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/*=========================================================================
Program: Visualization Toolkit
Module: vtkGaussianBlurPass.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.
=========================================================================*/
/**
* @class vtkGaussianBlurPass
* @brief Implement a post-processing Gaussian blur
* render pass.
*
* Blur the image renderered by its delegate. Blurring uses a Gaussian low-pass
* filter with a 5x5 kernel.
*
* This pass expects an initialized depth buffer and color buffer.
* Initialized buffers means they have been cleared with farest z-value and
* background color/gradient/transparent color.
* An opaque pass may have been performed right after the initialization.
*
* The delegate is used once.
*
* Its delegate is usually set to a vtkCameraPass or to a post-processing pass.
*
* This pass requires a OpenGL context that supports texture objects (TO),
* framebuffer objects (FBO) and GLSL. If not, it will emit an error message
* and will render its delegate and return.
*
* @par Implementation:
* As the filter is separable, it first blurs the image horizontally and then
* vertically. This reduces the number of texture sampling to 5 per pass.
* In addition, as texture sampling can already blend texel values in linear
* mode, by adjusting the texture coordinate accordingly, only 3 texture
* sampling are actually necessary.
* Reference: OpenGL Bloom Toturial by Philip Rideout, section
* Exploit Hardware Filtering http://prideout.net/bloom/index.php#Sneaky
*
* @sa
* vtkRenderPass
*/
#ifndef vtkGaussianBlurPass_h
#define vtkGaussianBlurPass_h
#include "vtkRenderingOpenGL2Module.h" // For export macro
#include "vtkImageProcessingPass.h"
class vtkDepthPeelingPassLayerList; // Pimpl
class vtkFrameBufferObject;
class vtkOpenGLHelper;
class vtkOpenGLRenderWindow;
class vtkTextureObject;
class VTKRENDERINGOPENGL2_EXPORT vtkGaussianBlurPass : public vtkImageProcessingPass
{
public:
static vtkGaussianBlurPass *New();
vtkTypeMacro(vtkGaussianBlurPass,vtkImageProcessingPass);
void PrintSelf(ostream& os, vtkIndent indent);
/**
* Perform rendering according to a render state \p s.
* \pre s_exists: s!=0
*/
virtual void Render(const vtkRenderState *s);
/**
* Release graphics resources and ask components to release their own
* resources.
* \pre w_exists: w!=0
*/
void ReleaseGraphicsResources(vtkWindow *w);
protected:
/**
* Default constructor. DelegatePass is set to NULL.
*/
vtkGaussianBlurPass();
/**
* Destructor.
*/
virtual ~vtkGaussianBlurPass();
/**
* Graphics resources.
*/
vtkFrameBufferObject *FrameBufferObject;
vtkTextureObject *Pass1; // render target for the scene
vtkTextureObject *Pass2; // render target for the horizontal pass
// Structures for the various cell types we render.
vtkOpenGLHelper *BlurProgram;
bool Supported;
bool SupportProbed;
private:
vtkGaussianBlurPass(const vtkGaussianBlurPass&) VTK_DELETE_FUNCTION;
void operator=(const vtkGaussianBlurPass&) VTK_DELETE_FUNCTION;
};
#endif
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