GPU-ready encoded path data produced by the Slug band decomposition algorithm. More...

#include "donner/svg/renderer/geode/GeodePathEncoder.h"

Classes
struct	Curve
	A quadratic Bézier curve segment (3 control points) stored as floats for GPU consumption. More...
struct	Band
	Compact metadata for one band. Layout matches the WGSL Band struct exactly. More...
struct	AxisStats
	Per-axis encode statistics retained with the path for diagnostics and perf tests. More...
struct	EncodingStats
	Output-neutral instrumentation for the CPU encoding result. More...
struct	BoundingPoint
	One path-space vertex in the convex bounding polygon. More...

Public Types
enum class	Outcome { Empty , Ready , Rejected }

Public Member Functions
std::size_t	geometryItemCount () const
std::size_t	retainedBytes () const
uint32_t	boundingDrawVertexCount () const
	Triangle-list vertex count emitted by the vertex shader for the bounding fan.
bool	empty () const
	Returns true if the encoded path has no bands (empty or degenerate path).
bool	rejected () const

Public Attributes
std::vector< Curve >	curves
	Canonical horizontal (Y-monotonic) curves.
std::vector< uint32_t >	curveIndices
	Per-band references into curves.
std::vector< Band >	bands
	Horizontal band metadata (Y-strips), for the horizontal ray.
Box2d	pathBounds
	Axis-aligned bounding box of the path.
std::array< BoundingPoint, kMaxBoundingVertices >	boundingVertices {}
	Small convex path enclosure, counter-clockwise in path space. The first vertex is the fan origin; the vertex shader expands (vertexCount - 2) * 3 triangle-list vertices from vertex_index. The selected enclosure is either a support-bounds polygon or its AABB fallback, so it always has 3 to kMaxBoundingVertices vertices for a nonempty path.
uint32_t	boundingVertexCount = 0
std::vector< Curve >	vCurves
	Vertical (X-monotonic) curve + band data, for the Slug vertical ray used by the dual-ray analytic coverage. These mirror curves/bands, but are split at X-extrema and binned into vertical (X-strip) bands.
std::vector< uint32_t >	vCurveIndices
	Per-band references into vCurves.
std::vector< Band >	vBands
	Vertical band metadata (X-strips), for the vertical ray.
std::vector< uint32_t >	hBandGrid
	Dense band-grid lookup, for the analytic dual-ray fragment shader (0041 §8.1). The shader finds its band in O(1) from the sample position: slot = hBandGrid[clamp(floor((y - yBase) / hStride), 0, hBandCount-1)] if (slot != kNoBand) iterate bands[slot]'s curves for the horizontal ray. vBandGrid indexes vBands by (x - xBase) / vStride for the vertical ray. The grids map dense grid cells onto the empty-skipped bands/vBands arrays, so no curve data is duplicated. Empty for a degenerate axis (count 0).
std::vector< uint32_t >	vBandGrid
	size == vBandCount; cell → index into vBands.
float	yBase = 0.0f
	Top edge of the horizontal band grid (path space).
float	hStride = 0.0f
	Height of each horizontal band cell (path space).
uint32_t	hBandCount = 0
	Number of horizontal band cells.
float	xBase = 0.0f
	Left edge of the vertical band grid (path space).
float	vStride = 0.0f
	Width of each vertical band cell (path space).
uint32_t	vBandCount = 0
	Number of vertical band cells.
EncodingStats	stats
	Encode diagnostics; does not affect rendering.
Outcome	outcome = Outcome::Empty

Static Public Attributes
static constexpr uint32_t	kMaxBoundingVertices = 8u
static constexpr uint32_t	kNoBand = 0xFFFFFFFFu
	Sentinel for a grid cell with no band (no curves overlap that strip).

Detailed Description

GPU-ready encoded path data produced by the Slug band decomposition algorithm.

This struct contains all the data needed by the Slug vertex and fragment shaders to render a filled path. It is produced by GeodePathEncoder::encode() and consumed by the GPU pipeline.

The data is organized as:

Curves: Canonical quadratic Bézier control points (3 × Vector2f per curve).
Curve references: Compact per-band indexes into the canonical curve arrays.
Bands: Compact offset/count pairs into the curve-reference arrays.
Bounding polygon: Up to eight convex vertices enclosing the path. The vertex shader triangulates and dilates it from vertex_index, so no resident vertex buffer is required.

Class Documentation

◆ donner::geode::EncodedPath::Curve

struct donner::geode::EncodedPath::Curve

A quadratic Bézier curve segment (3 control points) stored as floats for GPU consumption.

Class Members
float	p0x
float	p0y	Start point.
float	p1x
float	p1y	Control point.
float	p2x
float	p2y	End point.

◆ donner::geode::EncodedPath::Band

struct donner::geode::EncodedPath::Band

Compact metadata for one band. Layout matches the WGSL Band struct exactly.

Class Members
uint32_t	curveCount	Number of curve references in the band.
uint32_t	curveStart	First entry in the axis's curve-reference array.

◆ donner::geode::EncodedPath::AxisStats

struct donner::geode::EncodedPath::AxisStats

Per-axis encode statistics retained with the path for diagnostics and perf tests.

Class Members
uint32_t	canonicalCurveCount = 0	Curves stored exactly once for this ray.
uint32_t	curveReferenceCount = 0	Total indexes across all bands.
uint32_t	gridBandCount = 0	Dense band-grid cells.
uint32_t	maxCurvesPerBand = 0	Worst packed-band reference count.
double	meanCurvesPerBand = 0.0	Mean references per nonempty band.
uint32_t	nonemptyBandCount = 0	Packed nonempty band records.
uint32_t	omittedParallelCurves = 0	Curves proven parallel to this ray.
uint32_t	p95CurvesPerBand = 0	95th percentile nonempty-band count.

◆ donner::geode::EncodedPath::EncodingStats

struct donner::geode::EncodedPath::EncodingStats

Output-neutral instrumentation for the CPU encoding result.

Class Members
double	aabbArea = 0.0
double	boundingGeometryArea = 0.0
uint32_t	boundingGeometryVertexCount = 0
AxisStats	horizontal
AxisStats	vertical

◆ donner::geode::EncodedPath::BoundingPoint

struct donner::geode::EncodedPath::BoundingPoint

One path-space vertex in the convex bounding polygon.

Class Members
float	x
float	y

Member Data Documentation

◆ hBandGrid

std::vector<uint32_t> donner::geode::EncodedPath::hBandGrid

Dense band-grid lookup, for the analytic dual-ray fragment shader (0041 §8.1). The shader finds its band in O(1) from the sample position: slot = hBandGrid[clamp(floor((y - yBase) / hStride), 0, hBandCount-1)] if (slot != kNoBand) iterate bands[slot]'s curves for the horizontal ray. vBandGrid indexes vBands by (x - xBase) / vStride for the vertical ray. The grids map dense grid cells onto the empty-skipped bands/vBands arrays, so no curve data is duplicated. Empty for a degenerate axis (count 0).

size == hBandCount; cell → index into bands.

◆ vCurves

std::vector<Curve> donner::geode::EncodedPath::vCurves

Vertical (X-monotonic) curve + band data, for the Slug vertical ray used by the dual-ray analytic coverage. These mirror curves/bands, but are split at X-extrema and binned into vertical (X-strip) bands.

Canonical X-monotonic curves.

The documentation for this struct was generated from the following file:

donner/svg/renderer/geode/GeodePathEncoder.h

Classes

Public Types

Public Member Functions

Public Attributes

Static Public Attributes