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Implemented a more flexible blending system (fixes #298)

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This commit is contained in:
Thomas Galvin 2014-01-20 20:52:45 -05:00
parent 4a300547f3
commit 951b774c70
4 changed files with 293 additions and 42 deletions
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151
include/SFML/Graphics/BlendMode.hpp
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@ -25,22 +25,161 @@
#ifndef SFML_BLENDMODE_HPP
#define SFML_BLENDMODE_HPP
////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/Graphics/Export.hpp>
namespace sf
{
////////////////////////////////////////////////////////////
/// \ingroup graphics
/// \brief Available blending modes for drawing
/// \brief Blending modes for drawing
///
////////////////////////////////////////////////////////////
enum BlendMode
struct SFML_GRAPHICS_API BlendMode
{
BlendAlpha, ///< Pixel = Source * Source.a + Dest * (1 - Source.a)
BlendAdd, ///< Pixel = Source + Dest
BlendMultiply, ///< Pixel = Source * Dest
BlendNone ///< Pixel = Source
////////////////////////////////////////////////////////
/// \ingroup graphics
/// \brief Enumeration of the blending factors
///
////////////////////////////////////////////////////////
enum BlendFactor
{
Zero, ///< (0,0,0,0)
One, ///< (1,1,1,1)
SrcColor, ///< (src.r,src.g,src.b,src.a)
OneMinusSrcColor, ///< (1,1,1,1) - (src.r,src.g,src.b,src.a)
DstColor, ///< (dst.r,dst.g,dst.b,dst.a)
OneMinusDstColor, ///< (1,1,1,1) - (dst.r,dst.g,dst.b,dst.a)
SrcAlpha, ///< (src.a,src.a,src.a,src.a)
OneMinusSrcAlpha, ///< (1,1,1,1) - (src.a,src.a,src.a,src.a)
DstAlpha, ///< (dst.a,dst.a,dst.a,dst.a)
OneMinusDstAlpha, ///< (1,1,1,1) - (dst.a,dst.a,dst.a,dst.a)
};
////////////////////////////////////////////////////////
/// \ingroup graphics
/// \brief Enumeration of the blending equations
///
////////////////////////////////////////////////////////
enum BlendEquation
{
Add, ///< Pixel = Source * SourceFactor + Dst * DstFactor
Subtract, ///< Pixel = Source * SourceFactor - Dst * DstFactor
};
////////////////////////////////////////////////////////////
/// \brief Default constructor
///
/// Constructs a blending mode that does alpha blending.
///
////////////////////////////////////////////////////////////
BlendMode();
////////////////////////////////////////////////////////////
/// \brief Construct the blend mode given the factors and equation.
///
/// \param colorSourceFactor Specifies how to compute the source factor for the color channels.
/// \param colorDstFactor Specifies how to compute the destination factor for the color channels.
/// \param colorBlendEquation Specifies how to combine the source and destination colors.
/// \param alphaSourceFactor Specifies how to compute the source factor.
/// \param alphaDstFactor Specifies how to compute the destination factor.
/// \param alphaBlendEquation Specifies how to combine the source and destination alphas.
///
///
////////////////////////////////////////////////////////////
BlendMode(BlendFactor colorSourceFactor, BlendFactor colorDstFactor,
BlendEquation colorBlendEquation, BlendFactor alphaSourceFactor,
BlendFactor alphaDstFactor, BlendEquation alphaBlendEquation);
////////////////////////////////////////////////////////////
// Member Data
////////////////////////////////////////////////////////////
BlendFactor colorSrcFactor; ///< Source blending factor for the color channels
BlendFactor colorDstFactor; ///< Destination blending factor for the color channels
BlendEquation colorEquation; ///< Blending equation for the color channels
BlendFactor alphaSrcFactor; ///< Source blending factor for the alpha channel
BlendFactor alphaDstFactor; ///< Destination blending factor for the alpha channel
BlendEquation alphaEquation; ///< Blending equation for the alpha channel
};
////////////////////////////////////////////////////////////
/// \relates BlendMode
/// \brief Overload of the == operator
///
/// This operator compares two blending modes and checks if they are equal.
///
/// \param left Left operand
/// \param right Right operand
///
/// \return True if blending modes are equal, false if they are different
///
////////////////////////////////////////////////////////////
SFML_GRAPHICS_API bool operator ==(const BlendMode& left, const BlendMode& right);
////////////////////////////////////////////////////////////
/// \relates BlendMode
/// \brief Overload of the != operator
///
/// This operator compares two blending modes and checks if they are different.
///
/// \param left Left operand
/// \param right Right operand
///
/// \return True if blending modes are different, false if they are equal
///
////////////////////////////////////////////////////////////
SFML_GRAPHICS_API bool operator !=(const BlendMode& left, const BlendMode& right);
////////////////////////////////////////////////////////////
// Commonly used blending modes
////////////////////////////////////////////////////////////
SFML_GRAPHICS_API extern const BlendMode BlendAlpha;
SFML_GRAPHICS_API extern const BlendMode BlendAdd;
SFML_GRAPHICS_API extern const BlendMode BlendMultiply;
SFML_GRAPHICS_API extern const BlendMode BlendNone;
} // namespace sf
#endif // SFML_BLENDMODE_HPP
////////////////////////////////////////////////////////////
/// \class sf::BlendMode
/// \ingroup graphics
///
/// sf::BlendMode is a class that represents a blend mode. A
/// blend mode is composed of 6 components:
/// \li %Color Source Factor (colorSrcFactor)
/// \li %Color Destination Factor (colorDstFactor)
/// \li %Color Blend Equation (colorEquation)
/// \li Alpha Source Factor (alphaSrcFactor)
/// \li Alpha Destination Factor (alphaDstFactor)
/// \li Alpha Blend Equation (alphaEquation)
///
/// Each component has its own setter function. These make
/// modifying a blending mode rather easy:
///
/// \code
/// sf::BlendMode blendMode; // Standard alpha blending
/// blendMode.colorSrcFactor = sf::BlendMode::One; // Pre-multiplied alpha blending
/// blendMode.colorEquation = sf::BlendMode::Subtract; // An exotic subtraction blending mode
/// \endcode
///
/// The most common blending modes are defined as const
/// variables for convenience and compatibility with older
/// code:
///
/// \code
/// sf::BlendMode alphaBlending = sf::BlendAlpha;
/// sf::BlendMode additiveBlending = sf::BlendAdd;
/// sf::BlendMode multiplicativeBlending = sf::BlendMultipy;
/// sf::BlendMode noBlending = sf::BlendNone;
/// \endcode
///
////////////////////////////////////////////////////////////