BlendState.h

/*     Copyright 2015-2018 Egor Yusov
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 *  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 OF ANY PROPRIETARY RIGHTS.
 *
 *  In no event and under no legal theory, whether in tort (including negligence), 
 *  contract, or otherwise, unless required by applicable law (such as deliberate 
 *  and grossly negligent acts) or agreed to in writing, shall any Contributor be
 *  liable for any damages, including any direct, indirect, special, incidental, 
 *  or consequential damages of any character arising as a result of this License or 
 *  out of the use or inability to use the software (including but not limited to damages 
 *  for loss of goodwill, work stoppage, computer failure or malfunction, or any and 
 *  all other commercial damages or losses), even if such Contributor has been advised 
 *  of the possibility of such damages.
 */

#pragma once


#include "BasicTypes.h"

namespace Diligent
{


enum BLEND_FACTOR : Int8
{
    BLEND_FACTOR_UNDEFINED = 0,

    BLEND_FACTOR_ZERO,

    BLEND_FACTOR_ONE,

    BLEND_FACTOR_SRC_COLOR,

    BLEND_FACTOR_INV_SRC_COLOR,

    BLEND_FACTOR_SRC_ALPHA,

    BLEND_FACTOR_INV_SRC_ALPHA,

    BLEND_FACTOR_DEST_ALPHA,

    BLEND_FACTOR_INV_DEST_ALPHA,

    BLEND_FACTOR_DEST_COLOR,

    BLEND_FACTOR_INV_DEST_COLOR,

    BLEND_FACTOR_SRC_ALPHA_SAT,

    BLEND_FACTOR_BLEND_FACTOR,

    BLEND_FACTOR_INV_BLEND_FACTOR,

    BLEND_FACTOR_SRC1_COLOR,

    BLEND_FACTOR_INV_SRC1_COLOR,

    BLEND_FACTOR_SRC1_ALPHA,

    BLEND_FACTOR_INV_SRC1_ALPHA, 

    BLEND_FACTOR_NUM_FACTORS
};


enum BLEND_OPERATION : Int8
{
    BLEND_OPERATION_UNDEFINED = 0,
    
    BLEND_OPERATION_ADD,

    BLEND_OPERATION_SUBTRACT,

    BLEND_OPERATION_REV_SUBTRACT,

    BLEND_OPERATION_MIN,

    BLEND_OPERATION_MAX,

    BLEND_OPERATION_NUM_OPERATIONS
};


enum COLOR_MASK : Int32
{
    COLOR_MASK_RED      = 1,

    COLOR_MASK_GREEN    = 2,

    COLOR_MASK_BLUE     = 4,

    COLOR_MASK_ALPHA    = 8,

    COLOR_MASK_ALL  = ( ( ( COLOR_MASK_RED | COLOR_MASK_GREEN )  | COLOR_MASK_BLUE )  | COLOR_MASK_ALPHA ) 
};



enum LOGIC_OPERATION : Int8
{
    LOGIC_OP_CLEAR = 0,

    LOGIC_OP_SET,

    LOGIC_OP_COPY,

    LOGIC_OP_COPY_INVERTED,

    LOGIC_OP_NOOP,

    LOGIC_OP_INVERT,

    LOGIC_OP_AND,

    LOGIC_OP_NAND,

    LOGIC_OP_OR,

    LOGIC_OP_NOR,

    LOGIC_OP_XOR,

    LOGIC_OP_EQUIV,

    LOGIC_OP_AND_REVERSE,

    LOGIC_OP_AND_INVERTED,

    LOGIC_OP_OR_REVERSE,

    LOGIC_OP_OR_INVERTED,

    LOGIC_OP_NUM_OPERATIONS
};


struct RenderTargetBlendDesc
{
    Bool            BlendEnable;

    Bool            LogicOperationEnable;

    BLEND_FACTOR    SrcBlend;

    BLEND_FACTOR    DestBlend;

    BLEND_OPERATION BlendOp;

    BLEND_FACTOR    SrcBlendAlpha;

    BLEND_FACTOR    DestBlendAlpha;

    BLEND_OPERATION BlendOpAlpha;

    LOGIC_OPERATION LogicOp;

    Uint32          RenderTargetWriteMask;


    RenderTargetBlendDesc() :
        BlendEnable     ( False ),
        LogicOperationEnable(False),
        SrcBlend        ( BLEND_FACTOR_ONE ),
        DestBlend       ( BLEND_FACTOR_ZERO ),
        BlendOp         ( BLEND_OPERATION_ADD ),
        SrcBlendAlpha   ( BLEND_FACTOR_ONE ),
        DestBlendAlpha  ( BLEND_FACTOR_ZERO ),
        BlendOpAlpha    ( BLEND_OPERATION_ADD ),
        LogicOp         ( LOGIC_OP_NOOP ),
        RenderTargetWriteMask( COLOR_MASK_ALL )
    {}



    bool operator == (const RenderTargetBlendDesc& rhs)const
    {
        return BlendEnable           == rhs.BlendEnable    &&
               LogicOperationEnable  == rhs.LogicOperationEnable &&
               SrcBlend              == rhs.SrcBlend       &&
               DestBlend             == rhs.DestBlend      &&
               BlendOp               == rhs.BlendOp        &&
               SrcBlendAlpha         == rhs.SrcBlendAlpha  &&
               DestBlendAlpha        == rhs.DestBlendAlpha &&
               BlendOpAlpha          == rhs.BlendOpAlpha   &&
               LogicOp               == rhs.LogicOp        &&
               RenderTargetWriteMask == rhs.RenderTargetWriteMask;
    }
};


struct BlendStateDesc
{
    Bool AlphaToCoverageEnable;

    Bool IndependentBlendEnable;

    static constexpr int MaxRenderTargets = 8;

    RenderTargetBlendDesc RenderTargets[MaxRenderTargets];


    BlendStateDesc() : 
        AlphaToCoverageEnable(False),
        IndependentBlendEnable(False)
    {
    }
    

    bool operator == (const BlendStateDesc& RHS)const
    {
        bool bRTsEqual = true;
        for( int i = 0; i < MaxRenderTargets; ++i )
            if( !(RenderTargets[i] == RHS.RenderTargets[i]) )
            {
                bRTsEqual = false;
                break;
            }

        return  bRTsEqual &&
                AlphaToCoverageEnable == RHS.AlphaToCoverageEnable &&
                IndependentBlendEnable== RHS.IndependentBlendEnable;
    }
};

}