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BoundingShape Class Reference

This is the basis class for all bounding shapes. More...

#include <BoundingShape.h>

Inheritance diagram for BoundingShape

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Collaboration diagram for BoundingShape:

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List of all members.

Public Methods

 DECLARE_ABSTRACT_CLASS (BoundingShape,Object3D)
 BoundingShape ()
virtual ~BoundingShape ()
virtual bool hit (Ray *pRay)
 Test if the ray hits the bounding shape. More...

virtual bool hit (Ray *pRay,Vector3 &p1,Vector3 &p2)
 Test if the ray hits the bounding shape. More...

virtual bool getBounds (Bounds &bounds)const
 Query for the bounding box of the BoundingShape. More...


Detailed Description

This is the basis class for all bounding shapes.

Other raytracers use any Primitive Object also as a possible Boundingshape (e.g. POV-Ray). So why is it done differently here? Surly the same approach might fit here, but a explicit BoundingShape type fits better. Let's see why. First a bounding shape ist much more simple than a primitive. A primitive must contain code to accuratly calculate the intersection point. A bounding shape simply has to say "ray might intersect" or "ray definitly misses". So we have a boolean function instead of a 'heavy' point calculation. Also considerations for more than 1 intersection point are simply useless in a bounding shape. Normal and Texture calculations are also obsolete in a bounding shape. So what can we lean about it, use objects that fits it's purpose. This rule especially applies in performance questions. Hey and raytracing is time consuming enough. So let's take the chance an optimize the whole bounding shape stuff. Making a bounding shape what it is, much more simpler (in functionally and computation time) than the primitive "hiding" behind it.


Member Function Documentation

bool BoundingShape::getBounds ( Bounds & bounds ) const [virtual]
 

Query for the bounding box of the BoundingShape.

Parameters:
bounds   : bounds object containing the bounding area (box)
Returns:
false - inifite primitive (without bounds) true - non-infite primitive (with bounds)

bool BoundingShape::hit ( Ray * pRay,
Vector3 & p1,
Vector3 & p2 ) [virtual]
 

Test if the ray hits the bounding shape.

No intersection are calculated. NOTE: Only the miss case must be calculated with certainty. The hit case might also miss the shape (thats not good, but acceptable if calculation is faster) Keep in mind it's nothing you can see, its purely to speedup rendering.

RayArea: 0 <= distance < infinity

Parameters:
pRay   : the ray the intersection should made with
p1, p2   : two bounding intersection points
Returns:
true - intersection may exist (hit) false - no intersection exist (miss)

bool BoundingShape::hit ( Ray * pRay ) [virtual]
 

Test if the ray hits the bounding shape.

No intersection are calculated. NOTE: Only the miss case must be calculated with certainty. The hit case might also miss the shape (thats not good, but acceptable if calculation is faster) Keep in mind it's nothing you can see, its purely to speedup rendering.

RayArea: 0 <= distance < infinity

Parameters:
pRay   : the ray the intersection should made with
Returns:
true - intersection may exist (hit) false - no intersection exist (miss)


The documentation for this class was generated from the following file:
  • BoundingShape.h
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Copyright (c) 2001 Stefan Michel, All Rights Reserved.
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