/* -*-c++-*- */
/* osgEarth - Geospatial SDK for OpenSceneGraph
* Copyright 2018 Pelican Mapping
* http://osgearth.org
*
* osgEarth is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>
*/
#ifndef OSGEARTHUTIL_GLSL_COLOR_FILTER
#define OSGEARTHUTIL_GLSL_COLOR_FILTER

#include <osgEarthUtil/Common>
#include <osgEarth/ColorFilter>
#include <osg/Shader>

namespace osgEarth { namespace Util
{
    /**
     * Color filter that lets you inject custom GLSL code.
     */
    class OSGEARTHUTIL_EXPORT GLSLColorFilter : public osgEarth::ColorFilter
    {
    public:
        GLSLColorFilter();
        GLSLColorFilter(const Config& conf);
        virtual ~GLSLColorFilter() { }

        void setType(const osg::Shader::Type& type) { _type = type; }
        const osg::Shader::Type& getType() const { return _type.get(); }

        void setEntryPointFunctionName(const std::string& name) { _functionName = name; }

        void setCode(const std::string& code) { _code = code; }
        const std::string& getCode() const { return _code; }

    public: // ColorFilter
        virtual std::string getEntryPointFunctionName() const;
        virtual void install(osg::StateSet* stateSet) const;
        virtual Config getConfig() const;

    protected:
        unsigned                    _instanceId;
        optional<osg::Shader::Type> _type;
        optional<std::string>       _functionName;
        std::string                 _code;
        
        void init();
    };

} } // namespace osgEarth::Util

#endif // OSGEARTHUTIL_GLSL_COLOR_FILTER
