#version 450
#extension GL_ARB_separate_shader_objects : enable
#extension GL_ARB_shading_language_420pack : enable
#extension GL_EXT_nonuniform_qualifier : require

struct MatPropData
{
  int textureIndex;
  float highlightPosition;
  float thickness;
};

struct GenericData
{
  //! Delta time
  float dt;

  //! Elapsed time of the application
  float elapsedTime;

  //! Viewport width of the scene (excluding imgui, that means smaller than window)
  uint viewportWidth;

  //! Ditto but for height
  uint viewportHeight;
};


layout(location = 0) in struct
{
  vec4 vertPos; // location 0
  vec2 uv; // location = 1
  vec4 normal; // location = 2
  vec4 worldPos; // location = 3 
} In;

// material stuff
layout(location = 4) flat in struct
{
  int materialIndex;
  uint eid;
  uint lightLayerIndex;
  vec3 screenSpacePos;

} In2;

layout (set = 0, binding = 0) uniform GenericDataBuffer
{
  GenericData data;
} genericDataBuffer;

layout (set = 0, binding = 1) uniform sampler2D textures[]; // for textures (global)
layout (std430, set = 2, binding = 0) buffer MaterialProperties     // For materials 
{
  MatPropData data[];
} MatProp;

layout(location = 0) out vec4 position;
layout(location = 1) out uint outEntityID;
layout(location = 2) out uint lightLayerIndices;
layout(location = 3) out vec4 normals;
layout(location = 4) out vec4 albedo;
layout(location = 5) out vec4 worldSpacePosition;
layout(location = 6) out vec4 objectVFX;

float map (float value, float srcLow, float srcHigh, float dstLow, float dstHigh)
{
  return dstLow + (value - srcLow) * (dstHigh - dstLow) / (srcHigh - srcLow);
}

void main()
{
  position = In.vertPos;
  normals = In.normal;
  albedo = texture(textures[nonuniformEXT(MatProp.data[In2.materialIndex].textureIndex)], In.uv);
  worldSpacePosition = In.worldPos;

  outEntityID = In2.eid;
  lightLayerIndices = In2.lightLayerIndex;

  float vpHeight = float (In2.screenSpacePos.y) - MatProp.data[In2.materialIndex].highlightPosition;
  vpHeight = float (int (vpHeight) % genericDataBuffer.data.viewportHeight);
  float scanlineScale = MatProp.data[In2.materialIndex].thickness * (1.0f - In2.screenSpacePos.z) * 100.0f;

  float lowerLimit = vpHeight - scanlineScale;
  float upperLimit = vpHeight + scanlineScale;
  if (gl_FragCoord.y > lowerLimit && gl_FragCoord.y < upperLimit)
  {
    float opacity = 0.0f;
    opacity = map (abs (gl_FragCoord.y - vpHeight), 0.0f, upperLimit - vpHeight, 0.0f, 1.0f);
    opacity = 1.0f - clamp (opacity, 0.0f, 1.0f);


    objectVFX = vec4(opacity);
  }
  else
    objectVFX = vec4(0.0f, 0.0f, 0.0f, 1.0f);
}