/*

-----------------------------------------------------------------------------

This source file is part of OGRE

    (Object-oriented Graphics Rendering Engine)

For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2014 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy

of this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

copies of the Software, and to permit persons to whom the Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in

all copies or substantial portions of the Software.

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.

-----------------------------------------------------------------------------

*/

#ifndef __InstanceBatchHW_H__

#define __InstanceBatchHW_H__

#include "OgreInstanceBatch.h"

namespace Ogre

{

    /** \addtogroup Core

    *  @{

    */

    /** \addtogroup Scene

    *  @{

    */

    /** This is technique requires true instancing hardware support.

        Basically it creates a cloned vertex buffer from the original, with an extra buffer containing

        3 additional @c TEXCOORDS (12 bytes) repeated as much as the instance count.

        That will be used for each instance data.

        The main advantage of this technique is that it's <em>VERY</em> fast; but it doesn't support

        skeletal animation at all. Very reduced memory consumption and bandwidth. Great for particles,

        debris, bricks, trees, sprites.

        This batch is one of the few (if not the only) techniques that allows culling on an individual

        basis. This means we can save vertex shader performance for instances that aren't in scene or

        just not focused by the camera.

     */

    class _OgreExport InstanceBatchHW : public InstanceBatch

    {

        bool    mKeepStatic;

        void setupVertices( const SubMesh* baseSubMesh ) override;

        void setupIndices( const SubMesh* baseSubMesh ) override;

        bool checkSubMeshCompatibility( const SubMesh* baseSubMesh ) override;

        size_t updateVertexBuffer( Camera *currentCamera );

    public:

        InstanceBatchHW( InstanceManager *creator, MeshPtr &meshReference, const MaterialPtr &material,

                            size_t instancesPerBatch, const Mesh::IndexMap *indexToBoneMap,

                            const String &batchName );

        virtual ~InstanceBatchHW();

        /** @see InstanceBatch::calculateMaxNumInstances */

        size_t calculateMaxNumInstances( const SubMesh *baseSubMesh, uint16 flags ) const override;

        /** @see InstanceBatch::buildFrom */

        void buildFrom( const SubMesh *baseSubMesh, const RenderOperation &renderOperation ) override;

        /** Overloaded so that we don't perform needless updates when in static mode. Also doing that

            could cause glitches with shadow mapping (since Ogre thinks we're small/bigger than we

            really are when displaying, or that we're somewhere else)

        */

        void _boundsDirty(void) override;

        /** @see InstanceBatch::setStaticAndUpdate. While this flag is true, no individual per-entity

            cull check is made. This means if the camera is looking at only one instance, all instances

            are sent to the vertex shader (unlike when this flag is false). This saves a lot of CPU

            power and a bit of bus bandwidth.

        */

        void setStaticAndUpdate( bool bStatic ) override;

        bool isStatic() const override                       { return mKeepStatic; }

        //Renderable overloads

        void getWorldTransforms( Matrix4* xform ) const override;

        /** Overloaded to avoid updating skeletons (which we don't support), check visibility on a

            per unit basis and finally updated the vertex buffer */

        void _updateRenderQueue( RenderQueue* queue ) override;

    };

}

#endif