#include <gr_camera.h>

Inheritance diagram for kjb::Base_gl_interface:

Public Member Functions
	Base_gl_interface (double inear=10, double ifar=10000)

	Base_gl_interface (const Base_gl_interface &)
	bgl the Base_gl_interface to copy into this one More...

virtual Base_gl_interface &	operator= (const Base_gl_interface &src)
	bgl the Base_gl_interface to assign to this one More...

virtual	~Base_gl_interface ()

virtual void	swap (Self &other)

virtual void	set_gl_modelview () const
	Sets the gl modelview matrix based on the current camera parameters. More...

virtual void	set_gl_projection () const
	Sets the gl projection matrix based on the current camera parameters. More...

virtual void	mult_gl_projection () const
	Multiplies the current gl projection matrix with this camera's matrix. More...

void	prepare_for_rendering (bool clean_buffers) const
	Prepares the opengl for rendering by setting the gl modelview and projection matrix based on the current camera parameters It also clears the depth and the color buffers, and sets the background color to black. More...

void	set_near_clipping_plane (double inear)
	sets the near clipping plane distance from the camera More...

void	set_far_clipping_plane (double ifar)
	sets the far clipping plane distance from the camera More...

void	set_clipping_planes (double inear, double ifar)
	sets the near and far clipping plane distances from the camera More...

double	get_near () const
	gets the near clipping plane distance from the camera More...

double	get_far () const
	gets the far clipping plane distance from the camera More...

const Matrix &	get_modelview_matrix () const
	returns the gl modelview matrix More...

const Matrix &	get_projection_matrix () const
	returns the projection matrix; note: this needs to be preceeded by a glOrtho call with the window dimensions before sending this to opengl. More...

Matrix	get_gl_projection_matrix () const
	returns the exact matrix that opengl uses for its projection matrix. this is effectively glOrtho(-vp_width/2, vp_width/2, -vp_height/2, vp_height/2, znear, zfar), followed by glMultMatrix(get_projection_matrix(). Note that if the viewport size changes, you'll likely need to re-call this, or understand that the pixels sizes will change. More...

void	project_point (double &x, double &y, double &z, const kjb::Vector &point3D, double img_height) const

virtual bool	Polygon_visibility_test (const kjb::Polygon &p, double epsilon=0) const
	checks whether a given polygon is visible under the given camera parameters More...

void	set_modelview_entry (unsigned int row, unsigned int col, double value)
	sets an entry of the modelview matrix More...

void	set_projection_entry (unsigned int row, unsigned int col, double value)
	sets an entry of the projection matrix More...

double &	get_modelview_entry (unsigned int row, unsigned int col)
	returns an entry of the modelview matrix More...

double	get_modelview_entry (unsigned int row, unsigned int col) const
	returns an entry of the modelview matrix More...

double &	get_projection_entry (unsigned int row, unsigned int col)
	returns an entry of the projection matrix More...

double	get_projection_entry (unsigned int row, unsigned int col) const
	returns an entry of the projection matrix More...

Static Public Member Functions
static double	get_gl_viewport_aspect ()
	returns the ratio between the gl viewport width and the gl viewport height More...

static double	get_gl_viewport_width ()
	returns the gl viewport width More...

static double	get_gl_viewport_height ()
	returns the gl viewport height More...

static void	get_gl_viewport_size (double w, double h)
	gets the gl viewport width and height More...

static void	get_gl_viewport (double x, double y, double w, double h)
	gets all the g; viewport parameters (x,y,width,height) More...

static void	set_gl_viewport_size (double, double)
	sets the gl viewport size More...

static void	set_gl_viewport (double x, double y, double w, double h)
	sets all the gl viewport parameters (x,y,width,length) More...

static void	capture_gl_view (kjb_c::KJB_image **img_out)
	captures the gl view and stores it into a KJB_image More...

static void	capture_gl_view (const char *fname)
	captures the gl view and saves into a file More...

