//-----------------------------------------------------------------------------
// Scanline & Shadowmask Effect
//-----------------------------------------------------------------------------

texture DiffuseTexture;

sampler DiffuseSampler = sampler_state
{
  Texture   = <DiffuseTexture>;
  MipFilter = LINEAR;
  MinFilter = LINEAR;
  MagFilter = LINEAR;
  AddressU = CLAMP;
  AddressV = CLAMP;
  AddressW = CLAMP;
};

texture ShadowTexture;

sampler ShadowSampler = sampler_state
{
  Texture   = <ShadowTexture>;
  MipFilter = LINEAR;
  MinFilter = LINEAR;
  MagFilter = LINEAR;
  AddressU = WRAP;
  AddressV = WRAP;
  AddressW = WRAP;
};

//-----------------------------------------------------------------------------
// Vertex Definitions
//-----------------------------------------------------------------------------

struct VS_OUTPUT
{
  float4 Position : POSITION;
  float4 Color : COLOR0;
  float2 TexCoord : TEXCOORD0;
};

struct VS_INPUT
{
  float4 Position : POSITION;
  float4 Color : COLOR0;
  float2 TexCoord : TEXCOORD0;
  float2 Unused : TEXCOORD1;
};

struct PS_INPUT
{
  float4 Color : COLOR0;
  float2 TexCoord : TEXCOORD0;
};

//-----------------------------------------------------------------------------
// Scanline & Shadowmask Vertex Shader
//-----------------------------------------------------------------------------

uniform float2 ScreenDims;
uniform float2 SourceDims;
uniform float2 SourceRect;

VS_OUTPUT vs_main(VS_INPUT Input)
{
  VS_OUTPUT Output = (VS_OUTPUT)0;
  
  Output.Position = float4(Input.Position.xyz, 1.0f);
  Output.Position.xy /= ScreenDims;
  Output.Position.y = 1.0f - Output.Position.y;
  Output.Position.xy -= 0.5f;
  Output.Position *= float4(2.0f, 2.0f, 1.0f, 1.0f);
  Output.Color = Input.Color;
  Output.TexCoord = Input.TexCoord + 0.5f / SourceDims;

  return Output;
}

//-----------------------------------------------------------------------------
// Post-Processing Pixel Shader
//-----------------------------------------------------------------------------

uniform float PI = 3.14159265f;
uniform float Epsilon = 0.00000001f;

uniform float CurvatureAmount = 0.0f;
uniform float PincushionAmount = 0.0f;

uniform float ScanlineAlpha = 1.0f;
uniform float ScanlineScale = 1.0f;
uniform float ScanlineBrightScale = 1.0f;
// uniform float ScanlineBrightOffset = 1.0f;
uniform float ScanlineOffset = 1.0f;
uniform float ScanlineHeight = 0.5f;

uniform float ShadowAlpha = 0.0f;
uniform float2 ShadowCount = float2(320.0f, 240.0f);
uniform float2 ShadowUV = float2(0.375f, 0.375f);
uniform float2 ShadowDims = float2(8.0f, 8.0f);

uniform float3 Power = float3(1.0f, 1.0f, 1.0f);
uniform float3 Floor = float3(0.0f, 0.0f, 0.0f);

static const float MagicConst = 0.5f;

float4 ps_main(PS_INPUT Input) : COLOR
{
  float2 UsedArea = 1.0f / SourceRect;
  float2 HalfRect = SourceRect * 0.5f;
  float2 R2 = 1.0f / pow(length(UsedArea), 2.0f);
  
  // Warning: Magic constant
  float2 CoordCorrection0 = float2(UsedArea.x * (MagicConst) / SourceDims.x, UsedArea.y * (MagicConst) / SourceDims.y);
  float2 CoordCorrection1 = float2(UsedArea.x * (1.0f + MagicConst) / SourceDims.x, UsedArea.y * (1.0f + MagicConst) / SourceDims.y);
  
  // Reduce Pincushion Amount
  float CurvatureAmountReduced = CurvatureAmount * 0.25f;

  // -- Screen Pincushion Calculation --
  float2 PinUnitCoord = Input.TexCoord * UsedArea * 2.0f - 1.0f;
  float CurvatureR2 = pow(length(PinUnitCoord), 2.0f) * R2;
  float2 CurvatureCurve = PinUnitCoord * CurvatureAmountReduced * CurvatureR2;
  float2 BaseCoord = Input.TexCoord;
  float2 ScanCoord = BaseCoord - 0.5f / ScreenDims;
  
  BaseCoord -= HalfRect;
  BaseCoord *= 1.0f - CurvatureAmountReduced * UsedArea * 0.2f; // Warning: Magic constant
  BaseCoord += HalfRect;
  BaseCoord += CurvatureCurve;

  ScanCoord -= HalfRect;
  ScanCoord *= 1.0f - CurvatureAmountReduced * UsedArea * 0.2f; // Warning: Magic constant
  ScanCoord += HalfRect;
  ScanCoord += CurvatureCurve;

  float4 BaseTexel = tex2D(DiffuseSampler, BaseCoord);
  
  // BaseTexel.r = 0.5f; // debug
  // BaseTexel.g = 0.5f; // debug
  // BaseTexel.b = 0.5f; // debug
  // BaseTexel.a = 1.00f; // debug

  // -- Alpha Clipping (1px border in drawd3d does not work for some reason) --
  clip((BaseCoord < 1.0f / SourceDims) ? -1 : 1);
  clip((BaseCoord > (SourceRect + 1.0f / SourceDims)) ? -1 : 1);

