#version 150

in vec4 vPosition;
in vec2 vTexCoord;
in vec3 vNormal;

out vec2 texCoord;
out float fog_factor;
// output values that will be interpretated per-fragment
out vec3 fN0;
out vec3 fE0;
out vec3 fL0;
out vec3 fN1;
out vec3 fE1;
out vec3 fL1;

uniform int foggy;
uniform float fog_fac;
uniform vec3 eye_pos;
uniform mat4 model_view;
uniform mat4 projection;

void main() {
  texCoord = vTexCoord;
  gl_Position = projection * model_view * vPosition / vPosition.w;

  // light0
  vec4 LightPosition0 = vec4(eye_pos.x, eye_pos.y, eye_pos.z, 1.0);
  fN0 = vNormal;
  fE0 = -(model_view * vPosition).xyz;
  fL0 = LightPosition0.xyz - (model_view * vPosition).xyz;

  // light1
  vec4 LightPosition1 = vec4(0.5, 0.25, 10, 0.0);
  fN1 = vNormal;
  fE1 = -(model_view * vPosition).xyz;
  fL1 = LightPosition1.xyz;
  // fog
  if (foggy > 0) {
    // distance
    float dis = (vPosition.x - eye_pos.x) * (vPosition.x - eye_pos.x) +
                (vPosition.y - eye_pos.y) * (vPosition.y - eye_pos.y) +
                (vPosition.z - eye_pos.z) * (vPosition.z - eye_pos.z);
    fog_factor = exp(-dis * fog_fac);
  } else { // not foggy
    fog_factor = 1.0;
  }
}