307 lines
13 KiB
C++
307 lines
13 KiB
C++
/*
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* This program source code file is part of KiCad, a free EDA CAD application.
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*
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* Copyright (C) 2015-2016 Mario Luzeiro <mrluzeiro@ua.pt>
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* Copyright (C) 1992-2016 KiCad Developers, see AUTHORS.txt for contributors.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, you may find one here:
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* http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
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* or you may search the http://www.gnu.org website for the version 2 license,
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* or you may write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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/**
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* @file cpostshader_ssao.cpp
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* @brief Implements a post shader screen space ambient occlusion on software
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*/
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#include "cpostshader_ssao.h"
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#include "../3d_fastmath.h"
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CPOSTSHADER_SSAO::CPOSTSHADER_SSAO( const CCAMERA &aCamera ) :
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CPOSTSHADER( aCamera ),
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m_shadedBuffer( nullptr ),
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m_isUsingShadows( false )
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{
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}
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// There are differente sources for this shader on the web
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//https://github.com/scanberg/hbao/blob/master/resources/shaders/ssao_frag.glsl
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//http://www.gamedev.net/topic/556187-the-best-ssao-ive-seen/
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//http://www.gamedev.net/topic/556187-the-best-ssao-ive-seen/?view=findpost&p=4632208
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float CPOSTSHADER_SSAO::aoFF( const SFVEC2I &aShaderPos,
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const SFVEC3F &ddiff,
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const SFVEC3F &cnorm,
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const float aShadowAtSamplePos,
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const float aShadowAtCenterPos,
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int c1,
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int c2 ) const
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{
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const float shadowGain = 0.60f;
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const float aoGain = 1.0f;
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const float shadow_factor_at_sample = ( 1.0f - aShadowAtSamplePos ) * shadowGain;
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const float shadow_factor_at_center = ( 1.0f - aShadowAtCenterPos ) * shadowGain;
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float return_value = shadow_factor_at_center;
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const float rd = glm::length( ddiff );
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// This limits the zero of the function (see below)
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if( rd < 2.0f )
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{
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if( rd > FLT_EPSILON )
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{
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const SFVEC3F vv = glm::normalize( ddiff );
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// Calculate an attenuation distance factor, this was get the best
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// results by experimentation
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// Changing this factor will change how much shadow in relation to the
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// distance of the hit it will be in shadow
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// http://www.fooplot.com/#W3sidHlwZSI6MCwiZXEiOiIwLjgteCowLjYiLCJjb2xvciI6IiMwMDAwMDAifSx7InR5cGUiOjAsImVxIjoiMS8oeCp4KjAuNSsxKSIsImNvbG9yIjoiIzAwMDAwMCJ9LHsidHlwZSI6MTAwMCwid2luZG93IjpbIi0yLjU5Mjk0NTkyNTA5ODA0MSIsIjQuNTUzODc5NjU1NDQ1OTIzIiwiLTEuNzY3MDMwOTAzMjgxNjgxOCIsIjIuNjMxMDE1NjA3ODIyMjk3Il0sInNpemUiOls2NDksMzk5XX1d
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const float attDistFactor = 1.0f / ( rd * rd * 8.0f + 1.0f );
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const SFVEC2I vr = aShaderPos + SFVEC2I( c1, c2 );
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float sampledNormalFactor = glm::max( glm::dot( GetNormalAt( vr ), cnorm ), 0.0f );
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sampledNormalFactor = glm::max( 1.0f - sampledNormalFactor * sampledNormalFactor, 0.0f );
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const float shadowAttDistFactor = glm::max( glm::min( rd * 5.0f - 0.25f, 1.0f ), 0.0f );
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float shadowAttFactor = glm::min( sampledNormalFactor + shadowAttDistFactor, 1.0f );
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const float shadowFactor = glm::mix( shadow_factor_at_sample,
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shadow_factor_at_center,
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shadowAttFactor );
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// This is a dot product threshold factor.
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// it defines after wich angle we consider that the point starts to occlude.
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// if the value is high, it will discard low angles point
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const float aDotThreshold = 0.15f;
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// This is the dot product between the center pixel normal (the one that is being shaded)
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// and the vector from the center to the sampled point
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const float localNormalFactor = glm::dot( cnorm, vv );
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const float localNormalFactorWithThreshold = (glm::max( localNormalFactor, aDotThreshold ) - aDotThreshold) /
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(1.0f - aDotThreshold);
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const float aoFactor = localNormalFactorWithThreshold * aoGain * attDistFactor;
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return_value = glm::min( aoFactor + shadowFactor, 1.0f );
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}
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}
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return return_value;
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}
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float CPOSTSHADER_SSAO::giFF( const SFVEC2I &aShaderPos,
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const SFVEC3F &ddiff,
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const SFVEC3F &cnorm,
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const float aShadow,
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int c1,
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int c2 ) const
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{
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if( (ddiff.x > FLT_EPSILON) ||
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(ddiff.y > FLT_EPSILON) ||
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(ddiff.z > FLT_EPSILON) )
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{
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const SFVEC3F vv = glm::normalize( ddiff );
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const float rd = glm::length( ddiff );
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const SFVEC2I vr = aShaderPos + SFVEC2I( c1, c2 );
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const float attDistFactor = 1.0f / ( rd * rd + 1.0f );
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return ( glm::clamp( glm::dot( GetNormalAt( vr ), -vv), 0.0f, 1.0f ) *
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glm::clamp( glm::dot( cnorm, vv ), 0.0f, 1.0f ) * attDistFactor ) * ( 0.03f + aShadow ) * 3.0f;
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}
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return 0.0f;
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}
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SFVEC3F CPOSTSHADER_SSAO::Shade( const SFVEC2I &aShaderPos ) const
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{
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float cdepth = GetDepthAt( aShaderPos );
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if( cdepth > FLT_EPSILON )
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{
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cdepth = ( 30.0f / ( cdepth * 2.0f + 1.0f ) );
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// read current normal,position and color.