static void	capture_gl_view (const char *fname_fmt, uint32_t N)
	captures the gl view and saves into a file, by appending N to the filename More...

static void	capture_gl_view (kjb::Int_matrix &matrix)
	captures the gl view and stores it into a Int_matrix. The four bytes used by GL to represent the four channels (R,G,B,A) are packaged into a single integer. More...

static void	capture_gl_view (Image &img_out)
	captures the gl view and stores it into a c++ image More...

static void	set_gl_view (const kjb::Image &img_in)

static void	construct_image_from_int_matrix (kjb::Image &im, kjb::Int_matrix &m)

Protected Member Functions
	Base_gl_interface (const Matrix &, const Matrix &, double near, double far)
	constructs a Base_gl_interface from a modelview and a projection matrix More...

void	set_modelview_matrix (const Matrix &mv)
	sets the modelview matrix More...

void	set_projection_matrix (const Matrix &pm)
	sets the projection matrix More...

void	scale_modelview (double xscale, double yscale, double zscale)
	scales the modelview matrix using glScale More...

Detailed Description

the base interface between opengl and a camera parametrized in terms of modelview matrix, projection matrix, and near and far clipping planes. This class manipulates the modelview and the projection matrices by accessing them directly without calling glFrustum od gluPerspective. Please use it only if you know what you are doing. The clipping planes are handled by setting projection_matrix(2,2) = near + far; projection_matrix(2,3) = near*far; projection_matrix(3,2) = -1 and then by using applying the glOrtho transformation with parameters (-viewport_width/2, viewport_width/2, -viewport_height/2, viewport_height/2, near, far) This will clip stuff outside the viewing frustum and normalize the frustum itself to the normalized device coordinates opengl expects.

If you want to see the math, please go to http://sightations.wordpress.com/2010/08/03/simulating-calibrated-cameras-in-opengl

Constructor & Destructor Documentation

Base_gl_interface::Base_gl_interface	(	double	inear = `10`,
		double	ifar = `10000`
	)

Parameters

inear	Distance of the near clipping plane from the camera
ifar	Distance of the far clipping plane from the camera

Base_gl_interface::Base_gl_interface ( const Base_gl_interface & bgl )

bgl the Base_gl_interface to copy into this one

virtual kjb::Base_gl_interface::~Base_gl_interface ( )

inlinevirtual

Base_gl_interface::Base_gl_interface	(	const Matrix &	mv,
		const Matrix &	pj,
		double	inear,
		double	ifar
	)

protected

constructs a Base_gl_interface from a modelview and a projection matrix

Parameters

mv	input modelview matrix
pj	input projection matrix
inear	Distance of the near clipping plane from the camera
ifar	Distance of the far clipping plane from the camera

Member Function Documentation

void Base_gl_interface::capture_gl_view ( kjb_c::KJB_image ** img_out )

static

captures the gl view and stores it into a KJB_image

Parameters

img_out Result parameter. If *img_out is 0, an image is allocated; otherwise its space is re-used.

Exceptions

kjb::IO_error

void Base_gl_interface::capture_gl_view ( const char * fname )

static

captures the gl view and saves into a file

Parameters

fname File name to write the captured view image to.

Exceptions

kjb::IO_error

void Base_gl_interface::capture_gl_view	(	const char *	fname_fmt,
		uint32_t	N
	)

static

captures the gl view and saves into a file, by appending N to the filename

An example for fname_fmt is

image-%04d.tiff

Parameters

fname_fmt	Format for the file name with one printf style integer conversion for the file number.
N	Number of the captured image.

Exceptions

kjb::IO_error

void Base_gl_interface::capture_gl_view ( kjb::Int_matrix & matrix )

static

captures the gl view and stores it into a Int_matrix. The four bytes used by GL to represent the four channels (R,G,B,A) are packaged into a single integer.

Parameters

matrix Result parameter. The gl view will be stored into this int matrix. The four bytes used by GL to represent the four channels (R,G,B,A) are packaged into a single integer.

