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/******************************************************************/
/* This file is part of the homework assignments for CSCI-427/527 */
/* at The College of William & Mary and authored by Pieter Peers. */
/* No part of this file, whether altered or in original form, can */
/* be distributed or used outside the context of CSCI-427/527 */
/* without consent of either the College of William & Mary or */
/* Pieter Peers. */
/******************************************************************/
#include <cmath>
#include "constants.h"
#include "phongBrdf.h"
//////////////////
// Constructors //
//////////////////
phongBrdf::phongBrdf(const color& albedo, float sharpness)
{
_albedo = albedo;
_sharpness = sharpness;
}
phongBrdf::phongBrdf(const phongBrdf& src)
{
_albedo = src._albedo;
_sharpness = src._sharpness;
}
///////////////
// Operators //
///////////////
phongBrdf& phongBrdf::operator=(const phongBrdf& src)
{
_assign(src);
return *this;
}
/////////////
// Methods //
/////////////
color phongBrdf::shade(const vec3d& in, const vec3d& out) const
{
// HW3: Implement this.
// Returns the phong shaded color from a specular surface for an
// incident lighting direction of 'in', and view direction of 'out'.
// The surface normal = (0,0,1).
// Returns: shaded color
// Modifies: nothing.
if (out.z < EPSILON) { return color(0.0f); }
vec3d normal, r;
float r_dot_out;
normal = vec3d(0, 0, 1);
r = (2 * normal.dot(in) * normal) - in;
r_dot_out = r.dot(out);
if (r_dot_out < EPSILON) { return color(0.0f); }
else if (r_dot_out > EPSILON + 1) { r_dot_out = 1; }
return color(_albedo * pow(r_dot_out, _sharpness));
}
bool phongBrdf::isSpecular(void) const
{
// Consider low roughness to be diffuse.
// Use 5.0f as an arbitrary threshold.
return (_sharpness > 5.0f);
}
bool phongBrdf::isDiffuse(void) const
{
return !isSpecular();
}
/////////////////////
// Private Methods //
/////////////////////
void phongBrdf::_assign(const phongBrdf& src)
{
_albedo = src._albedo;
_sharpness = src._sharpness;
}
void phongBrdf::_swap(phongBrdf& src)
{
swap(_albedo, src._albedo);
std::swap(_sharpness, src._sharpness);
}
void phongBrdf::_print(std::ostream& s) const
{
s << "Phong BRDF: albedo=" << _albedo << ", sharpness=" << _sharpness;
}
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