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Some minor performance improvements on line tessellation
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@jebos
jebos committed Jul 6, 2023
1 parent a12b89e commit 26899b8
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Showing 2 changed files with 142 additions and 126 deletions.
262 changes: 136 additions & 126 deletions src/RiveQtQuickItem/riveqtpath.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -126,24 +126,145 @@ QVector<QVector<QVector2D>> RiveQtPath::toVertices()
return m_pathSegmentsData;
}

void RiveQtPath::addMiterJoin(QVector<QVector2D> &lineDataSegment, const QVector2D &p1, const QVector2D &p2, const QVector2D &offset)
{
lineDataSegment.append(p1 + offset);
lineDataSegment.append(p2 + offset);
lineDataSegment.append(p1 - offset);
lineDataSegment.append(p2 - offset);
};

void RiveQtPath::addRoundJoin(QVector<QVector2D> &lineDataSegment, const float &lineWidth, const QVector2D &p1, const QVector2D &p2,
const QVector2D &offset, int numSegments)
{
QVector2D prevPoint1 = p1 - offset;
QVector2D prevPoint2 = p1 + offset;

float angleStep = M_PI / numSegments;
float angle = atan2(offset.y(), offset.x());

for (int i = 0; i < numSegments; ++i) {
float newAngle = angle + angleStep * (i + 1);
QVector2D newOffset(cos(newAngle) * lineWidth / 2, sin(newAngle) * lineWidth / 2);
QVector2D newPoint1 = p1 - newOffset;
QVector2D newPoint2 = p1 + newOffset;

lineDataSegment.append(prevPoint1);
lineDataSegment.append(prevPoint2);
lineDataSegment.append(newPoint1);

lineDataSegment.append(newPoint1);
lineDataSegment.append(prevPoint2);
lineDataSegment.append(newPoint2);

prevPoint1 = newPoint1;
prevPoint2 = newPoint2;
}

lineDataSegment.append(prevPoint1);
lineDataSegment.append(prevPoint2);
lineDataSegment.append(p2 - offset);

lineDataSegment.append(p2 - offset);
lineDataSegment.append(prevPoint2);
lineDataSegment.append(p2 + offset);

lineDataSegment.append(p1 + offset);
lineDataSegment.append(p2 + offset);
lineDataSegment.append(p1 - offset);
lineDataSegment.append(p2 - offset);
};

void RiveQtPath::addBevelJoin(QVector<QVector2D> &lineDataSegment, const QVector2D &p1, const QVector2D &p2, const QVector2D &offset)
{
QVector2D p1_outer = p1 - offset;
QVector2D p1_inner = p1 + offset;
QVector2D p2_outer = p2 - offset;
QVector2D p2_inner = p2 + offset;

lineDataSegment.append(p1_outer);
lineDataSegment.append(p1_inner);
lineDataSegment.append(p2_inner);

lineDataSegment.append(p1_outer);
lineDataSegment.append(p2_inner);
lineDataSegment.append(p2_outer);
};

void RiveQtPath::addCap(QVector<QVector2D> &lineDataSegment, const float &lineWidth, const Qt::PenCapStyle &capStyle, const QVector2D &p,
const QVector2D &offset, const QVector2D &normal, const bool &isStart)
{
switch (capStyle) {
case Qt::PenCapStyle::FlatCap:
// No additional vertices needed for FlatCap
break;
case Qt::PenCapStyle::RoundCap: {
int numSegments = m_segmentCount;
float angleStep = M_PI / numSegments;
float startAngle = atan2(offset.y(), offset.x());

QVector<QVector2D> capVertices;
QVector2D previousOffset(cos(startAngle) * lineWidth / 2, sin(startAngle) * lineWidth / 2);
for (int i = 0; i < numSegments + 1; ++i) {
float newAngle = startAngle + angleStep * (i + 1);
QVector2D newOffset(cos(newAngle) * lineWidth / 2, sin(newAngle) * lineWidth / 2);

capVertices.append(p);
capVertices.append(p + previousOffset);
capVertices.append(p + newOffset);

previousOffset = newOffset;
}

if (isStart) {
lineDataSegment = capVertices + lineDataSegment;
} else {
lineDataSegment.append(capVertices);
}

break;
}
case Qt::PenCapStyle::SquareCap: {
QVector<QVector2D> capVertices;
capVertices.append(p - normal * (lineWidth / 2) + offset);
capVertices.append(p + normal * (lineWidth / 2) + offset);
capVertices.append(p - normal * (lineWidth / 2) - offset);
capVertices.append(p + normal * (lineWidth / 2) - offset);

if (isStart) {
lineDataSegment = capVertices + lineDataSegment;
} else {
lineDataSegment.append(capVertices);
}
break;
}
default:
// No additional vertices needed for other cap styles
break;
}
};

