#include "Include/PlatformDefines.hlsl"

#pragma kernel CSTreeInstantiationKernel

// Result buffer
RWStructuredBuffer<float4x4> gpuiInstanceData;

// Input buffers
RWStructuredBuffer<float4> treeData; // prototypeIndex - positionx3 - rotation - scalex2
RWStructuredBuffer<float4> treeScales;
RWStructuredBuffer<uint> counterBuffer;

uniform uint bufferSize;
//uniform float3 terrainSize;
//uniform float3 terrainPosition;
uniform uint prototypeIndex;
uniform bool isApplyRotation;
uniform bool isApplyTerrainHeight;

#include "Include/DataModel.hlsl"
#include "Include/Matrix.hlsl"

[numthreads(GPUI_THREADS, 1, 1)]
void CSTreeInstantiationKernel(uint3 id : SV_DispatchThreadID)
{
    if (id.x >= bufferSize)
        return;

    uint index = id.x * 2;
    float4 treeData1 = treeData[index];
    uint instancePI = uint(treeData1.x);

    if (instancePI != prototypeIndex)
        return;
    
    index++;
    float4 treeData2 = treeData[index];
    float4 treeScale = treeScales[prototypeIndex];
    
    float3 position = treeData1.yzw/* * terrainSize + terrainPosition*/;
    float4x4 rotation = isApplyRotation ? MatrixRotate(vector3Up, treeData2.x) : identityMatrix;
    float3 scale = (isApplyTerrainHeight ? treeData2.yzy : vector3One) * treeScale.xyz;

    uint instanceIndex;
    InterlockedAdd(counterBuffer[0], 1, instanceIndex);
    // Add tree 
    gpuiInstanceData[instanceIndex] = TRS(position, rotation, scale);
}