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skia / external / github.com / rive-app / rive-cpp / refs/heads/Tod-update-browserstack-devices / . / renderer / src / draw.cpp
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/*
* Copyright 2023 Rive
*/
#include "rive/renderer/draw.hpp"
#include "gr_inner_fan_triangulator.hpp"
#include "rive_render_path.hpp"
#include "rive_render_paint.hpp"
#include "rive/math/bezier_utils.hpp"
#include "rive/math/wangs_formula.hpp"
#include "rive/renderer/texture.hpp"
#include "gradient.hpp"
#include "shaders/constants.glsl"
#include "rive/profiler/profiler_macros.h"
namespace rive::gpu
{
namespace
{
// The final segment in an outerCurve patch is a bowtie join.
constexpr static size_t kJoinSegmentCount = 1;
constexpr static size_t kPatchSegmentCountExcludingJoin =
kOuterCurvePatchSegmentSpan - kJoinSegmentCount;
// Maximum # of outerCurve patches a curve on the path can be subdivided into.
constexpr static size_t kMaxCurveSubdivisions =
(kMaxParametricSegments + kPatchSegmentCountExcludingJoin - 1) /
kPatchSegmentCountExcludingJoin;
static uint32_t find_outer_cubic_subdivision_count(
const Vec2D pts[],
const wangs_formula::VectorXform& vectorXform)
{
float numSubdivisions =
ceilf(wangs_formula::cubic(pts, kParametricPrecision, vectorXform) *
(1.f / kPatchSegmentCountExcludingJoin));
return static_cast<uint32_t>(
math::clamp(numSubdivisions, 1, kMaxCurveSubdivisions));
}
constexpr static int NUM_SEGMENTS_IN_MITER_OR_BEVEL_JOIN = 5;
constexpr static int STROKE_OR_FEATHER_STYLE_FLAG = 8;
constexpr static int ROUND_JOIN_STYLE_FLAG = STROKE_OR_FEATHER_STYLE_FLAG << 1;
RIVE_ALWAYS_INLINE constexpr int style_flags(bool isStrokeOrFeather,
bool roundJoinStroked)
{
int styleFlags = (isStrokeOrFeather << 3) | (roundJoinStroked << 4);
assert(bool(styleFlags & STROKE_OR_FEATHER_STYLE_FLAG) ==
isStrokeOrFeather);
assert(bool(styleFlags & ROUND_JOIN_STYLE_FLAG) == roundJoinStroked);
return styleFlags;
}
// Switching on a StyledVerb reduces "if (stroked)" branching and makes the code
// cleaner.
enum class StyledVerb
{
filledMove = static_cast<int>(PathVerb::move),
strokedMove =
STROKE_OR_FEATHER_STYLE_FLAG | static_cast<int>(PathVerb::move),
roundJoinStrokedMove = STROKE_OR_FEATHER_STYLE_FLAG |
ROUND_JOIN_STYLE_FLAG |
static_cast<int>(PathVerb::move),
filledLine = static_cast<int>(PathVerb::line),
strokedLine =
STROKE_OR_FEATHER_STYLE_FLAG | static_cast<int>(PathVerb::line),
roundJoinStrokedLine = STROKE_OR_FEATHER_STYLE_FLAG |
ROUND_JOIN_STYLE_FLAG |
static_cast<int>(PathVerb::line),
filledQuad = static_cast<int>(PathVerb::quad),
strokedQuad =
STROKE_OR_FEATHER_STYLE_FLAG | static_cast<int>(PathVerb::quad),
roundJoinStrokedQuad = STROKE_OR_FEATHER_STYLE_FLAG |
ROUND_JOIN_STYLE_FLAG |
static_cast<int>(PathVerb::quad),
filledCubic = static_cast<int>(PathVerb::cubic),
strokedCubic =
STROKE_OR_FEATHER_STYLE_FLAG | static_cast<int>(PathVerb::cubic),
roundJoinStrokedCubic = STROKE_OR_FEATHER_STYLE_FLAG |
ROUND_JOIN_STYLE_FLAG |
static_cast<int>(PathVerb::cubic),
filledClose = static_cast<int>(PathVerb::close),
strokedClose =
STROKE_OR_FEATHER_STYLE_FLAG | static_cast<int>(PathVerb::close),
roundJoinStrokedClose = STROKE_OR_FEATHER_STYLE_FLAG |
ROUND_JOIN_STYLE_FLAG |
static_cast<int>(PathVerb::close),
};
RIVE_ALWAYS_INLINE constexpr StyledVerb styled_verb(PathVerb verb,
int styleFlags)
{
return static_cast<StyledVerb>(styleFlags | static_cast<int>(verb));
}
// When chopping strokes, switching on a "chop_key" reduces "if (areCusps)"
// branching and makes the code cleaner.
RIVE_ALWAYS_INLINE constexpr uint8_t chop_key(bool areCusps, uint8_t numChops)
{
return (numChops << 1) | static_cast<uint8_t>(areCusps);
}
RIVE_ALWAYS_INLINE constexpr uint8_t cusp_chop_key(uint8_t n)
{
return chop_key(true, n);
}
RIVE_ALWAYS_INLINE constexpr uint8_t simple_chop_key(uint8_t n)
{
return chop_key(false, n);
}
// Produces a cubic equivalent to the given line, for which Wang's formula also
// returns 1.
RIVE_ALWAYS_INLINE std::array<Vec2D, 4> convert_line_to_cubic(
const Vec2D line[2])
{
float4 endPts = simd::load4f(line);
float4 controlPts = simd::mix(endPts, endPts.zwxy, float4(1 / 3.f));
std::array<Vec2D, 4> cubic;
cubic[0] = line[0];
simd::store(&cubic[1], controlPts);
cubic[3] = line[1];
return cubic;
}
RIVE_ALWAYS_INLINE std::array<Vec2D, 4> convert_line_to_cubic(Vec2D p0,
Vec2D p1)
{
Vec2D line[2] = {p0, p1};
return convert_line_to_cubic(line);
}
// Chops a cubic into 2 * n + 1 segments, surrounding each cusp. The resulting
// cubics will be visually equivalent to the original when stroked, but the cusp
// won't have artifacts when rendered using the parametric/polar sorting
// algorithm.
//
// The size of dst[] must be 6 * n + 4 Vec2Ds.
static void chop_cubic_around_cusps(const Vec2D p[4],
Vec2D dst[/*6 * n + 4*/],
const float cuspT[],
int n,
float matrixMaxScale)
{
float t[4];
assert(n * 2 <= std::size(t));
// Generate chop points straddling each cusp with padding. This creates
// buffer space around the cusp that protects against fp32 precision issues.
for (int i = 0; i < n; ++i)
{
// If the cusps are extremely close together, don't allow the straddle
// points to cross.
float minT = i == 0 ? 0.f : (cuspT[i - 1] + cuspT[i]) * .5f;
float maxT = i + 1 == n ? 1.f : (cuspT[i + 1] + cuspT[i]) * .5f;
t[i * 2 + 0] = fmaxf(cuspT[i] - math::EPSILON, minT);
t[i * 2 + 1] = fminf(cuspT[i] + math::EPSILON, maxT);
}
math::chop_cubic_at(p, dst, t, n * 2);
for (int i = 0; i < n; ++i)
{
// Find the three chops at this cusp.
Vec2D* chops = dst + i * 6;
// Correct the chops to fall on the actual cusp point.
Vec2D cusp = math::eval_cubic_at(p, cuspT[i]);
chops[3] = chops[6] = cusp;
// The only purpose of the middle cubic is to capture the cusp's
// 180-degree rotation. Implement it as a sub-pixel 180-degree pivot.
Vec2D pivot = (chops[2] + chops[7]) * .5f;
pivot = (cusp - pivot).normalized() /
(matrixMaxScale * kPolarPrecision * 2) +
cusp;
chops[4] = chops[5] = pivot;
}
}
// Finds the starting tangent in a contour composed of the points [pts, end). If
// all points are equal, generates a tangent pointing horizontally to the right.
static Vec2D find_starting_tangent(const Vec2D pts[], const Vec2D* end)
{
assert(end > pts);
const Vec2D p0 = pts[0];
while (++pts < end)
{
Vec2D p = *pts;
if (p != p0)
{
return p - p0;
}
}
return {1, 0};
}
// Finds the ending tangent in a contour composed of the points [pts, end). If
// all points are equal, generates a tangent pointing horizontally to the left.
static Vec2D find_ending_tangent(const Vec2D pts[], const Vec2D* end)
{
assert(end > pts);
const Vec2D endpoint = end[-1];
while (--end > pts)
{
Vec2D p = end[-1];
if (p != endpoint)
{
return endpoint - p;
}
}
return {-1, 0};
}
static Vec2D find_join_tangent_full_impl(const Vec2D* joinPoint,
const Vec2D* end,
bool closed,
const Vec2D* p0)
{
// Find the first point in the contour not equal to *joinPoint and return
// the difference. RawPath should have discarded empty verbs, so this should
// be a fast operation.
for (const Vec2D* p = joinPoint + 1; p != end; ++p)
{
if (*p != *joinPoint)
{
return *p - *joinPoint;
}
}
if (closed)
{
for (const Vec2D* p = p0; p != joinPoint; ++p)
{
if (*p != *joinPoint)
{
return *p - *joinPoint;
}
}
}
// This should never be reached because RawPath discards empty verbs.
RIVE_UNREACHABLE();
}
RIVE_ALWAYS_INLINE Vec2D find_join_tangent(const Vec2D* joinPoint,
const Vec2D* end,
bool closed,
const Vec2D* p0)
{
// Quick early out for inlining and branch prediction: The next point in the
// contour is almost always the point that determines the join tangent.
const Vec2D* nextPoint = joinPoint + 1;
nextPoint = nextPoint != end ? nextPoint : p0;
Vec2D tangent = *nextPoint - *joinPoint;
return tangent != Vec2D{0, 0}
? tangent
: find_join_tangent_full_impl(joinPoint, end, closed, p0);
}
// Should an empty stroke emit round caps, square caps, or none?
//
// Just pick the cap type that makes the most sense for a contour that animates
// from non-empty to empty:
//
// * A non-closed contour with round caps and a CLOSED contour with round
// JOINS both converge to a
// circle when animated to empty.
// => round caps on the empty contour.
//
// * A non-closed contour with square caps converges to a square (albeit with
// potential rotation
// that is lost when the contour becomes empty).
// => square caps on the empty contour.
//
// * A closed contour with miter JOINS converges to... some sort of polygon
// with pointy corners.
// ~=> square caps on the empty contour.
//
// * All other contours converge to nothing.
// => butt caps on the empty contour, which are ignored.
