SLRaySamples2D Class Reference

Class for 2D disk sample points. More...

#include <SLRaySamples2D.h>

Public Member Functions
	SLRaySamples2D ()
	~SLRaySamples2D ()
void	samples (SLuint x, SLuint y, SLbool evenlyDistributed=true)
	Resets the sample point array by the sqrt of the no. of samples. More...
void	point (SLuint x, SLuint y, SLVec2f point)
SLuint	samplesX ()
SLuint	samplesY ()
SLuint	samples ()
SLVec2f	point (SLuint x, SLuint y)
SLuint	sizeInBytes ()

Private Member Functions
void	distribConcentric (SLbool evenlyDistributed)
SLVec2f	mapSquareToDisc (SLfloat x, SLfloat y)

Private Attributes
SLuint	_samplesX
	No. of samples in x direction. More...
SLuint	_samplesY
	No. of samples in y direction. More...
SLuint	_samples
	No. of samples = samplesX x samplesY. More...
SLVVec2f	_points
	samplepoints for distributed tracing More...

Detailed Description

Class for 2D disk sample points.

Definition at line 18 of file SLRaySamples2D.h.

Constructor & Destructor Documentation

SLRaySamples2D()

SLRaySamples2D::SLRaySamples2D ( )

inline

Definition at line 21 of file SLRaySamples2D.h.

{ samples(1, 1); }

~SLRaySamples2D()

SLRaySamples2D::~SLRaySamples2D ( )

inline

Definition at line 22 of file SLRaySamples2D.h.

{}

Member Function Documentation

distribConcentric()

void SLRaySamples2D::distribConcentric ( SLbool  evenlyDistributed )

private

Makes concentric 2D-samples points within a circle of certain radius. With the parameter evenlyDistributed=false will the samplepoints be denser towards the center.

Definition at line 31 of file SLRaySamples2D.cpp.

{
    if (_points.size())
    {
        SLfloat halfDeltaPhi = Utils::TWOPI / _samplesY * 0.5f;
        SLfloat phi, r, last_r = 1.0f;
 
        // Loop over radius r and angle phi
        for (SLint iR = (SLint)_samplesX - 1; iR >= 0; --iR)
        {
            r = ((SLfloat)iR) / _samplesX;
            if (evenlyDistributed) r = sqrt(r);
            r += (last_r - r) * 0.5f;
 
            // every 2nd circle is rotated by have delta phi for better distribution
            SLfloat iModPhi = (iR % 2) * halfDeltaPhi;
            for (SLint iPhi = (SLint)_samplesY - 1; iPhi >= 0; --iPhi)
            {
                phi = Utils::TWOPI * ((SLfloat)iPhi) / _samplesY + iModPhi;
                point((SLuint)iR, (SLuint)iPhi, SLVec2f(r * cos(phi), r * sin(phi)));
            }
            last_r = r;
        }
    }
}

mapSquareToDisc()

SLVec2f SLRaySamples2D::mapSquareToDisc ( SLfloat  x, SLfloat  y  )

private

Concentric mapping of a x,y-position Code taken from Peter Shirley out of "Realistic Ray Tracing"

Definition at line 60 of file SLRaySamples2D.cpp.

{
    SLfloat phi, r, u, v;
    SLfloat a = 2 * x - 1;
    SLfloat b = 2 * y - 1;
 
    if (a > -b)
    {
        if (a > b)
        {
            r   = a;
            phi = (Utils::PI / 4) * (b / a);
        }
        else
        {
            r   = b;
            phi = (Utils::PI / 4) * (2 - a / b);
        }
    }
    else
    {
        if (a < b)
        {
            r   = -a;
            phi = (Utils::PI / 4) * (4 + b / a);
        }
        else
        {
            r = -b;
            if (b != 0)
            {
                phi = (Utils::PI / 4) * (6 - a / b);
            }
            else
                phi = 0;
        }
    }
    u = r * cos(phi);
    v = r * sin(phi);
    return SLVec2f(u, v);
}

point() [1/2]

SLVec2f SLRaySamples2D::point ( SLuint  x, SLuint  y  )

inline

Definition at line 34 of file SLRaySamples2D.h.

{ return _points[x * _samplesY + y]; }

point() [2/2]

void SLRaySamples2D::point ( SLuint  x, SLuint  y, SLVec2f  point  )

inline

Definition at line 26 of file SLRaySamples2D.h.

    {
        _points[x * _samplesY + y].set(point);
    }

samples() [1/2]

SLuint SLRaySamples2D::samples ( )

inline

Definition at line 33 of file SLRaySamples2D.h.

{ return _samples; }

samples() [2/2]

void SLRaySamples2D::samples	(	SLuint	x,
		SLuint	y,
		SLbool	evenlyDistributed = true
	)

Resets the sample point array by the sqrt of the no. of samples.

Definition at line 16 of file SLRaySamples2D.cpp.

{
    assert(x > 0 && y > 0);
    _samplesX = x;
    _samplesY = y;
    _samples  = x * y;
    _points.resize(_samples);
    if (_samples > 1) distribConcentric(evenlyDistributed);
}

samplesX()

SLuint SLRaySamples2D::samplesX ( )

inline

Definition at line 31 of file SLRaySamples2D.h.

{ return _samplesX; }

samplesY()

SLuint SLRaySamples2D::samplesY ( )

inline

Definition at line 32 of file SLRaySamples2D.h.

{ return _samplesY; }

sizeInBytes()

SLuint SLRaySamples2D::sizeInBytes ( )

inline

Definition at line 35 of file SLRaySamples2D.h.

{ return (SLuint)(_points.size() * sizeof(SLVec2f)); }

Member Data Documentation

_points

SLVVec2f SLRaySamples2D::_points

private

samplepoints for distributed tracing

Definition at line 44 of file SLRaySamples2D.h.

_samples

SLuint SLRaySamples2D::_samples

private

No. of samples = samplesX x samplesY.

Definition at line 43 of file SLRaySamples2D.h.

_samplesX

SLuint SLRaySamples2D::_samplesX

private

No. of samples in x direction.

Definition at line 41 of file SLRaySamples2D.h.

_samplesY

SLuint SLRaySamples2D::_samplesY

private

No. of samples in y direction.

Definition at line 42 of file SLRaySamples2D.h.

---

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

• SLRaySamples2D.h
• SLRaySamples2D.cpp