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From Ravi Mathur, "Here is an update to BlendEquation that adds checking for the

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SGIX_blend_alpha_minmax and EXT_blend_logic_op extensions.  It is
tested with the osgblendequation example.  If the extensions are not
supported, a WARN level notification is generated."
This commit is contained in:
Robert Osfield
2005-10-28 13:18:09 +00:00
parent ab1bd48511
commit fa5ab64c94
2 changed files with 25 additions and 0 deletions
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4
include/osg/BlendEquation
View File

@@ -107,6 +107,8 @@ class OSG_EXPORT BlendEquation : public StateAttribute
void setBlendEquationSupported(bool flag) { _isBlendEquationSupported=flag; }
bool isBlendEquationSupported() const { return _isBlendEquationSupported; }
bool isSGIXMinMaxSupported() const { return _isSGIXMinMaxSupported; }
bool isLogicOpSupported() const { return _isLogicOpSupported; }
void setBlendEquationProc(void* ptr) { _glBlendEquation = ptr; }
void glBlendEquation(GLenum mode) const;
@@ -116,6 +118,8 @@ class OSG_EXPORT BlendEquation : public StateAttribute
~Extensions() {}
bool _isBlendEquationSupported;
bool _isSGIXMinMaxSupported;
bool _isLogicOpSupported;
void* _glBlendEquation;

21
src/osg/BlendEquation.cpp
View File

@@ -48,6 +48,21 @@ void BlendEquation::apply(State& state) const
return;
}
GLenum eqn = static_cast<GLenum>(_equation);
if((eqn == ALPHA_MIN || eqn == ALPHA_MAX) &&
!extensions->isSGIXMinMaxSupported())
{
notify(WARN)<<"Warning: BlendEquation::apply(..) failed, SGIX_blend_alpha_minmax extension is not supported by OpenGL driver." << std::endl;
return;
}
if(eqn == LOGIC_OP && !extensions->isLogicOpSupported())
{
notify(WARN)<<"Warning: BlendEquation::apply(..) failed, EXT_blend_logic_op extension is not supported by OpenGL driver." << std::endl;
return;
}
extensions->glBlendEquation(static_cast<GLenum>(_equation));
}
@@ -77,6 +92,9 @@ BlendEquation::Extensions::Extensions(const Extensions& rhs):
Referenced()
{
_isBlendEquationSupported = rhs._isBlendEquationSupported;
_isSGIXMinMaxSupported = rhs._isSGIXMinMaxSupported;
_isLogicOpSupported = rhs._isLogicOpSupported;
_glBlendEquation = rhs._glBlendEquation;
}
void BlendEquation::Extensions::lowestCommonDenominator(const Extensions& rhs)
@@ -89,6 +107,9 @@ void BlendEquation::Extensions::setupGLExtenions(unsigned int contextID)
{
_isBlendEquationSupported = isGLExtensionSupported(contextID,"GL_EXT_blend_equation") ||
strncmp((const char*)glGetString(GL_VERSION),"1.2",3)>=0;
_isSGIXMinMaxSupported = isGLExtensionSupported(contextID, "SGIX_blend_alpha_minmax");
_isLogicOpSupported = isGLExtensionSupported(contextID, "EXT_blend_logic_op");
_glBlendEquation = getGLExtensionFuncPtr("glBlendEquation", "glBlendEquationEXT");
}