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const SFVEC3F n = GetNormalAt( aShaderPos );
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const SFVEC3F p = GetPositionAt( aShaderPos );
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const float shadowAt0 = GetShadowFactorAt( aShaderPos );
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// initialize variables:
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float ao = 0.0f;
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SFVEC3F gi = SFVEC3F(0.0f);
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#define ROUNDS 3
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for( unsigned int i = 0; i < ROUNDS; ++i )
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{
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static const int limit[ROUNDS] = { 0x01, 0x03, 0x03 };
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const int pw = Fast_rand() & limit[i];
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const int ph = Fast_rand() & limit[i];
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const int npw = (int) ( ( pw + i ) * cdepth ) + ( i + 1 );
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const int nph = (int) ( ( ph + i ) * cdepth ) + ( i + 1 );
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const SFVEC3F ddiff = GetPositionAt( aShaderPos + SFVEC2I( npw, nph ) ) - p;
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const SFVEC3F ddiff2 = GetPositionAt( aShaderPos + SFVEC2I( npw, -nph ) ) - p;
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const SFVEC3F ddiff3 = GetPositionAt( aShaderPos + SFVEC2I( -npw, nph ) ) - p;
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const SFVEC3F ddiff4 = GetPositionAt( aShaderPos + SFVEC2I( -npw, -nph ) ) - p;
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const SFVEC3F ddiff5 = GetPositionAt( aShaderPos + SFVEC2I( pw, nph ) ) - p;
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const SFVEC3F ddiff6 = GetPositionAt( aShaderPos + SFVEC2I( pw, -nph ) ) - p;
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const SFVEC3F ddiff7 = GetPositionAt( aShaderPos + SFVEC2I( npw, ph ) ) - p;
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const SFVEC3F ddiff8 = GetPositionAt( aShaderPos + SFVEC2I(-npw, ph ) ) - p;
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const float shadowAt1 = GetShadowFactorAt( aShaderPos + SFVEC2I( +npw, nph ) );
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const float shadowAt2 = GetShadowFactorAt( aShaderPos + SFVEC2I( +npw, -nph ) );
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const float shadowAt3 = GetShadowFactorAt( aShaderPos + SFVEC2I( -npw, nph ) );
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const float shadowAt4 = GetShadowFactorAt( aShaderPos + SFVEC2I( -npw, -nph ) );
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const float shadowAt5 = GetShadowFactorAt( aShaderPos + SFVEC2I( +pw, nph ) );
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const float shadowAt6 = GetShadowFactorAt( aShaderPos + SFVEC2I( pw, -nph ) );
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const float shadowAt7 = GetShadowFactorAt( aShaderPos + SFVEC2I( npw, ph ) );
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const float shadowAt8 = GetShadowFactorAt( aShaderPos + SFVEC2I( -npw, ph ) );
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ao += aoFF( aShaderPos, ddiff , n, shadowAt1, shadowAt0, npw, nph );
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ao += aoFF( aShaderPos, ddiff2, n, shadowAt2, shadowAt0, npw, -nph );
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ao += aoFF( aShaderPos, ddiff3, n, shadowAt3, shadowAt0, -npw, nph );
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ao += aoFF( aShaderPos, ddiff4, n, shadowAt4, shadowAt0, -npw, -nph );
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ao += aoFF( aShaderPos, ddiff5, n, shadowAt5, shadowAt0, pw, nph );
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ao += aoFF( aShaderPos, ddiff6, n, shadowAt6, shadowAt0, pw, -nph );
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ao += aoFF( aShaderPos, ddiff7, n, shadowAt7, shadowAt0, npw, ph );
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ao += aoFF( aShaderPos, ddiff8, n, shadowAt8, shadowAt0, -npw, ph );
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gi += giFF( aShaderPos, ddiff , n, shadowAt1, npw, nph) *
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giColorCurve( GetColorAt( aShaderPos + SFVEC2I( npw, nph ) ) );
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gi += giFF( aShaderPos, ddiff2, n, shadowAt2, npw, -nph) *
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giColorCurve( GetColorAt( aShaderPos + SFVEC2I( npw,-nph ) ) );
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gi += giFF( aShaderPos, ddiff3, n, shadowAt3, -npw, nph) *
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giColorCurve( GetColorAt( aShaderPos + SFVEC2I( -npw, nph ) ) );
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gi += giFF( aShaderPos, ddiff4, n, shadowAt4, -npw, -nph) *
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giColorCurve( GetColorAt( aShaderPos + SFVEC2I( -npw,-nph ) ) );
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gi += giFF( aShaderPos, ddiff5, n, shadowAt5 , pw, nph) *
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giColorCurve( GetColorAt( aShaderPos + SFVEC2I( pw, nph ) ) );
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gi += giFF( aShaderPos, ddiff6, n, shadowAt6, pw,-nph) *
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giColorCurve( GetColorAt( aShaderPos + SFVEC2I( pw,-nph ) ) );
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gi += giFF( aShaderPos, ddiff7, n, shadowAt7, npw, ph) *
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giColorCurve( GetColorAt( aShaderPos + SFVEC2I( npw, ph ) ) );
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gi += giFF( aShaderPos, ddiff8, n, shadowAt8, -npw, ph) *