Exceptions

kjb::IO_error

void Base_gl_interface::capture_gl_view ( Image & img_out )

static

captures the gl view and stores it into a c++ image

Captures the gl view and stores it into a c++ image

Parameters

img_out Result parameter. The content of the GL frame buffer will be copied into this image, freeing the previous memory area pointed by this image

Exceptions

kjb::IO_error

void Base_gl_interface::construct_image_from_int_matrix	(	kjb::Image &	im,
		kjb::Int_matrix &	m
	)

static

Constructs an image from an int matrix. Each integer consists of four bytes, and each of them is interpreted as one of the GL channels (RGBA, or ABGR if the architecture is little endian). This is MOSTLY (if not only) used for DEBUGGING

Parameters

im	the image to be initialized from the matrix
m	the matrix to create the image from

double kjb::Base_gl_interface::get_far ( ) const

inline

gets the far clipping plane distance from the camera

kjb::Matrix Base_gl_interface::get_gl_projection_matrix ( ) const

returns the exact matrix that opengl uses for its projection matrix. this is effectively glOrtho(-vp_width/2, vp_width/2, -vp_height/2, vp_height/2, znear, zfar), followed by glMultMatrix(get_projection_matrix(). Note that if the viewport size changes, you'll likely need to re-call this, or understand that the pixels sizes will change.

void Base_gl_interface::get_gl_viewport	(	double *	x,
		double *	y,
		double *	w,
		double *	h
	)

static

gets all the g; viewport parameters (x,y,width,height)

Parameters

x	it will contain the x parameter of the gl viewport
y	it will contain the y parameter of the gl viewport
w	it will contain the width of the gl viewport
h	it will contain the height of the gl viewport

double Base_gl_interface::get_gl_viewport_aspect ( )

static

returns the ratio between the gl viewport width and the gl viewport height

Returns: The aspect ration of width to height for the GL viewport.

double Base_gl_interface::get_gl_viewport_height ( )

static

returns the gl viewport height

Returns: The viewport height in the GL.

void Base_gl_interface::get_gl_viewport_size	(	double *	w,
		double *	h
	)

static

gets the gl viewport width and height

Returns: The viewport height in the GL.

double Base_gl_interface::get_gl_viewport_width ( )

static

returns the gl viewport width

Returns: The viewport width in the GL.

double& kjb::Base_gl_interface::get_modelview_entry	(	unsigned int	row,
		unsigned int	col
	)

inline

returns an entry of the modelview matrix

double kjb::Base_gl_interface::get_modelview_entry	(	unsigned int	row,
		unsigned int	col
	)		const

inline

returns an entry of the modelview matrix

const Matrix& kjb::Base_gl_interface::get_modelview_matrix ( ) const

inline

returns the gl modelview matrix

double kjb::Base_gl_interface::get_near ( ) const

inline

gets the near clipping plane distance from the camera

double& kjb::Base_gl_interface::get_projection_entry	(	unsigned int	row,
		unsigned int	col
	)

inline

returns an entry of the projection matrix

double kjb::Base_gl_interface::get_projection_entry	(	unsigned int	row,
		unsigned int	col
	)		const

inline

returns an entry of the projection matrix

const Matrix& kjb::Base_gl_interface::get_projection_matrix ( ) const

inline

returns the projection matrix; note: this needs to be preceeded by a glOrtho call with the window dimensions before sending this to opengl.

void Base_gl_interface::mult_gl_projection ( ) const

virtual

Multiplies the current gl projection matrix with this camera's matrix.

