WebGL a PBRViewer display of various textures

Making the original
Let’s go straight to Shader
It’s confusing to see something else

Vertex shader

It’s basically computing normal vectors

#define USE_MATHS 1
#define USE_IBL 1
#define HAS_UV 1
#define HAS_NORMALS 1
#define HAS_TANGENTS 1
#define HAS_BASECOLORMAP 1
#define HAS_METALROUGHNESSMAP 1
#define HAS_NORMALMAP 1
#define HAS_OCCLUSIONMAP 1
#define USE_TEX_LOD 1
attribute vec4 a_Position; // Write vec4 with only three inputs. The last one defaults to 1.0?
#ifdef HAS_NORMALS
    attribute vec4 a_Normal;
#endif
#ifdef HAS_TANGENTS
    attribute vec4 a_Tangent;
#endif
#ifdef HAS_UV
    attribute vec2 a_UV;
#endif

uniform mat4 u_mvpMatrix;
uniform mat4 u_NormalMatrix;
varying vec3 v_Position;
varying vec2 v_UV;
#ifdef HAS_NORMALS
    #ifdef HAS_TANGENTS
        varying mat3 v_TBN;
    #else
        varying vec3 v_Normal;
    #endif
#endif

void main() {
    //u_NormalMatrix is the model matrix
    vec4 pos = u_NormalMatrix * a_Position;
    v_Position = vec3(pos.xyz) / pos.w;
    #ifdef HAS_NORMALS
        #ifdef HAS_TANGENTS
            vec3 normalW = normalize(vec3(u_NormalMatrix * vec4(a_Normal.xyz, 0.0)));
            vec3 tangentW = normalize(vec3(u_NormalMatrix * vec4(a_Tangent.xyz, 0.0)));
            vec3 bitangentW = cross(normalW, tangentW) * a_Tangent.w; //*w is not what I expected
            v_TBN = mat3(tangentW, bitangentW, normalW); //TBN
        #else // HAS_TANGENTS ! = 1
            v_Normal = normalize(vec3(u_NormalMatrix * a_Normal));
        #endif
    #endif
    
    gl_Position = u_mvpMatrix * a_Position; // needs w for proper perspective correction
}
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Chip shader

IBL map

#ifdef USE_IBL
    uniform samplerCube u_DiffuseEnvSampler;
    uniform samplerCube u_SpecularEnvSampler; // There are 60 cards in it
    uniform sampler2D u_brdfLUT;
#endif
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U_DiffuseEnvSampler six

U_SpecularEnvSampler has 60 specularenvroughness levels

U_brdfLUT is a

Normal vector calculation

#ifndef HAS_TANGENTS
    vec3 pos_dx = dFdx(v_Position);
    vec3 pos_dy = dFdy(v_Position);
    vec3 tex_dx = dFdx(vec3(v_UV, 0.0));
    vec3 tex_dy = dFdy(vec3(v_UV, 0.0));
    vec3 t = (tex_dy.t * pos_dx - tex_dx.t * pos_dy) / (tex_dx.s * tex_dy.t - tex_dy.s * tex_dx.t);
    #ifdef HAS_NORMALS
        vec3 ng = normalize(v_Normal);
    #else
        vec3 ng = cross(pos_dx, pos_dy);
    #endif

    t = normalize(t - ng * dot(ng, t));
    vec3 b = normalize(cross(ng, t));
    mat3 tbn = mat3(t, b, ng);
#else // HAS_TANGENTS && HAS_NORMALS
    mat3 tbn = v_TBN;
#endif
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#ifdef HAS_NORMALMAP
    vec3 n = texture2D(u_NormalSampler, v_UV).rgb; / / [0 ~ 1]
    n = normalize(tbn * (2.0 * n - 1.0)); / / [1 ~ 1]
#else
    vec3 n = tbn[2].xyz;
#endif
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You know the vectors and the angles between them

vec3 v = normalize(u_Camera - v_Position); //view 
vec3 l = normalize(u_LightDirection);      //light
vec3 h = normalize(l+v);                   //half
vec3 reflection = -normalize(reflect(v, n)); // reflection
float NdotL = clamp(dot(n, l), 0.0.1.0);  
float NdotV = clamp(dot(n, v), 0.0.1.0);
float NdotH = clamp(dot(n, h), 0.0.1.0);
float LdotH = clamp(dot(l, h), 0.0.1.0);
float VdotH = clamp(dot(v, h), 0.0.1.0);
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Metallicity/roughness

