qtdeclarative/examples/quick/scenegraph/graph/linenode.cpp

147 lines
3.9 KiB
C++

// Copyright (C) 2017 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "linenode.h"
#include <QtGui/QColor>
#include <QtQuick/QSGMaterial>
class LineShader : public QSGMaterialShader
{
public:
LineShader() {
setShaderFileName(VertexStage, QLatin1String(":/scenegraph/graph/shaders/line.vert.qsb"));
setShaderFileName(FragmentStage, QLatin1String(":/scenegraph/graph/shaders/line.frag.qsb"));
}
bool updateUniformData(RenderState &state, QSGMaterial *newMaterial, QSGMaterial *oldMaterial) override;
};
class LineMaterial : public QSGMaterial
{
public:
LineMaterial()
{
setFlag(Blending);
}
QSGMaterialType *type() const override
{
static QSGMaterialType type;
return &type;
}
QSGMaterialShader *createShader(QSGRendererInterface::RenderMode) const override
{
return new LineShader;
}
int compare(const QSGMaterial *m) const override
{
const LineMaterial *other = static_cast<const LineMaterial *>(m);
if (int diff = int(state.color.rgb()) - int(other->state.color.rgb()))
return diff;
if (int diff = state.size - other->state.size)
return diff;
if (int diff = state.spread - other->state.spread)
return diff;
return 0;
}
struct {
QColor color;
float size;
float spread;
} state;
};
bool LineShader::updateUniformData(RenderState &state, QSGMaterial *newMaterial, QSGMaterial *)
{
QByteArray *buf = state.uniformData();
Q_ASSERT(buf->size() >= 92);
if (state.isMatrixDirty()) {
const QMatrix4x4 m = state.combinedMatrix();
memcpy(buf->data(), m.constData(), 64);
}
if (state.isOpacityDirty()) {
const float opacity = state.opacity();
memcpy(buf->data() + 80, &opacity, 4);
}
LineMaterial *mat = static_cast<LineMaterial *>(newMaterial);
float c[4];
mat->state.color.getRgbF(&c[0], &c[1], &c[2], &c[3]);
memcpy(buf->data() + 64, c, 16);
memcpy(buf->data() + 84, &mat->state.size, 4);
memcpy(buf->data() + 88, &mat->state.spread, 4);
return true;
}
struct LineVertex {
float x;
float y;
float t;
inline void set(float xx, float yy, float tt) { x = xx; y = yy; t = tt; }
};
static const QSGGeometry::AttributeSet &attributes()
{
static QSGGeometry::Attribute attr[] = {
QSGGeometry::Attribute::create(0, 2, QSGGeometry::FloatType, true),
QSGGeometry::Attribute::create(1, 1, QSGGeometry::FloatType)
};
static QSGGeometry::AttributeSet set = { 2, 3 * sizeof(float), attr };
return set;
}
LineNode::LineNode(float size, float spread, const QColor &color)
: m_geometry(attributes(), 0)
{
setGeometry(&m_geometry);
m_geometry.setDrawingMode(QSGGeometry::DrawTriangleStrip);
LineMaterial *m = new LineMaterial;
m->state.color = color;
m->state.size = size;
m->state.spread = spread;
setMaterial(m);
setFlag(OwnsMaterial);
}
/*
* Assumes that samples have values in the range of 0 to 1 and scales them to
* the height of bounds. The samples are stretched out horizontally along the
* width of the bounds.
*
* The position of each pair of points is identical, but we use the third value
* "t" to shift the point up or down and to add antialiasing.
*/
void LineNode::updateGeometry(const QRectF &bounds, const QList<qreal> &samples)
{
m_geometry.allocate(samples.size() * 2);
float x = bounds.x();
float y = bounds.y();
float w = bounds.width();
float h = bounds.height();
float dx = w / (samples.size() - 1);
LineVertex *v = (LineVertex *) m_geometry.vertexData();
for (int i=0; i<samples.size(); ++i) {
v[i*2+0].set(x + dx * i, y + samples.at(i) * h, 0);
v[i*2+1].set(x + dx * i, y + samples.at(i) * h, 1);
}
markDirty(QSGNode::DirtyGeometry);
}