KiCad PCB EDA Suite
post_shader_ssao.cpp
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4  * Copyright (C) 2015-2016 Mario Luzeiro <[email protected]>
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24 
30 #include "post_shader_ssao.h"
31 #include "../3d_fastmath.h"
32 
33 
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 
47 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 
113 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 
133 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 
230 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 
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 
259 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 }
const SFVEC3F & GetColorAt(const SFVEC2F &aPos) const
#define ROUNDS
float GetDepthAt(const SFVEC2F &aPos) const
int Fast_rand(void)
Definition: 3d_fastmath.cpp:58
SFVEC3F ApplyShadeColor(const SFVEC2I &aShaderPos, const SFVEC3F &aInputColor, const SFVEC3F &aShadeColor) const override
Apply the final color process using a previous stage color.
POST_SHADER_SSAO(const CAMERA &aCamera)
glm::ivec2 SFVEC2I
Definition: xv3d_types.h:39
float giFF(const SFVEC2I &aShaderPos, const SFVEC3F &ddiff, const SFVEC3F &cnorm, const float aShadow, int c1, int c2) const
SFVEC3F giColorCurve(const SFVEC3F &aColor) const
Apply a curve transformation to the original color.
A class used to derive camera objects from.
Definition: camera.h:77
SFVEC3F Shade(const SFVEC2I &aShaderPos) const override
float aoFF(const SFVEC2I &aShaderPos, const SFVEC3F &ddiff, const SFVEC3F &cnorm, const float aShadowAtSamplePos, const float aShadowAtCenterPos, int c1, int c2) const
unsigned int GetIndex(const SFVEC2F &aPos) const
Definition: post_shader.h:66
Implements a post shader screen space ambient occlusion on software.
SFVEC3F Blur(const SFVEC2I &aShaderPos) const
SFVEC3F * m_shadedBuffer
glm::vec3 SFVEC3F
Definition: xv3d_types.h:44
const SFVEC3F & GetPositionAt(const SFVEC2F &aPos) const
const SFVEC3F & GetNormalAt(const SFVEC2F &aPos) const
const float & GetShadowFactorAt(const SFVEC2I &aPos) const