Metal (only 0 and 1)

roughness

#ifdef HAS_METALROUGHNESSMAP
    vec4 mrSample = texture2D(u_MetallicRoughnessSampler, v_UV);
    float roughness = clamp(mrSample.g, 0.04.1.0);
    float metallic = clamp(mrSample.b, 0.0.1.0);
#else
    float roughness = clamp(u_MetallicRoughnessValues.y, 0.04.1.0);
    float metallic = u_MetallicRoughnessValues.x;
#endif
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BaseColor

#ifdef HAS_BASECOLORMAP
    vec3 baseColor = texture2D(u_BaseColorSampler, v_UV).rgb;
#else
    vec3 baseColor = vec3(1.0.1.0.1.0);
#endif
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F0 and I don’t know how these two colors work out, right

vec3 f0 = vec3(0.04);
vec3 diffuseColor = mix(baseColor.rgb * (1.0 - f0), vec3(0..0..0.), metallic); // Metallicity to calculate diffuse
vec3 specularColor = mix(f0, baseColor, metallic); //F0 is related to specular.
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What is the purpose of calculating the reflection coefficient of 90

float reflectance = max(max(specularColor.r, specularColor.g), specularColor.b);
float reflectance90 = clamp(reflectance * 25.0.0.0.1.0);
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Plug in F0, what’s R90

vec3 specularEnvironmentR0 = specularColor.rgb; F0 = mix(F0, albedo, metallic);
vec3 specularEnvironmentR90 = vec3(1.0.1.0.1.0) * reflectance90;
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PBRinfo

struct PBRInfo {
    float NdotL;
    float NdotV;
    float NdotH;
    float LdotH;
    float VdotH;
    float roughness;
    float metalness;
    vec3 baseColor;
    vec3 reflectance0;  / / specularEnvironmentR0 is F0
    vec3 reflectance90; //specularEnvironmentR90
};
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Calculate Fresnel F

vec3 fresnelSchlick2(PBRInfo pbrInputs) {
    return pbrInputs.reflectance0 + (pbrInputs.reflectance90 - pbrInputs.reflectance0) * pow(clamp(1.0 - pbrInputs.VdotH, 0.0.1.0), 5.0);
}
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Calculate GGX

float SmithVisibilityGGX(PBRInfo pbrInputs) {
    return SmithVisibilityG1_var2(pbrInputs.NdotL, pbrInputs.roughness) * SmithVisibilityG1_var2(pbrInputs.NdotV, pbrInputs.roughness);
}
float SmithVisibilityG1_var2(float NdotV, float r) {
    float tanSquared = (1.0 - NdotV * NdotV) / max((NdotV * NdotV), 0.00001);
    return 2.0 / (1.0 + sqrt(1.0 + r * r * tanSquared));
}
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Calculate D

float GGX(PBRInfo pbrInputs) {
    float roughnessSq = pbrInputs.roughness*pbrInputs.roughness;
    float f = (pbrInputs.NdotH * roughnessSq - pbrInputs.NdotH) * pbrInputs.NdotH + 1.0;
    return roughnessSq / (M_PI * f * f);
}
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Calculate the diffuse part of direct illumination

vec3 diffuseContrib = (1.0 - F) * lambertianDiffuse(pbrInputs) * NdotL * u_LightColor;
vec3 lambertianDiffuse(PBRInfo pbrInputs) {
    return pbrInputs.baseColor / M_PI;
}
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Calculate the specular reflection of direct illumination

vec3 specContrib = M_PI * u_LightColor * F * G * D / 4.0*NdotL*NdotV;
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Direct illumination BRDF is calculated

vec3 color = (diffuseContrib + specContrib);
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Calculate BRDF of indirect illumination and see the formula below

finalColor = (diffuseLight + diffuseColor) + (specularLight * (specularColor * brdf.x + brdf.y))

#ifdef USE_IBL
    float mipCount = 9.0; // Resolution of 512x512 //10 order roughness
    float lod = (roughness * mipCount);      // LoD range [0-9]
    vec3 brdf = texture2D(u_brdfLUT, vec2(NdotV, 1.0 - roughness)).rgb;  //brdf
    vec3 diffuseLight = textureCube(u_DiffuseEnvSampler, n).rgb;  / / the ambient light
    #ifdef USE_TEX_LOD
        vec3 specularLight = textureCubeLodEXT(u_SpecularEnvSampler, reflection, lod).rgb;  Reflection is the roughness directed by reflection
    #else
        vec3 specularLight = textureCube(u_SpecularEnvSampler, reflection).rgb; ///
    #endif

    vec3 IBLcolor = (diffuseLight * diffuseColor * u_scaleIBLAmbient.x) + (specularLight * (specularColor * brdf.x + brdf.y) *u_scaleIBLAmbient.y);
    color += IBLcolor; / / plus the IBL
#endif
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The ao map

