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flare.hpp
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flare.hpp
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/**********************************************************\
*
* Hongwei Li
* Copyright (c) Hongwei Li
*
* File Name:
*
* flare.hpp
*
* Abstract:
*
* Small disk-like shape in the lens flare effect.
*
* Author:
*
* Hongwei Li
*
* History:
*
* Created on 2010-09-25 by hongwei.li@family.ust.hk
*
**********************************************************/
#ifndef FLARE_HPP
#define FLARE_HPP
// \brief the basic one, just a cirle (thin ring)
class Flare
{
public:
// \brief constructor
// \param canvasWidth the width of the canvas.
// \param canvasHeight ditto.
// \param cx the x corodinate of the center.
// \param cy ditto.
// \pram radius the radius of the circle.
// \param thickness the thickness of the circle.
// \praram rgb the color of the ring.
Flare(int canvasWidth,
int canvasHeight,
int cx,
int cy,
float radius,
float thickness,
float rgb[])
{
m_canvasWidth = canvasWidth;
m_canvasHeight = canvasHeight;
m_cx = cx;
m_cy = cy;
m_radius = radius;
m_innerRadius = radius - thickness * 0.5f;
m_outerRadius = radius + thickness * 0.5f;
m_thickness = thickness;
m_rgb[0] = rgb[0];
m_rgb[1] = rgb[1];
m_rgb[2] = rgb[2];
};
// \brief get the pixel of the canvas in which
// the circle is.
//
// \param i the pixel y coordinate.
// \param j the pixel x coordinate.
// \param c the returned color of the pixel.
void GetPixel(int i, int j, float c[])
{
float dx = (float)(j - m_cx);
float dy = (float)(i - m_cy);
float d = sqrt(dx * dx + dy * dy);
float d1 = d - m_innerRadius;
float d2 = d - m_outerRadius;
// Out of the circle.
if (d1 < 0 || d2 > 0)
{
c[0] = c[1] = c[2] = 0;
return;
}
c[0] = m_rgb[0];
c[1] = m_rgb[1];
c[2] = m_rgb[2];
// Anti-aliasing
if (d1 < 1.0f)
{
c[0] *= d1;
c[1] *= d1;
c[2] *= d1;
}
else if (d2 > -1.0f)
{
d2 = -d2;
c[0] *= d2;
c[1] *= d2;
c[2] *= d2;
}
};
private:
int m_canvasWidth; // FIXME: no use now.
int m_canvasHeight;
int m_cx;
int m_cy;
float m_radius;
float m_thickness;
float m_rgb[3];
float m_innerRadius;
float m_outerRadius;
};
// \brief the solid disk.
class FlareSolid
{
public:
FlareSolid(int canvasWidth,
int canvasHeight,
int cx,
int cy,
float radius,
float rgb[])
{
m_canvasWidth = canvasWidth;
m_canvasHeight = canvasHeight;
m_cx = cx;
m_cy = cy;
m_radius = radius;
m_rgb[0] = rgb[0];
m_rgb[1] = rgb[1];
m_rgb[2] = rgb[2];
};
void GetPixel(int i , int j, float c[])
{
float dx = (float)(j - m_cx);
float dy = (float)(i - m_cy);
float d = sqrt(dx * dx + dy * dy);
float o = d - m_radius;
// Out of the circle.
if (o > 0)
{
c[0] = c[1] = c[2] = 0;
return;
}
c[0] = m_rgb[0];
c[1] = m_rgb[1];
c[2] = m_rgb[2];
// Anti-aliasing
if (o > -1.0f)
{
o = -o;
c[0] *= o;
c[1] *= o;
c[2] *= o;
}
};
private:
int m_canvasWidth; // FIXME: no use now.
int m_canvasHeight;
int m_cx;
int m_cy;
float m_radius;
float m_rgb[3];
};
// \brief the solid disk with gradient filling inside.
class FlareGradient
{
public:
FlareGradient(int canvasWidth,
int canvasHeight,
int cx,
int cy,
float radius,
float rgb[],
float gamma)
{
m_canvasWidth = canvasWidth;
m_canvasHeight = canvasHeight;
m_cx = cx;
m_cy = cy;
m_radius = radius;
m_rgb[0] = rgb[0];
m_rgb[1] = rgb[1];
m_rgb[2] = rgb[2];
m_gamma = gamma;
};
void GetPixel(int i , int j, float c[])
{
float dx = (float)(j - m_cx);
float dy = (float)(i - m_cy);
float d = sqrt(dx * dx + dy * dy);
float o = d - m_radius;
// Out of the circle.
if (o > 0)
{
c[0] = c[1] = c[2] = 0;
return;
}
c[0] = m_rgb[0];
c[1] = m_rgb[1];
c[2] = m_rgb[2];
// FIXME: the faster sigma computation
// TODO: using lookup table?
float sigma = pow(1.0f - d / m_radius, m_gamma);
// Gradient
c[0] *= sigma;
c[1] *= sigma;
c[2] *= sigma;
};
private:
int m_canvasWidth; // FIXME: no use now.
int m_canvasHeight;
int m_cx;
int m_cy;
float m_radius;
float m_rgb[3];
float m_gamma;
};
#endif // !FLARE_HPP