Feat: disabling normalOffset calculation when not necessary

Author: solomon-gumball

webgl-shaders/FragmentShader.glsl

@@ -44,16 +44,17 @@ void main() {
     bool lightsEnabled = (u_flatShading == 0.0) && (u_numLights > 0.0 || length(u_ambientLight) > 0.0);
 
     vec3 normal = normalize(v_normal);
-    vec3 tangent = normalize(v_tangent);
-
-    tangent = normalize(tangent - dot(tangent, normal) * normal);
-    vec3 bitangent = cross(tangent, normal);
-    vec3 normalOffset = u_normals.x < 0.0 ? applyMaterial(u_normals) * 2.0 - 1.0 : vec3(0.0);
-    normalOffset.y *= 1.0;
-
-    mat3 TBNMatrix = mat3(tangent, bitangent, normal);
-    vec3 newNormal = normalize(TBNMatrix * normalOffset);
 
+    if (u_normals.x < 0.0) {
+        vec3 tangent = normalize(v_tangent);
+        tangent = normalize(tangent - dot(tangent, normal) * normal);
+        vec3 bitangent = cross(tangent, normal);
+        vec3 normalOffset = applyMaterial(u_normals) * 2.0 - 1.0;
+        normalOffset.y *= 1.0;
+        mat3 TBNMatrix = mat3(tangent, bitangent, normal);
+        normal = normalize(TBNMatrix * normalOffset);
+    }
+
     // normal = normalize(u_normalMatrix * normal);
 
     vec4 glossiness = u_glossiness.x < 0.0 ? applyMaterial(u_glossiness) : u_glossiness;
@@ -62,7 +63,7 @@ void main() {
     vec3 ambience = u_ambientLight * u_baseColor.rgb;
 
     vec4 color = !lightsEnabled ? material :
-        applyLight(material, newNormal, glossiness, numLights, ambience,
+        applyLight(material, normal, glossiness, numLights, ambience,
                    eyeVector, u_lightPosition, u_lightColor, v_position);
 
     gl_FragColor = color;