#ifdef HAS_OCCLUSIONMAP
    float ao = texture2D(u_OcclusionSampler, v_UV).r; //r
    color *= ao;  / / multiplied
#endif
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Self-illumination map

#ifdef HAS_EMISSIVEMAP
    vec3 emissive = texture2D(u_EmissiveSampler, v_UV).rgb;
    color += emissive;  // Add it directly
#endif
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#define USE_MATHS 1
#define USE_IBL 1
#define HAS_UV 1
#define HAS_NORMALS 1
#define HAS_TANGENTS 1
#define HAS_BASECOLORMAP 1
#define HAS_METALROUGHNESSMAP 1
#define HAS_NORMALMAP 1
#define HAS_EMISSIVEMAP 1
#define HAS_OCCLUSIONMAP 1
#define USE_TEX_LOD 1
#extension GL_EXT_shader_texture_lod: enable
#extension GL_OES_standard_derivatives : enable

precision highp float;
uniform vec3 u_LightDirection;
uniform vec3 u_LightColor;
#ifdef USE_IBL
    uniform samplerCube u_DiffuseEnvSampler;
    uniform samplerCube u_SpecularEnvSampler;
    uniform sampler2D u_brdfLUT;
#endif

#ifdef HAS_BASECOLORMAP
    uniform sampler2D u_BaseColorSampler;
#endif
#ifdef HAS_NORMALMAP
    uniform sampler2D u_NormalSampler;
#endif
#ifdef HAS_EMISSIVEMAP
    uniform sampler2D u_EmissiveSampler;
#endif
#ifdef HAS_METALROUGHNESSMAP
    uniform sampler2D u_MetallicRoughnessSampler;
#else
    uniform vec2 u_MetallicRoughnessValues;
#endif
#ifdef HAS_OCCLUSIONMAP
    uniform sampler2D u_OcclusionSampler;
#endif

uniform vec3 u_Camera;
uniform vec4 u_scaleDiffBaseMR;
uniform vec4 u_scaleFGDSpec;
uniform vec4 u_scaleIBLAmbient;
varying vec3 v_Position;
varying vec2 v_UV;
#ifdef HAS_NORMALS
    #ifdef HAS_TANGENTS
        varying mat3 v_TBN;
    #else
        varying vec3 v_Normal;
    #endif
#endif

struct PBRInfo {
    float NdotL;
    float NdotV;
    float NdotH;
    float LdotH;
    float VdotH;
    float roughness;
    float metalness;
    vec3 baseColor;
    vec3 reflectance0;
    vec3 reflectance90;
};
const float M_PI = 3.141592653589793;

// diffuse

vec3 disneyDiffuse(PBRInfo pbrInputs) {
    float f90 = 2.*pbrInputs.LdotH*pbrInputs.LdotH*pbrInputs.roughness - 0.5;
    return (pbrInputs.baseColor/M_PI)*(1.0+f90*pow((1.0-pbrInputs.NdotL), 5.0)) * (1.0+f90*pow((1.0-pbrInputs.NdotV), 5.0));
}
vec3 lambertianDiffuse(PBRInfo pbrInputs) {
    return pbrInputs.baseColor / M_PI;
}
// F
// r
vec3 fresnelSchlick2(PBRInfo pbrInputs) {
    return pbrInputs.reflectance0 + (pbrInputs.reflectance90 - pbrInputs.reflectance0) * pow(clamp(1.0 - pbrInputs.VdotH, 0.0.1.0), 5.0);
}
vec3 fresnelSchlick(PBRInfo pbrInputs) {
    return pbrInputs.metalness + (vec3(1.0) - pbrInputs.metalness) * pow(1.0 - pbrInputs.VdotH, 5.0);
}
// G
float microfacetCookTorrance(PBRInfo pbrInputs) {
    return min(min(2.*pbrInputs.NdotV*pbrInputs.NdotH/pbrInputs.VdotH, 2.*pbrInputs.NdotL*pbrInputs.NdotH/pbrInputs.VdotH), 1.0);
}
float microfacetSchlick(PBRInfo pbrInputs) {
    float k = pbrInputs.roughness * 0.79788; / / 0.79788 = SQRT (2.0/3.1415);
    
