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Commit 040b3ed

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author
Carmelo Fernandez Aguera
committedMay 19, 2021
WIP: Reviving the probe tool to analyze multiple scattering and energy conservation.
1 parent 1ef6325 commit 040b3ed

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11 files changed

+284
-58
lines changed

11 files changed

+284
-58
lines changed
 

‎CMakeLists.txt

+1-1
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,5 @@
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################################################################################
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# Rev project
3-
# Sample project that creates a simple scene graph
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################################################################################
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cmake_minimum_required (VERSION 3.10)
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project(revAll)
@@ -33,6 +32,7 @@ add_subdirectory(engine)
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if(REV_BUILD_TOOLS)
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add_subdirectory(tools/gltfOptimizer)
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set_target_properties(gltfOptimizer PROPERTIES FOLDER "tools")
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add_subdirectory(tools/probe)
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endif()
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# Compile sample projects

‎bin/ibl.png

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‎engine/src/math/linear.h

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@@ -37,6 +37,11 @@ namespace rev::math
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return a<b?a:b; // Same NaN behavior as simd
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}
3939

40+
inline float clamp(float t, float a, float b)
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{
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return max(a, min(b, t));
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}
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template<class T> struct minOp
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{
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T operator()(T a, T b) const { return (a < b) ? a : b; } // Same NaN behavior as simd

‎engine/src/math/noise.h

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Original file line numberDiff line numberDiff line change
@@ -11,42 +11,111 @@
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#include "numericTraits.h"
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#include <random>
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14-
namespace rev {
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namespace math {
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class SNoise
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namespace rev::math {
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class SNoise
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{
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public:
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// Simplex noise
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//static void setSimplexSeed(int _seed);
20+
static float simplex(float _x, float _y); // 2D simplex noise
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private:
22+
static int fastFloor(double _x);
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static Vec2f grad2[12];
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static unsigned char p[256];
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};
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class RandomGenerator
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{
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public:
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float scalar()
1732
{
18-
public:
19-
// Simplex noise
20-
//static void setSimplexSeed(int _seed);
21-
static float simplex(float _x, float _y); // 2D simplex noise
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private:
23-
static int fastFloor(double _x);
24-
25-
static Vec2f grad2[12];
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static unsigned char p[256];
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};
28-
29-
class RandomGenerator
33+
return distrib(engine);
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}
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math::Vec3f unit_vector()
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{
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public:
32-
float scalar()
33-
{
34-
return distrib(engine);
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}
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37-
math::Vec3f unit_vector()
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{
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auto theta = math::TwoPi*scalar();
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auto cosPhi = 2*scalar()-1;
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auto sinPhi = sqrt(1-cosPhi*cosPhi);
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return math::Vec3f(
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cos(theta)*sinPhi,
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sin(theta)*sinPhi,
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cosPhi);
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}
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private:
48-
std::default_random_engine engine;
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std::uniform_real_distribution<float> distrib;
50-
};
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}
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} // namespace rev
38+
auto theta = math::TwoPi*scalar();
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auto cosPhi = 2*scalar()-1;
40+
auto sinPhi = sqrt(1-cosPhi*cosPhi);
41+
return math::Vec3f(
42+
cos(theta)*sinPhi,
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sin(theta)*sinPhi,
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cosPhi);
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}
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private:
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std::default_random_engine engine;
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std::uniform_real_distribution<float> distrib;
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};
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51+
inline float RadicalInverse_VdC(uint32_t bits)
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{
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bits = (bits << 16u) | (bits >> 16u);
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bits = ((bits & 0x55555555u) << 1u) | ((bits & 0xAAAAAAAAu) >> 1u);
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bits = ((bits & 0x33333333u) << 2u) | ((bits & 0xCCCCCCCCu) >> 2u);
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bits = ((bits & 0x0F0F0F0Fu) << 4u) | ((bits & 0xF0F0F0F0u) >> 4u);
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bits = ((bits & 0x00FF00FFu) << 8u) | ((bits & 0xFF00FF00u) >> 8u);
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return float(bits) / 0x100000000;
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}
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//------------------------------------------------------------------------------
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inline Vec2f Hammersley(uint32_t i, uint32_t N)
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{
64+
return Vec2f(float(i) / N, RadicalInverse_VdC(i));
65+
}
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67+
inline Vec3f ImportanceSampleGGX(Vec2f Xi, float Roughness)
68+
{
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float a = Roughness * Roughness;
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float Phi = 2 * Pi * Xi.x();
71+
float CosTheta = sqrt((1 - Xi.y()) / (1 + (a * a - 1) * Xi.y()));
72+
float SinTheta = sqrt(1 - CosTheta * CosTheta);
73+
Vec3f H;
74+
H.x() = SinTheta * cos(Phi);
75+
H.y() = SinTheta * sin(Phi);
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H.z() = CosTheta;
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78+
return H;
79+
}
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81+
inline Vec3f ImportanceSampleGGX_r1(Vec2f Xi)
82+
{
83+
float Phi = 2 * Pi * Xi.x();
84+
float CosTheta = sqrt(1 - Xi.y());
85+
float SinTheta = sqrt(1 - CosTheta * CosTheta);
86+
Vec3f H;
87+
H.x() = SinTheta * cos(Phi);
88+
H.y() = SinTheta * sin(Phi);
89+
H.z() = CosTheta;
90+
91+
return H;
92+
}
93+
94+
inline float SmithGGXCorrelatedG2(float ndv, float ndl, float alpha)
95+
{
96+
float a2 = alpha * alpha;
97+
float GV = ndv * sqrt(a2 + (1 - a2) * ndl * ndl);
98+
float GL = ndl * sqrt(a2 + (1 - a2) * ndv * ndv);
99+
return 2 * ndv * ndl / (GL + GV);
100+
}
101+
102+
inline float SmithGGXCorrelatedG2_over_ndv(float ndv, float ndl, float alpha)
103+
{
104+
float a2 = alpha * alpha;
105+
float GV = ndv * sqrt(a2 + (1 - a2) * ndl * ndl);
106+
float GL = ndl * sqrt(a2 + (1 - a2) * ndv * ndv);
107+
return 2 * ndl / (GL + GV);
108+
}
109+
110+
111+
inline float SmithGGXCorrelatedG2_a1(float ndv, float ndl)
112+
{
113+
return 2 * ndv * ndl / (ndl + ndv);
114+
}
115+
116+
inline float SmithGGXCorrelatedG2_overNdv_ndv0(float alpha)
117+
{
118+
return 2 / alpha;
119+
}
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121+
} // namespace rev::math

