#ifndef __SKYUTILS_H__
#define __SKYUTILS_H__

#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
#include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/ShaderVariables.hlsl"

float4x4 _PixelCoordToViewDirWS;

#if defined(USING_STEREO_MATRICES)
    #define _PixelCoordToViewDirWS  _XRPixelCoordToViewDirWS[unity_StereoEyeIndex]
#endif

// Generates a world-space view direction for sky and atmospheric effects
float3 GetSkyViewDirWS(float2 positionCS)
{
    float4 viewDirWS = mul(float4(positionCS.xy, 1.0f, 1.0f), _PixelCoordToViewDirWS);
    return normalize(viewDirWS.xyz);
}

// Returns latlong coords from view direction
float2 GetLatLongCoords(float3 dir, float upperHemisphereOnly)
{
    const float2 invAtan = float2(0.1591, 0.3183); // float2(INV_TWO_PI, INV_PI)

    float fastATan2 = FastAtan2(dir.x, dir.z);
    float2 uv = float2(fastATan2, FastASin(dir.y)) * invAtan + 0.5;
    uv.y = upperHemisphereOnly ? uv.y * 2.0 - 1.0 : uv.y;
    return uv;
}

float3 RotationUp(float3 p, float2 cos_sin)
{
    float3 rotDirX = float3(cos_sin.x, 0, -cos_sin.y);
    float3 rotDirY = float3(cos_sin.y, 0,  cos_sin.x);

    return float3(dot(rotDirX, p), p.y, dot(rotDirY, p));
}

#endif // __SKYUTILS_H__