1 /*
2 * This program source code file is part of KiCad, a free EDA CAD application.
3 *
4 * Copyright (C) 2015-2016 Mario Luzeiro <mrluzeiro@ua.pt>
5 * Copyright (C) 2015-2020 KiCad Developers, see AUTHORS.txt for contributors.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2
10 * of the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, you may find one here:
19 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
20 * or you may search the http://www.gnu.org website for the version 2 license,
21 * or you may write to the Free Software Foundation, Inc.,
22 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
23 */
24
25 /**
26 * @file post_shader_ssao.cpp
27 * @brief Implement a post shader screen space ambient occlusion in software.
28 */
29
30 #include "post_shader_ssao.h"
31 #include "../3d_fastmath.h"
32
33
POST_SHADER_SSAO(const CAMERA & aCamera)34 POST_SHADER_SSAO::POST_SHADER_SSAO( const CAMERA& aCamera ) :
35 POST_SHADER( aCamera ),
36 m_shadedBuffer( nullptr ),
37 m_isUsingShadows( false )
38 {
39 }
40
41 // There are different sources for this shader on the web
42 //https://github.com/scanberg/hbao/blob/master/resources/shaders/ssao_frag.glsl
43
44 //http://www.gamedev.net/topic/556187-the-best-ssao-ive-seen/
45 //http://www.gamedev.net/topic/556187-the-best-ssao-ive-seen/?view=findpost&p=4632208
46
aoFF(const SFVEC2I & aShaderPos,const SFVEC3F & ddiff,const SFVEC3F & cnorm,const float aShadowAtSamplePos,const float aShadowAtCenterPos,int c1,int c2) const47 float POST_SHADER_SSAO::aoFF( const SFVEC2I& aShaderPos, const SFVEC3F& ddiff,
48 const SFVEC3F& cnorm, const float aShadowAtSamplePos,
49 const float aShadowAtCenterPos, int c1, int c2 ) const
50 {
51 const float shadowGain = 0.60f;
52 const float aoGain = 1.0f;
53
54 const float shadow_factor_at_sample = ( 1.0f - aShadowAtSamplePos ) * shadowGain;
55 const float shadow_factor_at_center = ( 1.0f - aShadowAtCenterPos ) * shadowGain;
56
57 float return_value = shadow_factor_at_center;
58
59 const float rd = glm::length( ddiff );
60
61 // This limits the zero of the function (see below)
62 if( rd < 2.0f )
63 {
64 if( rd > FLT_EPSILON )
65 {
66 const SFVEC3F vv = glm::normalize( ddiff );
67
68 // Calculate an attenuation distance factor, this was get the best
69 // results by experimentation
70 // Changing this factor will change how much shadow in relation to the
71 // distance of the hit it will be in shadow
72
73 // http://www.fooplot.com/#W3sidHlwZSI6MCwiZXEiOiIwLjgteCowLjYiLCJjb2xvciI6IiMwMDAwMDAifSx7InR5cGUiOjAsImVxIjoiMS8oeCp4KjAuNSsxKSIsImNvbG9yIjoiIzAwMDAwMCJ9LHsidHlwZSI6MTAwMCwid2luZG93IjpbIi0yLjU5Mjk0NTkyNTA5ODA0MSIsIjQuNTUzODc5NjU1NDQ1OTIzIiwiLTEuNzY3MDMwOTAzMjgxNjgxOCIsIjIuNjMxMDE1NjA3ODIyMjk3Il0sInNpemUiOls2NDksMzk5XX1d
74 const float attDistFactor = 1.0f / ( rd * rd * 8.0f + 1.0f );
75
76 const SFVEC2I vr = aShaderPos + SFVEC2I( c1, c2 );
77
78 float sampledNormalFactor = glm::max( glm::dot( GetNormalAt( vr ), cnorm ), 0.0f );
79
80 sampledNormalFactor = glm::max( 1.0f - sampledNormalFactor *
81 sampledNormalFactor, 0.0f );
82
83 const float shadowAttDistFactor = glm::max( glm::min( rd * 5.0f - 0.25f, 1.0f ), 0.0f );
84
85 float shadowAttFactor = glm::min( sampledNormalFactor + shadowAttDistFactor, 1.0f );
86
87 const float shadowFactor = glm::mix( shadow_factor_at_sample, shadow_factor_at_center,
88 shadowAttFactor );
89
90 // This is a dot product threshold factor.
