OpenSceneGraph/include/osg/ImageTexture

/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
 *
 * This library is open source and may be redistributed and/or modified under
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * OpenSceneGraph Public License for more details.
*/
/// author: Julien Valentin 2017 (mp3butcher@hotmail.com) 

#ifndef _GLImageUnitBinding_H
#define _GLImageUnitBinding_H

#include <osg/Export>
#include <osg/Texture>

namespace osg{
    /** Bind texture to an image unit (available only if GL version is 4.2 or greater)
    * The format parameter for the image unit need not exactly match the texture internal format,
    * but if it is set to 0, the texture internal format will be used.
    * See http://www.opengl.org/registry/specs/ARB/shader_image_load_store.txt
    * void bindToImageUnit(unsigned int unit, GLenum access, GLenum format=0, int level=0, bool layered=false, int layer=0);
    **/
    class OSG_EXPORT ImageTextureBinding : public osg::StateAttribute {
        public:
            /** Type of access that will be performed on the texture image. */
            enum ImageAccess
            {
                 NOT_USED = 0,
                 READ_ONLY = GL_READ_ONLY_ARB,
                 WRITE_ONLY = GL_WRITE_ONLY_ARB,
                 READ_WRITE = GL_READ_WRITE_ARB
            };

            ImageTextureBinding(
                            GLuint imageunit = 0,
                            osg::Texture* target = 0,
                            ImageAccess access = READ_ONLY,
                            GLenum format = GL_RGBA8,
                            int level = 0,
                            bool layered = GL_FALSE,
                            int layer = 0) : osg::StateAttribute(), 
                _target(target),
                _imageunit(imageunit),
                _level(level),
                _layered(layered),
                _layer(layer),
                _access(access),
                _format(format) {}

            ImageTextureBinding( const  ImageTextureBinding&o,osg::CopyOp op=osg::CopyOp::SHALLOW_COPY):
                osg::StateAttribute(o,op),
                _target(o._target),
                _imageunit(o._imageunit),
                _level(o._level),
                _layered(o._layered),
                _layer(o._layer),
                _access(o._access),
                _format(o._format) {}
        
            virtual ~ImageTextureBinding() {}

            META_StateAttribute(osg,ImageTextureBinding, IMAGETEXTURE)

            GLuint getImageUnit() const { return _imageunit; }
            void setImageUnit(GLuint i) { _imageunit=i; }

            GLint getLevel() const { return _level; }
            void setLevel(GLint i) { _level=i; }

            GLboolean getIsLayered() const { return _layered; }
            void setIsLayered( GLboolean i) { _layered=i; }

            GLint getLayer() const { return _layer; }
            void setLayer(GLint i) { _layer=i; }

            GLenum getAccess()const { return _access; }
            void setAccess(ImageAccess i) { _access=i; }

            GLenum getFormat()const { return _format; }
            void setFormat(GLenum i) { _format=i; }

            const osg::Texture *getTexture() const { return _target.get();}
            void setTexture(osg::Texture* target) { _target=target; }

            virtual void apply(osg::State&state) const;

            virtual int compare(const osg::StateAttribute &sa) const;

            virtual unsigned getMember() const { return static_cast<unsigned int>(_imageunit); }
        
        protected:
            osg::ref_ptr<osg::Texture> _target;
            GLuint _imageunit;
            GLint _level;
            GLboolean _layered;
            GLint _layer;
            GLenum _access;
            GLenum _format;

    };
}
#endif