skgpu::ganesh::TessellationPathRenderer Class Reference

#include <TessellationPathRenderer.h>

Inheritance diagram for skgpu::ganesh::TessellationPathRenderer:

Public Member Functions
const char *	name () const override
Public Member Functions inherited from skgpu::ganesh::PathRenderer
	PathRenderer ()=default
StencilSupport	getStencilSupport (const GrStyledShape &shape) const
CanDrawPath	canDrawPath (const CanDrawPathArgs &args) const
bool	drawPath (const DrawPathArgs &args)
void	stencilPath (const StencilPathArgs &args)
Public Member Functions inherited from SkRefCntBase
	SkRefCntBase ()
virtual	~SkRefCntBase ()
bool	unique () const
void	ref () const
void	unref () const

Static Public Member Functions
static bool	IsSupported (const GrCaps &)

Private Member Functions
StencilSupport	onGetStencilSupport (const GrStyledShape &) const override
CanDrawPath	onCanDrawPath (const CanDrawPathArgs &) const override
bool	onDrawPath (const DrawPathArgs &) override
void	onStencilPath (const StencilPathArgs &) override

Additional Inherited Members
Public Types inherited from skgpu::ganesh::PathRenderer
enum	StencilSupport { kNoSupport_StencilSupport , kStencilOnly_StencilSupport , kNoRestriction_StencilSupport }
enum class	CanDrawPath { kNo , kAsBackup , kYes }
Static Protected Member Functions inherited from skgpu::ganesh::PathRenderer
static void	GetPathDevBounds (const SkPath &path, SkISize devSize, const SkMatrix &matrix, SkRect *bounds)

Detailed Description

Definition at line 22 of file TessellationPathRenderer.h.

Member Function Documentation

IsSupported()

bool skgpu::ganesh::TessellationPathRenderer::IsSupported ( const GrCaps &  caps )

static

Definition at line 73 of file TessellationPathRenderer.cpp.

                                                             {
    return !caps.avoidStencilBuffers() &&
           caps.drawInstancedSupport() &&
           !caps.disableTessellationPathRenderer();
}

name()

const char * skgpu::ganesh::TessellationPathRenderer::name ( ) const

inlineoverridevirtual

Implements skgpu::ganesh::PathRenderer.

Definition at line 26 of file TessellationPathRenderer.h.

{ return "Tessellation"; }

onCanDrawPath()

PathRenderer::CanDrawPath skgpu::ganesh::TessellationPathRenderer::onCanDrawPath ( const CanDrawPathArgs &  args ) const

overrideprivatevirtual

Subclass implementation of canDrawPath()

Implements skgpu::ganesh::PathRenderer.

Definition at line 89 of file TessellationPathRenderer.cpp.

                                           {
    const GrStyledShape& shape = *args.fShape;
    if (args.fAAType == GrAAType::kCoverage ||
        shape.style().hasPathEffect() ||
        args.fViewMatrix->hasPerspective() ||
        shape.style().strokeRec().getStyle() == SkStrokeRec::kStrokeAndFill_Style ||
        !args.fProxy->canUseStencil(*args.fCaps)) {
        return CanDrawPath::kNo;
    }
    if (!shape.style().isSimpleFill()) {
        if (shape.inverseFilled()) {
            return CanDrawPath::kNo;
        }
        if (shape.style().strokeRec().getWidth() * args.fViewMatrix->getMaxScale() > 10000) {
            // crbug.com/1266446 -- Don't draw massively wide strokes with the tessellator. Since we
            // outset the viewport by stroke width for pre-chopping, astronomically wide strokes can
            // result in an astronomical viewport size, and therefore an exponential explosion chops
            // and memory usage. It is also simply inefficient to tessellate these strokes due to
            // the number of radial edges required. We're better off just converting them to a path
            // after a certain point.
            return CanDrawPath::kNo;
        }
    }
    if (args.fHasUserStencilSettings) {
        // Non-convex paths and strokes use the stencil buffer internally, so they can't support
        // draws with stencil settings.
        if (!shape.style().isSimpleFill() || !shape.knownToBeConvex() || shape.inverseFilled()) {
            return CanDrawPath::kNo;
        }
    }
    return CanDrawPath::kYes;
}

onDrawPath()

bool skgpu::ganesh::TessellationPathRenderer::onDrawPath ( const DrawPathArgs &  args )

overrideprivatevirtual

Subclass implementation of drawPath()

Implements skgpu::ganesh::PathRenderer.