//
static StrokeCap empty_stroke_cap(bool closed, StrokeJoin join, StrokeCap cap)
{
if (closed)
{
switch (join)
{
case StrokeJoin::round:
return StrokeCap::round;
case StrokeJoin::miter:
return StrokeCap::square;
case StrokeJoin::bevel:
return StrokeCap::butt;
}
}
return cap;
}
RIVE_ALWAYS_INLINE bool is_final_verb_of_contour(const RawPath::Iter& iter,
const RawPath::Iter& end)
{
return iter.rawVerbsPtr() + 1 == end.rawVerbsPtr();
}
RIVE_ALWAYS_INLINE uint32_t join_type_flags(StrokeJoin join)
{
switch (join)
{
case StrokeJoin::miter:
return MITER_REVERT_JOIN_CONTOUR_FLAG;
case StrokeJoin::round:
return ROUND_JOIN_CONTOUR_FLAG;
case StrokeJoin::bevel:
return BEVEL_JOIN_CONTOUR_FLAG;
}
RIVE_UNREACHABLE();
}
inline float find_feather_radius(float paintFeather)
{
// Blur magnitudes in design tools are customarily the width of two standard
// deviations, or, the length of the range -1stddev .. +1stddev.
return paintFeather * (FEATHER_TEXTURE_STDDEVS / 2);
}
inline float find_atlas_feather_scale_factor(float featherRadius,
float matrixMaxScale)
{
// In practice, and with "gaussian -> linear -> gaussian" filtering, we
// never need to render a blur with a radius larger than 16 pixels. After
// this point, we can just scale it up to whatever resolution it needs to be
// displayed at.
return 16.f / fmaxf(featherRadius * matrixMaxScale, 16);
}
static uint32_t feather_join_segment_count(float polarSegmentsPerRadian)
{
uint32_t n =
static_cast<uint32_t>(ceilf(polarSegmentsPerRadian * math::PI)) +
FEATHER_JOIN_HELPER_SEGMENT_COUNT;
n = std::max(n, FEATHER_JOIN_MIN_SEGMENT_COUNT);
// FEATHER_POLAR_SEGMENT_MIN_ANGLE should limit n long before we reach
// kMaxPolarSegments.
assert(n < gpu::kMaxPolarSegments);
return n;
}
} // namespace
Draw::Draw(IAABB pixelBounds,
const Mat2D& matrix,
BlendMode blendMode,
rcp<Texture> imageTexture,
ImageSampler imageSampler,
Type type) :
m_imageTextureRef(imageTexture.release()),
m_imageSampler(imageSampler),
m_pixelBounds(pixelBounds),
m_matrix(matrix),
m_blendMode(blendMode),
m_type(type)
{
if (m_blendMode != BlendMode::srcOver)
{
m_drawContents |= gpu::DrawContents::advancedBlend;
}
}
void Draw::setClipID(uint32_t clipID)
{
m_clipID = clipID;
// For clipUpdates, m_clipID refers to the ID we are writing to the stencil
// buffer (NOT the ID we are clipping against). It therefore doesn't affect
// the activeClip flag in that case.
if (!(m_drawContents & gpu::DrawContents::clipUpdate))
{
if (m_clipID != 0)
{
m_drawContents |= gpu::DrawContents::activeClip;
}
else
{
m_drawContents &= ~gpu::DrawContents::activeClip;
}
}
}
void Draw::releaseRefs() { safe_unref(m_imageTextureRef); }
PathDraw::CoverageType PathDraw::SelectCoverageType(
const RiveRenderPaint* paint,
float matrixMaxScale,
const gpu::PlatformFeatures& platformFeatures,
gpu::InterlockMode interlockMode)
{
if (paint->getFeather() != 0)
{
if (platformFeatures.alwaysFeatherToAtlas ||
interlockMode == gpu::InterlockMode::msaa ||
// Always switch to the atlas once we can render quarter-resultion.
find_atlas_feather_scale_factor(
find_feather_radius(paint->getFeather()),
matrixMaxScale) <= .5f)
{
return CoverageType::atlas;
}
}
if (interlockMode == gpu::InterlockMode::msaa)
{
return CoverageType::msaa;
}
if (interlockMode == gpu::InterlockMode::clockwiseAtomic)
{
return CoverageType::clockwiseAtomic;
}
return CoverageType::pixelLocalStorage;
}
DrawUniquePtr PathDraw::Make(RenderContext* context,
const Mat2D& matrix,
rcp<const RiveRenderPath> path,
FillRule fillRule,
const RiveRenderPaint* paint,
RawPath* scratchPath)
{
RIVE_PROF_SCOPE();
assert(path != nullptr);
assert(paint != nullptr);
CoverageType coverageType =
SelectCoverageType(paint,
matrix.findMaxScale(),
context->platformFeatures(),
context->frameInterlockMode());
// Compute the screen-space bounding box.
AABB mappedBounds;
if (context->frameInterlockMode() == gpu::InterlockMode::rasterOrdering &&
coverageType != CoverageType::atlas)
{
// In rasterOrdering mode we can use a looser bounding box since we
// don't do reordering.
mappedBounds = matrix.mapBoundingBox(path->getBounds());
}
else
{
// Otherwise find a tight bounding box in order to maximize reordering.
mappedBounds =
matrix.mapBoundingBox(path->getRawPath().points().data(),
path->getRawPath().points().count());
}
assert(mappedBounds.width() >= 0);
assert(mappedBounds.height() >= 0);
if (paint->getIsStroked() || paint->getFeather() != 0)
{
// Outset the path's bounding box to account for stroking & feathering.
float outset = 0;
if (paint->getIsStroked())
{
outset = paint->getThickness() * .5f;
if (paint->getJoin() == StrokeJoin::miter)
{
// Miter joins may be longer than the stroke radius.
outset *= RIVE_MITER_LIMIT;
}
else if (paint->getCap() == StrokeCap::square)
{
// The diagonal of a square cap is longer than the stroke
// radius.
outset *= math::SQRT2;
}
}
if (paint->getFeather() != 0)
{
outset += find_feather_radius(paint->getFeather());
}
AABB strokePixelOutset = matrix.mapBoundingBox({0, 0, outset, outset});
// Add an extra pixel to the stroke outset radius to account for:
// * Butt caps and bevel joins bleed out 1/2 AA width.
// * With Manhattan sytle AA, an AA width can be as large as sqrt(2).
// * The diagonal of that sqrt(2)/2 bleed is 1px in length.
mappedBounds = mappedBounds.outset(strokePixelOutset.width() + 1,
strokePixelOutset.height() + 1);
}
IAABB pixelBounds = mappedBounds.roundOut();
bool doTriangulation = false;
const AABB& localBounds = path->getBounds();
if (context->isOutsideCurrentFrame(pixelBounds))
{
return DrawUniquePtr();
}
if (!paint->getIsStroked() && paint->getFeather() == 0)
{
// Use interior triangulation to draw filled paths if they're large
// enough to benefit from it.
//
// FIXME! Implement interior triangulation for feathers.
//
// FIXME! Implement interior triangulation in msaa mode.
if (context->frameInterlockMode() != gpu::InterlockMode::msaa &&
path->getRawPath().verbs().count() < 1000 &&
gpu::find_transformed_area(localBounds, matrix) > 512.f * 512.f)
{
doTriangulation = true;
}
}
auto draw = context->make<PathDraw>(pixelBounds,
matrix,
std::move(path),
fillRule,
paint,
coverageType,
context->frameDescriptor());
if (doTriangulation)
{
draw->initForInteriorTriangulation(
context,
scratchPath,
localBounds.width() > localBounds.height()
? PathDraw::TriangulatorAxis::horizontal
: PathDraw::TriangulatorAxis::vertical);
}
else
{
draw->initForMidpointFan(context, paint);
}
return DrawUniquePtr(draw);
}
PathDraw::PathDraw(IAABB pixelBounds,
const Mat2D& matrix,
rcp<const RiveRenderPath> path,
FillRule initialFillRule,
const RiveRenderPaint* paint,
CoverageType coverageType,
const RenderContext::FrameDescriptor& frameDesc) :
Draw(pixelBounds,
matrix,
paint->getBlendMode(),
ref_rcp(paint->getImageTexture()),
paint->getImageSampler(),
Type::path),
m_pathRef(path.release()),
m_pathFillRule(frameDesc.clockwiseFillOverride ? FillRule::clockwise
: initialFillRule),
m_gradientRef(safe_ref(paint->getGradient())),
m_paintType(paint->getType()),
m_coverageType(coverageType)
{
assert(m_pathRef != nullptr);
assert(!m_pathRef->getRawPath().empty());
assert(paint != nullptr);
if (paint->getIsOpaque())
{
m_drawContents |= gpu::DrawContents::opaquePaint;
}
if (paint->getFeather() != 0)
{
m_featherRadius = find_feather_radius(paint->getFeather());
assert(!std::isnan(m_featherRadius)); // These should get culled in
// RiveRenderer::drawPath().
assert(m_featherRadius > 0);
}
if (paint->getIsStroked())
{
m_strokeRadius = paint->getThickness() * .5f;
// Ensure stroke radius is nonzero. (In PLS, zero radius means the path
// is filled.)
m_strokeRadius =
fmaxf(m_strokeRadius, std::numeric_limits<float>::min());
assert(!std::isnan(m_strokeRadius)); // These should get culled in
// RiveRenderer::drawPath().
assert(m_strokeRadius > 0);
}
// For atlased paths, m_drawContents refers to the rectangle being drawn
// into the main render target, not the step that generates the atlas mask.
if (m_coverageType != CoverageType::atlas)
{
if (isStroke())
{
m_drawContents |= gpu::DrawContents::stroke;
}
else
{
if (m_featherRadius)
{
m_drawContents |= gpu::DrawContents::featheredFill;
}
if (initialFillRule == FillRule::clockwise ||
frameDesc.clockwiseFillOverride)
{
m_drawContents |= gpu::DrawContents::clockwiseFill;
}
else if (initialFillRule == FillRule::nonZero)
{
m_drawContents |= gpu::DrawContents::nonZeroFill;
}
else if (initialFillRule == FillRule::evenOdd)
{
m_drawContents |= gpu::DrawContents::evenOddFill;
}
}
}
if (paint->getType() == gpu::PaintType::clipUpdate)
{
m_drawContents |= gpu::DrawContents::clipUpdate;
if (paint->getSimpleValue().outerClipID != 0)
{
m_drawContents |= gpu::DrawContents::activeClip;
}
}
if (isStroke())
{
// Stroke triangles are always forward.
m_contourDirections = gpu::ContourDirections::forward;
}
else if (initialFillRule == FillRule::clockwise)
{
// Clockwise paths need to be reversed when the matrix is left-handed,
// so that the intended forward triangles remain clockwise.
float det = matrix.xx() * matrix.yy() - matrix.yx() * matrix.xy();
if (det < 0)
{
m_contourDirections =
m_coverageType == CoverageType::msaa
? gpu::ContourDirections::reverse
: gpu::ContourDirections::forwardThenReverse;
m_contourFlags |= NEGATE_PATH_FILL_COVERAGE_FLAG; // ignored by msaa
}
else
{
m_contourDirections =
m_coverageType == CoverageType::msaa
? gpu::ContourDirections::forward
: gpu::ContourDirections::reverseThenForward;
}
}
else if (m_coverageType != CoverageType::msaa)
{
// atomic and rasterOrdering fills need reverse AND forward triangles.