91 // it defines after which angle we consider that the point starts to occlude.
92 // if the value is high, it will discard low angles point
93 const float aDotThreshold = 0.15f;
94
95 // This is the dot product between the center pixel normal (the one that is being
96 // shaded) and the vector from the center to the sampled point
97 const float localNormalFactor = glm::dot( cnorm, vv );
98
99 const float localNormalFactorWithThreshold =
100 ( glm::max( localNormalFactor, aDotThreshold ) - aDotThreshold ) /
101 ( 1.0f - aDotThreshold );
102
103 const float aoFactor = localNormalFactorWithThreshold * aoGain * attDistFactor;
104
105 return_value = glm::min( aoFactor + shadowFactor, 1.0f );
106 }
107 }
108
109 return return_value;
110 }
111
112
giFF(const SFVEC2I & aShaderPos,const SFVEC3F & ddiff,const SFVEC3F & cnorm,const float aShadow,int c1,int c2) const113 float POST_SHADER_SSAO::giFF( const SFVEC2I& aShaderPos, const SFVEC3F& ddiff,
114 const SFVEC3F& cnorm, const float aShadow, int c1, int c2 ) const
115 {
116 if( ( ddiff.x > FLT_EPSILON ) || ( ddiff.y > FLT_EPSILON ) || ( ddiff.z > FLT_EPSILON ) )
117 {
118 const SFVEC3F vv = glm::normalize( ddiff );
119 const float rd = glm::length( ddiff );
120 const SFVEC2I vr = aShaderPos + SFVEC2I( c1, c2 );
121
122 const float attDistFactor = 1.0f / ( rd * rd + 1.0f );
123
124 return ( glm::clamp( glm::dot( GetNormalAt( vr ), -vv), 0.0f, 1.0f ) *
125 glm::clamp( glm::dot( cnorm, vv ), 0.0f, 1.0f ) * attDistFactor ) *
126 ( 0.03f + aShadow ) * 3.0f;
127 }
128
129 return 0.0f;
130 }
131
132
Shade(const SFVEC2I & aShaderPos) const133 SFVEC3F POST_SHADER_SSAO::Shade( const SFVEC2I& aShaderPos ) const
134 {
135 float cdepth = GetDepthAt( aShaderPos );
136
137 if( cdepth > FLT_EPSILON )
138 {
139 cdepth = ( 30.0f / ( cdepth * 2.0f + 1.0f ) );
140
141 // read current normal, position and color.
142 const SFVEC3F n = GetNormalAt( aShaderPos );
143 const SFVEC3F p = GetPositionAt( aShaderPos );
144
145 const float shadowAt0 = GetShadowFactorAt( aShaderPos );
146
147 // initialize variables:
148 float ao = 0.0f;
149 SFVEC3F gi = SFVEC3F( 0.0f );
150
151 #define ROUNDS 3
152 for( unsigned int i = 0; i < ROUNDS; ++i )
153 {
154 static const int limit[ROUNDS] = { 0x01, 0x03, 0x03 };
155
156 const int pw = Fast_rand() & limit[i];
157 const int ph = Fast_rand() & limit[i];
158
159 const int npw = (int) ( ( pw + i ) * cdepth ) + ( i + 1 );
160 const int nph = (int) ( ( ph + i ) * cdepth ) + ( i + 1 );
161
162 const SFVEC3F ddiff = GetPositionAt( aShaderPos + SFVEC2I( npw, nph ) ) - p;
163 const SFVEC3F ddiff2 = GetPositionAt( aShaderPos + SFVEC2I( npw, -nph ) ) - p;
164 const SFVEC3F ddiff3 = GetPositionAt( aShaderPos + SFVEC2I( -npw, nph ) ) - p;
165 const SFVEC3F ddiff4 = GetPositionAt( aShaderPos + SFVEC2I( -npw, -nph ) ) - p;
