import Common;
import BRDF;
import MaterialParameter;

interface ILightEnv
{
    float3 illuminate<B:IBRDF>(LightingParameter input, B brdf);
};

struct DirectionalLight : ILightEnv
{
    float4 color;
    float4 direction;

    float3 illuminate<B:IBRDF>(LightingParameter params, B brdf)
    {
        float3 lightDir_TS = mul(params.tbn, direction.xyz);
        return brdf.evaluate(params.tbn, params.viewDir_TS, -normalize(lightDir_TS), color.xyz);
    }
};

struct PointLight : ILightEnv
{
    float4 position_WS;
    float4 colorRange;
    
    float3 illuminate<B:IBRDF>(LightingParameter params, B brdf)
    {
        float3 lightDir_WS = position_WS.xyz - params.position_WS;
        float3 lightDir_TS = mul(params.tbn, lightDir_WS);
        float d = length(lightDir_TS);
        float illuminance = max(1 - d / colorRange.w, 0);
        return illuminance * brdf.evaluate(params.tbn, params.viewDir_TS, normalize(lightDir_TS), colorRange.xyz);
    }

    bool insidePlane(Plane plane)
    {
        return true;//dot(plane.n, getViewPos().xyz) - plane.d < -colorRange.w;
    }

    bool insideFrustum(Frustum frustum, float zNear, float zFar)
    {
        bool result = true;

        //if(getViewPos().z - colorRange.w > zNear || getViewPos().z + colorRange.w < zFar)
        //{
        //    //result = false;
        //}
        //for(int i = 0; i < 4 && result; ++i)
        //{
        //    if(insidePlane(frustum.sides[i]))
        //    {
        //        //result = false;
        //    }
        //}
        return result;
    }
};

struct LightEnv
{
    StructuredBuffer<DirectionalLight> directionalLights;
    uint numDirectionalLights;
    StructuredBuffer<PointLight> pointLights;
    uint numPointLights;
};
layout(set=3)
ParameterBlock<LightEnv> pLightEnv;