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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
///
////////////////////////////////////////////////////////////

93
src/SFML/Graphics/BlendMode.cpp Normal file
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@ -0,0 +1,93 @@
////////////////////////////////////////////////////////////
//
// SFML - Simple and Fast Multimedia Library
// Copyright (C) 2007-2013 Laurent Gomila (laurent.gom@gmail.com)
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
// you must not claim that you wrote the original software.
// If you use this software in a product, an acknowledgment
// in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
// and must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//
////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/Graphics/BlendMode.hpp>
#include <SFML/Graphics/GLCheck.hpp>
namespace sf
{
////////////////////////////////////////////////////////////
// Commonly used blending modes
////////////////////////////////////////////////////////////
const BlendMode BlendAlpha(BlendMode::SrcAlpha, BlendMode::OneMinusSrcAlpha, BlendMode::Add,
BlendMode::One, BlendMode::OneMinusSrcAlpha, BlendMode::Add);
const BlendMode BlendAdd(BlendMode::SrcAlpha, BlendMode::One, BlendMode::Add,
BlendMode::One, BlendMode::One, BlendMode::Add);
const BlendMode BlendMultiply(BlendMode::DstColor, BlendMode::Zero, BlendMode::Add,
BlendMode::DstColor, BlendMode::Zero, BlendMode::Add);
const BlendMode BlendNone(BlendMode::One, BlendMode::Zero, BlendMode::Add,
BlendMode::One, BlendMode::Zero, BlendMode::Add);
////////////////////////////////////////////////////////////
BlendMode::BlendMode() :
colorSrcFactor(BlendMode::SrcAlpha),
colorDstFactor(BlendMode::OneMinusSrcAlpha),
colorEquation (BlendMode::Add),
alphaSrcFactor(BlendMode::One),
alphaDstFactor(BlendMode::OneMinusSrcAlpha),
alphaEquation (BlendMode::Add)
{
}
////////////////////////////////////////////////////////////
BlendMode::BlendMode(BlendFactor colorSourceFactor, BlendFactor colorDstFactor,
BlendEquation colorBlendEquation, BlendFactor alphaSourceFactor,
BlendFactor alphaDstFactor, BlendEquation alphaBlendEquation) :
colorSrcFactor(colorSourceFactor),
colorDstFactor(colorDstFactor),
colorEquation (colorBlendEquation),
alphaSrcFactor(alphaSourceFactor),
alphaDstFactor(alphaDstFactor),
alphaEquation (alphaBlendEquation)
{
}
////////////////////////////////////////////////////////////
bool operator ==(const BlendMode& left, const BlendMode& right)
{
return (left.colorSrcFactor == right.colorSrcFactor) &&
(left.colorDstFactor == right.colorDstFactor) &&
(left.colorEquation == right.colorEquation) &&
(left.alphaSrcFactor == right.alphaSrcFactor) &&
(left.alphaDstFactor == right.alphaDstFactor) &&
(left.alphaEquation == right.alphaEquation);
}
////////////////////////////////////////////////////////////
bool operator !=(const BlendMode& left, const BlendMode& right)
{
return !(left == right);
}
} // namespace sf

7
src/SFML/Graphics/CMakeLists.txt
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@ -4,6 +4,7 @@ set(SRCROOT ${PROJECT_SOURCE_DIR}/src/SFML/Graphics)
# all source files
set(SRC
${SRCROOT}/BlendMode.cpp
${INCROOT}/BlendMode.hpp
${SRCROOT}/Color.cpp
${INCROOT}/Color.hpp
@ -86,15 +87,15 @@ source_group("stb_image" FILES ${STB_SRC})
# let CMake know about our additional graphics libraries paths (on Windows and OSX)
if(SFML_OS_WINDOWS OR SFML_OS_MACOSX)
set(CMAKE_INCLUDE_PATH ${CMAKE_INCLUDE_PATH} "${PROJECT_SOURCE_DIR}/extlibs/headers/jpeg")
endif()
endif()
if(SFML_OS_WINDOWS)
set(CMAKE_INCLUDE_PATH ${CMAKE_INCLUDE_PATH} "${PROJECT_SOURCE_DIR}/extlibs/headers/libfreetype/windows")
set(CMAKE_INCLUDE_PATH ${CMAKE_INCLUDE_PATH} "${PROJECT_SOURCE_DIR}/extlibs/headers/libfreetype/windows/freetype")
elseif(SFML_OS_MACOSX)
set(CMAKE_INCLUDE_PATH ${CMAKE_INCLUDE_PATH} "${PROJECT_SOURCE_DIR}/extlibs/headers/libfreetype/osx")
set(CMAKE_INCLUDE_PATH ${CMAKE_INCLUDE_PATH} "${PROJECT_SOURCE_DIR}/extlibs/headers/libfreetype/osx/freetype2")
set(CMAKE_LIBRARY_PATH ${CMAKE_LIBRARY_PATH} "${PROJECT_SOURCE_DIR}/extlibs/libs-osx/Frameworks")
set(CMAKE_LIBRARY_PATH ${CMAKE_LIBRARY_PATH} "${PROJECT_SOURCE_DIR}/extlibs/libs-osx/Frameworks")
endif()
# find external libraries