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giColorCurve( GetColorAt( aShaderPos + SFVEC2I( -npw, ph ) ) );
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}
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// If it received direct light, it shouldn't consider much AO
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// shadowAt0 1.0 when no shadow
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const float reduceAOwhenNoShadow = m_isUsingShadows ? ( 1.0f - shadowAt0 * 0.3f ) : 1.0f;
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ao = reduceAOwhenNoShadow * ( ao / ( ROUNDS * 8.0f ) );
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ao = ( 1.0f - 1.0f / ( ao * ao * 5.0f + 1.0f ) ) * 1.2f;
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gi = ( gi / ( ROUNDS * 8.0f ) );
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float giL = glm::min( glm::length( gi ) * 4.0f, 1.0f );
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giL = ( 1.0f - 1.0f / ( giL * 4.0f + 1.0f ) ) * 1.5f;
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return glm::mix( SFVEC3F( ao ), -gi, giL );
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}
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else
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return SFVEC3F(0.0f);
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}
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SFVEC3F CPOSTSHADER_SSAO::ApplyShadeColor( const SFVEC2I &aShaderPos, const SFVEC3F &aInputColor, const SFVEC3F &aShadeColor ) const
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{
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SFVEC3F outColor;
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const SFVEC3F subtracted = aInputColor - aShadeColor;
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const SFVEC3F mixed = glm::mix( aInputColor,
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aInputColor * 0.50f - aShadeColor * 0.05f,
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glm::min( aShadeColor, 1.0f ) );
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outColor.r = ( aShadeColor.r < 0.0f ) ? subtracted.r : mixed.r;
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outColor.g = ( aShadeColor.g < 0.0f ) ? subtracted.g : mixed.g;
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outColor.b = ( aShadeColor.b < 0.0f ) ? subtracted.b : mixed.b;
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return outColor;
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}
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SFVEC3F CPOSTSHADER_SSAO::giColorCurve( const SFVEC3F &aColor ) const
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{
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const SFVEC3F vec1 = SFVEC3F(1.0f);
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// This option actually apply a gama since we are using linear color space
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// and the result shader will be applied after convert back to sRGB
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// http://fooplot.com/#W3sidHlwZSI6MCwiZXEiOiIxLjAtKDEuMC8oeCo5LjArMS4wKSkreCowLjEiLCJjb2xvciI6IiMwMDAwMDAifSx7InR5cGUiOjEwMDAsIndpbmRvdyI6WyItMC4wNjIxODQ2MTUzODQ2MTU1MDUiLCIxLjE0Mjk4NDYxNTM4NDYxNDYiLCItMC4xMjcwOTk5OTk5OTk5OTk3NyIsIjEuMTMyNiJdfV0-
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return vec1 - ( vec1 / (aColor * SFVEC3F(9.0f) + vec1) ) + aColor * SFVEC3F(0.10f);
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}
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SFVEC3F CPOSTSHADER_SSAO::Blur( const SFVEC2I& aShaderPos ) const
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{
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const float dCenter = GetDepthAt( aShaderPos );
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SFVEC3F shadedOut = SFVEC3F( 0.0f );
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float totalWeight = 1.0f;
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for( int y = -3; y < 3; y++ )
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{
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for( int x = -3; x < 3; x++ )
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{
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const unsigned int idx = GetIndex( SFVEC2I( aShaderPos.x + x, aShaderPos.y + y ) );
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const SFVEC3F s = m_shadedBuffer[idx];
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if( !( ( x == 0 ) && ( y == 0 ) ) )
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{
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const float d = GetDepthAt( SFVEC2I( aShaderPos.x + x, aShaderPos.y + y ) );
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const float depthAtt = ( dCenter - d ) * dCenter
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* 25.0f; // increse the value will get more sharpness effect
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const float depthAttSqr = depthAtt * depthAtt;
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float weight = ( 1.0f / ( depthAttSqr + 1.0f ) ) - 0.02f * depthAttSqr;
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weight = glm::max( weight, 0.0f );
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shadedOut += s * weight;
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totalWeight += weight;
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}
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else
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{
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shadedOut += s;
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}
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}
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}
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return shadedOut / totalWeight;
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}
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