if (frameDesc.clockwiseFillOverride &&
!m_pathRef->isClockwiseDominant(matrix))
{
// For clockwiseFill, this is also our opportunity to logically
// reverse the winding of the path, if it is predominantly
// counterclockwise.
m_contourDirections = gpu::ContourDirections::forwardThenReverse;
m_contourFlags |= NEGATE_PATH_FILL_COVERAGE_FLAG;
}
else
{
m_contourDirections = gpu::ContourDirections::reverseThenForward;
}
}
else
{
if (initialFillRule == FillRule::nonZero ||
frameDesc.clockwiseFillOverride)
{
// Emit "nonZero" msaa fills in a direction such that the dominant
// triangle winding area is always clockwise. This maximizes pixel
// throughput since we will draw counterclockwise triangles twice
// and clockwise only once.
m_contourDirections = m_pathRef->isClockwiseDominant(matrix)
? gpu::ContourDirections::forward
: gpu::ContourDirections::reverse;
}
else
{
// "evenOdd" msaa fills just get drawn twice, so any direction is
// fine.
m_contourDirections = gpu::ContourDirections::forward;
}
}
m_simplePaintValue = paint->getSimpleValue();
if (m_coverageType == CoverageType::atlas)
{
// Reserve two triangles for our on-screen rectangle that reads coverage
// from the atlas.
m_resourceCounts.maxTriangleVertexCount = 6;
}
RIVE_DEBUG_CODE(m_pathRef->lockRawPathMutations();)
RIVE_DEBUG_CODE(m_rawPathMutationID = m_pathRef->getRawPathMutationID();)
assert(isStroke() == (strokeRadius() > 0));
assert(isFeatheredFill() == (!isStroke() && featherRadius() > 0));
assert(!isFeatheredFill() || featherRadius() > 0);
}
void PathDraw::releaseRefs()
{
RIVE_PROF_SCOPE()
Draw::releaseRefs();
RIVE_DEBUG_CODE(m_pathRef->unlockRawPathMutations();)
m_pathRef->unref();
safe_unref(m_gradientRef);
}
void PathDraw::initForMidpointFan(RenderContext* context,
const RiveRenderPaint* paint)
{
RIVE_PROF_SCOPE()
// Only call init() once.
assert((m_resourceCounts.midpointFanTessVertexCount |
m_resourceCounts.outerCubicTessVertexCount) == 0);
if (isStrokeOrFeather())
{
m_strokeMatrixMaxScale = m_matrix.findMaxScale();
float r_ = 0;
if (m_featherRadius != 0)
{
r_ = m_featherRadius * m_strokeMatrixMaxScale;
// Inverse of 1/calc_polar_segments_per_radian at
// FEATHER_MIN_POLAR_SEGMENT_ANGLE.
//
// i.e., 1 / calc_polar_segments_per_radian<kPolarPrecision>(
// FEATHER_MIN_POLAR_SEGMENT_ANGLE) ==
// FEATHER_MAX_SCREEN_SPACE_RADIUS
//
constexpr static float FEATHER_MAX_SCREEN_SPACE_RADIUS =
1 / (kPolarPrecision *
(1 - COS_FEATHER_POLAR_SEGMENT_MIN_ANGLE_OVER_2));
assert(math::nearly_equal(
1 / math::calc_polar_segments_per_radian<kPolarPrecision>(
FEATHER_MAX_SCREEN_SPACE_RADIUS),
gpu::FEATHER_POLAR_SEGMENT_MIN_ANGLE));
// r_ is used to calculate how many polar segments are needed. Limit
// r_ for large feathers. (See FEATHER_POLAR_SEGMENT_MIN_ANGLE.)
r_ = std::min(r_, FEATHER_MAX_SCREEN_SPACE_RADIUS);
}
if (isStroke())
{
r_ += m_strokeRadius * m_strokeMatrixMaxScale;
}
m_polarSegmentsPerRadian =
math::calc_polar_segments_per_radian<kPolarPrecision>(r_);
m_strokeJoin = paint->getJoin();
m_strokeCap = paint->getCap();
}
// Count up how much temporary storage this function will need to reserve in
// CPU buffers.
const RawPath& rawPath = m_pathRef->getRawPath();
size_t contourCount = rawPath.countMoveTos();
assert(contourCount != 0);
m_contours = reinterpret_cast<ContourInfo*>(
context->perFrameAllocator().alloc(sizeof(ContourInfo) * contourCount));
size_t maxStrokedCurvesBeforeChops = 0;
size_t maxCurves = 0;
size_t maxRotations = 0;
// Reserve enough space to record all the info we might need for this path.
assert(rawPath.verbs()[0] == PathVerb::move);
// Every path has at least 1 (non-cubic) move.
size_t pathMaxLinesOrCurvesBeforeChops = rawPath.verbs().size() - 1;
// Stroked cubics can be chopped into a maximum of 5 segments.
size_t pathMaxLinesOrCurvesAfterChops =
isStrokeOrFeather() ? pathMaxLinesOrCurvesBeforeChops * 5
: pathMaxLinesOrCurvesBeforeChops;
maxCurves += pathMaxLinesOrCurvesAfterChops;
if (isStrokeOrFeather())
{
maxStrokedCurvesBeforeChops += pathMaxLinesOrCurvesBeforeChops;
maxRotations += pathMaxLinesOrCurvesAfterChops;
if (m_strokeJoin == StrokeJoin::round)
{
// If the stroke has round joins, we also record the rotations
// between (pre-chopped) joins in order to calculate how many
// vertices are in each round join.
maxRotations += pathMaxLinesOrCurvesBeforeChops;
}
}
// Each stroked curve will record the number of chops it requires (either 0,
// 1, or 2).
size_t maxChops = maxStrokedCurvesBeforeChops;
// We only chop into this queue if a cubic has one chop. More chops in a
// single cubic are rare and require a lot of memory, so if a cubic needs
// more chops we just re-chop the second time around. The maximum size this
// queue would need is therefore enough to chop each cubic once, or 5
// internal points per chop.
size_t maxChopVertices = maxStrokedCurvesBeforeChops * 5;
// +3 for each contour because we align each contour's curves and rotations
// on multiples of 4.
size_t maxPaddedRotations =
isStrokeOrFeather() ? maxRotations + contourCount * 3 : 0;
size_t maxPaddedCurves = maxCurves + contourCount * 3;
// Reserve intermediate space for the polar segment counts of each curve and
// round join.
if (isStrokeOrFeather())
{
m_numChops.reset(context->numChopsAllocator(), maxChops);
m_chopVertices.reset(context->chopVerticesAllocator(), maxChopVertices);
m_tangentPairs =
context->tangentPairsAllocator().alloc(maxPaddedRotations);
m_polarSegmentCounts =
context->polarSegmentCountsAllocator().alloc(maxPaddedRotations);
}
m_parametricSegmentCounts =
context->parametricSegmentCountsAllocator().alloc(maxPaddedCurves);
float parametricPrecision = gpu::kParametricPrecision;
if (m_featherRadius > 1)
{
// Once the blur radius is above ~50 pixels, we don't have to tessellate
// within 1/4px of the edge anymore.
// At this point, tessellate within strokeRadius/200 pixels of the edge.
// (parametricPrecision == 1/tolerance.)
parametricPrecision =
std::min(parametricPrecision * 100.f /
(m_featherRadius * m_strokeMatrixMaxScale),
parametricPrecision);
}
size_t lineCount = 0;
size_t unpaddedCurveCount = 0;
size_t unpaddedRotationCount = 0;
size_t emptyStrokeCountForCaps = 0;
// Iteration pass 1: Collect information on contour and curves counts for
// every path in the batch, and begin counting tessellated vertices.
size_t contourIdx = 0;
size_t curveIdx = 0;
// We measure rotations on both curves and round joins.
size_t rotationIdx = 0;
bool roundJoinStroked = isStroke() && m_strokeJoin == StrokeJoin::round;
wangs_formula::VectorXform vectorXform(m_matrix);
RawPath::Iter startOfContour = rawPath.begin();
RawPath::Iter end = rawPath.end();
// Original number of lines and curves, before chopping.
int preChopVerbCount = 0;
Vec2D endpointsSum{};
bool closed = !isStroke();
Vec2D lastTangent = {0, 1};
Vec2D firstTangent = {0, 1};
size_t roundJoinCount = 0;
size_t contourFirstCurveIdx = curveIdx;
assert(contourFirstCurveIdx % 4 == 0);
size_t contourFirstRotationIdx = rotationIdx;
assert(contourFirstRotationIdx % 4 == 0);
auto finishAndAppendContour = [&](RawPath::Iter iter) {
if (closed)
{
Vec2D finalPtInContour = iter.rawPtsPtr()[-1];
// Bit-cast to uint64_t because we don't want the special equality
// rules for NaN. If we're empty or otherwise return back to p0, we
// want to detect this, regardless of whether there are NaN values.
if (math::bit_cast<uint64_t>(startOfContour.movePt()) !=
math::bit_cast<uint64_t>(finalPtInContour))
{
assert(preChopVerbCount > 0);
if (roundJoinStroked)
{
// Round join before implicit closing line.
Vec2D tangent = startOfContour.movePt() - finalPtInContour;
assert(rotationIdx < maxPaddedRotations);
m_tangentPairs[rotationIdx++] = {lastTangent, tangent};
lastTangent = tangent;
++roundJoinCount;
}
++lineCount; // Implicit closing line.
// The first point in the contour hasn't gotten
// counted yet.
++preChopVerbCount;
endpointsSum += startOfContour.movePt();
}
if (roundJoinStroked && preChopVerbCount != 0)
{
// Round join back to the beginning of the contour.
