basic PBR example

examples/shaders/resources/shaders/glsl100/pbr.fs

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+#version 100
+
+precision mediump float;
+
+#define MAX_LIGHTS              4
+#define LIGHT_DIRECTIONAL       0
+#define LIGHT_POINT             1
+#define PI 3.14159265358979323846
+
+struct Light {
+    int enabled;
+    int type;
+    vec3 position;
+    vec3 target;
+    vec4 color;
+    float intensity;
+};
+
+// Input vertex attributes (from vertex shader)
+varying in vec3 fragPosition;
+varying in vec2 fragTexCoord;
+varying in vec4 fragColor;
+varying in vec3 fragNormal;
+varying in vec4 shadowPos;
+varying in mat3 TBN;
+
+
+// Input uniform values
+uniform int numOfLights;
+uniform sampler2D albedoMap;
+uniform sampler2D mraMap;
+uniform sampler2D normalMap;
+uniform sampler2D emissiveMap; // r: Hight g:emissive
+
+uniform vec2 tiling;
+uniform vec2 offset;
+
+uniform int useTexAlbedo;
+uniform int useTexNormal;
+uniform int useTexMRA;
+uniform int useTexEmissive;
+
+uniform vec4  albedoColor;
+uniform vec4  emissiveColor;
+uniform float normalValue;
+uniform float metallicValue;
+uniform float roughnessValue;
+uniform float aoValue;
+uniform float emissivePower;
+
+// Input lighting values
+uniform Light lights[MAX_LIGHTS];
+uniform vec3 viewPos;
+
+uniform vec3 ambientColor;
+uniform float ambient;
+
+// refl in range  0 to 1
+// returns base reflectivity to 1
+// incrase reflectivity when surface view at larger angle
+vec3 schlickFresnel(float hDotV,vec3 refl)
+{
+        return refl + (1.0 - refl) * pow(1.0 - hDotV,5.0);
+}
+
+float ggxDistribution(float nDotH,float roughness)
+{
+        float a = roughness * roughness * roughness * roughness;
+        float d = nDotH * nDotH * (a - 1.0) + 1.0;
+        d = PI * d * d;
+        return a / max(d,0.0000001);
+}
+
+float geomSmith(float nDotV,float nDotL,float roughness)
+{
+        float r = roughness + 1.0;
+        float k = r * r / 8.0;
+        float ik = 1.0 - k;
+        float ggx1 = nDotV / (nDotV * ik + k);
+        float ggx2 = nDotL / (nDotL * ik + k);
+        return ggx1 * ggx2;
+}
+
+vec3 pbr(){
+        vec3 albedo = texture2D(albedoMap,vec2(fragTexCoord.x*tiling.x+offset.x,fragTexCoord.y*tiling.y+offset.y)).rgb;
+        albedo = vec3(albedoColor.x*albedo.x,albedoColor.y*albedo.y,albedoColor.z*albedo.z);
+        float metallic = clamp(metallicValue,0.0,1.0);
+        float roughness = clamp(roughnessValue,0.0,1.0);
+        float ao = clamp(aoValue,0.0,1.0);
+        if(useTexMRA == 1) {
+            vec4 mra = texture2D(mraMap, vec2(fragTexCoord.x * tiling.x + offset.x, fragTexCoord.y * tiling.y + offset.y));
+            metallic = clamp(mra.r+metallicValue,0.04,1.0);
+            roughness = clamp(mra.g+roughnessValue,0.04,1.0);
+            ao = (mra.b+aoValue)*0.5;
+        }
+
+
+
+        vec3 N = normalize(fragNormal);
+        if(useTexNormal == 1) {
+            N = texture2D(normalMap, vec2(fragTexCoord.x * tiling.x + offset.y, fragTexCoord.y * tiling.y + offset.y)).rgb;
+            N = normalize(N * 2.0 - 1.0);
+            N = normalize(N * TBN);
+        }
+
+        vec3 V = normalize(viewPos - fragPosition);
+
+        vec3 e = vec3(0);
+        e = (texture2D(emissiveMap, vec2(fragTexCoord.x*tiling.x+offset.x, fragTexCoord.y*tiling.y+offset.y)).rgb).g * emissiveColor.rgb*emissivePower * float(useTexEmissive);
+
+        //return N;//vec3(metallic,metallic,metallic);
