#version 150

in vec2 texCoord;
in float fog_factor;

// per-fragment interpolated values from the vertex shader
in vec3 fN0;
in vec3 fL0;
in vec3 fE0;
in vec3 fN1;
in vec3 fL1;
in vec3 fE1;

out vec4 fColor;

uniform sampler2D tex;
uniform float obj_shi;
uniform float plane_light_on;

void main() {
  vec4 material_ambient;
  vec4 material_diffuse;
  vec4 material_specular;
  float material_shininess;
  if (texCoord.x > 10) { // cow
    fColor = vec4(0.1, 0.1, 0.1, 1);
    material_ambient = fColor;
    material_diffuse = vec4(1.0, 0.8, 0.0, 1.0);
    material_specular = vec4(1.0, 0.0, 1.0, 1.0);
    material_shininess = obj_shi; // cow's shininess
  } else { // tex
    fColor = texture(tex, texCoord);
    material_ambient = fColor;
    material_diffuse = fColor;
    material_specular = vec4(0.0, 0.0, 0.0, 0.0);
    material_shininess = 0.0;
  }

  // Normalize the input lighting vectors

  vec4 light0_ambient = vec4(0.2, 0.2, 0.2, 1.0);
  vec4 light0_diffuse = vec4(1.0, 1.0, 1.0, 1.0);
  vec4 light0_specular = vec4(1.0, 1.0, 1.0, 1.0);

  vec4 ambient_product0 = light0_ambient * material_ambient;
  vec4 diffuse_product0 = light0_diffuse * material_diffuse;
  vec4 specular_product0 = light0_specular * material_specular;

  vec3 N0 = normalize(fN0);
  vec3 E0 = normalize(fE0);
  vec3 L0 = normalize(fL0);
  vec3 H0 = normalize(L0 + E0);

  vec4 ambient0 = ambient_product0;

  float Kd0 = max(dot(L0, N0), 0.0);
  vec4 diffuse0 = Kd0 * diffuse_product0;

  float Ks0 = pow(max(dot(N0, H0), 0.0), material_shininess);
  vec4 specular0 = Ks0 * specular_product0;

  // discard the specular highlight if the light's behind the vertex
  if (dot(L0, N0) < 0.0) {
    specular0 = vec4(0.0, 0.0, 0.0, 1.0);
  }

  vec4 light1_ambient = vec4(0.2, 0.2, 0.2, 1.0);
  vec4 light1_diffuse = vec4(1.0, 1.0, 1.0, 1.0);
  vec4 light1_specular = vec4(1.0, 1.0, 1.0, 1.0);

  vec4 ambient_product1 = light1_ambient * material_ambient;
  vec4 diffuse_product1 = light1_diffuse * material_diffuse;
  vec4 specular_product1 = light1_specular * material_specular;

  vec3 N1 = normalize(fN1);
  vec3 E1 = normalize(fE1);
  vec3 L1 = normalize(fL1);
  vec3 H1 = normalize(L1 + E1);

  vec4 ambient1 = ambient_product0;

  float Kd1 = max(dot(L1, N1), 0.0);
  vec4 diffuse1 = Kd1 * diffuse_product1;

  float Ks1 = pow(max(dot(N1, H1), 0.0), material_shininess);
  vec4 specular1 = Ks1 * specular_product0;

  // discard the specular highlight if the light's behind the vertex
  if (dot(L1, N1) < 0.0) {
    specular1 = vec4(0.0, 0.0, 0.0, 1.0);
  }

  fColor = 0.5 * (plane_light_on * (ambient0 + diffuse0 + specular0) +
                  (ambient1 + diffuse1 + specular1));
  fColor.a = 1.0;

  // fog
  vec4 fogColor = vec4(0.5, 0.5, 0.5, 1);
  fColor = fColor * fog_factor + fogColor * (1 - fog_factor);
}