#version 430 core

in VS_OUT {
  vec3 Position; // world coordinates
  vec3 Normal;
  vec2 Texture;
} fs_in;

layout (location = 10) uniform vec4 EmissionColor;
layout (location = 11) uniform vec4 AmbientColor;
layout (location = 12) uniform vec4 DiffuseColor;
layout (location = 13) uniform vec4 SpecularColor;

layout (location = 14) uniform float shininess;

layout (location = 15) uniform sampler2D EmissionSampler;
layout (location = 16) uniform sampler2D AmbientSampler;
layout (location = 17) uniform sampler2D DiffuseSampler;
layout (location = 18) uniform sampler2D SpecularSampler;

layout (location = 19) uniform ivec4 TextureChannel;

layout (location = 0) out vec4 Position;
layout (location = 1) out vec4 Normal;
layout (location = 2) out vec4 Color;
layout (location = 3) out vec4 Block;

void main()
{
  vec4 emission;
  vec4 ambient;
  vec4 diffuse;
  vec4 specular;
  if (TextureChannel.x >= 0) { // emission
    emission = texture(EmissionSampler, fs_in.Texture.xy);
  } else {
    emission = EmissionColor;
  }
  if (TextureChannel.y >= 0) { // ambient
    ambient = texture(AmbientSampler, fs_in.Texture.xy);
  } else {
    ambient = AmbientColor;
  }
  if (TextureChannel.z >= 0) { // diffuse
    diffuse = texture(DiffuseSampler, fs_in.Texture.xy);
  } else {
    diffuse = DiffuseColor;
  }
  if (TextureChannel.w >= 0) { // specular
    specular = texture(SpecularSampler, fs_in.Texture.xy);
  } else {
    specular = SpecularColor;
  }

  vec3 color = emission.xyz * 0;
  color += ambient.xyz * 0.05;
  color += diffuse.xyz * 1;
  color += specular.xyz * 0 * 0.3;

  Position = vec4(fs_in.Position, 1.0);
  Normal = vec4(fs_in.Normal, 0.0);
  Color = vec4(color, 1.0);
  Block = vec4(0, 0, 0, 0);
}