+        //if  dia-electric use base reflectivity of 0.04 otherwise ut is a metal use albedo as base reflectivity
+        vec3 baseRefl = mix(vec3(0.04),albedo.rgb,metallic);
+        vec3 Lo = vec3(0.0);  // acumulate lighting lum
+
+        for(int i=0;i<numOfLights;++i){
+
+            vec3 L = normalize(lights[i].position - fragPosition);  // calc light vector
+            vec3 H = normalize(V + L);                              // calc halfway bisecting vector
+            float dist = length(lights[i].position - fragPosition); // calc distance to light
+            float attenuation = 1.0 / (dist * dist * 0.23);                // calc attenuation
+            vec3 radiance = lights[i].color.rgb * lights[i].intensity * attenuation;         // calc input radiance,light energy comming in
+
+            //Cook-Torrance BRDF distribution function
+            float nDotV = max(dot(N,V),0.0000001);
+            float nDotL = max(dot(N,L),0.0000001);
+            float hDotV = max(dot(H,V),0.0);
+            float nDotH = max(dot(N,H),0.0);
+            float D = ggxDistribution(nDotH,roughness); // larger the more micro-facets aligned to H
+            float G = geomSmith(nDotV,nDotL,roughness); // smaller the more micro-facets shadow
+            vec3 F = schlickFresnel(hDotV, baseRefl);  // fresnel proportion of specular reflectance
+
+            vec3 spec = (D * G * F) / (4.0 * nDotV * nDotL);
+            // difuse and spec light can't be above 1.0
+            // kD = 1.0 - kS  diffuse component is equal 1.0 - spec comonent
+            vec3 kD = vec3(1.0) - F;
+            //mult kD by the inverse of metallnes , only non-metals should have diffuse light
+            kD *= 1.0 - metallic;
+            Lo += ((kD * albedo.rgb / PI + spec) * radiance * nDotL)*float(lights[i].enabled); // angle of light has impact on result
+        }
+        vec3 ambient_final = (ambientColor + albedo)* ambient * 0.5;
+        return ambient_final+Lo*ao+e;
+}
+
+void main()
+{
+       vec3 color = pbr();
+
+        //HDR tonemapping
+        color = pow(color,color + vec3(1.0));
+        //gamma correction
+        color = pow(color,vec3(1.0/2.2));
+
+        gl_FragColor = vec4(color,1.0);
+
+}

examples/shaders/resources/shaders/glsl100/pbr.vs

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+#version 100
+
+// Input vertex attributes
+attribute  vec3 vertexPosition;
+attribute  vec2 vertexTexCoord;
+attribute  vec3 vertexNormal;
+attribute  vec3 vertexTangent;
+attribute  vec4 vertexColor;
+
+// Input uniform values
+uniform mat4 mvp;
+uniform mat4 matModel;
+uniform mat4 matNormal;
+uniform vec3 lightPos;
+uniform vec4 difColor;
+
+// Output vertex attributes (to fragment shader)
+varying vec3 fragPosition;
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+varying vec3 fragNormal;
+varying mat3 TBN;
+
+const float normalOffset = 0.1;
+
+// https://github.com/glslify/glsl-inverse
+mat3 inverse(mat3 m)
+{
+  float a00 = m[0][0], a01 = m[0][1], a02 = m[0][2];
+  float a10 = m[1][0], a11 = m[1][1], a12 = m[1][2];
+  float a20 = m[2][0], a21 = m[2][1], a22 = m[2][2];
+
+  float b01 = a22*a11 - a12*a21;
+  float b11 = -a22*a10 + a12*a20;
+  float b21 = a21*a10 - a11*a20;
+
+  float det = a00*b01 + a01*b11 + a02*b21;
+
+  return mat3(b01, (-a22*a01 + a02*a21), (a12*a01 - a02*a11),
+              b11, (a22*a00 - a02*a20), (-a12*a00 + a02*a10),
