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/*=========================================================================
Program: Visualization Toolkit
Module: vtkVolumeStateRAII.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
#ifndef vtkVolumeStateRAII_h
#define vtkVolumeStateRAII_h
// Only these states can be queries via glIsEnabled:
// http://www.khronos.org/opengles/sdk/docs/man/
class vtkVolumeStateRAII
{
public:
vtkVolumeStateRAII()
{
this->DepthTestEnabled = (glIsEnabled(GL_DEPTH_TEST) != 0);
this->BlendEnabled = (glIsEnabled(GL_BLEND) != 0);
this->CullFaceEnabled = (glIsEnabled(GL_CULL_FACE) != 0);
// Enable depth_sampler test
if (!this->DepthTestEnabled)
{
std::cerr << "enabling depth test" << std::endl;
glEnable(GL_DEPTH_TEST);
}
// Set the over blending function
// NOTE: It is important to choose GL_ONE vs GL_SRC_ALPHA as our colors
// will be premultiplied by the alpha value (doing front to back blending)
glBlendFunc(GL_ONE,GL_ONE_MINUS_SRC_ALPHA);
if (!this->BlendEnabled)
{
glEnable(GL_BLEND);
}
// Enable cull face
if (!this->CullFaceEnabled)
{
glEnable(GL_CULL_FACE);
}
}
~vtkVolumeStateRAII()
{
#ifdef __APPLE__
if (vtkOpenGLRenderWindow::GetContextSupportsOpenGL32())
#endif
{
glBindVertexArray(0);
}
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
if (!this->CullFaceEnabled)
{
glDisable(GL_CULL_FACE);
}
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
if (!this->BlendEnabled)
{
glDisable(GL_BLEND);
}
if (!this->DepthTestEnabled)
{
glDisable(GL_DEPTH_TEST);
}
}
private:
bool DepthTestEnabled;
bool BlendEnabled;
bool CullFaceEnabled;
};
#endif // vtkVolumeStateRAII_h
// VTK-HeaderTest-Exclude: vtkVolumeStateRAII.h
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