impeller::ShadowVertices Class Reference

#include <shadow_path_geometry.h>

Public Member Functions
constexpr	ShadowVertices ()
constexpr	ShadowVertices (std::vector< Point > vertices, std::vector< uint16_t > indices, std::vector< Scalar > gaussians)
size_t	GetVertexCount () const
size_t	GetIndexCount () const
	The count of the indices that define the mesh.
const std::vector< Point > &	GetVertices () const
const std::vector< uint16_t > &	GetIndices () const
const std::vector< Scalar > &	GetGaussians () const
bool	IsEmpty () const
std::optional< Rect >	GetBounds () const
GeometryResult	GetPositionBuffer (const ContentContext &renderer, const Entity &entity, RenderPass &pass) const

Static Public Member Functions
static std::shared_ptr< ShadowVertices >	Make (std::vector< Point > vertices, std::vector< uint16_t > indices, std::vector< Scalar > gaussians)

Static Public Attributes
static const std::shared_ptr< ShadowVertices >	kEmpty

Detailed Description

A class to hold a vertex mesh for rendering shadows. The vertices are each associated with a gaussian coefficent that represents where that vertex lives in the shadow from a value of 1.0 (at the edge of or fully in the darkest part of the umbra) to 0.0 at the edge of or fully outside the penumbra).

The vertices are also associated with a vector of indices that assemble them into a mesh that covers the full umbra and penumbra of the shape.

The mesh is usually intended to be rendered at device (pixel) resolution.

Definition at line 24 of file shadow_path_geometry.h.

Constructor & Destructor Documentation

ShadowVertices() [1/2]

constexpr impeller::ShadowVertices::ShadowVertices ( )

inlineconstexpr

Definition at line 35 of file shadow_path_geometry.h.

{}

ShadowVertices() [2/2]

constexpr impeller::ShadowVertices::ShadowVertices ( std::vector< Point >  vertices, std::vector< uint16_t >  indices, std::vector< Scalar >  gaussians  )

inlineconstexpr

Definition at line 37 of file shadow_path_geometry.h.

      : vertices_(std::move(vertices)),
        indices_(std::move(indices)),
        gaussians_(std::move(gaussians)) {}

Member Function Documentation

GetBounds()

std::optional< Rect > impeller::ShadowVertices::GetBounds

(

)

const

Definition at line 1385 of file shadow_path_geometry.cc.

                                                  {
  return Rect::MakePointBounds(vertices_);
}

References impeller::TRect< Scalar >::MakePointBounds().

GetGaussians()

const std::vector< Scalar > & impeller::ShadowVertices::GetGaussians ( ) const

inline

Definition at line 54 of file shadow_path_geometry.h.

{ return gaussians_; }

GetIndexCount()

size_t impeller::ShadowVertices::GetIndexCount ( ) const

inline

The count of the indices that define the mesh.

Definition at line 50 of file shadow_path_geometry.h.

{ return indices_.size(); }

Referenced by GetPositionBuffer().

GetIndices()

const std::vector< uint16_t > & impeller::ShadowVertices::GetIndices ( ) const

inline

Definition at line 53 of file shadow_path_geometry.h.

{ return indices_; }

Referenced by GetPositionBuffer().

GetPositionBuffer()

GeometryResult impeller::ShadowVertices::GetPositionBuffer	(	const ContentContext &	renderer,
		const Entity &	entity,
		RenderPass &	pass
	)		const

Definition at line 1415 of file shadow_path_geometry.cc.

                                                                         {
  using VS = ShadowVerticesVertexShader;
 
  size_t vertex_count = GetVertexCount();
 
  BufferView vertex_buffer = renderer.GetTransientsDataBuffer().Emplace(
      vertex_count * sizeof(VS::PerVertexData), alignof(VS::PerVertexData),
      [&](uint8_t* data) {
        VS::PerVertexData* vtx_contents =
            reinterpret_cast<VS::PerVertexData*>(data);
        for (size_t i = 0u; i < vertex_count; i++) {
          vtx_contents[i] = {
              .position = vertices_[i],
              .gaussian = gaussians_[i],
          };
        }
      });
 
  size_t index_count = GetIndexCount();
  const uint16_t* indices_data = GetIndices().data();
  BufferView index_buffer = {};
  index_buffer = renderer.GetTransientsIndexesBuffer().Emplace(
      indices_data, index_count * sizeof(uint16_t), alignof(uint16_t));
 
  return GeometryResult{
      .type = PrimitiveType::kTriangle,
      .vertex_buffer =
          {
              .vertex_buffer = vertex_buffer,
              .index_buffer = index_buffer,
              .vertex_count = index_count,
              .index_type = IndexType::k16bit,
          },
      .transform = entity.GetShaderTransform(pass),
  };
}

References data, impeller::HostBuffer::Emplace(), GetIndexCount(), GetIndices(), impeller::Entity::GetShaderTransform(), impeller::ContentContext::GetTransientsDataBuffer(), impeller::ContentContext::GetTransientsIndexesBuffer(), GetVertexCount(), i, impeller::k16bit, impeller::kTriangle, and impeller::GeometryResult::type.

GetVertexCount()

size_t impeller::ShadowVertices::GetVertexCount ( ) const

inline

The count of the unique (duplicates minimized) vertices in the mesh. This number is also the count of gaussian coefficients in the mesh since the two are assigned 1:1.

Definition at line 47 of file shadow_path_geometry.h.

{ return vertices_.size(); }

Referenced by GetPositionBuffer().

GetVertices()

const std::vector< Point > & impeller::ShadowVertices::GetVertices ( ) const

inline

Definition at line 52 of file shadow_path_geometry.h.

{ return vertices_; }

IsEmpty()

bool impeller::ShadowVertices::IsEmpty ( ) const

inline

True if and only if there was no shadow for the shape and therefore no mesh to generate.

Definition at line 58 of file shadow_path_geometry.h.

{ return vertices_.empty(); }

Make()

static std::shared_ptr< ShadowVertices > impeller::ShadowVertices::Make ( std::vector< Point >  vertices, std::vector< uint16_t >  indices, std::vector< Scalar >  gaussians  )

inlinestatic

Definition at line 28 of file shadow_path_geometry.h.

                                                                           {
    return std::make_shared<ShadowVertices>(
        std::move(vertices), std::move(indices), std::move(gaussians));
  }

Member Data Documentation

kEmpty

const std::shared_ptr< ShadowVertices > impeller::ShadowVertices::kEmpty

static

Initial value:

=
    std::make_shared<ShadowVertices>()

Definition at line 26 of file shadow_path_geometry.h.

---

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

• impeller/entity/geometry/shadow_path_geometry.h
• impeller/entity/geometry/shadow_path_geometry.cc