fragment.fs

in vec3 Normal;
in vec3 FragmentPos;

uniform vec3 viewPos;

uniform struct Fog {
    vec2 range;
    vec4 color;
} fog;

uniform struct PointLight {
	vec3 position;

	// attenuation
	float constant;
	float linear;
	float quadratic;

	vec3 ambient;
    vec3 diffuse;
    vec3 specular;
} light;

vec4 color(vec4 graphicsColor, sampler2D image, vec2 uv) 
{
    vec3 norm = normalize(Normal);
    vec3 lightDir = normalize(light.position - FragmentPos);
    float diff = max(dot(norm, lightDir), 0.0);

    // specular
    vec3 reflectDir = reflect(-lightDir, norm);
    vec3 viewDir = normalize(viewPos - FragmentPos);
    float spec = pow(max(dot(viewDir, reflectDir), 0.0), 1.0) * lovrMetalness;

	// attenuation
    float distance = length(light.position - FragmentPos);
    float attenuation = 1.0 / (light.constant + light.linear * distance + 
  			     light.quadratic * (distance * distance));
	
	// combine results
    vec3 ambient = light.ambient * vec3(texture(image, uv));
    vec3 diffuse = light.diffuse * diff * vec3(texture(image, uv));
    vec3 specular = light.specular * spec * vec3(texture(image, uv));
    ambient *= attenuation;
    diffuse *= attenuation;
    specular *= attenuation;
    vec4 baseColor = vec4((ambient + diffuse + specular), 1.0);

    // fog
    float near = fog.range.x;
    float far = fog.range.y;
    float fogAmount = clamp((distance - near) / (far - near), 0.0, 0.97);

    return mix(baseColor, fog.color, fogAmount);
}