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/*=========================================================================
Program: Visualization Toolkit
Module: vtkAbstractContextBufferId.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 vtkAbstractContextBufferId
* @brief 2D array of ids, used for picking.
*
*
* An 2D array where each element is the id of an entity drawn at the given
* pixel. The access is not specified in this class.
* The effective/concrete subclass vtkContextBufferId stores the whole buffer
* in RAM. The access to a value is fast and independent of the OpenGL.
* However it requires to first fill the whole buffer by transferring the
* buffer generated by OpenGL from the VRAM to the RAM. It is inefficient if
* the context of the scene changes during interaction.
*
* The effective/concrete subclass vtkOpenGLContextBufferId keeps the buffer id
* on the VRAM in a texture image. The access to a value is slower than a
* simple read access to an array but it does not require a large transfer of
* data from the VRAM to the RAM.
*
* @sa
* vtkContextBufferId, vtkOpenGLContextBufferId
*/
#ifndef vtkAbstractContextBufferId_h
#define vtkAbstractContextBufferId_h
#include "vtkObject.h"
#include "vtkRenderingContext2DModule.h" // For export macro
class vtkRenderWindow;
class VTKRENDERINGCONTEXT2D_EXPORT vtkAbstractContextBufferId : public vtkObject
{
public:
vtkTypeMacro(vtkAbstractContextBufferId, vtkObject);
void PrintSelf(ostream& os, vtkIndent indent) override;
static vtkAbstractContextBufferId* New();
//@{
/**
* Number of columns. Initial value is 0.
*/
vtkGetMacro(Width, int);
//@}
//@{
/**
* Set the number of columns. Initial value is 0.
*/
vtkSetMacro(Width, int);
//@}
//@{
/**
* Number of rows. Initial value is 0.
*/
vtkGetMacro(Height, int);
//@}
//@{
/**
* Set the number of rows. Initial value is 0.
*/
vtkSetMacro(Height, int);
//@}
//@{
/**
* Set/Get the OpenGL context owning the texture object resource.
*/
virtual void SetContext(vtkRenderWindow* context) = 0;
virtual vtkRenderWindow* GetContext() = 0;
//@}
/**
* Returns if the context supports the required extensions.
* \pre context_is_set: this->GetContext()!=0
*/
virtual bool IsSupported() = 0;
/**
* Allocate the memory for at least Width*Height elements.
* \pre positive_width: GetWidth()>0
* \pre positive_height: GetHeight()>0
*/
virtual void Allocate() = 0;
/**
* Tell if the buffer has been allocated.
*/
virtual bool IsAllocated() const = 0;
/**
* Copy the contents of the current read buffer to the internal structure
* starting at lower left corner of the framebuffer (srcXmin,srcYmin).
* \pre is_allocated: this->IsAllocated()
*/
virtual void SetValues(int srcXmin, int srcYmin) = 0;
/**
* Return item under abscissa x and ordinate y.
* Abscissa go from left to right.
* Ordinate go from bottom to top.
* The return value is -1 if there is no item.
* \pre is_allocated: IsAllocated()
* \post valid_result: result>=-1
*/
virtual vtkIdType GetPickedItem(int x, int y) = 0;
/**
* Release any graphics resources that are being consumed by this object.
* Default implementation is empty.
*/
virtual void ReleaseGraphicsResources();
protected:
vtkAbstractContextBufferId();
~vtkAbstractContextBufferId() override;
int Width;
int Height;
private:
vtkAbstractContextBufferId(const vtkAbstractContextBufferId&) = delete;
void operator=(const vtkAbstractContextBufferId&) = delete;
};
#endif // #ifndef vtkAbstractContextBufferId_h