assert(rotationIdx < maxPaddedRotations);
m_tangentPairs[rotationIdx++] = {lastTangent, firstTangent};
++roundJoinCount;
}
}
size_t strokeJoinCount = preChopVerbCount;
if (!closed)
{
strokeJoinCount = std::max<size_t>(strokeJoinCount, 1) - 1;
}
assert(contourIdx < contourCount);
m_contours[contourIdx++] = {
iter,
lineCount,
contourFirstCurveIdx,
curveIdx,
contourFirstRotationIdx,
rotationIdx,
isStroke() ? Vec2D() : endpointsSum * (1.f / preChopVerbCount),
closed,
strokeJoinCount,
0, // strokeCapSegmentCount
0, // paddingVertexCount
RIVE_DEBUG_CODE(0) // tessVertexCount
};
unpaddedCurveCount += curveIdx - contourFirstCurveIdx;
contourFirstCurveIdx = curveIdx =
math::round_up_to_multiple_of<4>(curveIdx);
unpaddedRotationCount += rotationIdx - contourFirstRotationIdx;
contourFirstRotationIdx = rotationIdx =
math::round_up_to_multiple_of<4>(rotationIdx);
};
const int styleFlags = style_flags(isStrokeOrFeather(), roundJoinStroked);
for (RawPath::Iter iter = startOfContour; iter != end; ++iter)
{
switch (styled_verb(iter.verb(), styleFlags))
{
case StyledVerb::roundJoinStrokedMove:
case StyledVerb::strokedMove:
case StyledVerb::filledMove:
if (iter != startOfContour)
{
finishAndAppendContour(iter);
startOfContour = iter;
}
preChopVerbCount = 0;
endpointsSum = {0, 0};
closed = !isStroke();
lastTangent = {0, 1};
firstTangent = {0, 1};
roundJoinCount = 0;
break;
case StyledVerb::roundJoinStrokedClose:
case StyledVerb::strokedClose:
case StyledVerb::filledClose:
assert(iter != startOfContour);
closed = true;
break;
case StyledVerb::roundJoinStrokedLine:
{
const Vec2D* p = iter.linePts();
Vec2D tangent = p[1] - p[0];
if (preChopVerbCount == 0)
{
firstTangent = tangent;
}
else
{
assert(rotationIdx < maxPaddedRotations);
m_tangentPairs[rotationIdx++] = {lastTangent, tangent};
++roundJoinCount;
}
lastTangent = tangent;
[[fallthrough]];
}
case StyledVerb::strokedLine:
case StyledVerb::filledLine:
{
const Vec2D* p = iter.linePts();
++preChopVerbCount;
endpointsSum += p[1];
++lineCount;
break;
}
case StyledVerb::roundJoinStrokedQuad:
case StyledVerb::strokedQuad:
case StyledVerb::filledQuad:
RIVE_UNREACHABLE();
break;
case StyledVerb::roundJoinStrokedCubic:
{
const Vec2D* p = iter.cubicPts();
Vec2D unchoppedTangents[2];
math::find_cubic_tangents(p, unchoppedTangents);
if (preChopVerbCount == 0)
{
firstTangent = unchoppedTangents[0];
}
else
{
assert(rotationIdx < maxPaddedRotations);
m_tangentPairs[rotationIdx++] = {lastTangent,
unchoppedTangents[0]};
++roundJoinCount;
}
lastTangent = unchoppedTangents[1];
[[fallthrough]];
}
case StyledVerb::strokedCubic:
{
const Vec2D* p = iter.cubicPts();
++preChopVerbCount;
endpointsSum += p[3];
// Chop strokes into sections that do not inflect (i.e, are
// convex), and do not rotate more than 180 degrees. This is
// required by the GPU parametric/polar sorter.
float t[2];
bool areCusps = false;
uint8_t numChops =
isStroke()
? math::find_cubic_convex_180_chops(p, t, &areCusps)
: 0; // Feathers already got chopped.
uint8_t chopKey = chop_key(areCusps, numChops);
m_numChops.push_back(chopKey);
Vec2D localChopBuffer[16];
switch (chopKey)
{
case cusp_chop_key(2): // 2 cusps
case cusp_chop_key(1): // 1 cusp
// We have to chop carefully around stroked cusps in
// order to avoid rendering artifacts. Luckily, cusps
// are extremely rare in real-world content.
m_chopVertices.push_back() = {t[0], t[1]};
chop_cubic_around_cusps(p,
localChopBuffer,
t,
numChops,
m_strokeMatrixMaxScale);
p = localChopBuffer;
numChops *= 2;
break;
case simple_chop_key(2): // 2 non-cusp chops
m_chopVertices.push_back() = {t[0], t[1]};
math::chop_cubic_at(p, localChopBuffer, t[0], t[1]);
p = localChopBuffer;
break;
case simple_chop_key(1): // 1 non-cusp chop
{
math::chop_cubic_at(p, localChopBuffer, t[0]);
p = localChopBuffer;
memcpy(m_chopVertices.push_back_n(5),
p + 1,
sizeof(Vec2D) * 5);
break;
}
}
// Calculate segment counts for each chopped section
// independently.
for (const Vec2D* end = p + numChops * 3 + 3; p != end;
p += 3, ++curveIdx, ++rotationIdx)
{
float n4 = wangs_formula::cubic_pow4(p,
parametricPrecision,
vectorXform);
// Record n^4 for now. This will get resolved later.
assert(curveIdx < maxPaddedCurves);
RIVE_INLINE_MEMCPY(m_parametricSegmentCounts + curveIdx,
&n4,
sizeof(uint32_t));
assert(rotationIdx < maxPaddedRotations);
if (isStroke())
{
math::find_cubic_tangents(
p,
m_tangentPairs[rotationIdx].data());
}
else
{
// FIXME: Feathered fills don't have polar segments for
// now, but we're leaving space for them in
// m_tangentPairs because we will convert them to use a
// similar concept of "polar joins" once we move them
// onto the GPU.
m_tangentPairs[rotationIdx] = {Vec2D{0, 1},
Vec2D{0, 1}};
}
}
break;
}
case StyledVerb::filledCubic:
{
const Vec2D* p = iter.cubicPts();
++preChopVerbCount;
endpointsSum += p[3];
float n4 = wangs_formula::cubic_pow4(p,
parametricPrecision,
vectorXform);
// Record n^4 for now. This will get resolved later.
assert(curveIdx < maxPaddedCurves);
RIVE_INLINE_MEMCPY(m_parametricSegmentCounts + curveIdx++,
&n4,
sizeof(uint32_t));
break;
}
}
}
if (startOfContour != end)
{
finishAndAppendContour(end);
}
assert(contourIdx == contourCount);
assert(contourCount > 0);
assert(curveIdx <= maxPaddedCurves);
assert(rotationIdx <= maxPaddedRotations);
// Because we write parametric segment counts in batches of 4.
assert(curveIdx % 4 == 0);
// Because we write polar segment counts in batches of 4.
assert(rotationIdx % 4 == 0);
assert(isStrokeOrFeather() || maxPaddedRotations == 0);
assert(isStrokeOrFeather() || rotationIdx == 0);
// Return any data we conservatively allocated but did not use.
if (isStrokeOrFeather())
{
m_numChops.shrinkToFit(context->numChopsAllocator(), maxChops);
m_chopVertices.shrinkToFit(context->chopVerticesAllocator(),
maxChopVertices);
context->tangentPairsAllocator().rewindLastAllocation(
maxPaddedRotations - rotationIdx);
context->polarSegmentCountsAllocator().rewindLastAllocation(
maxPaddedRotations - rotationIdx);
}
context->parametricSegmentCountsAllocator().rewindLastAllocation(
maxPaddedCurves - curveIdx);
// Iteration pass 2: Finish calculating the numbers of tessellation segments
// in each contour, using SIMD.
size_t contourFirstLineIdx = 0;
size_t tessVertexCount = 0;
for (size_t i = 0; i < contourCount; ++i)
{
ContourInfo* contour = &m_contours[i];
size_t contourLineCount = contour->endLineIdx - contourFirstLineIdx;
uint32_t contourVertexCount = math::lossless_numeric_cast<uint32_t>(
contourLineCount * 2); // Each line tessellates to 2 vertices.
uint4 mergedTessVertexSums4 = 0;
// Finish calculating and counting parametric segments for each curve.
size_t j;
for (j = contour->firstCurveIdx; j < contour->endCurveIdx; j += 4)
{
// Curves recorded their segment counts raised to the 4th power. Now
// find their roots and convert to integers in batches of 4.
assert(j + 4 <= curveIdx);
float4 n = simd::load4f(m_parametricSegmentCounts + j);
n = simd::ceil(simd::sqrt(simd::sqrt(n)));
n = simd::clamp(n, float4(1), float4(kMaxParametricSegments));
uint4 n_ = simd::cast<uint32_t>(n);
assert(j + 4 <= curveIdx);
simd::store(m_parametricSegmentCounts + j, n_);
mergedTessVertexSums4 += n_;
}
// We counted in batches of 4. Undo the values we counted from beyond
// the end of the path.
while (j-- > contour->endCurveIdx)
{
contourVertexCount -= m_parametricSegmentCounts[j];
}
if (isStrokeOrFeather())
{
// Finish calculating and counting polar segments for each stroked
// curve and round join.
for (j = contour->firstRotationIdx; j < contour->endRotationIdx;
j += 4)
{
// Measure the rotations of curves in batches of 4.
assert(j + 4 <= rotationIdx);
float4 tx0, ty0, tx1, ty1;
std::tie(tx0, ty0, tx1, ty1) =
simd::load4x4f(&m_tangentPairs[j][0].x);
float4 numer = tx0 * tx1 + ty0 * ty1;
float4 denom_pow2 =
(tx0 * tx0 + ty0 * ty0) * (tx1 * tx1 + ty1 * ty1);
float4 cosTheta = numer / simd::sqrt(denom_pow2);
cosTheta = simd::clamp(cosTheta, float4(-1), float4(1));
float4 theta = simd::fast_acos(cosTheta);
// Find polar segment counts from the rotation angles.
float4 n = simd::ceil(theta * m_polarSegmentsPerRadian);
n = simd::clamp(n, float4(1), float4(kMaxPolarSegments));
uint4 n_ = simd::cast<uint32_t>(n);
assert(j + 4 <= rotationIdx);
simd::store(m_polarSegmentCounts + j, n_);
// Polar and parametric segments share the first and final
// vertices. Therefore:
//
// parametricVertexCount = parametricSegmentCount + 1
//
// polarVertexCount = polarVertexCount + 1
//
// mergedVertexCount
// = parametricVertexCount + polarVertexCount - 2
// = parametricSegmentCount + 1 + polarSegmentCount + 1 - 2
// = parametricSegmentCount + polarSegmentCount
//
mergedTessVertexSums4 += n_;
}
// We counted in batches of 4. Undo the values we counted from
// beyond the end of the path.
while (j-- > contour->endRotationIdx)
{
contourVertexCount -= m_polarSegmentCounts[j];
}
// Count joins.
if (!isStroke())
{
assert(isFeatheredFill());
uint32_t numSegmentsInFeatherJoin =
feather_join_segment_count(m_polarSegmentsPerRadian);
contourVertexCount +=
contour->strokeJoinCount * (numSegmentsInFeatherJoin - 1);
}
else if (m_strokeJoin == StrokeJoin::round)
{
// Round joins share their beginning and ending vertices with
// the curve on either side. Therefore, the number of vertices
// we need to allocate for a round join is "joinSegmentCount -
// 1". Do all the -1's here.
contourVertexCount -= contour->strokeJoinCount;
}
else
{
// The shader needs 3 segments for each miter and bevel join
// (which translates to two interior vertices, since joins share
// their beginning and ending vertices with the curve on either
// side).
contourVertexCount += contour->strokeJoinCount *
(NUM_SEGMENTS_IN_MITER_OR_BEVEL_JOIN - 1);
}
// Count stroke caps, if any.
bool empty = contour->endLineIdx == contourFirstLineIdx &&
contour->endCurveIdx == contour->firstCurveIdx;
StrokeCap cap;
bool needsCaps = false;
if (!empty)
{
cap = m_strokeCap;
needsCaps = !contour->closed;
}
else if (isStroke())
{
cap = empty_stroke_cap(contour->closed,
m_strokeJoin,
m_strokeCap);
needsCaps = cap != StrokeCap::butt; // Ignore butt caps when the
// contour is empty.
