//#include "lib/shared/hash-functions.hlsl"
#include "lib/shared/point.hlsl"

cbuffer ParamConstants : register(b0)
{
    float DisplaceAmount;
    float DisplaceOffset;
    float Twist;
    float Shade;
    float SampleCount;
    float SampleRadius;
    float SampleSpread;
    float SampleOffset;
    float2 DisplaceMapOffset;
    float DisplaceMode;
}

cbuffer TimeConstants : register(b1)
{
    float globalTime;
    float time;
    float runTime;
    float beatTime;
}

cbuffer Resolution : register(b2)
{
    float TargetWidth;
    float TargetHeight;
}


struct vsOutput
{
    float4 position : SV_POSITION;
    float2 texCoord : TEXCOORD;
};

Texture2D<float4> Image : register(t0);
Texture2D<float4> DisplaceMap : register(t1);
sampler texSampler : register(s0);


float IsBetween( float value, float low, float high) {
    return (value >= low && value <= high) ? 1:0;
}


float4 psMain(vsOutput psInput) : SV_TARGET
{   
    int samples = (int)clamp(SampleCount+0.5,1,32);
    float displaceMapWidth, displaceMapHeight;
    DisplaceMap.GetDimensions(displaceMapWidth, displaceMapHeight);

    float2 uv = psInput.texCoord;
    
    float4 cx1,cx2, cy1, cy2;
    cx1=cx2=cy2=cy1= float4(0,0,0,0);
    int dSamples=2;
    float radius2 = 2;
    float sx = SampleRadius / displaceMapWidth;
    float sy = SampleRadius / displaceMapHeight;
    int sampleIndex = 1;

    float padding = 1;
    float paddingSum;
    float2 d = 0;

    if(DisplaceMode < 0.5) {
        for(sampleIndex = 1; sampleIndex < dSamples; sampleIndex++)
        {
            float4 cx1= DisplaceMap.Sample(texSampler, float2( uv.x + sx*sampleIndex, uv.y) + DisplaceMapOffset )*padding;
            float x1= (cx1.r + cx1.g + cx1.b) / 3;
            float4 cx2= DisplaceMap.Sample(texSampler, float2(uv.x - sx*sampleIndex, uv.y)  + DisplaceMapOffset )*padding; 
            float x2= (cx2.r + cx2.g + cx2.b) / 3;
            float4 cy1= DisplaceMap.Sample(texSampler, float2(uv.x,       uv.y + sy*sampleIndex)  + DisplaceMapOffset)*padding;
            float y1= (cy1.r + cy1.g + cy1.b) / 3;
            float4 cy2= DisplaceMap.Sample(texSampler, float2(uv.x,       uv.y - sy*sampleIndex)  + DisplaceMapOffset)*padding;    
            float y2= (cy2.r + cy2.g + cy2.b) / 3;
            d += float2( (x1-x2) , (y1-y2));

            paddingSum += padding;
            padding /= 1.5;
        }
    }
    else {
        float4 rgba= DisplaceMap.Sample(texSampler, uv + DisplaceMapOffset)*padding;
        d = (rgba.r + rgba.g + rgba.b) /3;
    }

    float a = (d.x == 0 && d.y==0) ? 0 :  atan2(d.x, d.y) + Twist / 180 * 3.14158;
    float2 direction = float2( sin(a), cos(a));
    float len = length(d);


    float2 p2 = direction * (-DisplaceAmount * len * 10 + DisplaceOffset);// * float2(height/ height, 1);
    float imgAspect = TargetWidth/TargetHeight;
    p2.x /=imgAspect;
        
    float4 t1= float4(0,0,0,0);
    for(float i=-0.5; i< 0.5; i+= 1.0001/ samples) 
    {    
        t1+=Image.Sample(texSampler, uv + p2 * (i*SampleSpread +1-SampleOffset)); 
    }    

    //c.r=1;
    float4 c2=t1/samples;
    c2.rgb *= (1-len*Shade*100);
    c2.a = clamp( c2.a, 0.00001,1);
    return c2;
}