#include "Common.hlsl"


[shader("raygeneration")]
void RayGen()
{
    // Initialize the ray payload
    RayHits rayPayload;
    rayPayload.hitCount = 0;
    SingleHit hitInitial;
    hitInitial.color = float4(0, 0, 0, 0);
    hitInitial.normal = float3(0, 0, 0);
    hitInitial.distance = 0.f;
    hitInitial.dayLight = 0;
    hitInitial.dynamicLight = 0;
    for (int index = 0; index < MAX_TRANSPACENT_HITS; index++)
    {
        rayPayload.hits[index] = hitInitial;
    }
    float3 color = float3(0, 0, 0);

    // Get the location within the dispatched 2D grid of work items
    // (often maps to pixels, so this could represent a pixel coordinate).
    float2 dispatchDimensions = float2(DispatchRaysDimensions().xy);
    uint2 dispatchIndex = DispatchRaysIndex().xy;
    float2 dispatchPercentage = (dispatchIndex + 0.5) / dispatchDimensions;
    
    if (useRays)
    {
        float2 d = (dispatchPercentage * 2.f - 1.f);
        RayDesc ray;
        ray.Origin = mul(inverseView, float4(0, 0, 0, 1)).xyz;
        float4 target = mul(inverseProjection, float4(d.x, -d.y, -1, 1));
        target.w = 1;
        ray.Direction = mul(inverseView, target).xyz - ray.Origin;
        ray.TMin = minDistance;
        ray.TMax = maxDistance;
        TraceRay(TLAS, /*RayFlags*/0, /*InstanceInclusionMask*/0xFF, /*RayContributionToHitGroupIndex*/0,
            /*MultiplierForGeometryContributionToHitGroupIndex*/0, /*MissShaderIndex*/0, ray, rayPayload);
        if (rayPayload.hitCount > 0)
        {
            float3 minLight = float3(0.1f, 0.1f, 0.1f);
            SingleHit lastHit = rayPayload.hits[rayPayload.hitCount - 1];
            float3 dayLight = unpackLight(lastHit.dayLight);
            float3 dynamicLight = unpackLight(lastHit.dynamicLight);
            float3 light = max(minLight, max(dynamicLight, dayLight));
            color = lastHit.color.rgb * light;
            for (int i = rayPayload.hitCount - 2; i >= 0; i--)
            {
                SingleHit currentHit = rayPayload.hits[i];
                dayLight = unpackLight(currentHit.dayLight);
                dynamicLight = unpackLight(currentHit.dynamicLight);
                light = max(minLight, max(dynamicLight, dayLight));
                color = currentHit.color.rgb * light * currentHit.color.a + color * (1 - currentHit.color.a);
            }
        }
    }
    
    uint outWidth, outHeight;
    gOutput.GetDimensions(outWidth, outHeight);
    uint2 outputIndex = uint2(dispatchPercentage * float2(outWidth, outHeight));
    if (renderGui)
    {
        uint guiWidth, guiHeight;
        guiTexture.GetDimensions(guiWidth, guiHeight);
        uint2 guiIndex = uint2(dispatchPercentage * float2(guiWidth, guiHeight));
        float4 guiColor = guiTexture[guiIndex];
        color = color * (1 - guiColor.a) + guiColor.rgb * guiColor.a;
    }
    gOutput[outputIndex] = float4(color, 1.f);
}