}
if (needsCaps)
{
// We emulate stroke caps as 180-degree joins.
if (cap == StrokeCap::round)
{
// Round caps rotate 180 degrees.
float strokeCapSegmentCount =
ceilf(m_polarSegmentsPerRadian * math::PI);
// +2 because round caps emulated as joins need to emit
// vertices at T=0 and T=1, unlike normal round joins.
strokeCapSegmentCount += 2;
// Make sure not to exceed kMaxPolarSegments.
strokeCapSegmentCount =
fminf(strokeCapSegmentCount, kMaxPolarSegments);
contour->strokeCapSegmentCount =
static_cast<uint32_t>(strokeCapSegmentCount);
}
else
{
contour->strokeCapSegmentCount =
NUM_SEGMENTS_IN_MITER_OR_BEVEL_JOIN;
}
// PLS expects all patches to have >0 tessellation vertices, so
// for the case of an empty patch with a stroke cap,
// contour->strokeCapSegmentCount can't be zero. Also,
// pushContourToRenderContext() uses "strokeCapSegmentCount !=
// 0" to tell if it needs stroke caps.
assert(contour->strokeCapSegmentCount >= 2);
// As long as a contour isn't empty, we can tack the end cap
// onto the join section of the final curve in the stroke.
// Otherwise, we need to introduce 0-tessellation-segment curves
// with non-empty joins to carry the caps.
emptyStrokeCountForCaps += empty ? 2 : 1;
contourVertexCount += (contour->strokeCapSegmentCount - 1) * 2;
}
}
else
{
// Fills don't have polar segments:
//
// mergedVertexCount = parametricVertexCount =
// parametricSegmentCount + 1
//
// Just collect the +1 for each non-stroked curve.
size_t contourCurveCount =
contour->endCurveIdx - contour->firstCurveIdx;
contourVertexCount += contourCurveCount;
}
contourVertexCount += simd::reduce_add(mergedTessVertexSums4);
// Add padding vertices until the number of tessellation vertices in the
// contour is an exact multiple of kMidpointFanPatchSegmentSpan. This
// ensures that patch boundaries align with contour boundaries.
contour->paddingVertexCount =
math::padding_to_align_up<kMidpointFanPatchSegmentSpan>(
contourVertexCount);
contourVertexCount += contour->paddingVertexCount;
assert(contourVertexCount % kMidpointFanPatchSegmentSpan == 0);
RIVE_DEBUG_CODE(contour->tessVertexCount = contourVertexCount;)
tessVertexCount += contourVertexCount;
contourFirstLineIdx = contour->endLineIdx;
}
assert(contourFirstLineIdx == lineCount);
RIVE_DEBUG_CODE(m_pendingLineCount = lineCount);
RIVE_DEBUG_CODE(m_pendingCurveCount = unpaddedCurveCount);
RIVE_DEBUG_CODE(m_pendingRotationCount = unpaddedRotationCount);
RIVE_DEBUG_CODE(m_pendingEmptyStrokeCountForCaps = emptyStrokeCountForCaps);
if (tessVertexCount > 0)
{
m_resourceCounts.pathCount = 1;
m_resourceCounts.contourCount = contourCount;
// maxTessellatedSegmentCount does not get doubled when we emit both
// forward and mirrored contours because the forward and mirrored pair
// both get packed into a single gpu::TessVertexSpan.
m_resourceCounts.maxTessellatedSegmentCount =
lineCount + unpaddedCurveCount + emptyStrokeCountForCaps;
m_resourceCounts.midpointFanTessVertexCount =
gpu::ContourDirectionsAreDoubleSided(m_contourDirections)
? tessVertexCount * 2
: tessVertexCount;
}
}
void PathDraw::initForInteriorTriangulation(RenderContext* context,
RawPath* scratchPath,
TriangulatorAxis triangulatorAxis)
{
RIVE_PROF_SCOPE()
assert(simd::all(m_resourceCounts.toVec() == 0)); // Only call init() once.
assert(!isStrokeOrFeather());
assert(m_strokeRadius == 0);
// Every path has at least 1 (non-cubic) move.
size_t originalNumChopsSize = m_pathRef->getRawPath().verbs().size() - 1;
m_numChops.reset(context->numChopsAllocator(), originalNumChopsSize);
iterateInteriorTriangulation(
InteriorTriangulationOp::countDataAndTriangulate,
&context->perFrameAllocator(),
scratchPath,
triangulatorAxis,
nullptr);
m_numChops.shrinkToFit(context->numChopsAllocator(), originalNumChopsSize);
}
bool PathDraw::allocateResources(RenderContext::LogicalFlush* flush)
{
RIVE_PROF_SCOPE()
const RenderContext::FrameDescriptor& frameDesc = flush->frameDescriptor();
// Allocate a gradient if needed. Do this first since it's more expensive to
// fail after setting up an atlas draw than a gradient draw.
if (m_gradientRef != nullptr &&
!flush->allocateGradient(m_gradientRef,
&m_simplePaintValue.colorRampLocation))
{
return false;
}
// Allocate a coverage buffer range or atlas region if needed.
if (m_coverageType == CoverageType::atlas ||
m_coverageType == CoverageType::clockwiseAtomic)
{
constexpr static int PADDING = 2;
// We don't need any coverage space for areas outside the viewport.
// TODO: Account for active clips as well once we have the info.
IAABB renderTargetBounds = {
0,
0,
static_cast<int32_t>(frameDesc.renderTargetWidth),
static_cast<int32_t>(frameDesc.renderTargetHeight),
};
IAABB visibleBounds = renderTargetBounds.intersect(m_pixelBounds);
if (m_coverageType == CoverageType::atlas)
{
const float scaleFactor =
find_atlas_feather_scale_factor(m_featherRadius,
m_strokeMatrixMaxScale);
auto w = static_cast<uint16_t>(
ceilf(visibleBounds.width() * scaleFactor));
auto h = static_cast<uint16_t>(
ceilf(visibleBounds.height() * scaleFactor));
uint16_t x, y;
if (!flush->allocateAtlasDraw(this,
w,
h,
PADDING,
&x,
&y,
&m_atlasScissor))
{
return false; // There wasn't room for our path in the atlas.
}
m_atlasTransform.scaleFactor = scaleFactor;
m_atlasTransform.translateX = x - visibleBounds.left * scaleFactor;
m_atlasTransform.translateY = y - visibleBounds.top * scaleFactor;
m_atlasScissorEnabled = visibleBounds != m_pixelBounds;
}
else
{
// Round up width and height to multiples of 32 for tiling.
uint32_t coverageWidth = math::round_up_to_multiple_of<32>(
visibleBounds.width() + PADDING * 2);
uint32_t coverageHeight = math::round_up_to_multiple_of<32>(
visibleBounds.height() + PADDING * 2);
// Get our coverage allocation.
size_t offset = flush->allocateCoverageBufferRange(coverageHeight *
coverageWidth);
if (offset == -1)
{
return false; // There wasn't room for our coverage buffer.
}
m_coverageBufferRange.offset =
math::lossless_numeric_cast<uint32_t>(offset);
m_coverageBufferRange.pitch = coverageWidth;
m_coverageBufferRange.offsetX = -visibleBounds.left + PADDING;
m_coverageBufferRange.offsetY = -visibleBounds.top + PADDING;
}
}
return true;
}
void PathDraw::countSubpasses()
{
RIVE_PROF_SCOPE()
m_subpassCount = 1;
m_prepassCount = 0;
switch (m_coverageType)
{
case CoverageType::pixelLocalStorage:
case CoverageType::atlas:
m_subpassCount = 1;
break;
case CoverageType::clockwiseAtomic:
if (!isStroke())
{
m_prepassCount = 1; // Borrowed coverage.
}
m_subpassCount = 1;
break;
case CoverageType::msaa:
{
if (isStroke())
{
m_subpassCount = 1; // Strokes can be rendered in a single pass.
}
else if ((m_drawContents & gpu::kNestedClipUpdateMask) ==
gpu::kNestedClipUpdateMask)
{
// Nested clip updates only have a stencil pass. (The reset is
// handled by a separate msaaStencilClipReset draw.)
m_subpassCount = 1;
}
else if (m_drawContents & gpu::DrawContents::evenOddFill)
{
m_subpassCount = 2; // MSAA "slow" path: stencil-then-cover.
}
else
{
// MSAA "fast" path: (effectively) single pass rendering.
m_subpassCount = 3;
}
if (isOpaque())
{
const bool usesClipping =
m_drawContents & (gpu::DrawContents::activeClip |
gpu::DrawContents::clipUpdate);
if (!usesClipping)
{
// Render this path front-to-back instead of back-to-front.
assert(m_prepassCount == 0);
m_prepassCount = m_subpassCount;
m_subpassCount = 0;
}
}
}
}
if (m_triangulator != nullptr)
{
// Each tessellation draw has a corresponding interior triangles draw.
m_prepassCount *= 2;
m_subpassCount *= 2;
}
}
void PathDraw::pushToRenderContext(RenderContext::LogicalFlush* flush,
int subpassIndex)
{
RIVE_PROF_SCOPE()
// Make sure the rawPath in our path reference hasn't changed since we began
// holding!
assert(m_rawPathMutationID == m_pathRef->getRawPathMutationID());
assert(!m_pathRef->getRawPath().empty());
assert(m_resourceCounts.outerCubicTessVertexCount == 0 ||
m_resourceCounts.midpointFanTessVertexCount == 0);
uint32_t tessVertexCount = math::lossless_numeric_cast<uint32_t>(
m_resourceCounts.outerCubicTessVertexCount |
m_resourceCounts.midpointFanTessVertexCount);
if (tessVertexCount == 0)
{
return;
}
if (m_pathID == 0)
{
// Reserve our pathID and write out a path record.
m_pathID = flush->pushPath(this);
}
switch (m_coverageType)
{
case CoverageType::pixelLocalStorage:
{
if (subpassIndex == 0)
{
// Tessellation (midpoint fan or outer cubic).
uint32_t tessLocation =
allocateTessellationVertices(flush, tessVertexCount);
pushTessellationData(flush, tessVertexCount, tessLocation);
pushTessellationDraw(flush, tessVertexCount, tessLocation);
}
else
{
// Interior triangles.
assert(m_triangulator != nullptr);
assert(subpassIndex == 1);
RIVE_DEBUG_CODE(m_numInteriorTriangleVerticesPushed +=)
flush->pushInteriorTriangulationDraw(this,
m_pathID,
gpu::WindingFaces::all);
assert(m_numInteriorTriangleVerticesPushed <=
m_triangulator->maxVertexCount());
}
break;
}
case CoverageType::clockwiseAtomic:
if (!isStroke())
{
// The subpass and prepass each emit half the vertices.
assert(m_prepassCount == m_subpassCount);
assert(tessVertexCount % 2 == 0);
tessVertexCount /= 2;
}
switch (subpassIndex)
{
case -1: // Tessellation (borrowed, midpointFan or outerCubic).
assert(!isStroke());
m_prepassTessLocation =
allocateTessellationVertices(flush, tessVertexCount);
pushTessellationDraw(
flush,
tessVertexCount,
m_prepassTessLocation,
gpu::ShaderMiscFlags::borrowedCoveragePrepass);
break;
case 0: // Tessellation (midpointFan or outerCubic).