// TODO: Optimize, this gets called each frame for a stroke/path
// there will be shortcuts and caching possible
QVector<QVector<QVector2D>> RiveQtPath::toVerticesLine(const QPen &pen)
{
if (m_pathSegmentOutlineDataDirty) {
generateOutlineVertices();
m_pathOutlineData.clear();
}

m_pathOutlineData.clear();

if (m_pathSegmentsOutlineData.isEmpty()) {
return m_pathOutlineData;
}

if (!m_pathOutlineData.isEmpty()) {
return m_pathOutlineData;
}

qreal lineWidth = pen.widthF();

Qt::PenJoinStyle joinType = pen.joinStyle();
Qt::PenCapStyle capStyle = pen.capStyle();
const Qt::PenJoinStyle &joinType = pen.joinStyle();
const Qt::PenCapStyle &capStyle = pen.capStyle();

for (QVector<QVector2D> pathData : qAsConst(m_pathSegmentsOutlineData)) {
if (pathData.size() <= 1) {
Expand All @@ -155,129 +276,17 @@ QVector<QVector<QVector2D>> RiveQtPath::toVerticesLine(const QPen &pen)
int count = pathData.count();
int endIndex = count; // m_isClosed ? count : count - 1;

auto addMiterJoin = [&](const QVector2D &p1, const QVector2D &p2, const QVector2D &offset) {
lineDataSegment.append(p1 + offset);
lineDataSegment.append(p2 + offset);
lineDataSegment.append(p1 - offset);
lineDataSegment.append(p2 - offset);
};

auto addRoundJoin = [&](const QVector2D &p1, const QVector2D &p2, const QVector2D &offset, int numSegments) {
QVector2D prevPoint1 = p1 - offset;
QVector2D prevPoint2 = p1 + offset;

float angleStep = M_PI / numSegments;
float angle = atan2(offset.y(), offset.x());

for (int i = 0; i < numSegments; ++i) {
float newAngle = angle + angleStep * (i + 1);
QVector2D newOffset(cos(newAngle) * lineWidth / 2, sin(newAngle) * lineWidth / 2);
QVector2D newPoint1 = p1 - newOffset;
QVector2D newPoint2 = p1 + newOffset;

lineDataSegment.append(prevPoint1);
lineDataSegment.append(prevPoint2);
lineDataSegment.append(newPoint1);

lineDataSegment.append(newPoint1);
lineDataSegment.append(prevPoint2);
lineDataSegment.append(newPoint2);

prevPoint1 = newPoint1;
prevPoint2 = newPoint2;
}

lineDataSegment.append(prevPoint1);
lineDataSegment.append(prevPoint2);
lineDataSegment.append(p2 - offset);

lineDataSegment.append(p2 - offset);
lineDataSegment.append(prevPoint2);
lineDataSegment.append(p2 + offset);

lineDataSegment.append(p1 + offset);
lineDataSegment.append(p2 + offset);
lineDataSegment.append(p1 - offset);
lineDataSegment.append(p2 - offset);
};

auto addBevelJoin = [&](const QVector2D &p1, const QVector2D &p2, const QVector2D &offset) {
QVector2D p1_outer = p1 - offset;
QVector2D p1_inner = p1 + offset;
QVector2D p2_outer = p2 - offset;
QVector2D p2_inner = p2 + offset;

lineDataSegment.append(p1_outer);
lineDataSegment.append(p1_inner);
lineDataSegment.append(p2_inner);

lineDataSegment.append(p1_outer);
lineDataSegment.append(p2_inner);
lineDataSegment.append(p2_outer);
};

auto addCap = [&](const QVector2D &p, const QVector2D &offset, const QVector2D &normal, bool isStart) {
switch (capStyle) {
case Qt::PenCapStyle::FlatCap:
// No additional vertices needed for FlatCap
break;
case Qt::PenCapStyle::RoundCap: {
int numSegments = 20;
float angleStep = M_PI / numSegments;
float startAngle = atan2(offset.y(), offset.x());

QVector<QVector2D> capVertices;
QVector2D previousOffset(cos(startAngle) * lineWidth / 2, sin(startAngle) * lineWidth / 2);
for (int i = 0; i < numSegments + 1; ++i) {
float newAngle = startAngle + angleStep * (i + 1);
QVector2D newOffset(cos(newAngle) * lineWidth / 2, sin(newAngle) * lineWidth / 2);

capVertices.append(p);
capVertices.append(p + previousOffset);
capVertices.append(p + newOffset);

previousOffset = newOffset;
}

if (isStart) {
lineDataSegment = capVertices + lineDataSegment;
} else {
lineDataSegment.append(capVertices);
}

break;
}
case Qt::PenCapStyle::SquareCap: {
QVector<QVector2D> capVertices;
capVertices.append(p - normal * (lineWidth / 2) + offset);
capVertices.append(p + normal * (lineWidth / 2) + offset);
capVertices.append(p - normal * (lineWidth / 2) - offset);
capVertices.append(p + normal * (lineWidth / 2) - offset);

