347 };
348 } else {
349 StripPathVertexWriter writer(
350 reinterpret_cast<Point*>(point_buffer.GetBuffer()->OnGetContents() +
351 point_buffer.GetRange().offset),
352 reinterpret_cast<uint16_t*>(
353 index_buffer.GetBuffer()->OnGetContents() +
354 index_buffer.GetRange().offset));
355 PathTessellator::PathToFilledVertices(path, writer, tolerance);
356 FML_DCHECK(writer.GetPointCount() <= point_count);
357 FML_DCHECK(writer.GetIndexCount() <= (point_count + contour_count));
358 point_buffer.GetBuffer()->Flush(point_buffer.GetRange());
359 index_buffer.GetBuffer()->Flush(index_buffer.GetRange());
360
361 return VertexBuffer{
362 .vertex_buffer = std::move(point_buffer),
363 .index_buffer = std::move(index_buffer),
364 .vertex_count = writer.GetIndexCount(),
365 .index_type = IndexType::k16bit,
366 };
367 }
368 }
369
370 FML_DCHECK(point_buffer_);
371 FML_DCHECK(index_buffer_);
372 TessellateConvexInternal(path, *point_buffer_, *index_buffer_, tolerance);
373
374 if (point_buffer_->empty()) {
375 return VertexBuffer{
376 .vertex_buffer = {},
377 .index_buffer = {},
378 .vertex_count = 0u,
379 .index_type = IndexType::k16bit,
380 };
381 }
382
383 BufferView vertex_buffer = host_buffer.Emplace(
384 point_buffer_->data(), sizeof(Point) * point_buffer_->size(),
385 alignof(Point));
386
387 BufferView index_buffer = host_buffer.Emplace(
388 index_buffer_->data(), sizeof(uint16_t) * index_buffer_->size(),
389 alignof(uint16_t));
390
391 return VertexBuffer{
392 .vertex_buffer = std::move(vertex_buffer),
393 .index_buffer = std::move(index_buffer),
394 .vertex_count = index_buffer_->size(),
395 .index_type = IndexType::k16bit,
396 };
397 }
impeller::PathTessellator::PathToFilledVertices
static void PathToFilledVertices(const PathSource &source, VertexWriter &writer, Scalar scale)
Definition: path_tessellator.cc:307
impeller::PathTessellator::CountFillStorage
static std::pair< size_t, size_t > CountFillStorage(const PathSource &source, Scalar scale)
Definition: path_tessellator.cc:297
impeller::Tessellator::TessellateConvexInternal
static void TessellateConvexInternal(const PathSource &path, std::vector< Point > &point_buffer, std::vector< uint16_t > &index_buffer, Scalar tolerance)
Definition: tessellator.cc:399
impeller::IndexType::k16bit
@ k16bit
impeller::Point
TPoint< Scalar > Point
Definition: point.h:327

References impeller::PathTessellator::CountFillStorage(), impeller::HostBuffer::Emplace(), impeller::DeviceBuffer::Flush(), impeller::BufferView::GetBuffer(), impeller::BufferView::GetRange(), index_buffer_, impeller::k16bit, impeller::Range::offset, impeller::DeviceBuffer::OnGetContents(), impeller::PathTessellator::PathToFilledVertices(), point_buffer_, TessellateConvexInternal(), and impeller::VertexBuffer::vertex_buffer.

## ◆ TessellateConvexInternal()

void impeller::Tessellator::TessellateConvexInternal | ( | const PathSource & | path,
|  | std::vector< Point > & | point_buffer,
|  | std::vector< uint16_t > & | index_buffer,
|  | Scalar | tolerance
| ) |  |
| static

Visible for testing.

This method only exists for the ease of benchmarking without using the real allocator needed by the [host_buffer].

Definition at line 399 of file tessellator.cc.

402 {
403 point_buffer.clear();
404 index_buffer.clear();
405
406 GLESPathVertexWriter writer(point_buffer, index_buffer);
407
408 PathTessellator::PathToFilledVertices(path, writer, tolerance);
409 }

References impeller::PathTessellator::PathToFilledVertices().

Referenced by impeller::BM_Convex(), TessellateConvex(), and impeller::testing::TEST().

## Member Data Documentation

## ◆ index_buffer_

std::unique_ptr<std::vector<uint16_t> > impeller::Tessellator::index_buffer_
| protected

Definition at line 380 of file tessellator.h.

Referenced by TessellateConvex(), and Tessellator().

## ◆ kCircleTolerance

constexpr Scalar impeller::Tessellator::kCircleTolerance = 0.1f
| staticconstexpr

The pixel tolerance used by the algorighm to determine how many divisions to create for a circle.

No point on the polygon of vertices should deviate from the true circle by more than this tolerance.

Definition at line 263 of file tessellator.h.

Referenced by impeller::testing::TEST().

## ◆ point_buffer_

std::unique_ptr<std::vector<Point> > impeller::Tessellator::point_buffer_
| protected

Used for polyline generation.

Definition at line 379 of file tessellator.h.

Referenced by TessellateConvex(), and Tessellator().

## ◆ stroke_points_

std::vector<Point> impeller::Tessellator::stroke_points_
| protected

Used for stroke path generation.

Definition at line 382 of file tessellator.h.

Referenced by GetStrokePointCache().

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

- impeller/tessellator/tessellator.h
- impeller/tessellator/tessellator.cc