Phong Shader: Fixed light specular component rotates with camera - webgl

Question

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.
Here is my code:
Vertex Shader
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);
}
Fragment Shader
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);
}

Answer 1

f_position is a camera space position, so to get the viewDir vector for your specular component you should only perform vec3 viewDir = normalize(-f_position); or work with world space coordinates