if (isStart) {
lineDataSegment = capVertices + lineDataSegment;
} else {
lineDataSegment.append(capVertices);
}
break;
}
default:
// No additional vertices needed for other cap styles
break;
}
};

for (int i = 0; i < (m_isClosed ? endIndex : endIndex - 1); ++i) {
const QVector2D p1 = pathData[i];
const QVector2D p2 = pathData[(i + 1) % (endIndex)]; // if endIndex, take 0
const QVector2D &p1 = pathData[i];
const QVector2D &p2 = pathData[(i + 1) % (endIndex)]; // if endIndex, take 0
const QVector2D diff = p2 - p1;

const QVector2D normal = QVector2D(-diff.y(), diff.x()).normalized();

const QVector2D offset = normal * (lineWidth / 2.0);

if (!m_isClosed && (i == 0 || (i == endIndex && endIndex > 3))) {
addRoundJoin(p1, p2, offset, 20);
addRoundJoin(lineDataSegment, lineWidth, p1, p2, offset, m_segmentCount);
} else {
switch (joinType) {
case Qt::PenJoinStyle::MiterJoin:
Expand All @@ -287,18 +296,18 @@ QVector<QVector<QVector2D>> RiveQtPath::toVerticesLine(const QPen &pen)
// break;
// the fallthrough is intendend here
case Qt::PenJoinStyle::RoundJoin:
addRoundJoin(p1, p2, offset, 20);
addRoundJoin(lineDataSegment, lineWidth, p1, p2, offset, m_segmentCount);
break;
case Qt::PenJoinStyle::BevelJoin:
addBevelJoin(p1, p2, offset);
addBevelJoin(lineDataSegment, p1, p2, offset);
break;
default:
// add both while this shouldn't end here since we handle all known rive cases
// SvgMiterJoin = 0x100,
// MPenJoinStyle = 0x1c0
qCDebug(rqqpRendering) << "Unknown join type is handled using defaults. This should not happen.";
addMiterJoin(p1, p2, offset);
addRoundJoin(p1, p2, offset, 20);
addMiterJoin(lineDataSegment, p1, p2, offset);
addRoundJoin(lineDataSegment, lineWidth, p1, p2, offset, m_segmentCount);
}
}
}
Expand All @@ -309,8 +318,8 @@ QVector<QVector<QVector2D>> RiveQtPath::toVerticesLine(const QPen &pen)
QVector2D endNormal(-pathData.last().y() + pathData[count - 2].y(), pathData.last().x() - pathData[count - 2].x());
endNormal.normalize();

addCap(pathData.first(), startNormal * (lineWidth / 2.0), startNormal, true);
addCap(pathData.last(), -endNormal * (lineWidth / 2.0), endNormal, false);
addCap(lineDataSegment, lineWidth, capStyle, pathData.first(), startNormal * (lineWidth / 2.0), startNormal, true);
addCap(lineDataSegment, lineWidth, capStyle, pathData.last(), -endNormal * (lineWidth / 2.0), endNormal, false);
}

// TODO: this converts the created TRIANGLE STRIP to TRIANGLES
Expand All @@ -333,6 +342,8 @@ QVector<QVector<QVector2D>> RiveQtPath::toVerticesLine(const QPen &pen)
m_pathOutlineData.append(triangledSegmentData);
}

m_pathSegmentOutlineDataDirty = false;

return m_pathOutlineData;
}

Expand Down Expand Up @@ -479,7 +490,6 @@ void RiveQtPath::generateOutlineVertices()
m_pathSegmentsOutlineData.append(subPath.path()->m_pathSegmentsOutlineData);
m_pathSegmentsOutlineData.append(qpainterPathToOutlineVector2D(transformedPath));
}
m_pathSegmentOutlineDataDirty = false;
}

SubPath::SubPath(RiveQtPath *path, const QMatrix4x4 &transform)
Expand Down
6 changes: 6 additions & 0 deletions src/RiveQtQuickItem/riveqtpath.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -58,6 +58,12 @@ class RiveQtPath : public rive::RenderPath
bool m_pathSegmentOutlineDataDirty { true };

unsigned m_segmentCount { 10 };
void addMiterJoin(QVector<QVector2D> &lineDataSegment, const QVector2D &p1, const QVector2D &p2, const QVector2D &offset);
void addRoundJoin(QVector<QVector2D> &lineDataSegment, const float &lineWidth, const QVector2D &p1, const QVector2D &p2, const QVector2D &offset,
int numSegments);
void addBevelJoin(QVector<QVector2D> &lineDataSegment, const QVector2D &p1, const QVector2D &p2, const QVector2D &offset);
void addCap(QVector<QVector2D> &lineDataSegment, const float &lineWidth, const Qt::PenCapStyle &capStyle, const QVector2D &p,
const QVector2D &offset, const QVector2D &normal, const bool &isStart);
};

class SubPath
Expand Down

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