+              b21, (-a21*a00 + a01*a20), (a11*a00 - a01*a10))/det;
+}
+
+// https://github.com/glslify/glsl-transpose
+mat3 transpose(mat3 m)
+{
+  return mat3(m[0][0], m[1][0], m[2][0],
+              m[0][1], m[1][1], m[2][1],
+              m[0][2], m[1][2], m[2][2]);
+}
+
+void main()
+{
+
+    // calc binormal from vertex normal and tangent
+    vec3 vertexBinormal = cross(vertexNormal, vertexTangent);
+    // calc fragment normal based on normal transformations
+    mat3 normalMatrix = transpose(inverse(mat3(matModel)));
+    // calc fragment position based on model transformations
+
+    fragPosition = vec3(matModel*vec4(vertexPosition, 1.0));
+
+    fragTexCoord = vertexTexCoord*2.0;
+
+    fragNormal = normalize(normalMatrix*vertexNormal);
+    vec3 fragTangent = normalize(normalMatrix*vertexTangent);
+    fragTangent = normalize(fragTangent - dot(fragTangent, fragNormal)*fragNormal);
+    vec3 fragBinormal = normalize(normalMatrix*vertexBinormal);
+    fragBinormal = cross(fragNormal, fragTangent);
+
+    TBN = transpose(mat3(fragTangent, fragBinormal, fragNormal));
+
+    // Calculate final vertex position
+    gl_Position = mvp * vec4(vertexPosition, 1.0);
+}

examples/shaders/resources/shaders/glsl120/pbr.fs

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+#version 120
+
+precision mediump float;
+
+#define MAX_LIGHTS              4
+#define LIGHT_DIRECTIONAL       0
+#define LIGHT_POINT             1
+#define PI 3.14159265358979323846
+
+struct Light {
+    int enabled;
+    int type;
+    vec3 position;
+    vec3 target;
+    vec4 color;
+    float intensity;
+};
+
+// Input vertex attributes (from vertex shader)
+varying in vec3 fragPosition;
+varying in vec2 fragTexCoord;
+varying in vec4 fragColor;
+varying in vec3 fragNormal;
+varying in vec4 shadowPos;
+varying in mat3 TBN;
+
+
+// Input uniform values
+uniform int numOfLights;
+uniform sampler2D albedoMap;
+uniform sampler2D mraMap;
+uniform sampler2D normalMap;
+uniform sampler2D emissiveMap; // r: Hight g:emissive
+
+uniform vec2 tiling;
+uniform vec2 offset;
+
+uniform int useTexAlbedo;
+uniform int useTexNormal;
+uniform int useTexMRA;
+uniform int useTexEmissive;
+
+uniform vec4  albedoColor;
+uniform vec4  emissiveColor;
+uniform float normalValue;
+uniform float metallicValue;
+uniform float roughnessValue;
+uniform float aoValue;
+uniform float emissivePower;
+
+// Input lighting values
+uniform Light lights[MAX_LIGHTS];
+uniform vec3 viewPos;
+
+uniform vec3 ambientColor;
+uniform float ambient;
+
+// refl in range  0 to 1
+// returns base reflectivity to 1
+// incrase reflectivity when surface view at larger angle
+vec3 schlickFresnel(float hDotV,vec3 refl)
+{
+        return refl + (1.0 - refl) * pow(1.0 - hDotV,5.0);
+}
+
+float ggxDistribution(float nDotH,float roughness)
+{
+        float a = roughness * roughness * roughness * roughness;
+        float d = nDotH * nDotH * (a - 1.0) + 1.0;
+        d = PI * d * d;
+        return a / max(d,0.0000001);
+}
+
+float geomSmith(float nDotV,float nDotL,float roughness)
+{
+        float r = roughness + 1.0;
+        float k = r * r / 8.0;
+        float ik = 1.0 - k;
+        float ggx1 = nDotV / (nDotV * ik + k);
+        float ggx2 = nDotL / (nDotL * ik + k);
+        return ggx1 * ggx2;
+}
+
+vec3 pbr(){
+        vec3 albedo = texture2D(albedoMap,vec2(fragTexCoord.x*tiling.x+offset.x,fragTexCoord.y*tiling.y+offset.y)).rgb;
