// Hit information, aka ray payload
// This sample only carries a shading color and hit distance.
// Note that the rayPayload should be kept as small as possible,
// and that its size must be declared in the corresponding
// D3D12_RAYTRACING_SHADER_CONFIG pipeline subobjet.

#pragma pack_matrix(row_major)
#define MAX_TRANSPACENT_HITS 5

struct SingleHit
{
    float4 color;
    float3 normal;
    float distance;
    int dayLight;
    int dynamicLight;
};

struct [raypayload] RayHits
{
    SingleHit hits[MAX_TRANSPACENT_HITS] : write(caller, closesthit, anyhit, miss) : read(caller, anyhit, closesthit, miss);
int hitCount : write(caller, anyhit, closesthit, miss) : read(caller, anyhit, closesthit, miss);
};

// Attributes output by the raytracing when hitting a surface,
// here the barycentric coordinates
struct ChunkHitAttributes
{
    float2 texCoord;
    float3 normal;
    int textureId;
    int dayLight;
    int dynamicLight;
};

struct SimpleBlocksAttributes
{
    float2 bary;
};

struct VertexData
{
    float2 texcoord;
    float3 normal;
};

int packLight(float3 light)
{
    uint r = (uint) (light.r * 255.0) & 0xFF;
    uint g = (uint) (light.g * 255.0) & 0xFF;
    uint b = (uint) (light.b * 255.0) & 0xFF;
    return (int) ((r << 16) | (g << 8) | b);
}

float3 unpackLight(int light)
{
    float r = ((light >> 16) & 0xFF) / 255.0f;
    float g = ((light >> 8) & 0xFF) / 255.0f;
    float b = (light & 0xFF) / 255.0f;
    return float3(r, g, b);
}

void applyHit(inout RayHits rayPayload, in SingleHit hit)
{
    for (int i = 0; i < rayPayload.hitCount; i++)
    {
        if (rayPayload.hits[i].distance > hit.distance)
        {
            SingleHit tmpHit = rayPayload.hits[i];
            rayPayload.hits[i] = hit;
            if (hit.color.w == 1.f)
            {
                rayPayload.hitCount = i + 1;
            }
            else
            {
                for (int j = i + 1; j < rayPayload.hitCount + 1 && j < MAX_TRANSPACENT_HITS; j++)
                {
                    SingleHit tmpHit2 = rayPayload.hits[j];
                    rayPayload.hits[j] = tmpHit;
                    tmpHit = tmpHit2;
                }
            }
            return;
        }
        else
        {
            if (rayPayload.hits[i].color.w == 1.f)
            {
                return;
            }
        }
    }
    if (rayPayload.hitCount < MAX_TRANSPACENT_HITS)
    {
        rayPayload.hits[rayPayload.hitCount] = hit;
        rayPayload.hitCount++;
    }
}

// Global resources
Texture2D<float4> textures[] : register(t0, space1);
SamplerState gSampler : register(s0, space0);
cbuffer DX12ShaderLightInfo : register(b0, space1)
{
    float3 dayLightFactor;
    uint padding;
    float3 dayLightDirection;
};
// Raytracing acceleration structure, accessed as a SRV
RaytracingAccelerationStructure TLAS : register(t0, space0);

RWTexture2D<float4> gOutput : register(u0);
RWTexture2D<float4> guiTexture : register(u1);
cbuffer RayGenerationSettings : register(b0, space0)
{
    int renderGui;
    int useRays;
    float minDistance;
    float maxDistance;
    float4x4 inverseView;
    float4x4 inverseProjection;
};

float3 getLight(ByteAddressBuffer lightBuffer, int index)
{
    uint raw = lightBuffer.Load((index / 4) * 4);
    uint shift = (index % 4) * 8;
    float r = ((raw >> shift) & 0xFF) / 255.0;
    shift += 8;
    if (shift == 32)
    {
        raw = lightBuffer.Load((index / 4) * 4 + 4);
        shift = 0;
    }
    float g = ((raw >> shift) & 0xFF) / 255.0;
    shift += 8;
    if (shift == 32)
    {
        raw = lightBuffer.Load((index / 4) * 4 + 4);
        shift = 0;
    }
    float b = ((raw >> shift) & 0xFF) / 255.0;
    return float3(r, g, b);
}