Definition at line 123 of file TessellationPathRenderer.cpp.

                                                                  {
    auto sdc = args.fSurfaceDrawContext;
 
    SkPath path;
    args.fShape->asPath(&path);
 
    const SkRect pathDevBounds = args.fViewMatrix->mapRect(args.fShape->bounds());
    float n4 = wangs_formula::worst_case_cubic_p4(tess::kPrecision,
                                                  pathDevBounds.width(),
                                                  pathDevBounds.height());
    if (n4 > tess::kMaxSegmentsPerCurve_p4) {
        // The path is extremely large. Pre-chop its curves to keep the number of tessellation
        // segments tractable. This will also flatten curves that fall completely outside the
        // viewport.
        SkRect viewport = SkRect::Make(*args.fClipConservativeBounds);
        if (!args.fShape->style().isSimpleFill()) {
            // Outset the viewport to pad for the stroke width.
            const SkStrokeRec& stroke = args.fShape->style().strokeRec();
            float inflationRadius;
            if (stroke.isHairlineStyle()) {
                // SkStrokeRec::getInflationRadius() doesn't handle hairlines robustly. Instead
                // find the inflation of an equivalent stroke in device space with a width of 1.
                inflationRadius = SkStrokeRec::GetInflationRadius(stroke.getJoin(),
                                                                  stroke.getMiter(),
                                                                  stroke.getCap(), 1);
            } else {
                inflationRadius = stroke.getInflationRadius() * args.fViewMatrix->getMaxScale();
            }
            viewport.outset(inflationRadius, inflationRadius);
        }
        path = PreChopPathCurves(tess::kPrecision, path, *args.fViewMatrix, viewport);
    }
 
    // Handle strokes first.
    if (!args.fShape->style().isSimpleFill()) {
        SkASSERT(!path.isInverseFillType());  // See onGetStencilSupport().
        SkASSERT(args.fUserStencilSettings->isUnused());
        const SkStrokeRec& stroke = args.fShape->style().strokeRec();
        SkASSERT(stroke.getStyle() != SkStrokeRec::kStrokeAndFill_Style);
        auto op = GrOp::Make<StrokeTessellateOp>(args.fContext, args.fAAType, *args.fViewMatrix,
                                                 path, stroke, std::move(args.fPaint));
        sdc->addDrawOp(args.fClip, std::move(op));
        return true;
    }
 
    // Handle empty paths.
    if (pathDevBounds.isEmpty()) {
        if (path.isInverseFillType()) {
            args.fSurfaceDrawContext->drawPaint(args.fClip, std::move(args.fPaint),
                                                *args.fViewMatrix);
        }
        return true;
    }
 
    // Handle convex paths. Make sure to check 'path' for convexity since it may have been
    // pre-chopped, not 'fShape'.
    if (path.isConvex() && !path.isInverseFillType()) {
        auto op = GrOp::Make<PathTessellateOp>(args.fContext,
                                               args.fSurfaceDrawContext->arenaAlloc(),
                                               args.fAAType,
                                               args.fUserStencilSettings,
                                               *args.fViewMatrix,
                                               path,
                                               std::move(args.fPaint),
                                               pathDevBounds);
        sdc->addDrawOp(args.fClip, std::move(op));
        return true;
    }
 
    SkASSERT(args.fUserStencilSettings->isUnused());  // See onGetStencilSupport().
    const SkRect& drawBounds = path.isInverseFillType()
            ? args.fSurfaceDrawContext->asSurfaceProxy()->backingStoreBoundsRect()
            : pathDevBounds;
    auto op = make_non_convex_fill_op(args.fContext,
                                      args.fSurfaceDrawContext->arenaAlloc(),
                                      FillPathFlags::kNone,
                                      args.fAAType,
                                      drawBounds,
                                      *args.fClipConservativeBounds,
                                      *args.fViewMatrix,
                                      path,
                                      std::move(args.fPaint));
    sdc->addDrawOp(args.fClip, std::move(op));
    return true;
}

onGetStencilSupport()

PathRenderer::StencilSupport skgpu::ganesh::TessellationPathRenderer::onGetStencilSupport ( const GrStyledShape &  ) const

overrideprivatevirtual

Subclass overrides if it has any limitations of stenciling support.