84
src/SFML/Graphics/RenderTarget.cpp
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@ -35,6 +35,41 @@
#include <iostream>
namespace
{
// Convert an sf::BlendMode::BlendFactor constant to the corresponding OpenGL constant.
sf::Uint32 factorToGlConstant(sf::BlendMode::BlendFactor blendFactor)
{
switch (blendFactor)
{
default:
case sf::BlendMode::Zero: return GL_ZERO;
case sf::BlendMode::One: return GL_ONE;
case sf::BlendMode::SrcColor: return GL_SRC_COLOR;
case sf::BlendMode::OneMinusSrcColor: return GL_ONE_MINUS_SRC_COLOR;
case sf::BlendMode::DstColor: return GL_DST_COLOR;
case sf::BlendMode::OneMinusDstColor: return GL_ONE_MINUS_DST_COLOR;
case sf::BlendMode::SrcAlpha: return GL_SRC_ALPHA;
case sf::BlendMode::OneMinusSrcAlpha: return GL_ONE_MINUS_SRC_ALPHA;
case sf::BlendMode::DstAlpha: return GL_DST_ALPHA;
case sf::BlendMode::OneMinusDstAlpha: return GL_ONE_MINUS_DST_ALPHA;
}
}
// Convert an sf::BlendMode::BlendEquation constant to the corresponding OpenGL constant.
sf::Uint32 equationToGlConstant(sf::BlendMode::BlendEquation blendEquation)
{
switch (blendEquation)
{
default:
case sf::BlendMode::Add: return GL_FUNC_ADD;
case sf::BlendMode::Subtract: return GL_FUNC_SUBTRACT;
}
}
}
namespace sf
{
////////////////////////////////////////////////////////////
@ -355,38 +390,20 @@ void RenderTarget::applyCurrentView()
////////////////////////////////////////////////////////////
void RenderTarget::applyBlendMode(BlendMode mode)
{
switch (mode)
{
// glBlendFuncSeparateEXT is used when available to avoid an incorrect alpha value when the target
// is a RenderTexture -- in this case the alpha value must be written directly to the target buffer
// Apply the blend mode, falling back to the non-separate versions if necessary
if (GLEW_EXT_blend_func_separate)
glCheck(glBlendFuncSeparateEXT(factorToGlConstant(mode.colorSrcFactor),
factorToGlConstant(mode.colorDstFactor), factorToGlConstant(mode.alphaSrcFactor),
factorToGlConstant(mode.alphaDstFactor)));
else
glCheck(glBlendFunc(factorToGlConstant(mode.colorSrcFactor),
factorToGlConstant(mode.colorDstFactor)));
// Alpha blending
default :
case BlendAlpha :
if (GLEW_EXT_blend_func_separate)
glCheck(glBlendFuncSeparateEXT(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA));
else
glCheck(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA));
break;
// Additive blending
case BlendAdd :
if (GLEW_EXT_blend_func_separate)
glCheck(glBlendFuncSeparateEXT(GL_SRC_ALPHA, GL_ONE, GL_ONE, GL_ONE));
else
glCheck(glBlendFunc(GL_SRC_ALPHA, GL_ONE));
break;
// Multiplicative blending
case BlendMultiply :
glCheck(glBlendFunc(GL_DST_COLOR, GL_ZERO));
break;
// No blending
case BlendNone :
glCheck(glBlendFunc(GL_ONE, GL_ZERO));
break;
}
if (GLEW_EXT_blend_equation_separate)
glCheck(glBlendEquationSeparateEXT(equationToGlConstant(mode.colorEquation),
equationToGlConstant(mode.alphaEquation)));
else
glCheck(glBlendEquation(equationToGlConstant(mode.colorEquation)));
m_cache.lastBlendMode = mode;
}
@ -436,8 +453,9 @@ void RenderTarget::applyShader(const Shader* shader)
// to render them.
//
// * Blending mode
// It's a simple integral value, so we can easily check
// whether the value to apply is the same as before or not.
// Since it overloads the == operator, we can easily check
// whether any of the 6 blending components changed and,
// thus, whether we need to update the blend mode.
//
// * Texture
// Storing the pointer or OpenGL ID of the last used texture