ProgramUniformBlock.h

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/*********************************************************\
 *  File: ProgramUniformBlock.h                          *
 *
 *  Copyright (C) 2002-2012 The PixelLight Team (http://www.pixellight.org/)
 *
 *  This file is part of PixelLight.
 *
 *  PixelLight 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 3 of the License, or
 *  (at your option) any later version.
 *
 *  PixelLight 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
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with PixelLight. If not, see <http://www.gnu.org/licenses/>.
\*********************************************************/


#ifndef __PLRENDERER_PROGRAMUNIFORMBLOCK_H__
#define __PLRENDERER_PROGRAMUNIFORMBLOCK_H__
#pragma once


//[-------------------------------------------------------]
//[ Includes                                              ]
//[-------------------------------------------------------]
#include "PLRenderer/PLRenderer.h"


//[-------------------------------------------------------]
//[ Forward declarations                                  ]
//[-------------------------------------------------------]
namespace PLCore {
    class String;
}
namespace PLRenderer {
    class UniformBuffer;
}


//[-------------------------------------------------------]
//[ Namespace                                             ]
//[-------------------------------------------------------]
namespace PLRenderer {


//[-------------------------------------------------------]
//[ Classes                                               ]
//[-------------------------------------------------------]
/**
*  @brief
*    Abstract renderer program uniform block
*
*  @remarks
*    The behavior of the "SetUniformBuffer()"-method depends on the used internal shader API. When using Cg,
*    a call of the "SetUniformBuffer()"-method has only an effect when then program is going to be set in the
*    near future - meaning it has no effect when the program, the uniform block is part of, is already the program
*    currently used for rendering. When using GLSL, the "SetUniformBuffer()"-method is accessing a global UBO
*    binding point, meaning that it doesn't matter whether or not the program, the uniform block is part of, is
*    currently used for rendering. For performance reasons, this abstract program uniform block interface can't
*    compensate those differences. It has to be as lightweight as possible in order to keep the interface performance
*    impact as low as possible. So, to be on the safe side, do only call the "SetUniformBuffer()"-method if the program,
*    the uniform block is part of, is currently not used for rendering.
*
*  @note
*    - Do only call the "SetUniformBuffer()"-method when the program, the uniform block is part of, is currently not used for rendering
*/
class ProgramUniformBlock {


    //[-------------------------------------------------------]
    //[ Public virtual ProgramUniformBlock functions          ]
    //[-------------------------------------------------------]
    public:
        /**
        *  @brief
        *    Sets the uniform buffer feeding this uniform block with data
        *
        *  @param[in] pUniformBuffer
        *    The uniform buffer feeding this uniform block with data, can be a null pointer
        *  @param[in] nBindingPoint
        *    Binding point to use
        *
        *  @return
        *    'true' if all went fine, else 'false' (maybe the number of bytes within the given uniform buffer
        *    is less than the number of bytes within this uniform block or there's a shader language mismatch)
        *
        *  @remarks
        *    The binding point is somewhat similar a texture unit. The total number of binding points
        *    which can be used at the same time during rendering are limited to e.g. 45 (just an example!)
        *    binding points.
        */
        virtual bool SetUniformBuffer(UniformBuffer *pUniformBuffer, PLCore::uint32 nBindingPoint) = 0;

        /**
        *  @brief
        *    Returns the uniform block index
        *
        *  @return
        *    The uniform block index
        */
        virtual PLCore::uint32 GetIndex() const = 0;

        /**
        *  @brief
        *    Returns the uniform block data size (in bytes)
        *
        *  @return
        *    The uniform block data size (in bytes)
        */
        virtual PLCore::uint32 GetSize() const = 0;

        /**
        *  @brief
        *    Returns the offset (in bytes) of an uniform inside the uniform block
        *
        *  @param[in] sUniformName
        *    Name of the uniform
        *
        *  @return
        *    The offset (in bytes) of an uniform inside the uniform block
        */
        virtual PLCore::uint32 GetUniformOffset(const PLCore::String &sUniformName) const = 0;

        /**
        *  @brief
        *    Returns the size (in bytes) of an uniform inside the uniform block
        *
        *  @return
        *    The size (in bytes) of an uniform inside the uniform block
        */
        virtual PLCore::uint32 GetUniformSize(const PLCore::String &sUniformName) const = 0;

        /**
        *  @brief
        *    Returns the number of array elements of an uniform inside the uniform block
        *
        *  @return
        *    The number of array elements of an uniform inside the uniform block, 1 for none array uniforms
        */
        virtual PLCore::uint32 GetUniformNumOfArrayElements(const PLCore::String &sUniformName) const = 0;


    //[-------------------------------------------------------]
    //[ Protected functions                                   ]
    //[-------------------------------------------------------]
    protected:
        /**
        *  @brief
        *    Constructor
        */
        PLRENDERER_API ProgramUniformBlock();

        /**
        *  @brief
        *    Destructor
        */
        PLRENDERER_API virtual ~ProgramUniformBlock();


    //[-------------------------------------------------------]
    //[ Private functions                                     ]
    //[-------------------------------------------------------]
    private:
        /**
        *  @brief
        *    Copy constructor
        *
        *  @param[in] cSource
        *    Source to copy from
        */
        ProgramUniformBlock(const ProgramUniformBlock &cSource);

        /**
        *  @brief
        *    Copy operator
        *
        *  @param[in] cSource
        *    Source to copy from
        *
        *  @return
        *    Reference to this instance
        */
        ProgramUniformBlock &operator =(const ProgramUniformBlock &cSource);


};


//[-------------------------------------------------------]
//[ Namespace                                             ]
//[-------------------------------------------------------]
} // PLRenderer


#endif // __PLRENDERER_PROGRAMUNIFORMBLOCK_H__