166 const SFVEC3F ddiff5 = GetPositionAt( aShaderPos + SFVEC2I( pw, nph ) ) - p;
167 const SFVEC3F ddiff6 = GetPositionAt( aShaderPos + SFVEC2I( pw, -nph ) ) - p;
168 const SFVEC3F ddiff7 = GetPositionAt( aShaderPos + SFVEC2I( npw, ph ) ) - p;
169 const SFVEC3F ddiff8 = GetPositionAt( aShaderPos + SFVEC2I(-npw, ph ) ) - p;
170
171 const float shadowAt1 = GetShadowFactorAt( aShaderPos + SFVEC2I( +npw, nph ) );
172 const float shadowAt2 = GetShadowFactorAt( aShaderPos + SFVEC2I( +npw, -nph ) );
173 const float shadowAt3 = GetShadowFactorAt( aShaderPos + SFVEC2I( -npw, nph ) );
174 const float shadowAt4 = GetShadowFactorAt( aShaderPos + SFVEC2I( -npw, -nph ) );
175 const float shadowAt5 = GetShadowFactorAt( aShaderPos + SFVEC2I( +pw, nph ) );
176 const float shadowAt6 = GetShadowFactorAt( aShaderPos + SFVEC2I( pw, -nph ) );
177 const float shadowAt7 = GetShadowFactorAt( aShaderPos + SFVEC2I( npw, ph ) );
178 const float shadowAt8 = GetShadowFactorAt( aShaderPos + SFVEC2I( -npw, ph ) );
179
180 ao += aoFF( aShaderPos, ddiff , n, shadowAt1, shadowAt0, npw, nph );
181 ao += aoFF( aShaderPos, ddiff2, n, shadowAt2, shadowAt0, npw, -nph );
182 ao += aoFF( aShaderPos, ddiff3, n, shadowAt3, shadowAt0, -npw, nph );
183 ao += aoFF( aShaderPos, ddiff4, n, shadowAt4, shadowAt0, -npw, -nph );
184 ao += aoFF( aShaderPos, ddiff5, n, shadowAt5, shadowAt0, pw, nph );
185 ao += aoFF( aShaderPos, ddiff6, n, shadowAt6, shadowAt0, pw, -nph );
186 ao += aoFF( aShaderPos, ddiff7, n, shadowAt7, shadowAt0, npw, ph );
187 ao += aoFF( aShaderPos, ddiff8, n, shadowAt8, shadowAt0, -npw, ph );
188
189 gi += giFF( aShaderPos, ddiff , n, shadowAt1, npw, nph) *
190 giColorCurve( GetColorAt( aShaderPos + SFVEC2I( npw, nph ) ) );
191 gi += giFF( aShaderPos, ddiff2, n, shadowAt2, npw, -nph) *
192 giColorCurve( GetColorAt( aShaderPos + SFVEC2I( npw,-nph ) ) );
193 gi += giFF( aShaderPos, ddiff3, n, shadowAt3, -npw, nph) *
194 giColorCurve( GetColorAt( aShaderPos + SFVEC2I( -npw, nph ) ) );
195 gi += giFF( aShaderPos, ddiff4, n, shadowAt4, -npw, -nph) *
196 giColorCurve( GetColorAt( aShaderPos + SFVEC2I( -npw,-nph ) ) );
197 gi += giFF( aShaderPos, ddiff5, n, shadowAt5 , pw, nph) *
198 giColorCurve( GetColorAt( aShaderPos + SFVEC2I( pw, nph ) ) );
199 gi += giFF( aShaderPos, ddiff6, n, shadowAt6, pw,-nph) *
200 giColorCurve( GetColorAt( aShaderPos + SFVEC2I( pw,-nph ) ) );
201 gi += giFF( aShaderPos, ddiff7, n, shadowAt7, npw, ph) *
202 giColorCurve( GetColorAt( aShaderPos + SFVEC2I( npw, ph ) ) );
203 gi += giFF( aShaderPos, ddiff8, n, shadowAt8, -npw, ph) *
204 giColorCurve( GetColorAt( aShaderPos + SFVEC2I( -npw, ph ) ) );
205 }
206
207 // If it received direct light, it shouldn't consider much AO
208 // shadowAt0 1.0 when no shadow
209 const float reduceAOwhenNoShadow = m_isUsingShadows ? ( 1.0f - shadowAt0 * 0.3f ) : 1.0f;
210
211 ao = reduceAOwhenNoShadow * ( ao / ( ROUNDS * 8.0f ) );