  // -- Scanline Simulation --
  float InnerSine = ScanCoord.y * SourceDims.y * ScanlineScale;
  float ScanBrightMod = sin(InnerSine * PI + ScanlineOffset * SourceDims.y);
  float3 ScanBrightness = lerp(1.0f, (pow(ScanBrightMod * ScanBrightMod, ScanlineHeight) * ScanlineBrightScale + 1.0f) * 0.5f, ScanlineAlpha);
  float3 Scanned = BaseTexel.rgb * ScanBrightness;

  // -- Color Compression (increasing the floor of the signal without affecting the ceiling) --
  Scanned = Floor + (1.0f - Floor) * Scanned;

  float2 ShadowMaskSize = float2(
    ShadowCount.x < 0.0f ? SourceDims.x * SourceRect.x / ShadowCount.x * -1.0f : ShadowCount.x, 
    ShadowCount.y < 0.0f ? SourceDims.y * SourceRect.y / ShadowCount.y * -1.0f : ShadowCount.y);
  float2 ShadowFrac = frac(BaseCoord * ShadowMaskSize * UsedArea);
  float2 ShadowCoord = ShadowFrac * ShadowUV + 1.5f / ShadowDims;
  float3 ShadowTexel = lerp(1.0f, tex2D(ShadowSampler, ShadowCoord).rgb, ShadowAlpha);
  
  // -- Final Pixel --
  float4 Output = float4(Scanned * ShadowTexel, BaseTexel.a) * Input.Color;
  
  Output.r = pow(Output.r, Power.r);
  Output.g = pow(Output.g, Power.g);
  Output.b = pow(Output.b, Power.b);
  Output.a = 1.0f;
  
  // Output.r = 0.25f; // debug
  // Output.g = 0.25f; // debug
  // Output.b = 0.25f; // debug
  
  float2 DefaultUsedArea = float2(10.0f / 7.0f, 1.0f);
  // float2 DefaultUsedArea = float2(4.0f / 3.0f, 1.0f);
  
  float2 CurvatureCoord = Input.TexCoord;
  CurvatureCoord -= HalfRect;
  CurvatureCoord *= 1.0f - CurvatureAmountReduced * UsedArea * MagicConst; // Warning: Magic constant
  // CurvatureCoord += HalfRect;
  CurvatureCoord += CurvatureCurve;
  
  // CurvatureCoord *= UsedArea * DefaultUsedArea;
  // CurvatureCoord *= UsedArea * DefaultUsedArea * 1.5f;
  CurvatureCoord *= UsedArea * DefaultUsedArea * 1.25f;
  
  // -- Vignetting --
  float2 VignetteCoord = CurvatureCoord;
  
  float VignetteAmount = 1.0f - saturate(dot(VignetteCoord, VignetteCoord));
  float VignetteDarkness = pow(1.0f - PincushionAmount, 2.0f);
  float VignetteRadius = PincushionAmount * 2.0f + 1.0f;
  float Vignette = pow(VignetteAmount, VignetteRadius) + VignetteDarkness;
  
  Output.rgb *= saturate(Vignette);  
  
  // Output.r = 0.25f; // debug
  // Output.g = 0.25f; // debug
  // Output.b = 0.25f; // debug
  
  // -- Light Spot --  
  float2 SpotCoord = CurvatureCoord;
  SpotCoord += float2(-0.25f, 0.25f) * DefaultUsedArea;
  
  // float SpotAmount = 1.0f - saturate(pow(dot(SpotCoord, SpotCoord), 0.5f));
  // float SpotRadius = CurvatureAmount * 2.0f + 4.0f;
  // float Spot = pow(SpotAmount, SpotRadius) * 0.25f;
  float SpotAmount = 1.0f - saturate(pow(dot(SpotCoord, SpotCoord), 0.25f));
  float SpotRadius = CurvatureAmount * 4.0f + 2.0f;
  float Spot = pow(SpotAmount, SpotRadius) * 0.5f;
  
  // -- Light Reflection --
  float2 ReflectionCoord = BaseCoord * UsedArea;
  
  ReflectionCoord.x = 1.0f + CoordCorrection1.x - ReflectionCoord.x;
  ReflectionCoord.y = 0.0f + CoordCorrection0.y + ReflectionCoord.y;
  
  float ReflectionAmount = pow(ReflectionCoord.x * ReflectionCoord.y, 0.25f);
  float Reflection = ReflectionAmount * 0.125f;
  
  Output.rgb += (saturate(Reflection) + saturate(Spot)) * CurvatureAmount;
  
  // -- Round Corners --
  float2 CornerCoords = BaseCoord * UsedArea;
  
  float radius = 0.0f;
  
  if (CurvatureAmount > 0.0f)
  {
    radius = pow(CurvatureAmount, 0.125f) * 0.125f;
  }
  
  float threshold = pow(radius, 4.0f);
  
  if (
    (CornerCoords.x - CoordCorrection0.x) * (CornerCoords.y - CoordCorrection0.y) <= threshold ||
    (1.0f + CoordCorrection1.x - CornerCoords.x) * (CornerCoords.y - CoordCorrection0.y) <= threshold ||
    (CornerCoords.x - CoordCorrection0.x) * (1.0f + CoordCorrection1.y - CornerCoords.y) <= threshold ||
    (1.0f + CoordCorrection1.x - CornerCoords.x) * (1.0f + CoordCorrection1.y - CornerCoords.y) <= threshold
  )
  {
    Output.rgb = float3(0.0f, 0.0f, 0.0f);
  }
  
  return Output;
}

//-----------------------------------------------------------------------------
// Scanline & Shadowmask Effect
//-----------------------------------------------------------------------------

technique ScanMaskTechnique
{
  pass Pass0
  {
    Lighting = FALSE;

    //Sampler[0] = <DiffuseSampler>;

    VertexShader = compile vs_3_0 vs_main();
    PixelShader  = compile ps_3_0 ps_main();
  }
}