    // alternately, k can be defined with
    // float k = (pbrInputs.roughness + 1)*(pbrInputs.roughness + 1)/8;
    
    float l = pbrInputs.LdotH / (pbrInputs.LdotH * (1.0 - k) + k);
    float n = pbrInputs.NdotH / (pbrInputs.NdotH * (1.0 - k) + k);
    return l * n;
}
float microfacetSmith_var1(PBRInfo pbrInputs) {
    float NdotL2 = pbrInputs.NdotL * pbrInputs.NdotL;
    float NdotV2 = pbrInputs.NdotV * pbrInputs.NdotV;
    float v = ( 1. + sqrt ( pbrInputs.roughness * (1. - NdotL2 ) / NdotL2 + 1.)) * 0.5;
    float l = ( 1. + sqrt ( pbrInputs.roughness * (1. - NdotV2 ) / NdotV2 + 1.)) * 0.5;
    return (1. / max((1. + v + l ), 0.000001));
}
float SmithVisibilityG1_var2(float NdotV, float r) {
    float tanSquared = (1.0 - NdotV * NdotV) / max((NdotV * NdotV), 0.00001);
    return 2.0 / (1.0 + sqrt(1.0 + r * r * tanSquared));
}
float SmithG1(float NdotV, float r) {
    return 2.0 * NdotV / (NdotV + sqrt(r*r+(1.0-r*r)*(NdotV*NdotV)));
}
float SmithVisibilityGGX(PBRInfo pbrInputs) {
    return SmithVisibilityG1_var2(pbrInputs.NdotL, pbrInputs.roughness) * SmithVisibilityG1_var2(pbrInputs.NdotV, pbrInputs.roughness);
}
// D
float GGX(PBRInfo pbrInputs) {
    float roughnessSq = pbrInputs.roughness*pbrInputs.roughness;
    float f = (pbrInputs.NdotH * roughnessSq - pbrInputs.NdotH) * pbrInputs.NdotH + 1.0;
    return roughnessSq / (M_PI * f * f);
}
void main() {
    // Normal Map
    #ifndef HAS_TANGENTS
        vec3 pos_dx = dFdx(v_Position);
        vec3 pos_dy = dFdy(v_Position);
        vec3 tex_dx = dFdx(vec3(v_UV, 0.0));
        vec3 tex_dy = dFdy(vec3(v_UV, 0.0));
        vec3 t = (tex_dy.t * pos_dx - tex_dx.t * pos_dy) / (tex_dx.s * tex_dy.t - tex_dy.s * tex_dx.t);
        #ifdef HAS_NORMALS
            vec3 ng = normalize(v_Normal);
        #else
            vec3 ng = cross(pos_dx, pos_dy);
        #endif
        
        t = normalize(t - ng * dot(ng, t));
        vec3 b = normalize(cross(ng, t));
        mat3 tbn = mat3(t, b, ng);
    #else // HAS_TANGENTS && HAS_NORMALS
        mat3 tbn = v_TBN;
    #endif
    
    #ifdef HAS_NORMALMAP
        vec3 n = texture2D(u_NormalSampler, v_UV).rgb;
        n = normalize(tbn * (2.0 * n - 1.0));
    #else
        vec3 n = tbn[2].xyz;
    #endif
    
    vec3 v = normalize(u_Camera - v_Position);
    vec3 l = normalize(u_LightDirection);
    vec3 h = normalize(l+v);
    vec3 reflection = -normalize(reflect(v, n));
    float NdotL = clamp(dot(n, l), 0.0.1.0);
    float NdotV = clamp(dot(n, v), 0.0.1.0);
    float NdotH = clamp(dot(n, h), 0.0.1.0);
    float LdotH = clamp(dot(l, h), 0.0.1.0);
    float VdotH = clamp(dot(v, h), 0.0.1.0);
    #ifdef HAS_METALROUGHNESSMAP
        vec4 mrSample = texture2D(u_MetallicRoughnessSampler, v_UV);
        float roughness = clamp(mrSample.g, 0.04.1.0);
        float metallic = clamp(mrSample.b, 0.0.1.0);
    #else
        float roughness = clamp(u_MetallicRoughnessValues.y, 0.04.1.0);
        float metallic = u_MetallicRoughnessValues.x;
    #endif
    
    #ifdef HAS_BASECOLORMAP
        vec3 baseColor = texture2D(u_BaseColorSampler, v_UV).rgb;
    #else
        vec3 baseColor = vec3(1.0.1.0.1.0);
    #endif
    
    vec3 f0 = vec3(0.04);
    // is this the same? test!
    
    vec3 diffuseColor = mix(baseColor.rgb * (1.0 - f0), vec3(0..0..0.), metallic);
    // Vec3 diffuseColor = baseColor * (1.0-metallic);
    
    vec3 specularColor = mix(f0, baseColor, metallic);
    #ifdef USE_MATHS
        
        // Compute reflectance.
        float reflectance = max(max(specularColor.r, specularColor.g), specularColor.b);
        
        // For typical incident reflectance range (between 4% to 100%) set the grazing reflectance to 100% for typical fresnel effect.
        
