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221 lines
8.9 KiB
221 lines
8.9 KiB
/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield |
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* |
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* This library is open source and may be redistributed and/or modified under |
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* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or |
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* (at your option) any later version. The full license is in LICENSE file |
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* included with this distribution, and on the openscenegraph.org website. |
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* |
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* This library is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* OpenSceneGraph Public License for more details. |
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*/ |
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#ifndef OSG_BLENDFUNC |
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#define OSG_BLENDFUNC 1 |
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#include <osg/StateAttribute> |
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#ifndef GL_VERSION_1_2 |
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#define GL_CONSTANT_COLOR 0x8001 |
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#define GL_ONE_MINUS_CONSTANT_COLOR 0x8002 |
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#define GL_CONSTANT_ALPHA 0x8003 |
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#define GL_ONE_MINUS_CONSTANT_ALPHA 0x8004 |
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#define GL_BLEND_COLOR 0x8005 |
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#endif |
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#ifndef GL_VERSION_1_4 |
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#define GL_BLEND_DST_RGB 0x80C8 |
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#define GL_BLEND_SRC_RGB 0x80C9 |
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#define GL_BLEND_DST_ALPHA 0x80CA |
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#define GL_BLEND_SRC_ALPHA 0x80CB |
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#endif |
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namespace osg { |
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/** Encapsulates OpenGL blend/transparency state. |
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* |
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* Blending combines incoming fragment with a fragment |
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* already present in the target buffer. |
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* |
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* OpenGL 1.1 supports following source and destination blending factors: |
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* GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, |
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* GL_DST_ALPHA, GL_ONE_MINUS_DST_ALPHA, |
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* GL_ZERO, GL_ONE. |
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* |
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* Moreover, there are three source-only blending factors: |
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* GL_DST_COLOR, GL_ONE_MINUS_DST_COLOR, GL_SRC_ALPHA_SATURATE |
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* and two destination-only blending factors: |
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* GL_SRC_COLOR, GL_ONE_MINUS_SRC_COLOR. |
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* OpenGL 1.4 allowed to use these five blending factors |
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* as both - source and destination blending factors. |
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* |
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* Following four source and destination blending factors |
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* were added by Imaging subset of OpenGL 1.2 |
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* and made mandatory by OpenGL 1.4: |
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* GL_CONSTANT_COLOR, GL_ONE_MINUS_CONSTANT_COLOR, |
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* GL_CONSTANT_ALPHA, GL_ONE_MINUS_CONSTANT_ALPHA |
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* |
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* OpenGL 1.4 further provides glBlendFuncSeparate |
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* (promoted from GL_EXT_blend_func_separate). |
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* It makes possible to set blending functions for RGB and Alpha separately. |
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* Before, it was possible to set just one blending function for RGBA. |
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*/ |
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class OSG_EXPORT BlendFunc : public StateAttribute |
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{ |
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public : |
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BlendFunc(); |
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BlendFunc(GLenum source, GLenum destination); |
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BlendFunc(GLenum source, GLenum destination, GLenum source_alpha, GLenum destination_alpha); |
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/** Copy constructor using CopyOp to manage deep vs shallow copy. */ |
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BlendFunc(const BlendFunc& trans,const CopyOp& copyop=CopyOp::SHALLOW_COPY): |
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StateAttribute(trans,copyop), |
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_source_factor(trans._source_factor), |
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_destination_factor(trans._destination_factor), |
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_source_factor_alpha(trans._source_factor_alpha), |
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_destination_factor_alpha(trans._destination_factor_alpha) {} |
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META_StateAttribute(osg, BlendFunc,BLENDFUNC); |
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/** Return -1 if *this < *rhs, 0 if *this==*rhs, 1 if *this>*rhs. */ |
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virtual int compare(const StateAttribute& sa) const |
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{ |
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// Check for equal types, then create the rhs variable |
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// used by the COMPARE_StateAttribute_Parameter macros below. |
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COMPARE_StateAttribute_Types(BlendFunc,sa) |
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// Compare each parameter in turn against the rhs. |
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COMPARE_StateAttribute_Parameter(_source_factor) |
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COMPARE_StateAttribute_Parameter(_destination_factor) |
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COMPARE_StateAttribute_Parameter(_source_factor_alpha) |
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COMPARE_StateAttribute_Parameter(_destination_factor_alpha) |
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return 0; // Passed all the above comparison macros, so must be equal. |
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} |
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virtual bool getModeUsage(StateAttribute::ModeUsage& usage) const |
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{ |
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usage.usesMode(GL_BLEND); |
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return true; |
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} |
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enum BlendFuncMode { |
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DST_ALPHA = GL_DST_ALPHA, |
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DST_COLOR = GL_DST_COLOR, |
