Physically based rendering with textures

Shaders/pbr.fs

@@ -7,10 +7,11 @@ in vec3 Normal;
 
 uniform vec3 camPos;
 
-uniform vec3 albedo;
-uniform float metallic;
-uniform float roughness;
-uniform float ao;
+uniform sampler2D albedoMap;
+uniform sampler2D metallicMap;
+uniform sampler2D normalMap;
+uniform sampler2D roughnessMap;
+uniform sampler2D aoMap;
 
 uniform vec3 lightPositions[4];
 uniform vec3 lightColors[4];
@@ -59,8 +60,31 @@ float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
     return ggx1 * ggx2;
 }
 
-void main(){
+vec3 getNormalFromNormalMap(){
+    vec3 tangentNormal = texture(normalMap, TexCoords).xyz * 2.0 - 1.0;
+
+    vec3 Q1 = dFdx(WorldPos);
+    vec3 Q2 = dFdy(WorldPos);
+    vec2 st1 = dFdx(TexCoords);
+    vec2 st2 = dFdy(TexCoords);
+
     vec3 N = normalize(Normal);
+    vec3 T = normalize(Q1 *st2.t - Q2*st1.t);
+    vec3 B = -normalize(cross(N, T));
+    mat3 TBN = mat3(T, B, N);
+
+    return normalize(TBN * tangentNormal);
+}
+
+void main(){
+
+    vec3 albedo = pow(texture(albedoMap, TexCoords).rgb, vec3(2.2));
+    float metallic = texture(metallicMap, TexCoords).r;
+    float roughness = texture(roughnessMap, TexCoords).r;
+    float ao = texture(aoMap, TexCoords).r;
+
+
+    vec3 N = getNormalFromNormalMap();
     vec3 V = normalize(camPos - WorldPos);
     
     vec3 F0 = vec3(0.04);
@@ -98,8 +122,9 @@ void main(){
     vec3 ambient = vec3(0.03) * albedo * ao;
     vec3 color = ambient + Lo;
 
-    // Gamma correct the result 
+    // HDR tonemapping
     color = color / (color + vec3(1.0));
+    // gamma correct
     color = pow(color, vec3(1.0/2.2));
 
     FragColor = vec4(color, 1.0);