{
uint32_t tessLocation =
allocateTessellationVertices(flush, tessVertexCount);
pushTessellationData(flush, tessVertexCount, tessLocation);
pushTessellationDraw(flush, tessVertexCount, tessLocation);
break;
}
case -2: // Interior triangles (borrowed).
case 1: // Interior triangles.
assert(!isStroke());
assert(m_triangulator != nullptr);
RIVE_DEBUG_CODE(m_numInteriorTriangleVerticesPushed +=)
flush->pushInteriorTriangulationDraw(
this,
m_pathID,
subpassIndex < 0 ? gpu::WindingFaces::negative
: gpu::WindingFaces::positive,
subpassIndex < 0
? gpu::ShaderMiscFlags::borrowedCoveragePrepass
: gpu::ShaderMiscFlags::none);
assert(m_numInteriorTriangleVerticesPushed <=
m_triangulator->maxVertexCount());
break;
default:
RIVE_UNREACHABLE();
}
break;
case CoverageType::msaa:
{
assert(m_prepassCount == 0 || m_subpassCount == 0);
int passCount = m_prepassCount | m_subpassCount;
int passIdx = subpassIndex + m_prepassCount;
if (passIdx == 0)
{
m_msaaTessLocation =
allocateTessellationVertices(flush, tessVertexCount);
pushTessellationData(flush,
tessVertexCount,
m_msaaTessLocation);
}
constexpr static gpu::DrawType MSAA_FILL_TYPES[][3] = {
// Nested clip update (passCount == 1; the reset is handled by a
// separate msaaStencilClipReset draw.)
{
gpu::DrawType::msaaMidpointFanPathsStencil,
},
// Slow path (passCount == 2): stencil-then-cover
{
gpu::DrawType::msaaMidpointFanPathsStencil,
gpu::DrawType::msaaMidpointFanPathsCover,
},
// Fast path (passCount == 3): (mostly) single pass rendering.
{
gpu::DrawType::msaaMidpointFanBorrowedCoverage,
gpu::DrawType::msaaMidpointFans,
gpu::DrawType::msaaMidpointFanStencilReset,
},
};
assert(passCount <= 3);
assert(passIdx < passCount);
gpu::DrawType msaaDrawType =
isStroke() ? gpu::DrawType::msaaStrokes
: MSAA_FILL_TYPES[passCount - 1][passIdx];
flush->pushMidpointFanDraw(this,
msaaDrawType,
tessVertexCount,
m_msaaTessLocation);
break;
}
case CoverageType::atlas:
// Atlas draws only have one subpass -- the rectangular blit from
// the atlas to the screen. The step that renders coverage to the
// offscreen atlas is handled separately, outside the subpass
// system.
assert(subpassIndex == 0);
flush->pushAtlasBlit(this, m_pathID);
break;
}
}
void PathDraw::pushTessellationDraw(RenderContext::LogicalFlush* flush,
uint32_t tessVertexCount,
uint32_t tessLocation,
gpu::ShaderMiscFlags shaderMiscFlags)
{
if (m_triangulator != nullptr)
{
assert(!isStroke());
flush->pushOuterCubicsDraw(this,
gpu::DrawType::outerCurvePatches,
tessVertexCount,
tessLocation,
shaderMiscFlags);
}
else
{
flush->pushMidpointFanDraw(
this,
isFeatheredFill() ? gpu::DrawType::midpointFanCenterAAPatches
: gpu::DrawType::midpointFanPatches,
tessVertexCount,
tessLocation,
shaderMiscFlags);
}
}
void PathDraw::pushAtlasTessellation(RenderContext::LogicalFlush* flush,
uint32_t* tessVertexCount,
uint32_t* tessBaseVertex)
{
RIVE_PROF_SCOPE()
assert(m_coverageType == CoverageType::atlas);
assert(m_resourceCounts.outerCubicTessVertexCount == 0 ||
m_resourceCounts.midpointFanTessVertexCount == 0);
*tessVertexCount = math::lossless_numeric_cast<uint32_t>(
m_resourceCounts.outerCubicTessVertexCount |
m_resourceCounts.midpointFanTessVertexCount);
if (*tessVertexCount == 0)
{
assert(m_pathID == 0);
return;
}
*tessBaseVertex = allocateTessellationVertices(flush, *tessVertexCount);
pushTessellationData(flush, *tessVertexCount, *tessBaseVertex);
}
void PathDraw::pushTessellationData(RenderContext::LogicalFlush* flush,
uint32_t tessVertexCount,
uint32_t tessLocation)
{
RIVE_PROF_SCOPE()
// Determine where to fill in forward and mirrored tessellations.
uint32_t forwardTessVertexCount, forwardTessLocation,
mirroredTessVertexCount, mirroredTessLocation;
switch (m_contourDirections)
{
case gpu::ContourDirections::forward:
forwardTessVertexCount = tessVertexCount;
forwardTessLocation = tessLocation;
mirroredTessLocation = mirroredTessVertexCount = 0;
break;
case gpu::ContourDirections::reverse:
forwardTessVertexCount = forwardTessLocation = 0;
mirroredTessVertexCount = tessVertexCount;
mirroredTessLocation = tessLocation + tessVertexCount;
break;
case gpu::ContourDirections::reverseThenForward:
if (m_coverageType == CoverageType::clockwiseAtomic && !isStroke())
{
// The tessellation for borrowed coverage was allocated at a
// different location than the forward tessellation, both with
// "tessVertexCount" vertices.
assert(m_prepassTessLocation != 0); // With padding, this will
// only be zero if it wasn't
// initialized.
forwardTessVertexCount = mirroredTessVertexCount =
tessVertexCount;
forwardTessLocation = tessLocation;
mirroredTessLocation = m_prepassTessLocation + tessVertexCount;
}
else
{
// The reverse and forward tessellations are allocated
// contiguously, with a combined vertex count of
// "tessVertexCount". (tessVertexCount/2 vertices each.)
assert(tessVertexCount % 2 == 0);
forwardTessVertexCount = mirroredTessVertexCount =
tessVertexCount / 2;
forwardTessLocation = mirroredTessLocation =
tessLocation + tessVertexCount / 2;
}
break;
case gpu::ContourDirections::forwardThenReverse:
if (m_coverageType == CoverageType::clockwiseAtomic && !isStroke())
{
// The tessellation for borrowed coverage was allocated at a
// different location than the forward tessellation, both with
// "tessVertexCount" vertices.
assert(m_prepassTessLocation != 0); // With padding, this will
// only be zero if it wasn't
// initialized.
forwardTessVertexCount = mirroredTessVertexCount =
tessVertexCount;
forwardTessLocation = m_prepassTessLocation;
mirroredTessLocation = tessLocation + tessVertexCount;
}
else
{
// The reverse and forward tessellations are allocated
// contiguously, with a combined vertex count of
// "tessVertexCount". (tessVertexCount/2 vertices each.)
assert(tessVertexCount % 2 == 0);
forwardTessVertexCount = mirroredTessVertexCount =
tessVertexCount / 2;
forwardTessLocation = tessLocation;
mirroredTessLocation = tessLocation + tessVertexCount;
}
break;
}
// Write out the TessVertexSpans and path contours.
RenderContext::TessellationWriter tessWriter(flush,
m_pathID,
m_contourDirections,
forwardTessVertexCount,
forwardTessLocation,
mirroredTessVertexCount,
mirroredTessLocation);
if (m_triangulator != nullptr)
{
iterateInteriorTriangulation(
InteriorTriangulationOp::pushOuterCubicTessellationData,
nullptr,
nullptr,
TriangulatorAxis::dontCare,
&tessWriter);
}
else
{
pushMidpointFanTessellationData(&tessWriter);
}
}
void PathDraw::pushMidpointFanTessellationData(
RenderContext::TessellationWriter* tessWriter)
{
RIVE_PROF_SCOPE()
const RawPath& rawPath = m_pathRef->getRawPath();
RawPath::Iter startOfContour = rawPath.begin();
for (size_t i = 0; i < m_resourceCounts.contourCount; ++i)
{
// Push a contour and curve records.
const ContourInfo& contour = m_contours[i];
assert(startOfContour.verb() == PathVerb::move);
assert(isStroke() || contour.closed); // Fills are always closed.
RIVE_DEBUG_CODE(m_pendingStrokeJoinCount =
isStrokeOrFeather() ? contour.strokeJoinCount : 0;)
RIVE_DEBUG_CODE(m_pendingStrokeCapCount =
contour.strokeCapSegmentCount != 0 ? 2 : 0;)
const Vec2D* pts = startOfContour.rawPtsPtr();
size_t curveIdx = contour.firstCurveIdx;
size_t rotationIdx = contour.firstRotationIdx;
const RawPath::Iter end = contour.endOfContour;
uint32_t joinTypeFlags = 0;
bool roundJoinStroked = false;
// Emit a starting cap before the next cubic?
bool needsFirstEmulatedCapAsJoin = false;
uint32_t emulatedCapAsJoinFlags = 0;
if (isStrokeOrFeather())
{
joinTypeFlags = isStroke() ? join_type_flags(m_strokeJoin)
: FEATHER_JOIN_CONTOUR_FLAG;
roundJoinStroked = joinTypeFlags == ROUND_JOIN_CONTOUR_FLAG;
if (contour.strokeCapSegmentCount != 0)
{
StrokeCap cap =
!contour.closed
? m_strokeCap
: empty_stroke_cap(true, m_strokeJoin, m_strokeCap);
switch (cap)
{
case StrokeCap::butt:
emulatedCapAsJoinFlags = BEVEL_JOIN_CONTOUR_FLAG;
break;
case StrokeCap::square:
emulatedCapAsJoinFlags = MITER_CLIP_JOIN_CONTOUR_FLAG;
break;
case StrokeCap::round:
emulatedCapAsJoinFlags = ROUND_JOIN_CONTOUR_FLAG;
break;
}
emulatedCapAsJoinFlags |= EMULATED_STROKE_CAP_CONTOUR_FLAG;
needsFirstEmulatedCapAsJoin = true;
}
}
// Make a data record for this current contour on the GPU.
uint32_t contourIDWithFlags =
m_contourFlags |
tessWriter->pushContour(contour.midpoint,
isStroke(),
contour.closed,
contour.paddingVertexCount);
// When we don't have round joins, the number of segments per join is
// constant. (Round joins have a variable number of segments per join,
// depending on the angle.)
uint32_t numSegmentsInNotRoundJoin;
if (isFeatheredFill())
{
numSegmentsInNotRoundJoin =
feather_join_segment_count(m_polarSegmentsPerRadian);
}
else
{
numSegmentsInNotRoundJoin = NUM_SEGMENTS_IN_MITER_OR_BEVEL_JOIN;
}
// Convert all curves in the contour to cubics and push them to the GPU.
const int styleFlags =
style_flags(isStrokeOrFeather(), roundJoinStroked);
Vec2D joinTangent = {0, 1};
int joinSegmentCount = 1;
Vec2D implicitClose[2]; // In case we need an implicit closing line.
