using UnityEngine;
using UnityEngine.Rendering;

namespace Misaki.AoVolume
{
    [GenerateHLSL(PackingRules.Exact, false)]
    internal struct GPUFrustum
    {
        // The data of the 6 planes of the frustum
        public Vector3 normal0;
        public float dist0;
        public Vector3 normal1;
        public float dist1;
        public Vector3 normal2;
        public float dist2;
        public Vector3 normal3;
        public float dist3;
        public Vector3 normal4;
        public float dist4;
        public Vector3 normal5;
        public float dist5;

        // The data of the 8 corners of the frustum
        public Vector4 corner0;
        public Vector4 corner1;
        public Vector4 corner2;
        public Vector4 corner3;
        public Vector4 corner4;
        public Vector4 corner5;
        public Vector4 corner6;
        public Vector4 corner7;
    }

    [GenerateHLSL(PackingRules.Exact, false)]
    internal struct OrientedBoundingBox
    {
        // 4 x float3 = 48 bytes.
        // TODO: pack the axes into 16-bit UNORM per channel, and consider a quaternionic representation.
        public Vector3 center;
        public Vector3 right;
        public Vector3 up;

        public Vector3 extent;

        //public ushort quatX;
        //public ushort quatY;
        //public ushort quatZ;
        //public ushort quatW;

        public readonly Vector3 Forward => Vector3.Cross(up, right);

        public OrientedBoundingBox(Matrix4x4 trs)
        {
            var vecX = (Vector3)trs.GetColumn(0);
            var vecY = (Vector3)trs.GetColumn(1);
            var vecZ = (Vector3)trs.GetColumn(2);

            center = trs.GetColumn(3);
            right = vecX * (1.0f / vecX.magnitude);
            up = vecY * (1.0f / vecY.magnitude);

            extent.x = 0.5f * vecX.magnitude;
            extent.y = 0.5f * vecY.magnitude;
            extent.z = 0.5f * vecZ.magnitude;
        }
    }

    [GenerateHLSL(PackingRules.Exact, false)]
    internal struct CullingData
    {
        public float fadeStart;
        public float fadeEnd;
    }
}