polynode.cpp

/*
    SPDX-FileCopyrightText: 2016 Artem Fedoskin <afedoskin3@gmail.com>
    SPDX-License-Identifier: GPL-2.0-or-later
*/
 
#include "polynode.h"
 
#include <QPolygon>
#include <QSGFlatColorMaterial>
#include <QSGGeometry>
#include <QSGGeometryNode>
 
extern "C" {
#include "libtess/tessellate.h"
}
 
PolyNode::PolyNode() : m_geometryNode(new QSGGeometryNode), m_material(new QSGFlatColorMaterial)
{
    m_geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), 0);
    m_geometryNode->setGeometry(m_geometry);
    m_geometryNode->setFlag(QSGNode::OwnsGeometry);
 
    m_geometryNode->setOpaqueMaterial(m_material);
    m_geometryNode->setFlag(QSGNode::OwnsMaterial);
 
    appendChildNode(m_geometryNode);
}
 
void PolyNode::setColor(QColor color)
{
    if (color != m_material->color())
    {
        m_material->setColor(color);
        m_geometryNode->markDirty(QSGNode::DirtyMaterial);
    }
}
 
void PolyNode::setLineWidth(int width)
{
    if (width != m_geometry->lineWidth())
    {
        m_geometry->setLineWidth(width);
        m_geometryNode->markDirty(QSGNode::DirtyGeometry);
    }
}
 
void PolyNode::updateGeometry(const QPolygonF &polygon, bool filled)
{
    if (!filled)
    {
        m_geometry->setDrawingMode(GL_LINE_STRIP);
        int size = polygon.size();
        m_geometry->allocate(size);
 
        QSGGeometry::Point2D *vertex = m_geometry->vertexDataAsPoint2D();
 
        for (int i = 0; i < size; ++i)
        {
            vertex[i].x = polygon[i].x();
            vertex[i].y = polygon[i].y();
        }
    }
    else
    {
        m_geometry->setDrawingMode(GL_TRIANGLES);
 
        double *coordinates_out;
        int *tris_out;
        int nverts, ntris, i;
        QPolygonF pol = polygon;
        int polySize = pol.size() * 2;
        std::vector<double> vertices_array(polySize);
 
        for (int i = 0; i < polySize; i += 2)
        {
            vertices_array[i]     = pol[i / 2].x();
            vertices_array[i + 1] = pol[i / 2].y();
        }
 
        const double *contours_array[] = { &vertices_array[0], &vertices_array[0] + polySize };
        int contours_size              = 2;
 
        tessellate(&coordinates_out, &nverts, &tris_out, &ntris, contours_array, contours_array + contours_size);
 
        m_geometry->allocate(3 * ntris);
        QSGGeometry::Point2D *vertex = m_geometry->vertexDataAsPoint2D();
 
        for (i = 0; i < 3 * ntris; ++i)
        {
            //int tris = tris_out[i];
            vertex[i].x = coordinates_out[tris_out[i] * 2];
            vertex[i].y = coordinates_out[tris_out[i] * 2 + 1];
        }
        free(coordinates_out);
        if (tris_out)
            free(tris_out);
    }
    m_geometryNode->markDirty(QSGNode::DirtyGeometry);
}