Reimplemented from skgpu::ganesh::PathRenderer.

Definition at line 79 of file TessellationPathRenderer.cpp.

                                          {
    if (!shape.style().isSimpleFill() || shape.inverseFilled()) {
        // Don't bother with stroke stencilling or inverse fills yet. The Skia API doesn't support
        // clipping by a stroke, and the stencilling code already knows how to invert a fill.
        return kNoSupport_StencilSupport;
    }
    return shape.knownToBeConvex() ? kNoRestriction_StencilSupport : kStencilOnly_StencilSupport;
}

onStencilPath()

void skgpu::ganesh::TessellationPathRenderer::onStencilPath ( const StencilPathArgs &  args )

overrideprivatevirtual

Subclass implementation of stencilPath(). Subclass must override iff it ever returns kStencilOnly in onGetStencilSupport().

Reimplemented from skgpu::ganesh::PathRenderer.

Definition at line 209 of file TessellationPathRenderer.cpp.

                                                                        {
    SkASSERT(args.fShape->style().isSimpleFill());  // See onGetStencilSupport().
    SkASSERT(!args.fShape->inverseFilled());  // See onGetStencilSupport().
 
    auto sdc = args.fSurfaceDrawContext;
    GrAAType aaType = (GrAA::kYes == args.fDoStencilMSAA) ? GrAAType::kMSAA : GrAAType::kNone;
 
    SkRect pathDevBounds;
    args.fViewMatrix->mapRect(&pathDevBounds, args.fShape->bounds());
 
    SkPath path;
    args.fShape->asPath(&path);
 
    float n4 = wangs_formula::worst_case_cubic_p4(tess::kPrecision,
                                                  pathDevBounds.width(),
                                                  pathDevBounds.height());
    if (n4 > tess::kMaxSegmentsPerCurve_p4) {
        SkRect viewport = SkRect::Make(*args.fClipConservativeBounds);
        path = PreChopPathCurves(tess::kPrecision, path, *args.fViewMatrix, viewport);
    }
 
    // Make sure to check 'path' for convexity since it may have been pre-chopped, not 'fShape'.
    if (path.isConvex()) {
        constexpr static GrUserStencilSettings kMarkStencil(
            GrUserStencilSettings::StaticInit<
                0x0001,
                GrUserStencilTest::kAlways,
                0xffff,
                GrUserStencilOp::kReplace,
                GrUserStencilOp::kKeep,
                0xffff>());
 
        GrPaint stencilPaint;
        stencilPaint.setXPFactory(GrDisableColorXPFactory::Get());
        auto op = GrOp::Make<PathTessellateOp>(args.fContext,
                                               args.fSurfaceDrawContext->arenaAlloc(),
                                               aaType,
                                               &kMarkStencil,
                                               *args.fViewMatrix,
                                               path,
                                               std::move(stencilPaint),
                                               pathDevBounds);
        sdc->addDrawOp(args.fClip, std::move(op));
        return;
    }
 
    auto op = make_non_convex_fill_op(args.fContext,
                                      args.fSurfaceDrawContext->arenaAlloc(),
                                      FillPathFlags::kStencilOnly,
                                      aaType,
                                      pathDevBounds,
                                      *args.fClipConservativeBounds,
                                      *args.fViewMatrix,
                                      path,
                                      GrPaint());
    sdc->addDrawOp(args.fClip, std::move(op));
}

---

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

• third_party/skia/src/gpu/ganesh/ops/TessellationPathRenderer.h
• third_party/skia/src/gpu/ganesh/ops/TessellationPathRenderer.cpp