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ONE = GL_ONE, |
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ONE_MINUS_DST_ALPHA = GL_ONE_MINUS_DST_ALPHA, |
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ONE_MINUS_DST_COLOR = GL_ONE_MINUS_DST_COLOR, |
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ONE_MINUS_SRC_ALPHA = GL_ONE_MINUS_SRC_ALPHA, |
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ONE_MINUS_SRC_COLOR = GL_ONE_MINUS_SRC_COLOR, |
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SRC_ALPHA = GL_SRC_ALPHA, |
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SRC_ALPHA_SATURATE = GL_SRC_ALPHA_SATURATE, |
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SRC_COLOR = GL_SRC_COLOR, |
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CONSTANT_COLOR = GL_CONSTANT_COLOR, |
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ONE_MINUS_CONSTANT_COLOR = GL_ONE_MINUS_CONSTANT_COLOR, |
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CONSTANT_ALPHA = GL_CONSTANT_ALPHA, |
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ONE_MINUS_CONSTANT_ALPHA = GL_ONE_MINUS_CONSTANT_ALPHA, |
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ZERO = GL_ZERO |
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}; |
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inline void setFunction( GLenum source, GLenum destination ) |
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{ |
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_source_factor = source; |
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_destination_factor = destination; |
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_source_factor_alpha = source; |
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_destination_factor_alpha = destination; |
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} |
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inline void setFunction( GLenum source_rgb, GLenum destination_rgb, GLenum source_alpha, GLenum destination_alpha ) |
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{ |
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_source_factor = source_rgb; |
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_destination_factor = destination_rgb; |
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_source_factor_alpha = source_alpha; |
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_destination_factor_alpha = destination_alpha; |
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} |
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void setSource(GLenum source) { _source_factor = _source_factor_alpha = source; } |
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inline GLenum getSource() const { return _source_factor; } |
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void setSourceRGB(GLenum source) { _source_factor = source; } |
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inline GLenum getSourceRGB() const { return _source_factor; } |
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void setSourceAlpha(GLenum source) { _source_factor_alpha = source; } |
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inline GLenum getSourceAlpha() const { return _source_factor_alpha; } |
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void setDestination(GLenum destination) { _destination_factor = _destination_factor_alpha = destination; } |
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inline GLenum getDestination() const { return _destination_factor; } |
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void setDestinationRGB(GLenum destination) { _destination_factor = destination; } |
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inline GLenum getDestinationRGB() const { return _destination_factor; } |
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void setDestinationAlpha(GLenum destination) { _destination_factor_alpha = destination; } |
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inline GLenum getDestinationAlpha() const { return _destination_factor_alpha; } |
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virtual void apply(State& state) const; |
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/** Encapsulates queries of extension availability, obtains extension |
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* function pointers, and provides convenience wrappers for |
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* calling extension functions. */ |
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class OSG_EXPORT Extensions : public osg::Referenced |
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{ |
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public: |
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Extensions(unsigned int contextID); |
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Extensions(const Extensions& rhs); |
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void lowestCommonDenominator(const Extensions& rhs); |
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void setupGLExtensions(unsigned int contextID); |
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void setBlendFuncSeparateSupported(bool flag) { _isBlendFuncSeparateSupported=flag; } |
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bool isBlendFuncSeparateSupported() const { return _isBlendFuncSeparateSupported; } |
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void glBlendFuncSeparate(GLenum sfactorRGB, |
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GLenum dfactorRGB, |
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GLenum sfactorAlpha, |
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GLenum dfactorAlpha) const; |
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protected: |
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~Extensions() {} |
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typedef void (GL_APIENTRY * GLBlendFuncSeparateProc) (GLenum sfactorRGB, |
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GLenum dfactorRGB, |
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GLenum sfactorAlpha, |
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GLenum dfactorAlpha); |
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bool _isBlendFuncSeparateSupported; |
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GLBlendFuncSeparateProc _glBlendFuncSeparate; |
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}; |
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/** Returns the Extensions object for the given context. |
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* If createIfNotInitalized is true and the Extensions object doesn't |
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* exist, getExtensions() creates it on the given context. |
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* Returns NULL if createIfNotInitalized is false and the Extensions |
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* object doesn't exist. */ |
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static Extensions* getExtensions(unsigned int contextID,bool createIfNotInitalized); |
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/** setExtensions() allows users to override the extensions across graphics contexts. |
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* Typically used when you have different extensions supported across graphics pipes, |
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* but need to ensure that they all use the same low common denominator extensions. */ |
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static void setExtensions(unsigned int contextID,Extensions* extensions); |
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protected : |
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virtual ~BlendFunc(); |
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GLenum _source_factor; |
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GLenum _destination_factor; |
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GLenum _source_factor_alpha; |
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GLenum _destination_factor_alpha; |
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}; |
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} |
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#endif
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