LightDesc Class Reference

#include <imtl.h>

Class Description

See also

Class RenderData, Class LightRayTraversal, Class ObjLightDesc, Class ShadeContext, Class Color, Class Point3.

Description:

This class has a method Illuminate() used to determine the color and direction of the light striking the point sc.P() and a method to get the position of the light. It also has two public data members that determine if the diffuse and specular colors of objects are affected.

Data Members:

BOOL affectDiffuse;

This data member is available in release 2.0 and later only.

If TRUE the light affects the diffuse color; otherwise it does not.

BOOL affectSpecular;

This data member is available in release 2.0 and later only.

If TRUE the light affects the specular color; otherwise it does not.

BOOL ambientOnly;

This data member is available in release 3.0 and later only.

If TRUE the light affects the ambient color only; otherwise it does not.

DWORD extra;

This data member is available in release 3.0 and later only.

This is not currently used and is available for use in the future.

Inheritance diagram for LightDesc:

Public Member Functions
	LightDesc ()
virtual BOOL	Illuminate (ShadeContext &sc, Point3 &normal, Color &color, Point3 &dir, float &dot_nl, float &diffuseCoef)
virtual Point3	LightPosition ()
virtual CoreExport void	DeleteThis ()
Public Member Functions inherited from RenderData
virtual INT_PTR	Execute (int cmd, ULONG_PTR arg1=0, ULONG_PTR arg2=0, ULONG_PTR arg3=0)
Public Member Functions inherited from InterfaceServer
virtual UtilExport	~InterfaceServer ()
	Destructor. More...
virtual UtilExport BaseInterface *	GetInterface (Interface_ID id)

Public Attributes
BOOL	affectDiffuse
BOOL	affectSpecular
BOOL	ambientOnly
DWORD	extra

Additional Inherited Members
Static Public Member Functions inherited from MaxHeapOperators
static UtilExport void *	operator new (size_t size)
	Standard new operator used to allocate objects If there is insufficient memory, an exception will be thrown. More...
static UtilExport void *	operator new (size_t size, const std::nothrow_t &e)
	Standard new operator used to allocate objects if there is insufficient memory, NULL will be returned. More...
static UtilExport void *	operator new (size_t size, const char *filename, int line)
	New operator used to allocate objects that takes the filename and line number where the new was called If there is insufficient memory, an exception will be thrown. More...
static UtilExport void *	operator new (size_t size, int block_type, const char *filename, int line)
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static UtilExport void *	operator new (size_t size, const std::nothrow_t &e, const char *filename, int line)
	New operator used to allocate objects that takes the filename and line number where the new was called If there is insufficient memory, NULL will be returned. More...
static UtilExport void *	operator new (size_t size, unsigned long flags)
	New operator used to allocate objects that takes extra flags to specify special operations If there is insufficient memory, an exception will be thrown. More...
static UtilExport void *	operator new (size_t size, const std::nothrow_t &e, unsigned long flags)
	New operator used to allocate objects that takes extra flags to specify special operations If there is insufficient memory, NULL will be returned. More...
static UtilExport void *	operator new[] (size_t size)
	New operator used to allocate arrays of objects If there is insufficient memory, an exception will be thrown. More...
static UtilExport void *	operator new[] (size_t size, const std::nothrow_t &e)
	New operator used to allocate arrays of objects If there is insufficient memory, NULL will be returned. More...
static UtilExport void *	operator new[] (size_t size, const char *filename, int line)
	New operator used to allocate arrays of objects If there is insufficient memory, an exception will be thrown. More...
static UtilExport void *	operator new[] (size_t size, int block_type, const char *filename, int line)
	New operator used to allocate arrays of objects. More...
static UtilExport void *	operator new[] (size_t size, const std::nothrow_t &e, const char *filename, int line)
	New operator used to allocate arrays of objects If there is insufficient memory, NULL will be returned. More...
static UtilExport void *	operator new[] (size_t size, unsigned long flags)
	New operator used to allocate arrays of objects If there is insufficient memory, an exception will be thrown. More...
static UtilExport void *	operator new[] (size_t size, const std::nothrow_t &e, unsigned long flags)
	New operator used to allocate arrays of objects If there is insufficient memory, NULL will be returned. More...
static UtilExport void	operator delete (void *ptr)
	Standard delete operator used to deallocate an object If the pointer is invalid, an exception will be thrown. More...
static UtilExport void	operator delete (void *ptr, const std::nothrow_t &e)
	Standard delete operator used to deallocate an object If the pointer is invalid, nothing will happen. More...
static UtilExport void	operator delete (void *ptr, const char *filename, int line)
	Delete operator used to deallocate an object that takes the filename and line number where the delete was called If the pointer is invalid, an exception will be thrown. More...
static UtilExport void	operator delete (void *ptr, int block_type, const char *filename, int line)
	Delete operator used to deallocate an object that takes the type of memory, filename and line number where the delete was called If the pointer is invalid, an exception will be thrown. More...
static UtilExport void	operator delete (void *ptr, const std::nothrow_t &e, const char *filename, int line)
	Delete operator used to deallocate an object that takes the filename and line number where the delete was called If the pointer is invalid, nothing will happen. More...
static UtilExport void	operator delete (void *ptr, unsigned long flags)
	Delete operator used to deallocate an object that takes extra flags to specify special operations If the pointer is invalid, an exception will be thrown. More...
static UtilExport void	operator delete (void *ptr, const std::nothrow_t &e, unsigned long flags)
	Delete operator used to deallocate an object that takes extra flags to specify special operations If the pointer is invalid, nothing will happen. More...
static UtilExport void	operator delete[] (void *ptr)
	Standard delete operator used to deallocate an array of objects If the pointer is invalid, an exception will be thrown. More...
static UtilExport void	operator delete[] (void *ptr, const std::nothrow_t &e)
	Standard delete operator used to deallocate an array of objects If the pointer is invalid, nothing will happen. More...
static UtilExport void	operator delete[] (void *ptr, const char *filename, int line)
	Delete operator used to deallocate an array of objects that takes the filename and line number where the delete was called If the pointer is invalid, an exception will be thrown. More...
static UtilExport void	operator delete[] (void *ptr, int block_type, const char *filename, int line)
	Delete operator used to deallocate an array of objects that takes the type of memory, filename and line number where the delete was called If the pointer is invalid, an exception will be thrown. More...
static UtilExport void	operator delete[] (void *ptr, const std::nothrow_t &e, const char *filename, int line)
	Delete operator used to deallocate an array of objects that takes the filename and line number where the delete was called If the pointer is invalid, nothing will happen. More...
static UtilExport void	operator delete[] (void *ptr, unsigned long flags)
	Delete operator used to deallocate an array of objects that takes extra flags to specify special operations If the pointer is invalid, an exception will be thrown. More...
static UtilExport void	operator delete[] (void *ptr, const std::nothrow_t &e, unsigned long flags)
	Delete operator used to deallocate an array of objects that takes extra flags to specify special operations If the pointer is invalid, an exception will be thrown. More...
static UtilExport void *	operator new (size_t size, void *placement_ptr)
	Placement new operator. More...
static UtilExport void	operator delete (void *ptr, void *placement_ptr)
	Placement delete operator. More...

