Create a simple ImageLayer of a given color

[sebalaig]

Hi,

I'm trying to create a uniform ImageLayer of a given color.
I tried by overriding createImageImplementation(const TileKey&, ProgressCallback* progress) but it crashes in TileLayer::openImplementation() while inserting layer. It looks like it is because the layer option is not defined properly, here is the call stask :

I do not know how to do that.
Could you help me please ? Thank you in advance for your help.

[gwaldron]

Can you show your layer's class definition please?

[sebalaig]

Thank you for your help :)
Here is my class definition :

class EmptyLayer : public osgEarth::ImageLayer
{
public:
    EmptyLayer() {}
    virtual ~EmptyLayer() {}

    osgEarth::GeoImage createImageImplementation(const osgEarth::TileKey&, osgEarth::ProgressCallback* progress) const override
    {
        osg::ref_ptr<osg::Image> image = new osg::Image();        
        image->allocateImage(1, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE);
        image->setColor(osg::Vec4(255, 0, 0, 255), 0, 0, 0);   // hardcoded red for now
        return GeoImage(image, key.getExtent());
    }
};

Best regards

[sebalaig]

I had to instanciate the option by calling the Layer constructor from the EmptyLayer constructor :

EmptyLayer::EmptyLayer(const osg::Vec4& color) :
    osgEarth::ImageLayer(new ImageLayer::Options(), nullptr),
    _color(color)
{
    ImageLayer::init();
}

I also had to call the ImageLayer::init() unless the _mutex was not instanciated and removing the layer led to a crash.

The following code is ok:

class PLUGINS_EXPORT EmptyLayer : public osgEarth::ImageLayer
{
    public:
        explicit EmptyLayer(const osg::Vec4& color);
        virtual ~EmptyLayer();

        osgEarth::Status openImplementation() override;
        osgEarth::GeoImage createImageImplementation(const osgEarth::TileKey&, osgEarth::ProgressCallback* progress) const override;

    private:
        osg::Vec4 _color;
};

EmptyLayer::EmptyLayer(const osg::Vec4& color) :
    osgEarth::ImageLayer(new ImageLayer::Options(), nullptr),
    _color(color)
{
    ImageLayer::init();
}

EmptyLayer::~EmptyLayer()
{
}

Status EmptyLayer::openImplementation()
{
    Status parent = ImageLayer::openImplementation();
    if (parent.isError())
        return parent;

    if (!getProfile())
    {
        setProfile(Profile::create(Profile::GLOBAL_GEODETIC));
    }

    return Status::NoError;
}

GeoImage EmptyLayer::createImageImplementation(const TileKey& key, ProgressCallback* progress) const
 {
    osg::ref_ptr<osg::Image> image = ImageUtils::createOnePixelImage(_color);

    return GeoImage(image.get(), key.getExtent());
}

Any feedback is welcomed ;)
Thank you in advance.