C++ QMatrix4x4::isIdentity方法代码示例

void QSGTextMaskShader::updateState(const RenderState &state, QSGMaterial *newEffect, QSGMaterial *oldEffect)
{
    QSGTextMaskMaterial *material = static_cast<QSGTextMaskMaterial *>(newEffect);
    QSGTextMaskMaterial *oldMaterial = static_cast<QSGTextMaskMaterial *>(oldEffect);
    Q_ASSERT(oldEffect == 0 || newEffect->type() == oldEffect->type());
    bool updated = material->ensureUpToDate();
    Q_ASSERT(material->texture());

    Q_ASSERT(oldMaterial == 0 || oldMaterial->texture());
    if (updated
            || oldMaterial == 0
            || oldMaterial->texture()->textureId() != material->texture()->textureId()) {
        program()->setUniformValue(m_textureScale_id, QVector2D(1.0 / material->cacheTextureWidth(),
                                                               1.0 / material->cacheTextureHeight()));
        glBindTexture(GL_TEXTURE_2D, material->texture()->textureId());

        // Set the mag/min filters to be nearest. We only need to do this when the texture
        // has been recreated.
        if (updated) {
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        }
    }

    if (state.isMatrixDirty()) {
        QMatrix4x4 transform = state.modelViewMatrix();
        qreal xTranslation = transform(0, 3);
        qreal yTranslation = transform(1, 3);

        // Remove translation and check identity to see if matrix is only translating.
        // If it is, we can round the translation to make sure the text is pixel aligned,
        // which is the only thing that works with GL_NEAREST filtering. Adding rotations
        // and scales to native rendered text is not a prioritized use case, since the
        // default rendering type is designed for that.
        transform(0, 3) = 0.0;
        transform(1, 3) = 0.0;
        if (transform.isIdentity()) {
            transform(0, 3) = qRound(xTranslation);
            transform(1, 3) = qRound(yTranslation);

            transform = state.projectionMatrix() * transform;
            program()->setUniformValue(m_matrix_id, transform);
        } else {
            program()->setUniformValue(m_matrix_id, state.combinedMatrix());
        }
    }
}

static void appendPin(int subdivisions, float radius, float length, const QColor &col, GeometryData* geom, const QMatrix4x4 &transform = QMatrix4x4())
{
    Q_ASSERT(subdivisions >= 3);

    GeometryData temp;
    temp.setDataFormat(GeometryData::PositionNormalColor);

    // Create vertices at the end of the pin.
    // These have x = 1, and y and z vary.
    float angleDelta = 1.0f/(float)subdivisions;
    for ( int i = 0; i < subdivisions; i++ )
    {
        float rot = i * angleDelta * 2.0f * M_PI;
        float yDisplacement = (float)radius * qCos(rot);
        float zDisplacement = (float)radius * qSin(rot);

        // TODO: Normal
        temp.appendVertex(QVector3D(length, yDisplacement, zDisplacement), QVector3D(), col);
    }

    // Create the origin vertex.
    temp.appendVertex(QVector3D(0,0,0), QVector3D(), col);

    // Create each of the outer faces.
    int originIndex = temp.vertexCount() - 1;
    for ( int i = 0; i < subdivisions; i++ )
    {
        int index0 = i;
        int index1 = i == (subdivisions - 1) ? 0 : i+1;
        temp.appendIndexTriangle(originIndex, index1, index0);
    }

    // Create the end face.
    for ( int i = 1; i < subdivisions-1; i++ )
    {
        temp.appendIndexTriangle(0, i, i+1);
    }

    if ( !transform.isIdentity() )
    {
        temp.transform(transform);
    }

    geom->append(temp);
}

QDebug operator<<(QDebug d, const QSGTransformNode *n)
{
    if (!n) {
        d << "TransformNode(null)";
        return d;
    }
    const QMatrix4x4 m = n->matrix();
    d << "TransformNode(";
    d << hex << (const void *) n << dec;
    if (m.isIdentity())
        d << "identity";
    else if (m.determinant() == 1 && m(0, 0) == 1 && m(1, 1) == 1 && m(2, 2) == 1)
        d << "translate" << m(0, 3) << m(1, 3) << m(2, 3);
    else
        d << "det=" << n->matrix().determinant();
#ifdef QSG_RUNTIME_DESCRIPTION
    d << QSGNodePrivate::description(n);
#endif
    d << (n->isSubtreeBlocked() ? "*BLOCKED*" : "");
    d << ')';
    return d;
}