for (auto iter = startOfContour; iter != end; ++iter)
{
StyledVerb styledVerb = styled_verb(iter.verb(), styleFlags);
switch (styledVerb)
{
case StyledVerb::filledMove:
case StyledVerb::strokedMove:
case StyledVerb::roundJoinStrokedMove:
implicitClose[1] = iter.movePt(); // In case we need an
// implicit closing line.
break;
case StyledVerb::filledClose:
case StyledVerb::strokedClose:
case StyledVerb::roundJoinStrokedClose:
assert(contour.closed);
break;
case StyledVerb::roundJoinStrokedLine:
{
if (contour.closed || !is_final_verb_of_contour(iter, end))
{
joinTangent = m_tangentPairs[rotationIdx][1];
joinSegmentCount = m_polarSegmentCounts[rotationIdx];
++rotationIdx;
RIVE_DEBUG_CODE(--m_pendingRotationCount;)
RIVE_DEBUG_CODE(--m_pendingStrokeJoinCount;)
}
else
{
// End with a 180-degree join that looks like the stroke
// cap.
joinTangent =
-find_ending_tangent(pts, end.rawPtsPtr());
joinTypeFlags = emulatedCapAsJoinFlags;
joinSegmentCount = contour.strokeCapSegmentCount;
RIVE_DEBUG_CODE(--m_pendingStrokeCapCount;)
}
goto line_common;
}
case StyledVerb::strokedLine:
if (contour.closed || !is_final_verb_of_contour(iter, end))
{
joinTangent = find_join_tangent(iter.linePts() + 1,
end.rawPtsPtr(),
contour.closed,
pts);
joinSegmentCount = numSegmentsInNotRoundJoin;
RIVE_DEBUG_CODE(--m_pendingStrokeJoinCount;)
}
else
{
// End with a 180-degree join that looks like the stroke
// cap.
joinTangent =
-find_ending_tangent(pts, end.rawPtsPtr());
joinTypeFlags = emulatedCapAsJoinFlags;
joinSegmentCount = contour.strokeCapSegmentCount;
RIVE_DEBUG_CODE(--m_pendingStrokeCapCount;)
}
[[fallthrough]];
case StyledVerb::filledLine:
line_common:
{
std::array<Vec2D, 4> cubic =
convert_line_to_cubic(iter.linePts());
if (needsFirstEmulatedCapAsJoin)
{
// Emulate the start cap as a 180-degree join before the
// first stroke.
pushEmulatedStrokeCapAsJoinBeforeCubic(
tessWriter,
cubic.data(),
contour.strokeCapSegmentCount,
contourIDWithFlags | emulatedCapAsJoinFlags);
needsFirstEmulatedCapAsJoin = false;
}
tessWriter->pushCubic(cubic.data(),
m_contourDirections,
joinTangent,
1,
1,
joinSegmentCount,
contourIDWithFlags | joinTypeFlags);
RIVE_DEBUG_CODE(--m_pendingLineCount;)
break;
}
case StyledVerb::roundJoinStrokedQuad:
case StyledVerb::strokedQuad:
case StyledVerb::filledQuad:
RIVE_UNREACHABLE();
break;
case StyledVerb::roundJoinStrokedCubic:
case StyledVerb::strokedCubic:
{
const Vec2D* p = iter.cubicPts();
uint8_t chopKey = m_numChops.pop_front();
uint8_t numChops = 0;
Vec2D localChopBuffer[16];
switch (chopKey)
{
case cusp_chop_key(2): // 2 cusps
case cusp_chop_key(1): // 1 cusp
// We have to chop carefully around stroked cusps in
// order to avoid rendering artifacts. Luckily,
// cusps are extremely rare in real-world content.
chop_cubic_around_cusps(
p,
localChopBuffer,
&m_chopVertices.pop_front().x,
chopKey >> 1,
m_strokeMatrixMaxScale);
p = localChopBuffer;
// The bottom bit of chopKey is 1, meaning
// "areCusps". Clearing the bottom bit leaves
// "numChops * 2", which is the number of chops a
// cusp needs!
numChops = chopKey ^ 1;
break;
case simple_chop_key(2): // 2 non-cusp chops
{
// Curves that need 2 chops are rare in real-world
// content. Just re-chop the curve this time around
// as well.
auto [t0, t1] = m_chopVertices.pop_front();
math::chop_cubic_at(p, localChopBuffer, t0, t1);
p = localChopBuffer;
numChops = 2;
break;
}
case simple_chop_key(1): // 1 non-cusp chop
// Single-chop curves were saved in the
// m_chopVertices queue.
localChopBuffer[0] = p[0];
memcpy(localChopBuffer + 1,
m_chopVertices.pop_front_n(5),
sizeof(Vec2D) * 5);
localChopBuffer[6] = p[3];
p = localChopBuffer;
numChops = 1;
break;
}
if (needsFirstEmulatedCapAsJoin)
{
// Emulate the start cap as a 180-degree join before the
// first stroke.
pushEmulatedStrokeCapAsJoinBeforeCubic(
tessWriter,
p,
contour.strokeCapSegmentCount,
contourIDWithFlags | emulatedCapAsJoinFlags);
needsFirstEmulatedCapAsJoin = false;
}
// Push chops before the final one.
for (size_t end = curveIdx + numChops; curveIdx != end;
++curveIdx, ++rotationIdx, p += 3)
{
uint32_t parametricSegmentCount =
m_parametricSegmentCounts[curveIdx];
uint32_t polarSegmentCount =
m_polarSegmentCounts[rotationIdx];
tessWriter->pushCubic(p,
m_contourDirections,
joinTangent,
parametricSegmentCount,
polarSegmentCount,
1,
contourIDWithFlags |
joinTypeFlags);
RIVE_DEBUG_CODE(--m_pendingCurveCount;)
RIVE_DEBUG_CODE(--m_pendingRotationCount;)
}
// Push the final chop, with a join.
uint32_t parametricSegmentCount =
m_parametricSegmentCounts[curveIdx++];
uint32_t polarSegmentCount =
m_polarSegmentCounts[rotationIdx++];
RIVE_DEBUG_CODE(--m_pendingRotationCount;)
if (contour.closed || !is_final_verb_of_contour(iter, end))
{
if (styledVerb == StyledVerb::roundJoinStrokedCubic)
{
joinTangent = m_tangentPairs[rotationIdx][1];
joinSegmentCount =
m_polarSegmentCounts[rotationIdx];
++rotationIdx;
RIVE_DEBUG_CODE(--m_pendingRotationCount;)
}
else
{
joinTangent = find_join_tangent(iter.cubicPts() + 3,
end.rawPtsPtr(),
contour.closed,
pts);
joinSegmentCount = numSegmentsInNotRoundJoin;
}
RIVE_DEBUG_CODE(--m_pendingStrokeJoinCount;)
}
else
{
// End with a 180-degree join that looks like the stroke
// cap.
joinTangent =
-find_ending_tangent(pts, end.rawPtsPtr());
joinTypeFlags = emulatedCapAsJoinFlags;
joinSegmentCount = contour.strokeCapSegmentCount;
RIVE_DEBUG_CODE(--m_pendingStrokeCapCount;)
}
tessWriter->pushCubic(p,
m_contourDirections,
joinTangent,
parametricSegmentCount,
polarSegmentCount,
joinSegmentCount,
contourIDWithFlags | joinTypeFlags);
RIVE_DEBUG_CODE(--m_pendingCurveCount;)
break;
}
case StyledVerb::filledCubic:
{
uint32_t parametricSegmentCount =
m_parametricSegmentCounts[curveIdx++];
tessWriter->pushCubic(iter.cubicPts(),
m_contourDirections,
Vec2D{},
parametricSegmentCount,
1,
1,
contourIDWithFlags);
RIVE_DEBUG_CODE(--m_pendingCurveCount;)
break;
}
}
}
if (needsFirstEmulatedCapAsJoin)
{
// The contour was empty. Emit both caps on p0.
Vec2D p0 = pts[0], left = {p0.x - 1, p0.y},
right = {p0.x + 1, p0.y};
pushEmulatedStrokeCapAsJoinBeforeCubic(
tessWriter,
std::array{p0, right, right, right}.data(),
contour.strokeCapSegmentCount,
contourIDWithFlags | emulatedCapAsJoinFlags);
pushEmulatedStrokeCapAsJoinBeforeCubic(
tessWriter,
std::array{p0, left, left, left}.data(),
contour.strokeCapSegmentCount,
contourIDWithFlags | emulatedCapAsJoinFlags);
}
else if (contour.closed)
{
implicitClose[0] = end.rawPtsPtr()[-1];
// Bit-cast to uint64_t because we don't want the special equality
// rules for NaN. If we're empty or otherwise return back to p0, we
// want to detect this, regardless of whether there are NaN values.
if (math::bit_cast<uint64_t>(implicitClose[0]) !=
math::bit_cast<uint64_t>(implicitClose[1]))
{
// Draw a line back to the beginning of the contour.
std::array<Vec2D, 4> cubic =
convert_line_to_cubic(implicitClose);
// Closing join back to the beginning of the contour.
if (roundJoinStroked)
{
joinTangent = m_tangentPairs[rotationIdx][1];
joinSegmentCount = m_polarSegmentCounts[rotationIdx];
++rotationIdx;
RIVE_DEBUG_CODE(--m_pendingRotationCount;)
RIVE_DEBUG_CODE(--m_pendingStrokeJoinCount;)
}
else if (isStrokeOrFeather())
{
joinTangent = find_starting_tangent(pts, end.rawPtsPtr());
joinSegmentCount = numSegmentsInNotRoundJoin;
RIVE_DEBUG_CODE(--m_pendingStrokeJoinCount;)
}
tessWriter->pushCubic(cubic.data(),
m_contourDirections,
joinTangent,
1,
1,
joinSegmentCount,
contourIDWithFlags | joinTypeFlags);
RIVE_DEBUG_CODE(--m_pendingLineCount;)
}
}
assert(curveIdx == contour.endCurveIdx);
assert(rotationIdx == contour.endRotationIdx);
assert(m_pendingStrokeJoinCount == 0);
assert(m_pendingStrokeCapCount == 0);
startOfContour = contour.endOfContour;
}
// Make sure we only pushed the amount of data we reserved.
assert(m_pendingLineCount == 0);
assert(m_pendingCurveCount == 0);
assert(m_pendingRotationCount == 0);
assert(m_pendingEmptyStrokeCountForCaps == 0);
}
void PathDraw::pushEmulatedStrokeCapAsJoinBeforeCubic(
RenderContext::TessellationWriter* tessWriter,
const Vec2D cubic[],
uint32_t strokeCapSegmentCount,
uint32_t contourIDWithFlags)
{
RIVE_PROF_SCOPE()
// Reverse the cubic and push it with zero parametric and polar segments,
// and a 180-degree join tangent. This results in a solitary join,
// positioned immediately before the provided cubic, that looks like the
// desired stroke cap.
