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50
51#include "gridnode.h"
52
53#include "qmath.h"
54
55#define GRID_SIZE 32
56
57GridNode::GridNode()
58 : m_geometry(QSGGeometry::defaultAttributes_Point2D(), 0)
59{
60 setGeometry(&m_geometry);
61 m_geometry.setDrawingMode(GL_LINES);
62
63 setMaterial(&m_material);
64 m_material.setColor(Qt::gray);
65}
66
67/*
68 * The function hardcodes a fixed set of grid lines and scales
69 * those to the bounding rect.
70 */
71void GridNode::setRect(const QRectF &rect)
72{
73 int vCount = int((rect.width() - 1) / GRID_SIZE);
74 int hCount = int((rect.height() - 1) / GRID_SIZE);
75
76 int lineCount = vCount + hCount;
77
78 QSGGeometry *g = geometry();
79
80 g->allocate(vertexCount: lineCount * 2);
81
82 float x = rect.x();
83 float y = rect.y();
84 float w = rect.width();
85 float h = rect.height();
86
87 QSGGeometry::Point2D *v = g->vertexDataAsPoint2D();
88
89 // Then write the vertical lines
90 for (int i=0; i<vCount; ++i) {
91 float dx = (i + 1) * GRID_SIZE;
92 v[i*2].set(nx: dx, ny: y);
93 v[i*2+1].set(nx: dx, ny: y + h);
94 }
95 v += vCount * 2;
96 // Then write the horizontal lines
97 for (int i=0; i<hCount; ++i) {
98 float dy = (i + 1) * GRID_SIZE;
99 v[i*2].set(nx: x, ny: dy);
100 v[i*2+1].set(nx: x + w, ny: dy);
101 }
102
103 // Tell the scenegraph we updated the geometry..
104 markDirty(bits: QSGNode::DirtyGeometry);
105}
106

source code of qtdeclarative/examples/quick/scenegraph/graph/gridnode.cpp