+        albedo = vec3(albedoColor.x*albedo.x,albedoColor.y*albedo.y,albedoColor.z*albedo.z);
+        float metallic = clamp(metallicValue,0.0,1.0);
+        float roughness = clamp(roughnessValue,0.0,1.0);
+        float ao = clamp(aoValue,0.0,1.0);
+        if(useTexMRA == 1) {
+            vec4 mra = texture2D(mraMap, vec2(fragTexCoord.x * tiling.x + offset.x, fragTexCoord.y * tiling.y + offset.y));
+            metallic = clamp(mra.r+metallicValue,0.04,1.0);
+            roughness = clamp(mra.g+roughnessValue,0.04,1.0);
+            ao = (mra.b+aoValue)*0.5;
+        }
+
+
+
+        vec3 N = normalize(fragNormal);
+        if(useTexNormal == 1) {
+            N = texture2D(normalMap, vec2(fragTexCoord.x * tiling.x + offset.y, fragTexCoord.y * tiling.y + offset.y)).rgb;
+            N = normalize(N * 2.0 - 1.0);
+            N = normalize(N * TBN);
+        }
+
+        vec3 V = normalize(viewPos - fragPosition);
+
+        vec3 e = vec3(0);
+        e = (texture2D(emissiveMap, vec2(fragTexCoord.x*tiling.x+offset.x, fragTexCoord.y*tiling.y+offset.y)).rgb).g * emissiveColor.rgb*emissivePower * float(useTexEmissive);
+
+        //return N;//vec3(metallic,metallic,metallic);
+        //if  dia-electric use base reflectivity of 0.04 otherwise ut is a metal use albedo as base reflectivity
+        vec3 baseRefl = mix(vec3(0.04),albedo.rgb,metallic);
+        vec3 Lo = vec3(0.0);  // acumulate lighting lum
+
+        for(int i=0;i<numOfLights;++i){
+
+            vec3 L = normalize(lights[i].position - fragPosition);  // calc light vector
+            vec3 H = normalize(V + L);                              // calc halfway bisecting vector
+            float dist = length(lights[i].position - fragPosition); // calc distance to light
+            float attenuation = 1.0 / (dist * dist * 0.23);                // calc attenuation
+            vec3 radiance = lights[i].color.rgb * lights[i].intensity * attenuation;         // calc input radiance,light energy comming in
+
+            //Cook-Torrance BRDF distribution function
+            float nDotV = max(dot(N,V),0.0000001);
+            float nDotL = max(dot(N,L),0.0000001);
+            float hDotV = max(dot(H,V),0.0);
+            float nDotH = max(dot(N,H),0.0);
+            float D = ggxDistribution(nDotH,roughness); // larger the more micro-facets aligned to H
+            float G = geomSmith(nDotV,nDotL,roughness); // smaller the more micro-facets shadow
+            vec3 F = schlickFresnel(hDotV, baseRefl);  // fresnel proportion of specular reflectance
+
+            vec3 spec = (D * G * F) / (4.0 * nDotV * nDotL);
+            // difuse and spec light can't be above 1.0
+            // kD = 1.0 - kS  diffuse component is equal 1.0 - spec comonent
+            vec3 kD = vec3(1.0) - F;
+            //mult kD by the inverse of metallnes , only non-metals should have diffuse light
+            kD *= 1.0 - metallic;
+            Lo += ((kD * albedo.rgb / PI + spec) * radiance * nDotL)*float(lights[i].enabled); // angle of light has impact on result
+        }
+        vec3 ambient_final = (ambientColor + albedo)* ambient * 0.5;
+        return ambient_final+Lo*ao+e;
+}
+
+void main()
+{
+       vec3 color = pbr();
+
+        //HDR tonemapping
+        color = pow(color,color + vec3(1.0));
+        //gamma correction
+        color = pow(color,vec3(1.0/2.2));
+
+        gl_FragColor = vec4(color,1.0);
+
+}