#include "Terrain/ConstantBuffers.hlsl"
#include "Terrain/ClipmapCommonPS.hlsl"
#include "Terrain/ClipmapNormals.hlsl"
#include "Terrain/ComputeColor.hlsl"
#include "Shaders/RangeOut.hlsl"

cbuffer CustomParameters
{
  float4 GeLiveRange;
  float4 startColorHsv;
  float4 endColorHsv;
  float4 staticColor1;
  float4 staticRange1;
  float4 staticColor2;
  float4 staticRange2;
  float4 staticColor3;
  float4 staticRange3;
  float4 staticColor4;
  float4 staticRange4;
  float4 wrapMode;
};

float sampleTexture(Texture2D source, float2 texCoords)
{
  float2 dimensions;
  source.GetDimensions(dimensions.x, dimensions.y);

  float2 offset = float2(0.5 / dimensions.x, -0.5 / dimensions.y);

  float center = 0;
  float dist = 0;
  float h = sampleHeightNoData(source, texCoords, offset, center, dist);

  return h;
}

float computeTextureValue(VertexIn In)
{
  int index = 0;

  float h1 = sampleTexture(imageryTexture[index], In.ImageryTexCoords[index].xy);
  float h2 = sampleTexture(coarseImageryTexture[index], In.ImageryTexCoords[index].zw);

  float h = lerp(h1, h2, In.BlendFactor);

  return h;
}

float4 hsv2rgb(float4 c)
{
    float4 K = float4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
    float3 p = abs(frac(c.xxx + K.xyz) * 6.0 - K.www);
    float3 rgb = c.z * lerp(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
    return float4(rgb.xyz, c.w);
}

float customMod(float x, float y)
{
    return x - y * floor(x / y);
}

float4 colorFromValue(float value)
{
    float step = (value - GeLiveRange.x) / GeLiveRange.z;

    if (staticRange1.x == 1 && value >= staticRange1.y && value <= staticRange1.z)
    {
        return staticColor1;
    }
    if (staticRange2.x == 1 && value >= staticRange2.y && value <= staticRange2.z)
    {
        return staticColor2;
    }
    if (staticRange3.x == 1 && value >= staticRange3.y && value <= staticRange3.z)
    {
        return staticColor3;
    }
    if (staticRange4.x == 1 && value >= staticRange4.y && value <= staticRange4.z)
    {
        return staticColor4;
    }

    if (wrapMode.x == 0)
    {
        step = clamp(step, 0, 1);
    }
    else if (wrapMode.x == 1)
    {
        step = customMod(step, 1);
    }
    else if (wrapMode.x == 2 && (step < 0 || step > 1))
    {
        discard;
    }

    float4 hsv = lerp(startColorHsv, endColorHsv, step);

    return hsv2rgb(hsv);
}

float4 computeCustomColorGeLive(VertexIn In)
{
  float value;
  if (GeLiveRange.w == 1) {
    value = computeTextureValue(In);
  } else {
    value = In.WorldPosition.z;
  }

  float4 result = colorFromValue(value);
  return result;
}

void surfaceFunction(VertexIn In, out RangeOut Out)
{
  float value;
  if (GeLiveRange.w == 0) {
    value = computeTextureValue(In);
  } else {
    value = In.WorldPosition.z;
  }
  Out.Attributes = float4(value, 0, -2, 1);
}

SurfaceOut surfaceFunction(in VertexIn In)
{
  testClipping(In);

  color = computeCustomColorGeLive(In);

  SurfaceOut Out = (SurfaceOut)0;
  Out.Color = color;
  float3 n = normalize(mul(computeNormal(In, 1), (float3x3)viewMatrix));
  if (!isfinite(n.z)) {
	Out.Normal = normalize(mul(float3(0, 0, 1), (float3x3)viewMatrix));
  } else {
	Out.Normal = n;
  }
  Out.Specular = float3(0.0, 0.0, 0.0);
  Out.SpecularPower = 10;

  return Out;
}