#include "Assets/_Content/Shaders/Include/Noises.hlsl"

float2 WorldToScreenUV(float3 posWS)
{
    float4 clip = TransformWorldToHClip(posWS);
    float2 ndc = clip.xy / clip.w; // [-1, 1]
    return ndc * .5 + .5; // [0, 1]
}

float3 GetBillboardPositionWS(float3 PositionOS, float3 PivotWS, float3 ViewDirWS)
{
    float3 upWS = normalize(TransformObjectToWorldDir(float3(0, 1, 0)));

    float3 rightWS = cross(upWS, ViewDirWS);

    if (dot(rightWS, rightWS) < 1e-5)
        rightWS = normalize(TransformObjectToWorldDir(float3(1, 0, 0)));
    else
        rightWS = normalize(rightWS);

    float3 forwardWS = normalize(cross(rightWS, upWS));

    return PivotWS + PositionOS.x * rightWS + PositionOS.y * upWS + PositionOS.z * forwardWS;
}

float3 ApplayerTaperAndScale(float3 PositionOS, float3 Scale)
{
    float taper = lerp(Scale.z, 1, saturate(PositionOS.y));

    float3 p = PositionOS;
    p.xy *= Scale.xy;
    p.x *= taper;

    return p;
}

void Ray_float
(
    float3 Color,
    float3 PositionOS,
    float4 ScreenPos,
    uint Orthographic,
    out float3 OutPosition,
    out float3 OutColor
)
{
    float3 pivot = TransformObjectToWorld(float3(0, 0, 0));

    float3 scale = float3
    (
        length(TransformObjectToWorld(float3(1, 0, 0)) - pivot),
        length(TransformObjectToWorld(float3(0, 1, 0)) - pivot),
        length(TransformObjectToWorld(float3(0, 0, 1)) - pivot)
    );

    float3 viewDir = lerp(normalize(pivot - _WorldSpaceCameraPos.xyz), GetViewForwardDir(), Orthographic);

    float3 pOS_0 = ApplayerTaperAndScale(PositionOS, scale);
    float3 pOS_1 = ApplayerTaperAndScale(float3( .5, PositionOS.y, 0), scale);
    float3 pOS_2 = ApplayerTaperAndScale(float3(-.5, PositionOS.y, 0), scale);
              
    float3 pWS_0 = GetBillboardPositionWS(pOS_0, pivot, viewDir);
    float3 pWS_1 = GetBillboardPositionWS(pOS_1, pivot, viewDir);
    float3 pWS_2 = GetBillboardPositionWS(pOS_2, pivot, viewDir);

    float2 pSC_0 = ScreenPos.xy;
    float2 pSC_1 = WorldToScreenUV(pWS_1);
    float2 pSC_2 = WorldToScreenUV(pWS_2);
    
    float2 uv = float2(distance(pSC_0.x, pSC_2.x) / distance(pSC_1.x, pSC_2.x), pOS_0.y / scale.y);
    
    OutPosition = TransformWorldToObject(pWS_0);
    OutColor = float3(uv, 0);
}