QSGGeometry Class

struct MyPoint2D {
    float x;
    float y;
    float r;
    float g;
    float b;
    float a;

    void set(float x_, float y_, float r_, float g_, float b_, float a_) {
        x = x_;
        y = y_;
        r = r_;
        g = g_;
        b = b_;
        a = a_;
    }
};

QSGGeometry::Attribute MyPoint2D_Attributes[] = {
    QSGGeometry::Attribute::create(0, 2, GL_FLOAT, true),
    QSGGeometry::Attribute::create(1, 4, GL_FLOAT, false)
};

QSGGeometry::AttributeSet MyPoint2D_AttributeSet = {
    2,
    sizeof(MyPoint2D),
    MyPoint2D_Attributes
};

...

geometry = new QSGGeometry(MyPoint2D_AttributeSet, 2);
geometry->setDrawingMode(GL_LINES);

MyPoint2D *vertices = static_cast<MyPoint2D *>(geometry->vertexData());
vertices[0].set(0, 0, 1, 0, 0, 1);
vertices[1].set(width(), height(), 0, 0, 1, 1);

Member Function Documentation

QSGGeometry::QSGGeometry(const QSGGeometry::AttributeSet &attributes, int vertexCount, int indexCount = 0, int indexType = UnsignedShortType)

Constructs a geometry object based on attributes.

The object allocate space for vertexCount vertices based on the accumulated size in attributes and for indexCount.

The indexType maps to the OpenGL index type and can be GL_UNSIGNED_SHORT and GL_UNSIGNED_BYTE. On OpenGL implementations that support it, such as desktop OpenGL, GL_UNSIGNED_INT can also be used.

Geometry objects are constructed with GL_TRIANGLE_STRIP as default drawing mode.

The attribute structure is assumed to be POD and the geometry object assumes this will not go away. There is no memory management involved.

[virtual] QSGGeometry::~QSGGeometry()

Destroys the geometry object and the vertex and index data it has allocated.

void QSGGeometry::allocate(int vertexCount, int indexCount = 0)

Resizes the vertex and index data of this geometry object to fit vertexCount vertices and indexCount indices.

Vertex and index data will be invalidated after this call and the caller must mark the associated geometry node as dirty, by calling node->markDirty(QSGNode::DirtyGeometry) to ensure that the renderer has a chance to update internal buffers.

int QSGGeometry::attributeCount() const

Returns the number of attributes in the attrbute set used by this geometry.

const QSGGeometry::Attribute *QSGGeometry::attributes() const

Returns an array with the attributes of this geometry. The size of the array is given with attributeCount().

[static] const QSGGeometry::AttributeSet &QSGGeometry::defaultAttributes_ColoredPoint2D()

Convenience function which returns attributes to be used for per vertex colored 2D drawing.

[static] const QSGGeometry::AttributeSet &QSGGeometry::defaultAttributes_Point2D()

Convenience function which returns attributes to be used for 2D solid color drawing.

[static] const QSGGeometry::AttributeSet &QSGGeometry::defaultAttributes_TexturedPoint2D()

Convenience function which returns attributes to be used for textured 2D drawing.

unsigned int QSGGeometry::drawingMode() const

Returns the drawing mode of this geometry.

The default value is GL_TRIANGLE_STRIP.

See also setDrawingMode().

int QSGGeometry::indexCount() const

Returns the number of indices in this geometry object.

void *QSGGeometry::indexData()

Returns a pointer to the raw index data of this geometry object.

See also indexDataAsUShort() and indexDataAsUInt().

const void *QSGGeometry::indexData() const

Returns a pointer to the raw index data of this geometry object.

See also indexDataAsUShort() and indexDataAsUInt().

uint *QSGGeometry::indexDataAsUInt()

Convenience function to access the index data as a mutable array of 32-bit unsigned integers.

const uint *QSGGeometry::indexDataAsUInt() const

Convenience function to access the index data as an immutable array of 32-bit unsigned integers.

quint16 *QSGGeometry::indexDataAsUShort()

Convenience function to access the index data as a mutable array of 16-bit unsigned integers.

const quint16 *QSGGeometry::indexDataAsUShort() const

Convenience function to access the index data as an immutable array of 16-bit unsigned integers.

QSGGeometry::DataPattern QSGGeometry::indexDataPattern() const

Returns the usage pattern for indices in this geometry. The default pattern is AlwaysUploadPattern.

See also setIndexDataPattern().

int QSGGeometry::indexType() const

Returns the primitive type used for indices in this geometry object.

float QSGGeometry::lineWidth() const

Gets the current line or point width or to be used for this geometry. This property only applies to line width when the drawingMode is DrawLines, DarwLineStrip, or DrawLineLoop. For desktop OpenGL, it also applies to point size when the drawingMode is DrawPoints.

The default value is 1.0

Note: When not using OpenGL, support for point and line drawing may be limited. For example, some APIs do not support point sprites and so setting a size other than 1 is not possible. Some backends may be able implement support via geometry shaders, but this is not guaranteed to be always available.

See also setLineWidth() and drawingMode().

void QSGGeometry::markIndexDataDirty()

Mark that the vertices in this geometry has changed and must be uploaded again.

This function only has an effect when the usage pattern for vertices is StaticData and the renderer that renders this geometry uploads the geometry into Vertex Buffer Objects (VBOs).

void QSGGeometry::markVertexDataDirty()

Mark that the vertices in this geometry has changed and must be uploaded again.

This function only has an effect when the usage pattern for vertices is StaticData and the renderer that renders this geometry uploads the geometry into Vertex Buffer Objects (VBOs).

void QSGGeometry::setDrawingMode(unsigned int mode)

Sets the mode to be used for drawing this geometry.

The default value is QSGGeometry::DrawTriangleStrip.

See also drawingMode() and DrawingMode.

void QSGGeometry::setIndexDataPattern(QSGGeometry::DataPattern p)

Sets the usage pattern for indices to p.

The default is AlwaysUploadPattern. When set to anything other than the default, the user must call markIndexDataDirty() after changing the index data, in addition to calling QSGNode::markDirty() with QSGNode::DirtyGeometry.

See also indexDataPattern().

void QSGGeometry::setLineWidth(float width)

Sets the line or point width to be used for this geometry to width. This property only applies to line width when the drawingMode is DrawLines, DrawLineStrip, or DrawLineLoop. For Desktop OpenGL, it also applies to point size when the drawingMode is DrawPoints.

Note: How line width and point size are treated is implementation dependent: The application should not rely on these, but rather create triangles or similar to draw areas. On OpenGL ES, line width support is limited and point size is unsupported.

See also lineWidth() and drawingMode().

void QSGGeometry::setVertexDataPattern(QSGGeometry::DataPattern p)

Sets the usage pattern for vertices to p.

The default is AlwaysUploadPattern. When set to anything other than the default, the user must call markVertexDataDirty() after changing the vertex data, in addition to calling QSGNode::markDirty() with QSGNode::DirtyGeometry.

See also vertexDataPattern().

int QSGGeometry::sizeOfIndex() const

Returns the byte size of the index type.

This value is either 1 when index type is GL_UNSIGNED_BYTE or 2 when index type is GL_UNSIGNED_SHORT. For Desktop OpenGL, GL_UNSIGNED_INT with the value 4 is also supported.

int QSGGeometry::sizeOfVertex() const

Returns the size in bytes of one vertex.

This value comes from the attributes.

[static] void QSGGeometry::updateColoredRectGeometry(QSGGeometry *g, const QRectF &rect)

Updates the geometry g with the coordinates in rect.

The function assumes the geometry object contains a single triangle strip of QSGGeometry::ColoredPoint2D vertices

[static] void QSGGeometry::updateRectGeometry(QSGGeometry *g, const QRectF &rect)

Updates the geometry g with the coordinates in rect.

The function assumes the geometry object contains a single triangle strip of QSGGeometry::Point2D vertices

[static] void QSGGeometry::updateTexturedRectGeometry(QSGGeometry *g, const QRectF &rect, const QRectF &textureRect)

Updates the geometry g with the coordinates in rect and texture coordinates from textureRect.

textureRect should be in normalized coordinates.

g is assumed to be a triangle strip of four vertices of type QSGGeometry::TexturedPoint2D.

int QSGGeometry::vertexCount() const

Returns the number of vertices in this geometry object.

void *QSGGeometry::vertexData()

Returns a pointer to the raw vertex data of this geometry object.

See also vertexDataAsPoint2D() and vertexDataAsTexturedPoint2D().

const void *QSGGeometry::vertexData() const

Returns a pointer to the raw vertex data of this geometry object.

See also vertexDataAsPoint2D() and vertexDataAsTexturedPoint2D().

QSGGeometry::ColoredPoint2D *QSGGeometry::vertexDataAsColoredPoint2D()

Convenience function to access the vertex data as a mutable array of QSGGeometry::ColoredPoint2D.

const QSGGeometry::ColoredPoint2D *QSGGeometry::vertexDataAsColoredPoint2D() const

Convenience function to access the vertex data as an immutable array of QSGGeometry::ColoredPoint2D.

QSGGeometry::Point2D *QSGGeometry::vertexDataAsPoint2D()

Convenience function to access the vertex data as a mutable array of QSGGeometry::Point2D.

const QSGGeometry::Point2D *QSGGeometry::vertexDataAsPoint2D() const

Convenience function to access the vertex data as an immutable array of QSGGeometry::Point2D.

QSGGeometry::TexturedPoint2D *QSGGeometry::vertexDataAsTexturedPoint2D()

Convenience function to access the vertex data as a mutable array of QSGGeometry::TexturedPoint2D.

const QSGGeometry::TexturedPoint2D *QSGGeometry::vertexDataAsTexturedPoint2D() const

Convenience function to access the vertex data as an immutable array of QSGGeometry::TexturedPoint2D.

QSGGeometry::DataPattern QSGGeometry::vertexDataPattern() const

Returns the usage pattern for vertices in this geometry. The default pattern is AlwaysUploadPattern.

See also setVertexDataPattern().