# SbProjector Class Reference
[Projector classes (mostly for internal use)]

`#include <Inventor/projectors/SbProjector.h>`

Inheritance diagram for SbProjector:

List of all members.

## Detailed Description

The SbProjector class is the abstract base projector class.

Projectors are used in the Coin library for mapping 2D coordinates (typically from the position of the mouse cursor in the rendering window) to 3D "world" coordinates.

Mapping 2D coordinates to 3D coordinates is something which is done extensively in the dragger classes, to provide the user with a convenient and natural way of interacting with the 3D geometry of scenes.

For a usage example, see the class documentation for SbSphereSheetProjector.

The application programmer should normally not need to care about the projector classes, unless there are special needs in the application.

See also:
  SoDragger

## Public Member Functions

virtual SbVec3f | project (const SbVec2f &point)=0
virtual void | setViewVolume (const SbViewVolume &vol)
const SbViewVolume & | getViewVolume (void) const
virtual void | setWorkingSpace (const SbMatrix &space)
const SbMatrix & | getWorkingSpace (void) const
virtual SbProjector * | copy (void) const=0

## Protected Member Functions

| SbProjector (void)
virtual | ~SbProjector ()
SbLine | getWorkingLine (const SbVec2f &point) const
float | findVanishingDistance (void) const
SbBool | verifyProjection (const SbVec3f &projpt) const

## Protected Attributes

SbViewVolume | viewVol
SbMatrix | worldToWorking
SbMatrix | workingToWorld

## Constructor & Destructor Documentation

SbProjector::SbProjector | ( | void |  | ) | `[protected]`

| The constructor initializes the workingspace matrix to an identity matrix.

SbProjector::~SbProjector | ( |  | ) | `[inline, protected, virtual]`

| Destructor is protected, as this is an abstract class.

## Member Function Documentation

SbVec3f SbProjector::project | ( | const SbVec2f & | point | ) | `[pure virtual]`

| Project the 2D point from normalized viewport coordinates to a 3D point. The mapping will be done in accordance with the type of the projector. Implemented in SbCylinderPlaneProjector, SbCylinderProjector, SbCylinderSectionProjector, SbCylinderSheetProjector, SbLineProjector, SbPlaneProjector, SbSpherePlaneProjector, SbSphereSectionProjector, and SbSphereSheetProjector.

void SbProjector::setViewVolume | ( | const SbViewVolume & | vol | ) | `[virtual]`

Set the viewing volume the projections will take place in.

See also:
  getViewVolume()

const SbViewVolume & SbProjector::getViewVolume | ( | void |  | ) | const

Return the current viewing volume used by the projections.

See also:
  setViewVolume()

void SbProjector::setWorkingSpace | ( | const SbMatrix & | space | ) | `[virtual]`

| Sets the matrix used for converting from the projector's coordinate system to the world coordinate system. Reimplemented in SbCylinderProjector, and SbSphereProjector.

const SbMatrix & SbProjector::getWorkingSpace | ( | void |  | ) | const

Returns projector-to-world matrix.

See also:
  setWorkingSpace()

SbProjector * SbProjector::copy | ( | void |  | ) | const`[pure virtual]`

Construct and return a copy of this projector. The caller is responsible for destructing the new instance.

Note that if the Coin library has been built as a DLL under Microsoft Windows and you use this method from application code, you must make sure that both the Coin DLL and the application executable is using the same instance of a C Run-Time (CRT) library. Otherwise, you will get memory heap corruption upon deallocating the returned instances, eventually leading to mysterious crashes.

Implemented in SbCylinderPlaneProjector, SbCylinderSectionProjector, SbCylinderSheetProjector, SbLineProjector, SbPlaneProjector, SbSpherePlaneProjector, SbSphereSectionProjector, and SbSphereSheetProjector.

SbLine SbProjector::getWorkingLine | ( | const SbVec2f & | point | ) | const`[protected]`

| From the 2D point in normalized screenspace coordinates, calculate the line passing through the scene. Typically used for tracking intersection points for the mouse cursor.

float SbProjector::findVanishingDistance | ( | void |  | ) | const`[protected]`

Finds the unit cube vanishing distance for the current projector view volume. The view volume must be a perspective view volume.

This method was not part of the Inventor v2.1 API, and is an extension specific to Coin.

Since:
  1.1.0

SbBool SbProjector::verifyProjection | ( | const SbVec3f & | projpt | ) | const`[protected]`

Verifies that projpt is a valid projection for the current view volume. For perspective view volumes, it does this by checking that the projection point is in front of the eye plane. For orthographic projections, this method always returns TRUE.

This method was not part of the Inventor v2.1 API, and is an extension specific to Coin.

Since:
  1.1.0

## Member Data Documentation

SbProjector::viewVol `[protected]`

| The viewVol definition.

SbProjector::worldToWorking `[protected]`

| The matrix which converts from world coordinates to coordinates in the projector's local coordinate system.

SbProjector::workingToWorld `[protected]`

| The matrix which converts from coordinates in the projector's local coordinate system to world coordinates.

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

- SbProjector.h
- SbProjector.cpp