vec3 viewDir = normalize(fragPos - viewPos);
vec3 reflectDir = reflect(-lightDir, normal);
float specular = pow(max(0, dot(viewDir, reflectDir)), 128);
vec3 viewDir = normalize(fragPos - viewPos);
vec3 reflectDir = reflect(-lightDir, normal);
float specular = pow(max(0, dot(viewDir, reflectDir)), 128);