        // For very low reflectance range on highly diffuse objects (below 4%), incrementally reduce grazing reflecance to 0%.
        float reflectance90 = clamp(reflectance * 25.0.0.0.1.0);
        vec3 specularEnvironmentR0 = specularColor.rgb;
        vec3 specularEnvironmentR90 = vec3(1.0.1.0.1.0) * reflectance90;
        PBRInfo pbrInputs = PBRInfo(
        NdotL, NdotV, NdotH, LdotH, VdotH, roughness, metallic, diffuseColor, specularEnvironmentR0, specularEnvironmentR90
        );
        vec3 F = fresnelSchlick2(pbrInputs);
        //vec3 F = fresnelSchlick(pbrInputs);
        
        //float G = microfacetCookTorrance(pbrInputs);
        //float G = microfacetSmith(pbrInputs);
        //float G = microfacetSchlick(pbrInputs);
        float G = SmithVisibilityGGX(pbrInputs);
        float D = GGX(pbrInputs);
        vec3 diffuseContrib = (1.0 - F) * lambertianDiffuse(pbrInputs) * NdotL * u_LightColor;
        // Vec3 diffuseContrib = (1.0-f) * disneyDiffuse(pbrInputs) * NdotL * u_LightColor;
        
        
        vec3 specContrib = M_PI * u_LightColor * F * G * D / 4.0*NdotL*NdotV;
        vec3 color = (diffuseContrib + specContrib);
    #endif
    
    #ifdef USE_IBL
        float mipCount = 9.0; // resolution of 512x512
        
        float lod = (roughness * mipCount);
        vec3 brdf = texture2D(u_brdfLUT, vec2(NdotV, 1.0 - roughness)).rgb;
        vec3 diffuseLight = textureCube(u_DiffuseEnvSampler, n).rgb;
        #ifdef USE_TEX_LOD
            vec3 specularLight = textureCubeLodEXT(u_SpecularEnvSampler, reflection, lod).rgb; // This is correct
        #else
            vec3 specularLight = textureCube(u_SpecularEnvSampler, reflection).rgb;
        #endif
        
        vec3 IBLcolor = (diffuseLight * diffuseColor * u_scaleIBLAmbient.x) + (specularLight * (specularColor * brdf.x + brdf.y) *u_scaleIBLAmbient.y);
        color += IBLcolor;
    #endif
    
    #ifdef HAS_OCCLUSIONMAP
        float ao = texture2D(u_OcclusionSampler, v_UV).r;
        color *= ao;
    #endif
    
    #ifdef HAS_EMISSIVEMAP
        vec3 emissive = texture2D(u_EmissiveSampler, v_UV).rgb;
        color += emissive;
    #endif
    
    #ifdef USE_MATHS
        // mix in overrides
        color = mix(color, F, u_scaleFGDSpec.x);
        color = mix(color, vec3(G), u_scaleFGDSpec.y);
        color = mix(color, vec3(D), u_scaleFGDSpec.z);
        color = mix(color, specContrib, u_scaleFGDSpec.w);
        color = mix(color, diffuseContrib, u_scaleDiffBaseMR.x);
        color = mix(color, baseColor, u_scaleDiffBaseMR.y);
        color = mix(color, vec3(metallic), u_scaleDiffBaseMR.z);
        color = mix(color, vec3(roughness), u_scaleDiffBaseMR.w);
    #endif
    
    gl_FragColor = vec4(color, 1.0);
    //gl_FragColor = vec4(n * 0.5 + 0.5, 1.0);
    
    //gl_FragColor = vec4(NdotV, NdotV, NdotV, 1.0);
    //gl_FragColor = vec4(v_uv. rg, 0.0, 1.0);
}

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WebGL a PBRViewer display of various textures

Vertex shader

Chip shader

IBL map

Normal vector calculation

You know the vectors and the angles between them

Metallicity/roughness

BaseColor

F0 and I don’t know how these two colors work out, right

What is the purpose of calculating the reflection coefficient of 90

Plug in F0, what’s R90

PBRinfo

Calculate Fresnel F

Calculate GGX

Calculate D

Calculate the diffuse part of direct illumination

Calculate the specular reflection of direct illumination

Direct illumination BRDF is calculated

Calculate BRDF of indirect illumination and see the formula below

The ao map

Self-illumination map

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