[Quick3D] Vertex coloring

[0x5FB5]

I've created custom QQuick3DGeometry class. Is it possible to set color to vertex from a code to make some heights different?

Here's how it works:

...
    for (int y = 0; y < MATRIX_SIZE; ++y) {
        for (int x = 0; x < MATRIX_SIZE; ++x) {
            QVector3D vertex(x * MATRIX_SCALE, y * MATRIX_SCALE, m_testMatrix[x][y] * MATRIX_SCALE);

            *p++ = vertex.x();
            *p++ = vertex.y();
            *p++ = vertex.z();

            vertex.setY((y + 1) * MATRIX_SCALE);
            vertex.setZ(m_testMatrix[x][y + 1] * MATRIX_SCALE);

            *p++ = vertex.x();
            *p++ = vertex.y();
            *p++ = vertex.z();
        }
    }

    setVertexData(vertexData);
    setPrimitiveType(QQuick3DGeometry::PrimitiveType::LineStrip);
    setStride(stride);
    addAttribute(QQuick3DGeometry::Attribute::PositionSemantic, 0, QQuick3DGeometry::Attribute::F32Type);
    addAttribute(QQuick3DGeometry::Attribute::ColorSemantic, 4, QQuick3DGeometry::Attribute::U32Type);

I found that I can add color attribute, but I don't understand how to add color data to vertex. If it possible to make this without shaders, will be awesome

[djdan]

Can you provide full code?

[0x5FB5]

Just like in official tutorial with custom point cloud

#include "heightmapgeometry.h"

HeightMapGeometry::HeightMapGeometry()
{
    m_pFrameTimer = new QTimer(this);
    connect(m_pFrameTimer, &QTimer::timeout, this, &HeightMapGeometry::m_update);
    m_pFrameTimer->start(120);

    m_generateTestMatrix();

    m_updateGeometry();
}

void HeightMapGeometry::m_updateGeometry()
{
    clear();

    int stride = 3 * sizeof(float);

    QByteArray vertexData(3 * stride, Qt::Initialization::Uninitialized);

    vertexData.resize(stride * (MATRIX_SIZE * MATRIX_SIZE * 2));

    float *p = reinterpret_cast<float *>(vertexData.data());

    for (int y = 0; y < MATRIX_SIZE; ++y) {
        for (int x = 0; x < MATRIX_SIZE; ++x) {
            QVector3D vertex(x * MATRIX_SCALE, y * MATRIX_SCALE, m_testMatrix[x][y] * MATRIX_SCALE);

            *p++ = vertex.x();
            *p++ = vertex.y();
            *p++ = vertex.z();

            vertex.setY((y + 1) * MATRIX_SCALE);
            vertex.setZ(m_testMatrix[x][y + 1] * MATRIX_SCALE);

            *p++ = vertex.x();
            *p++ = vertex.y();
            *p++ = vertex.z();
        }
    }

    setVertexData(vertexData);
    setPrimitiveType(QQuick3DGeometry::PrimitiveType::LineStrip);
    setStride(stride);

    addAttribute(QQuick3DGeometry::Attribute::PositionSemantic, 0, QQuick3DGeometry::Attribute::F32Type);
}

float HeightMapGeometry::m_generateTestMatrix()
{
    for (int i = 0; i < MATRIX_SIZE; ++i) {
        for (int j = 0; j < MATRIX_SIZE; ++j) {
            float num = QRandomGenerator::global()->generateDouble() * (1.f - 0.f) + 0.f;
            m_testMatrix[i][j] = num;
        }
    }
}

void HeightMapGeometry::m_update()
{
    m_generateTestMatrix();
    m_updateGeometry();
    update();
}