title: Phong Shader: Fixed light specular component rotates with camera
body: <p>I wrote a Phong shader for WebGL. My Scene supports camera rotation using Euler Angles. The light should be fixed in the scene. As soon as I rotate the camera the specular effects on objects move as well. Translation also seems to have strange effects on the specular component. I 
  (hopefully) made sure that calculations are performed in eye space. I first want to find out if my shaders are correct.</p>
  
  <p>Here is my code:</p>
  
  <p>Vertex Shader</p>
  
  <pre><code>struct Light {
    vec3 position;
  
    /* ... */
  };
  
  uniform Light u_light;
  uniform mat4 u_modelViewProjMat;
  uniform mat4 u_modelViewMat;
  uniform mat4 u_viewMat;
  uniform mat3 u_normalMat;
  
  in vec3 a_position;
  in vec3 a_normal;
  in vec2 a_texCoord;
  
  out vec2 v_texCoord;
  out vec3 v_normal;
  out vec3 f_position;
  out vec3 v_lightPos;
  
  void main() {
    v_normal = u_normalMat * a_normal;
    v_texCoord = a_texCoord;
    f_position = vec3(u_modelViewMat * vec4(a_position, 1.0));
    v_lightPos = vec3(u_viewMat * vec4(u_light.position, 1.0));
    gl_Position = u_modelViewProjMat * vec4(a_position, 1.0);
  }
  </code></pre>
  
  <p>Fragment Shader</p>
  
  <pre><code>struct Material {
    sampler2D diffuse;
    vec3 specular;
    float shininess;
  };
  
  struct Light {
      /* ... */
      vec3 ambient;
      vec3 diffuse;
      vec3 specular;
  };
  
  uniform Material u_material;
  uniform Light u_light;
  uniform vec3 u_eyePosition;
  
  in vec2 v_texCoord;
  in vec3 v_normal;
  in vec3 f_position;
  in vec3 v_lightPos;
  
  out vec4 outColor;
  
  void main() {
    vec3 texture = vec3(texture(u_material.diffuse, v_texCoord));
  
    // ambient
    vec3 ambient = u_light.ambient * texture;
  
    // diffuse
    vec3 normal = normalize(v_normal);
    vec3 lightDir = normalize(v_lightPos - f_position);
    float diff = max(dot(normal, lightDir), 0.0);
    vec3 diffuse = u_light.diffuse * diff * texture;
  
    // specular
    vec3 viewDir = normalize(u_eyePosition - f_position);
    vec3 reflectDir = reflect(-lightDir, normal);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), u_material.shininess);
    vec3 specular = u_light.specular * (spec * u_material.specular);
  
    outColor = vec4((ambient + diffuse + specular), 1.0);
  }
  </code></pre>