File size: 3,473 Bytes
2252f3d
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
#version 330

uniform vec3 SHCoeffs[9];
uniform uint analytic;

uniform uint hasNormalMap;
uniform uint hasAlbedoMap;

uniform sampler2D AlbedoMap;
uniform sampler2D NormalMap;

in VertexData {
    vec3 Position;
    vec3 ModelNormal;
    vec3 CameraNormal;
    vec2 Texcoord;
    vec3 Tangent;
    vec3 Bitangent;
    vec3 PRT1;
    vec3 PRT2;
    vec3 PRT3;
} VertexIn;

layout (location = 0) out vec4 FragColor;
layout (location = 1) out vec4 FragPosition;
layout (location = 2) out vec4 FragNormal;

vec4 gammaCorrection(vec4 vec, float g)
{
    return vec4(pow(vec.x, 1.0/g), pow(vec.y, 1.0/g), pow(vec.z, 1.0/g), vec.w);
}

vec3 gammaCorrection(vec3 vec, float g)
{
    return vec3(pow(vec.x, 1.0/g), pow(vec.y, 1.0/g), pow(vec.z, 1.0/g));
}

void evaluateH(vec3 n, out float H[9])
{
    float c1 = 0.429043, c2 = 0.511664,
        c3 = 0.743125, c4 = 0.886227, c5 = 0.247708;

    H[0] = c4;
    H[1] = 2.0 * c2 * n[1];
    H[2] = 2.0 * c2 * n[2];
    H[3] = 2.0 * c2 * n[0];
    H[4] = 2.0 * c1 * n[0] * n[1];
    H[5] = 2.0 * c1 * n[1] * n[2];
    H[6] = c3 * n[2] * n[2] - c5;
    H[7] = 2.0 * c1 * n[2] * n[0];
    H[8] = c1 * (n[0] * n[0] - n[1] * n[1]);
}

vec3 evaluateLightingModel(vec3 normal)
{
    float H[9];
    evaluateH(normal, H);
    vec3 res = vec3(0.0);
    for (int i = 0; i < 9; i++) {
        res += H[i] * SHCoeffs[i];
    }
    return res;
}

// nC: coarse geometry normal, nH: fine normal from normal map
vec3 evaluateLightingModelHybrid(vec3 nC, vec3 nH, mat3 prt)
{
    float HC[9], HH[9];
    evaluateH(nC, HC);
    evaluateH(nH, HH);
    
    vec3 res = vec3(0.0);
    vec3 shadow = vec3(0.0);
    vec3 unshadow = vec3(0.0);
    for(int i = 0; i < 3; ++i){
        for(int j = 0; j < 3; ++j){
            int id = i*3+j;
            res += HH[id]* SHCoeffs[id];
            shadow += prt[i][j] * SHCoeffs[id];
            unshadow += HC[id] * SHCoeffs[id];
        }
    }
    vec3 ratio = clamp(shadow/unshadow,0.0,1.0);
    res = ratio * res;

    return res;
}

vec3 evaluateLightingModelPRT(mat3 prt)
{
    vec3 res = vec3(0.0);
    for(int i = 0; i < 3; ++i){
        for(int j = 0; j < 3; ++j){
            res += prt[i][j] * SHCoeffs[i*3+j];
        }
    }

    return res;
}

void main()
{
    vec2 uv = VertexIn.Texcoord;
    vec3 nM = normalize(VertexIn.ModelNormal);
    vec3 nC = normalize(VertexIn.CameraNormal);
    vec3 nml = nC;
    mat3 prt = mat3(VertexIn.PRT1, VertexIn.PRT2, VertexIn.PRT3);

    vec4 albedo, shading;
    if(hasAlbedoMap == uint(0))
        albedo = vec4(1.0);
    else
        albedo = texture(AlbedoMap, uv);//gammaCorrection(texture(AlbedoMap, uv), 1.0/2.2);

    if(hasNormalMap == uint(0))
    {
        if(analytic == uint(0))
            shading = vec4(evaluateLightingModelPRT(prt), 1.0f);
        else
            shading = vec4(evaluateLightingModel(nC), 1.0f);
    }
    else
    {
        vec3 n_tan = normalize(texture(NormalMap, uv).rgb*2.0-vec3(1.0));

        mat3 TBN = mat3(normalize(VertexIn.Tangent),normalize(VertexIn.Bitangent),nC);
        vec3 nH = normalize(TBN * n_tan);

        if(analytic == uint(0))
            shading = vec4(evaluateLightingModelHybrid(nC,nH,prt),1.0f);
        else
            shading = vec4(evaluateLightingModel(nH), 1.0f);
    
        nml = nH;
    }

    shading = gammaCorrection(shading, 2.2);
    FragColor = clamp(albedo * shading, 0.0, 1.0);
    FragPosition = vec4(VertexIn.Position,1.0);
    FragNormal = vec4(0.5*(nM+vec3(1.0)),1.0);
}