Constructor & Destructor Documentation

LightDesc ( )

inline

Remarks

Constructor. The affectDiffuse and affectSpecular data members are set to TRUE.

{ affectDiffuse = affectSpecular = TRUE; ambientOnly = FALSE; }

Member Function Documentation

virtual BOOL Illuminate ( ShadeContext &  sc, Point3 &  normal, Color &  color, Point3 &  dir, float &  dot_nl, float &  diffuseCoef  )

inlinevirtual

Remarks

This method is called to determine the color and direction of illumination from the light that is hitting the point (sc.P()).

Parameters:

ShadeContext& sc

Describes the properties of the point to shade. The point itself is sc.P().

Point3& normal

The normal to the surface in camera space.

Color& color

The color that is returned. This is the brightness of light striking the point (sc.P())

Point3 &dir

The direction that the light is coming from.

float &dot_nl

This provides a bit of optimization as most lights will have to calculate this quantity. This is the dot product between the light vector and the normal to the surface.

float &diffuseCoef

This parameter should be set by the Illuminate function. The default value is the same as dot_nl. It will be used by shading functions instead of dot_nl to compute the diffuse illumination of the surface. The built-in lights use the new "Contrast" parameter (which has a range of [0..100]) to compute the diffuseCoef from the dot_nl by the Contrast function:

// precomputed:
float a = contrast/200.0f + 0.5f;                 // so "a" varies from .5 to 1.0
kA = (2.0f-1.0f/a);
kB = 1.0f-kA;

// called by Illuminate() to compute diffuseCoef from dot_nl.
float ContrastFunc(float nl)
{
// the "Bias" function described in Graphics Gems IV, pp. 401ff
    return (contrast==0.0f)? nl : nl/(kA*nl+kB);
}

Returns

Returns FALSE if the hitpoint is outside the effective range of the light or if the normal of the surface faces away from the light. This is a hint to the material that the light did not calculate its illumination because it is assumed it wasn't going to be used. If TRUE the point is being illuminated.

Default Implementation:

{ return 0;}

{ return 0;}

virtual Point3 LightPosition ( )

inlinevirtual

Remarks

Returns the position of the light.

Default Implementation:

{ return Point3(0,0,0); }

Reimplemented in ObjLightDesc.

{ return Point3(0,0,0); } 

virtual CoreExport void DeleteThis ( )

virtual

Remarks

This method is used to delete an instance of the class.

Default Implementation:

{delete this; }

Implements RenderData.

Member Data Documentation

BOOL affectDiffuse

BOOL affectSpecular

BOOL ambientOnly

DWORD extra