assert(strokeCapSegmentCount >= 2);
tessWriter->pushCubic(
std::array{cubic[3], cubic[2], cubic[1], cubic[0]}.data(),
m_contourDirections,
math::find_cubic_tan0(cubic),
0,
0,
strokeCapSegmentCount,
contourIDWithFlags);
RIVE_DEBUG_CODE(--m_pendingStrokeCapCount;)
RIVE_DEBUG_CODE(--m_pendingEmptyStrokeCountForCaps;)
}
void PathDraw::iterateInteriorTriangulation(
InteriorTriangulationOp op,
TrivialBlockAllocator* allocator,
RawPath* scratchPath,
TriangulatorAxis triangulatorAxis,
RenderContext::TessellationWriter* tessWriter)
{
RIVE_PROF_SCOPE()
Vec2D chops[kMaxCurveSubdivisions * 3 + 1];
const RawPath& rawPath = m_pathRef->getRawPath();
assert(!rawPath.empty());
wangs_formula::VectorXform vectorXform(m_matrix);
size_t patchCount = 0;
size_t contourCount = 0;
Vec2D p0 = {0, 0};
if (op == InteriorTriangulationOp::countDataAndTriangulate)
{
scratchPath->rewind();
}
// Used with InteriorTriangulationOp::pushOuterCubicData.
uint32_t contourIDWithFlags = 0;
for (const auto [verb, pts] : rawPath)
{
switch (verb)
{
case PathVerb::move:
if (contourCount != 0 && pts[-1] != p0)
{
if (op ==
InteriorTriangulationOp::pushOuterCubicTessellationData)
{
tessWriter->pushCubic(
convert_line_to_cubic(pts[-1], p0).data(),
m_contourDirections,
{0, 0},
kPatchSegmentCountExcludingJoin,
1,
kJoinSegmentCount,
contourIDWithFlags |
CULL_EXCESS_TESSELLATION_SEGMENTS_CONTOUR_FLAG);
}
++patchCount;
}
if (op == InteriorTriangulationOp::countDataAndTriangulate)
{
scratchPath->move(pts[0]);
}
else
{
contourIDWithFlags =
m_contourFlags |
tessWriter->pushContour({0, 0},
isStroke(),
/*closed=*/true,
0);
}
p0 = pts[0];
++contourCount;
break;
case PathVerb::line:
if (op == InteriorTriangulationOp::countDataAndTriangulate)
{
scratchPath->line(pts[1]);
}
else
{
tessWriter->pushCubic(
convert_line_to_cubic(pts).data(),
m_contourDirections,
{0, 0},
kPatchSegmentCountExcludingJoin,
1,
kJoinSegmentCount,
contourIDWithFlags |
CULL_EXCESS_TESSELLATION_SEGMENTS_CONTOUR_FLAG);
}
++patchCount;
break;
case PathVerb::quad:
RIVE_UNREACHABLE();
case PathVerb::cubic:
{
uint32_t numSubdivisions;
if (op == InteriorTriangulationOp::countDataAndTriangulate)
{
numSubdivisions =
find_outer_cubic_subdivision_count(pts, vectorXform);
m_numChops.push_back(numSubdivisions);
}
else
{
numSubdivisions = m_numChops.pop_front();
}
if (numSubdivisions == 1)
{
if (op == InteriorTriangulationOp::countDataAndTriangulate)
{
scratchPath->line(pts[3]);
}
else
{
tessWriter->pushCubic(
pts,
m_contourDirections,
{0, 0},
kPatchSegmentCountExcludingJoin,
1,
kJoinSegmentCount,
contourIDWithFlags |
CULL_EXCESS_TESSELLATION_SEGMENTS_CONTOUR_FLAG);
}
}
else
{
// Passing nullptr for the 'tValues' causes it to chop the
// cubic uniformly in T.
math::chop_cubic_at(pts,
chops,
nullptr,
numSubdivisions - 1);
const Vec2D* chop = chops;
for (size_t i = 0; i < numSubdivisions; ++i)
{
if (op ==
InteriorTriangulationOp::countDataAndTriangulate)
{
scratchPath->line(chop[3]);
}
else
{
tessWriter->pushCubic(
chop,
m_contourDirections,
{0, 0},
kPatchSegmentCountExcludingJoin,
1,
kJoinSegmentCount,
contourIDWithFlags |
CULL_EXCESS_TESSELLATION_SEGMENTS_CONTOUR_FLAG);
}
chop += 3;
}
}
patchCount += numSubdivisions;
break;
}
case PathVerb::close:
break;
}
}
Vec2D lastPt = rawPath.points().back();
if (contourCount != 0 && lastPt != p0)
{
if (op == InteriorTriangulationOp::pushOuterCubicTessellationData)
{
tessWriter->pushCubic(
convert_line_to_cubic(lastPt, p0).data(),
m_contourDirections,
{0, 0},
kPatchSegmentCountExcludingJoin,
1,
kJoinSegmentCount,
contourIDWithFlags |
CULL_EXCESS_TESSELLATION_SEGMENTS_CONTOUR_FLAG);
}
++patchCount;
}
if (op == InteriorTriangulationOp::countDataAndTriangulate)
{
assert(m_triangulator == nullptr);
assert(triangulatorAxis != TriangulatorAxis::dontCare);
m_triangulator = allocator->make<GrInnerFanTriangulator>(
*scratchPath,
m_matrix,
triangulatorAxis == TriangulatorAxis::horizontal
? GrTriangulator::Comparator::Direction::kHorizontal
: GrTriangulator::Comparator::Direction::kVertical,
// clockwise and nonZero paths both get triangulated as nonZero,
// because clockwise fill still needs the backwards triangles for
// borrowed coverage.
m_pathFillRule == FillRule::evenOdd ? FillRule::evenOdd
: FillRule::nonZero,
allocator);
float matrixDeterminant =
m_matrix[0] * m_matrix[3] - m_matrix[2] * m_matrix[1];
if ((matrixDeterminant < 0) !=
static_cast<bool>(m_contourFlags & NEGATE_PATH_FILL_COVERAGE_FLAG))
{
m_triangulator->negateWinding();
}
// We also draw each "grout" triangle using an outerCubic patch.
patchCount += m_triangulator->groutList().count();
if (patchCount > 0)
{
m_resourceCounts.pathCount = 1;
m_resourceCounts.contourCount = contourCount;
// maxTessellatedSegmentCount does not get doubled when we emit both
// forward and mirrored contours because the forward and mirrored
// pair both get packed into a single gpu::TessVertexSpan.
m_resourceCounts.maxTessellatedSegmentCount = patchCount;
// outerCubic patches emit their tessellated geometry twice: once
// forward and once mirrored.
m_resourceCounts.outerCubicTessVertexCount =
gpu::ContourDirectionsAreDoubleSided(m_contourDirections)
? patchCount * kOuterCurvePatchSegmentSpan * 2
: patchCount * kOuterCurvePatchSegmentSpan;
m_resourceCounts.maxTriangleVertexCount +=
m_triangulator->maxVertexCount();
}
}
else
{
assert(m_triangulator != nullptr);
// Submit grout triangles, retrofitted into outerCubic patches.
for (auto* node = m_triangulator->groutList().head(); node;
node = node->fNext)
{
Vec2D triangleAsCubic[4] = {node->fPts[0],
node->fPts[1],
{0, 0},
node->fPts[2]};
tessWriter->pushCubic(triangleAsCubic,
m_contourDirections,
{0, 0},
kPatchSegmentCountExcludingJoin,
1,
kJoinSegmentCount,
contourIDWithFlags |
RETROFITTED_TRIANGLE_CONTOUR_FLAG);
++patchCount;
}
assert(contourCount == m_resourceCounts.contourCount);
assert(patchCount == m_resourceCounts.maxTessellatedSegmentCount);
assert(patchCount * kOuterCurvePatchSegmentSpan * 2 ==
m_resourceCounts.outerCubicTessVertexCount ||
patchCount * kOuterCurvePatchSegmentSpan ==
m_resourceCounts.outerCubicTessVertexCount);
}
}
ImageRectDraw::ImageRectDraw(RenderContext* context,
IAABB pixelBounds,
const Mat2D& matrix,
BlendMode blendMode,
rcp<Texture> imageTexture,
const ImageSampler imageSampler,
float opacity) :
Draw(pixelBounds,
matrix,
blendMode,
std::move(imageTexture),
imageSampler,
Type::imageRect),
m_opacity(opacity)
{
// If we support image paints for paths, the client should draw a
// rectangular path with an image paint instead of using this draw.
assert(!context->frameSupportsImagePaintForPaths());
m_resourceCounts.imageDrawCount = 1;
}
void ImageRectDraw::pushToRenderContext(RenderContext::LogicalFlush* flush,
int subpassIndex)
{
assert(subpassIndex == 0);
flush->pushImageRectDraw(this);
}
ImageMeshDraw::ImageMeshDraw(IAABB pixelBounds,
const Mat2D& matrix,
BlendMode blendMode,
rcp<Texture> imageTexture,
const ImageSampler imageSampler,
rcp<RenderBuffer> vertexBuffer,
rcp<RenderBuffer> uvBuffer,
rcp<RenderBuffer> indexBuffer,
uint32_t indexCount,
float opacity) :
Draw(pixelBounds,
matrix,
blendMode,
std::move(imageTexture),
imageSampler,
Type::imageMesh),
m_vertexBufferRef(vertexBuffer.release()),
m_uvBufferRef(uvBuffer.release()),
m_indexBufferRef(indexBuffer.release()),
m_indexCount(indexCount),
m_opacity(opacity)
{
assert(m_vertexBufferRef != nullptr);
assert(m_uvBufferRef != nullptr);
assert(m_indexBufferRef != nullptr);
m_resourceCounts.imageDrawCount = 1;
}
void ImageMeshDraw::pushToRenderContext(RenderContext::LogicalFlush* flush,
int subpassIndex)
{
assert(subpassIndex == 0);
flush->pushImageMeshDraw(this);
}
void ImageMeshDraw::releaseRefs()
{
Draw::releaseRefs();
m_vertexBufferRef->unref();
m_uvBufferRef->unref();
m_indexBufferRef->unref();
}
StencilClipReset::StencilClipReset(RenderContext* context,
uint32_t previousClipID,
gpu::DrawContents previousClipDrawContents,
ResetAction resetAction) :
Draw(context->getClipContentBounds(previousClipID),
Mat2D(),
BlendMode::srcOver,
nullptr,
ImageSampler::LinearClamp(),
Type::stencilClipReset),
m_previousClipID(previousClipID)
{
constexpr static gpu::DrawContents FILL_RULE_FLAGS =
gpu::DrawContents::nonZeroFill | gpu::DrawContents::evenOddFill |
gpu::DrawContents::clockwiseFill;
m_drawContents |= previousClipDrawContents & FILL_RULE_FLAGS;
switch (resetAction)
{
case ResetAction::intersectPreviousClip:
m_drawContents |= gpu::DrawContents::activeClip;
[[fallthrough]];
case ResetAction::clearPreviousClip:
m_drawContents |= gpu::DrawContents::clipUpdate;
break;
}
m_resourceCounts.maxTriangleVertexCount = 6;
}
void StencilClipReset::pushToRenderContext(RenderContext::LogicalFlush* flush,
int subpassIndex)
{
assert(subpassIndex == 0);
flush->pushStencilClipResetDraw(this);
}
} // namespace rive::gpu