212
213 ao = ( 1.0f - 1.0f / ( ao * ao * 5.0f + 1.0f ) ) * 1.2f;
214
215 gi = ( gi / ( ROUNDS * 8.0f ) );
216
217 float giL = glm::min( glm::length( gi ) * 4.0f, 1.0f );
218
219 giL = ( 1.0f - 1.0f / ( giL * 4.0f + 1.0f ) ) * 1.5f;
220
221 return glm::mix( SFVEC3F( ao ), -gi, giL );
222 }
223 else
224 {
225 return SFVEC3F( 0.0f );
226 }
227 }
228
229
ApplyShadeColor(const SFVEC2I & aShaderPos,const SFVEC3F & aInputColor,const SFVEC3F & aShadeColor) const230 SFVEC3F POST_SHADER_SSAO::ApplyShadeColor( const SFVEC2I& aShaderPos, const SFVEC3F& aInputColor,
231 const SFVEC3F& aShadeColor ) const
232 {
233 SFVEC3F outColor;
234
235 const SFVEC3F subtracted = aInputColor - aShadeColor;
236 const SFVEC3F mixed = glm::mix( aInputColor, aInputColor * 0.50f - aShadeColor * 0.05f,
237 glm::min( aShadeColor, 1.0f ) );
238
239 outColor.r = ( aShadeColor.r < 0.0f ) ? subtracted.r : mixed.r;
240 outColor.g = ( aShadeColor.g < 0.0f ) ? subtracted.g : mixed.g;
241 outColor.b = ( aShadeColor.b < 0.0f ) ? subtracted.b : mixed.b;
242
243 return outColor;
244 }
245
246
giColorCurve(const SFVEC3F & aColor) const247 SFVEC3F POST_SHADER_SSAO::giColorCurve( const SFVEC3F& aColor ) const
248 {
249 const SFVEC3F vec1 = SFVEC3F( 1.0f );
250
251 // This option actually apply a gamma since we are using linear color space
252 // and the result shader will be applied after convert back to sRGB
253
254 // http://fooplot.com/#W3sidHlwZSI6MCwiZXEiOiIxLjAtKDEuMC8oeCo5LjArMS4wKSkreCowLjEiLCJjb2xvciI6IiMwMDAwMDAifSx7InR5cGUiOjEwMDAsIndpbmRvdyI6WyItMC4wNjIxODQ2MTUzODQ2MTU1MDUiLCIxLjE0Mjk4NDYxNTM4NDYxNDYiLCItMC4xMjcwOTk5OTk5OTk5OTk3NyIsIjEuMTMyNiJdfV0-
255 return vec1 - ( vec1 / (aColor * SFVEC3F(9.0f) + vec1) ) + aColor * SFVEC3F(0.10f);
256 }
257
258
Blur(const SFVEC2I & aShaderPos) const259 SFVEC3F POST_SHADER_SSAO::Blur( const SFVEC2I& aShaderPos ) const
260 {
261 const float dCenter = GetDepthAt( aShaderPos );
262
263 SFVEC3F shadedOut = SFVEC3F( 0.0f );
264
265 float totalWeight = 1.0f;
266
267 for( int y = -3; y < 3; y++ )
268 {
269 for( int x = -3; x < 3; x++ )
270 {
271
272 const unsigned int idx = GetIndex( SFVEC2I( aShaderPos.x + x, aShaderPos.y + y ) );
273
274 const SFVEC3F s = m_shadedBuffer[idx];
275
276 if( !( ( x == 0 ) && ( y == 0 ) ) )
277 {
278
279 const float d = GetDepthAt( SFVEC2I( aShaderPos.x + x, aShaderPos.y + y ) );
280
281 // Increasing the value will get more sharpness effect.
282 const float depthAtt = ( dCenter - d ) * dCenter * 25.0f;
283
284 const float depthAttSqr = depthAtt * depthAtt;
285
286 float weight = ( 1.0f / ( depthAttSqr + 1.0f ) ) - 0.02f * depthAttSqr;
287
288 weight = glm::max( weight, 0.0f );
289
290 shadedOut += s * weight;
291 totalWeight += weight;
292 }
293 else
294 {
295 shadedOut += s;
296 }
297 }
298 }
299
300 return shadedOut / totalWeight;
301 }
302