Base_gl_interface & Base_gl_interface::operator= ( const Base_gl_interface & src )

virtual

bgl the Base_gl_interface to assign to this one

bool Base_gl_interface::Polygon_visibility_test	(	const kjb::Polygon &	p,
		double	epsilon = `0`
	)		const

virtual

checks whether a given polygon is visible under the given camera parameters

Checks whether a polygon is visible under the current camera by checking that the dot product between the polygon normal and the normalized vector between the camera and the polygon center is bigger than epsilon (whose default value is zero)

Parameters

p	the polygon to test
epsilon	the constant to compare the dot product with (default = 0)

Reimplemented in kjb::Parametric_camera_gl_interface.

void Base_gl_interface::prepare_for_rendering ( bool clean_buffers ) const

Prepares the opengl for rendering by setting the gl modelview and projection matrix based on the current camera parameters It also clears the depth and the color buffers, and sets the background color to black.

Prepares the opengl for rendering by setting the gl modelview and projection matrix based on the current camera parameters It also clears the depth and the color buffers, and sets the background color to black

Parameters

clean_buffers if true, the color and the depth buffer will be cleared

void Base_gl_interface::project_point	(	double &	x,
		double &	y,
		double &	z,
		const kjb::Vector &	point3D,
		double	img_height
	)		const

void Base_gl_interface::scale_modelview	(	double	xscale,
		double	yscale,
		double	zscale
	)

protected

scales the modelview matrix using glScale

Scales the gl modelview matrix using glScaled.

Parameters

xscale	the scale along the x axis
yscale	the scale along the y axis
zscale	the scale along the z axis

void Base_gl_interface::set_clipping_planes	(	double	inear,
		double	ifar
	)

sets the near and far clipping plane distances from the camera

Parameters

inear	Distance of the near clipping plane from the camera
far	Distance of the far clipping plane from the camera

void Base_gl_interface::set_far_clipping_plane ( double ifar )

sets the far clipping plane distance from the camera

Parameters

ifar	Distance of the far clipping plane from the camera

void Base_gl_interface::set_gl_modelview ( ) const

virtual

Sets the gl modelview matrix based on the current camera parameters.

Sets the gl modelview matrix using the current camera parameters.

void Base_gl_interface::set_gl_projection ( ) const

virtual

Sets the gl projection matrix based on the current camera parameters.

Sets the gl projection matrix using the current camera parameters. For the details on math, please see the class description

void Base_gl_interface::set_gl_view ( const kjb::Image & img_in )

static

Puts the content of the input image in the GL frame buffer

Put the content of the input image in the GL frame buffer

Parameters

img_in The input image

void Base_gl_interface::set_gl_viewport	(	double	x,
		double	y,
		double	w,
		double	h
	)

static

sets all the gl viewport parameters (x,y,width,length)

Parameters

x	the new x parameter for the gl viewport
y	the new y parameter for the gl viewport
w	the new gl viewport size
h	the new gl viewport height

void Base_gl_interface::set_gl_viewport_size	(	double	w,
		double	h
	)

static

sets the gl viewport size

Parameters

w	the new gl viewport size
h	the new gl viewport height

void kjb::Base_gl_interface::set_modelview_entry	(	unsigned int	row,
		unsigned int	col,
		double	value
	)

inline

sets an entry of the modelview matrix

void kjb::Base_gl_interface::set_modelview_matrix ( const Matrix & mv )

protected

sets the modelview matrix

void Base_gl_interface::set_near_clipping_plane ( double inear )

sets the near clipping plane distance from the camera

Parameters

inear Distance of the near clipping plane from the camera

void kjb::Base_gl_interface::set_projection_entry	(	unsigned int	row,
		unsigned int	col,
		double	value
	)

inline

sets an entry of the projection matrix

void kjb::Base_gl_interface::set_projection_matrix ( const Matrix & pm )

protected

sets the projection matrix

virtual void kjb::Base_gl_interface::swap ( Self & other )

inlinevirtual

Swap contents with another Perspective_camera. This is implemented to run much more quickly than: Perspective_camera tmp = b; b = a; a = tmp;

Reimplemented in kjb::Parametric_camera_gl_interface.

The documentation for this class was generated from the following files:

/work/kobus/src/lib/gr_cpp/gr_camera.h
/work/kobus/src/lib/gr_cpp/gr_camera.cpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation