CkViewpoint Class Reference

Describes a method for converting universe locations to screen pixels and back again: a projection matrix. More...

#include <ckviewpoint.h>

Collaboration diagram for CkViewpoint:


Public Types
enum	{ nClip = 4 }
Public Member Functions
	CkViewpoint (const CkVector3d &E_, const CkVector3d &R_, CkVector3d Y_=CkVector3d(0, 1, 1.0e-8))
	Build a camera at eye point E pointing toward R, with up vector Y.
	CkViewpoint (const CkVector3d &E_, const CkVector3d &R_, const CkVector3d &X_, const CkVector3d &Y_, int w, int h)
	Build a camera at eye point E for view plane with origin R and X and Y as pixel sizes.
	CkViewpoint (const CkVector3d &R_, const CkVector3d &X_, const CkVector3d &Y_, const CkVector3d &Z_, int w, int h, bool yesThisIsPerspective)
	Build an orthogonal camera for a view plane with origin R and X and Y as pixel sizes, and the given Z axis.
void	disablePerspective (void)
	Make this perspective camera orthogonal-- turn off perspective.
void	discretize (int w, int h, double hFOV)
	Make this camera, fresh-built with the above constructor, have this X and Y resolution and horizontal full field-of-view (degrees).
void	discretizeFlip (int w, int h, double hFOV)
	Like discretize, but flips the Y axis (for typical raster viewing).
void	flip (void)
	Flip the image's Y axis (for typical raster viewing).
void	window (int w, int h, int x, int y)
	Extract a window with this width and height, with origin at this pixel.
	CkViewpoint ()
	For use by pup:.
const CkVector3d &	getEye (void) const
	Return the center of projection (eye point).
bool	isOrthographic (void) const
	Return true if this is an orthographic (perspective-free) camera.
const CkVector3d &	getOrigin (void) const
	Return the projection plane origin (View Reference Point).
const CkVector3d &	getX (void) const
	Return the projection plane pixel-length X axis.
const CkVector3d &	getY (void) const
	Return the projection plane pixel-length Y axis (View Up Vector).
const CkVector3d &	getZ (void) const
	Return the z-unit-length Z axis (from reference towards camera).
int	getXsize (void) const
	Return the number of pixels in the X direction.
int	getWidth (void) const
int	getYsize (void) const
	Return the number of pixels in the Y direction.
int	getHeight (void) const
const CkMatrix3d &	getMatrix (void) const
	Return the 4x4 projection matrix.
CkVector3d	project (const CkVector3d &in) const
	Project this point into the camera volume.
CkHalfspace3d	getClip (int i) const
	Get our i'th clipping plane.
bool	allOffscreen (int n, const CkVector3d *p) const
	Return true if any convex combination of these points is still offscreen.
CkVector2d	project_noz (const CkVector3d &in) const
	Project this point onto the screen, returning zero for the z axis.
void	project_noz (const float in, int x, int *y) const
CkVector3d	viewplane (const CkVector2d &v) const
	Backproject this view plane point into world coordinates.
CkVector3d	projectViewplane (const CkVector3d &u) const
	Project, the back-project this universe point:.
CkRay	getRay (const CkVector3d &univ) const
CkRay	getPixelRay (const CkVector2d &screen) const
CkVector3d	toCamera (const CkVector3d &pt) const
	Get a universe-coords vector pointing to the camera from this point.
bool	isInbounds (const CkVector2d &screen) const
void	clip (CkVector2d &screen) const
void	makeOpenGL (double *dest, double z_near, double z_far) const
void	pup (PUP::er &p)
Private Member Functions
void	buildM (void)
	Fill our projection matrix m with values from E, R, X, Y, Z.
Private Attributes
float	projX [4]
float	projY [4]
float	projZ [4]
float	projW [4]
CkVector3d	E
CkVector3d	R
CkVector3d	X
CkVector3d	Y
CkVector3d	Z
CkMatrix3d	m
int	wid
int	ht
bool	isPerspective

Detailed Description

Describes a method for converting universe locations to screen pixels and back again: a projection matrix.

Definition at line 110 of file ckviewpoint.h.

Member Enumeration Documentation

anonymous enum

Enumerator:

nClip

Definition at line 210 of file ckviewpoint.h.

Constructor & Destructor Documentation

CkViewpoint::CkViewpoint	(	const CkVector3d &	E_,
		const CkVector3d &	R_,
		CkVector3d	Y_ = `CkVector3d(0, 1, 1.0e-8)`
	)

Build a camera at eye point E pointing toward R, with up vector Y.

The up vector is not allowed to be parallel to E-R. This is an easy-to-use, but restricted (no off-axis) routine. It is normally followed by discretize or discretizeFlip.

CkViewpoint::CkViewpoint	(	const CkVector3d &	E_,
		const CkVector3d &	R_,
		const CkVector3d &	X_,
		const CkVector3d &	Y_,
		int	w,
		int	h
	)

Build a camera at eye point E for view plane with origin R and X and Y as pixel sizes.

CkViewpoint::CkViewpoint	(	const CkVector3d &	R_,
		const CkVector3d &	X_,
		const CkVector3d &	Y_,
		const CkVector3d &	Z_,
		int	w,
		int	h,
		bool	yesThisIsPerspective
	)

Build an orthogonal camera for a view plane with origin R and X and Y as pixel sizes, and the given Z axis.

For a parallel-projection camera (yesThisIsPerspective==false) and project(R_+x*X_+y*Y_+z*Z_) = (x,y,z)

CkViewpoint::CkViewpoint ( ) [inline]

For use by pup:.

Definition at line 166 of file ckviewpoint.h.

References ht, and wid.

Member Function Documentation

void CkViewpoint::buildM ( void ) [private]

Fill our projection matrix m with values from E, R, X, Y, Z.

void CkViewpoint::disablePerspective ( void )

Make this perspective camera orthogonal-- turn off perspective.

void CkViewpoint::discretize	(	int	w,
		int	h,
		double	hFOV
	)

Make this camera, fresh-built with the above constructor, have this X and Y resolution and horizontal full field-of-view (degrees).

This routine rescales X and Y to have the appropriate length for the field of view, and shifts the projection origin by (-w/2,-h/2).

void CkViewpoint::discretizeFlip	(	int	w,
		int	h,
		double	hFOV
	)

Like discretize, but flips the Y axis (for typical raster viewing).

void CkViewpoint::flip ( void )

Flip the image's Y axis (for typical raster viewing).

void CkViewpoint::window	(	int	w,
		int	h,
		int	x,
		int	y
	)

Extract a window with this width and height, with origin at this pixel.

const CkVector3d& CkViewpoint::getEye ( void ) const [inline]

Return the center of projection (eye point).

Definition at line 169 of file ckviewpoint.h.

References E.

Referenced by getPixelRay(), getRay(), and toCamera().

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bool CkViewpoint::isOrthographic ( void ) const [inline]

Return true if this is an orthographic (perspective-free) camera.

Definition at line 171 of file ckviewpoint.h.

References isPerspective.

const CkVector3d& CkViewpoint::getOrigin ( void ) const [inline]

Return the projection plane origin (View Reference Point).

Definition at line 174 of file ckviewpoint.h.

References R.

const CkVector3d& CkViewpoint::getX ( void ) const [inline]

Return the projection plane pixel-length X axis.

Definition at line 176 of file ckviewpoint.h.

References X.

const CkVector3d& CkViewpoint::getY ( void ) const [inline]

Return the projection plane pixel-length Y axis (View Up Vector).

Definition at line 178 of file ckviewpoint.h.

References Y.

const CkVector3d& CkViewpoint::getZ ( void ) const [inline]

Return the z-unit-length Z axis (from reference towards camera).

Definition at line 180 of file ckviewpoint.h.

References Z.

int CkViewpoint::getXsize ( void ) const [inline]

Return the number of pixels in the X direction.

Definition at line 183 of file ckviewpoint.h.

References wid.

int CkViewpoint::getWidth ( void ) const [inline]

Definition at line 184 of file ckviewpoint.h.

References wid.

int CkViewpoint::getYsize ( void ) const [inline]

Return the number of pixels in the Y direction.

Definition at line 186 of file ckviewpoint.h.

References ht.

int CkViewpoint::getHeight ( void ) const [inline]

Definition at line 187 of file ckviewpoint.h.

References ht.

const CkMatrix3d& CkViewpoint::getMatrix ( void ) const [inline]

Return the 4x4 projection matrix.

This is a column-wise matrix, meaning the translation portion is the rightmost column.

Definition at line 191 of file ckviewpoint.h.

References m.

CkVector3d CkViewpoint::project ( const CkVector3d & in ) const [inline]

Project this point into the camera volume.

The projected screen point is (return.x,return.y);

return.z is 1.0/depth: +inf at the eye to 1 at the projection plane. This is the "perspective scale value"; the screen size multiplier needed because of perspective.

Definition at line 199 of file ckviewpoint.h.

References float, m, PUP::w, CkVector3dT< real >::x, CkVector3dT< real >::y, and CkVector3dT< real >::z.

Referenced by impl_LV3D_Array::LV3D_FlatRender().

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