C++ Box3f::intersects方法代码示例

void ViewportGadget::trackDrag( const DragDropEvent &event )
{
	// early out if tracking is off for any reason.

	if( !getDragTracking() || !getCameraEditable() )
	{
		m_dragTrackingIdleConnection.disconnect();
		return;
	}

	// we automatically scroll to track drags when the mouse is
	// near the edge of our viewport. figure out an inset box within
	// which we _don't_ perform tracking - if the mouse leaves this then
	// we'll track it.

	const V2i viewport = getViewport();
	const float borderWidth = std::min( std::min( viewport.x, viewport.y ) / 8.0f, 60.0f );

	const Box3f viewportBox(
		V3f( borderWidth, borderWidth, -1000.0f ),
		V3f( viewport.x - borderWidth, viewport.y - borderWidth, 1000.0f )
	);

	// figure out the offset, if any, of the mouse outside this central box.

	V2f offset( 0.0f );
	if( !viewportBox.intersects( event.line.p0 ) )
	{
		const V3f offset3 = event.line.p0 - closestPointOnBox( event.line.p0, viewportBox );
		offset = V2f( offset3.x, offset3.y );
	}

	const float offsetLength = clamp( offset.length(), 0.0f, borderWidth );

	// update our tracking threshold. the mouse has to go past this offset before
	// tracking starts. this allows us to avoid tracking too early when a drag is
	// started inside the tracking area, but the user is dragging back into the
	// center of frame.

	m_dragTrackingThreshold = std::min( offsetLength, m_dragTrackingThreshold );

	// figure out our drag velocity. we ramp up the speed of the scrolling from 0
	// to a maximum at the edge of the viewport, and clamp it so it doesn't get any
	// faster outside of the viewport. although getting even faster when the mouse
	// is outside the viewport might be nice, it results in an inconsistent
	// experience where a viewport edge is at the edge of the screen and the mouse
	// can't go any further.

	m_dragTrackingVelocity = -offset.normalized() * borderWidth * lerpfactor( offsetLength, m_dragTrackingThreshold, borderWidth );

	// we don't actually do the scrolling in this function - instead we ensure that
	// trackDragIdle will be called to apply the scrolling on idle events.
	// this allows the scrolling to happen even when the mouse isn't moving.

	if( m_dragTrackingVelocity.length() > 0.0001 )
	{
		m_dragTrackingEvent = event;
		if( !m_dragTrackingIdleConnection.connected() )
		{
			m_dragTrackingTime = currentTime();
			m_dragTrackingIdleConnection = idleSignal().connect( boost::bind( &ViewportGadget::trackDragIdle, this ) );
		}
	}
	else
	{
		m_dragTrackingIdleConnection.disconnect();
	}
}