kicad/3d-viewer/3d_math.h

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/*
* This program source code file is part of KiCad, a free EDA CAD application.
*
* Copyright (C) 2015-2016 Mario Luzeiro <mrluzeiro@ua.pt>
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* Copyright (C) 1992-2020 KiCad Developers, see AUTHORS.txt for contributors.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, you may find one here:
* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
* or you may search the http://www.gnu.org website for the version 2 license,
* or you may write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*/
/**
* @file 3d_math.h
* @brief Defines math related functions
*/
#ifndef _3D_MATH_H
#define _3D_MATH_H
#include <plugins/3dapi/xv3d_types.h>
#include "3d_fastmath.h"
/**
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* https://en.wikipedia.org/wiki/Spherical_coordinate_system
*
* @param aInclination θ [0, π]
* @param aAzimuth φ [0, 2π]
* @return Cartesian coordinates
*/
inline SFVEC3F SphericalToCartesian( float aInclination, float aAzimuth )
{
float sinInc = glm::sin( aInclination );
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return SFVEC3F( sinInc * glm::cos( aAzimuth ), sinInc * glm::sin( aAzimuth ),
glm::cos( aInclination ) );
}
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/**
* @todo This is not correct because it is not a gaussian random.
*/
inline SFVEC3F UniformRandomHemisphereDirection()
{
// It was experienced that this function is slow! do not use it :/
// SFVEC3F b( (rand()/(float)RAND_MAX) - 0.5f,
// (rand()/(float)RAND_MAX) - 0.5f,
// (rand()/(float)RAND_MAX) - 0.5f );
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SFVEC3F b( Fast_RandFloat() * 0.5f, Fast_RandFloat() * 0.5f, Fast_RandFloat() * 0.5f );
return b;
}
// https://pathtracing.wordpress.com/2011/03/03/cosine-weighted-hemisphere/
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inline SFVEC3F CosWeightedRandomHemisphereDirection( const SFVEC3F& n )
{
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const float Xi1 = (float) rand() / (float) RAND_MAX;
const float Xi2 = (float) rand() / (float) RAND_MAX;
const float theta = acos( sqrt( 1.0f - Xi1 ) );
const float phi = 2.0f * glm::pi<float>() * Xi2;
const float xs = sinf( theta ) * cosf( phi );
const float ys = cosf( theta );
const float zs = sinf( theta ) * sinf( phi );
const SFVEC3F y( n.x, n.y, n.z );
SFVEC3F h = y;
if( fabs( h.x ) <= fabs( h.y ) && fabs( h.x ) <= fabs( h.z ) )
h.x= 1.0f;
else if( fabs( h.y ) <= fabs( h.x ) && fabs( h.y ) <= fabs( h.z ) )
h.y= 1.0f;
else
h.z= 1.0f;
const SFVEC3F x = glm::normalize( glm::cross( h, y ) );
const SFVEC3F z = glm::normalize( glm::cross( x, y ) );
SFVEC3F direction = xs * x + ys * y + zs * z;
return glm::normalize( direction );
}
/**
* Based on:
* https://github.com/mmp/pbrt-v3/blob/master/src/core/reflection.h
* See also:
* http://www.flipcode.com/archives/Raytracing_Topics_Techniques-Part_3_Refractions_and_Beers_Law.shtml
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*
* @param aInVector incoming vector.
* @param aNormal normal in the intersection point.
* @param aRin_over_Rout incoming refraction index / out refraction index.
* @param aOutVector the refracted vector.
* @return true
*/
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inline bool Refract( const SFVEC3F &aInVector, const SFVEC3F &aNormal, float aRin_over_Rout,
SFVEC3F& aOutVector )
{
float cosThetaI = -glm::dot( aNormal, aInVector );
float sin2ThetaI = glm::max( 0.0f, 1.0f - cosThetaI * cosThetaI );
float sin2ThetaT = aRin_over_Rout * aRin_over_Rout * sin2ThetaI;
// Handle total internal reflection for transmission
if( sin2ThetaT >= 1.0f )
return false;
float cosThetaT = sqrtf( 1.0f - sin2ThetaT );
aOutVector = glm::normalize( aRin_over_Rout * aInVector +
( aRin_over_Rout * cosThetaI - cosThetaT ) *
aNormal );
return true;
}
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inline float mapf( float x, float in_min, float in_max, float out_min, float out_max )
{
x = glm::clamp( x, in_min, in_max );
return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}
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inline float RGBtoGray( const SFVEC3F &aColor )
{
return (aColor.r * 0.2126f +
aColor.g * 0.7152f +
aColor.b * 0.0722f);
}
inline SFVEC3F MaterialDiffuseToColorCAD( const SFVEC3F &aDiffuseColor )
{
// convert to a discret scale of grays
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const float luminance = glm::min(
( ( (float) ( (unsigned int) ( 4.0f * RGBtoGray( aDiffuseColor ) ) ) + 0.5f ) / 4.0f )
* 1.0f,
1.0f );
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const float maxValue = glm::max( glm::max( glm::max( aDiffuseColor.r, aDiffuseColor.g ),
aDiffuseColor.b ), FLT_EPSILON );
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return ( aDiffuseColor / SFVEC3F( maxValue ) ) * 0.125f + luminance * 0.875f;
}
// http://fooplot.com/#W3sidHlwZSI6MCwiZXEiOiJ4KngqMiIsImNvbG9yIjoiIzAwMDAwMCJ9LHsidHlwZSI6MCwiZXEiOiItKCh4LTEpXjIpKjIrMSIsImNvbG9yIjoiIzAwMDAwMCJ9LHsidHlwZSI6MTAwMCwid2luZG93IjpbIi0xLjM4NzUwMDAwMDAwMDAwMDIiLCIxLjg2MjQ5OTk5OTk5OTk5OTgiLCItMC43IiwiMS4zIl19XQ--
inline float QuadricEasingInOut( float t )
{
if( t <= 0.5f )
{
return t * t * 2.0f;
}
else
{
t = t - 1.0f;
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return -2.0f * ( t * t ) + 1.0f;
}
}
// http://www.wolframalpha.com/input/?i=t%5E2(3-2t)
inline float BezierBlend( float t )
{
return t * t * ( 3.0f - 2.0f * t );
}
#endif // 3D_MATH_H