‎samples/gltfViewer/shaders/gbuffer.frag

+16-6
Original file line numberDiff line numberDiff line change
@@ -55,15 +55,25 @@ vec3 directLight(
5555
{
5656
float r = max(1e-4, roughness);
5757
// Single bounce specular lighting0
58-
vec3 specular = specularBRDF(specularColor, ndh, ndl, ndv, hdv, r);
58+
vec3 specular = specularBRDF(specularColor, ndh, ndl, ndv, hdv, r); // Single scattering
5959

6060
// Energy compensation - substract single bounce specular from the light that goes into diffuse
61-
vec2 reflectedLight = textureLod(iblLUT, vec2(ndl, roughness), 0).xy;
62-
vec3 totalFresnel = specularColor * reflectedLight.x + reflectedLight.y;
63-
64-
vec3 kD = diffuseColor * (1-totalFresnel);
61+
vec2 Fss_wi = textureLod(iblLUT, vec2(ndl, roughness), 0).xy;
62+
vec3 FssRss_wi = specularColor * Fss_wi.x + Fss_wi.y; // Single scattering
63+
float Eavg = 1-0.6*roughness;
64+
float Ess_wi = Fss_wi.x + Fss_wi.y;
65+
vec2 Fss_wo = textureLod(iblLUT, vec2(ndv, roughness), 0).xy;
66+
vec3 FssRss_wo = specularColor * Fss_wo.x + Fss_wo.y; // Single scattering
67+
vec3 Favg = (20+specularColor)/21;
68+
vec3 Fwi = FssRss_wi / Ess_wi;
69+
70+
vec3 num = (Fwi-FssRss_wi)*FssRss_wo;
71+
vec3 den = 1-Favg+Eavg*Favg;
72+
vec3 FmsRms = num/den;
73+
74+
vec3 kD = diffuseColor * (1-FssRss_wi);
6575
vec3 diffuse = kD / PI;
66-
return (specular + diffuse) * ndl * lightColor;
76+
return (specular + FmsRms + diffuse) * ndl * lightColor;
6777
}
6878

6979
vec3 envLight(

‎samples/gltfViewer/shaders/postPro.frag

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@@ -48,7 +48,7 @@ void main()
4848

4949
// Gather slight bloom
5050
vec4 hdrColor = vec4(0);
51-
int bloomWin = 5;
51+
int bloomWin = 0;
5252
ivec2 minPos = max(pixelPos-bloomWin, ivec2(0));
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ivec2 maxPos = min(pixelPos+bloomWin, ivec2(pushC.windowSize-1));
5454

‎scripts/brdf.py

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@@ -0,0 +1,2 @@
1+
import numpy as np
2+
from math import *

‎tools/probe/CMakeLists.txt

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@@ -0,0 +1,14 @@
1+
################################################################################
2+
# Rev project
3+
# Light probe processing tool
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# And brdf study
5+
################################################################################
6+
7+
add_executable(probeTool
8+
main.cpp
9+
Heitz/MicrosurfaceScattering.h
10+
Heitz/MicrosurfaceScattering.cpp)
11+
target_include_directories(probeTool PUBLIC ../../engine/src)
12+
target_include_directories(probeTool PUBLIC ../../include)
13+
target_link_libraries(probeTool LINK_PUBLIC revCore revGfx revMath)
14+
set_target_properties(probeTool PROPERTIES FOLDER "tools")

‎tools/probe/Heitz/MicrosurfaceScattering.cpp

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‎tools/probe/Heitz/MicrosurfaceScattering.h

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