/usr/include/vtk-7.1/vtkSobelGradientMagnitudePass.h is in libvtk7-dev 7.1.1+dfsg1-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 | /*=========================================================================
Program: Visualization Toolkit
Module: vtkSobelGradientMagnitudePass.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 vtkSobelGradientMagnitudePass
* @brief Implement a post-processing edge
* detection with a Sobel gradient magnitude render pass.
*
* Detect the edges of the image renderered by its delegate. Edge-detection
* uses a Sobel high-pass filter (3x3 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:
* To compute the gradient magnitude, the x and y components of the gradient
* (Gx and Gy) have to be computed first. Each computation of Gx and Gy uses
* a separable filter.
* The first pass takes the image from the delegate as the single input
* texture.
* The first pass has two outputs, one for the first part of Gx, Gx1, result of
* a convolution with (-1 0 1), one for the first part of Gy, Gy1, result of a
* convolution with (1 2 1).
* The second pass has two inputs, Gx1 and Gy1. Kernel (1 2 1)^T is applied
* to Gx1 and kernel (-1 0 1)^T is applied to Gx2. It gives the values for
* Gx and Gy. Thoses values are then used to compute the magnitude of the
* gradient which is stored in the render target.
* The gradient computation happens per component (R,G,B). A is arbitrarly set
* to 1 (full opacity).
*
* @par Implementation:
* \image html vtkSobelGradientMagnitudePassFigure.png
* \image latex vtkSobelGradientMagnitudePassFigure.eps
*
* @sa
* vtkRenderPass
*/
#ifndef vtkSobelGradientMagnitudePass_h
#define vtkSobelGradientMagnitudePass_h
#include "vtkRenderingOpenGL2Module.h" // For export macro
#include "vtkImageProcessingPass.h"
class vtkDepthPeelingPassLayerList; // Pimpl
class vtkFrameBufferObject;
class vtkOpenGLHelper;
class vtkOpenGLRenderWindow;
class vtkTextureObject;
class VTKRENDERINGOPENGL2_EXPORT vtkSobelGradientMagnitudePass : public vtkImageProcessingPass
{
public:
static vtkSobelGradientMagnitudePass *New();
vtkTypeMacro(vtkSobelGradientMagnitudePass,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.
*/
vtkSobelGradientMagnitudePass();
/**
* Destructor.
*/
virtual ~vtkSobelGradientMagnitudePass();
/**
* Graphics resources.
*/
vtkFrameBufferObject *FrameBufferObject;
vtkTextureObject *Pass1; // render target for the scene
vtkTextureObject *Gx1; // render target 0 for the first shader
vtkTextureObject *Gy1; // render target 1 for the first shader
// Structures for the various cell types we render.
vtkOpenGLHelper *Program1; // shader to compute Gx1 and Gy1
vtkOpenGLHelper *Program2; // shader to compute |G| from Gx1 and Gy1
private:
vtkSobelGradientMagnitudePass(const vtkSobelGradientMagnitudePass&) VTK_DELETE_FUNCTION;
void operator=(const vtkSobelGradientMagnitudePass&) VTK_DELETE_FUNCTION;
};
#endif
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