#define WIDTH 512
#define HEIGHT 424

#pragma kernel CSMain

#include "UnityCG.cginc"

RWStructuredBuffer<float4> KinectPositionBuffer;
RWStructuredBuffer<float4> KinectVelocityBuffer;
RWStructuredBuffer<float4> KinectGridBuffer;

AppendStructuredBuffer<float4> HomePositionBuffer;
AppendStructuredBuffer<float4> HomeVelocityBuffer;

//Texture2D<float4> PositionTexture;
//Texture2D<float4> VelocityTexture;
Texture2D<float4> MotionTexture;
Texture2DArray<float4> MotionTextureArray;

float4 ClipMin;
float4 ClipMax;
float4x4 ModelMatrix;
float4 FluidSize;
float4 FluidRoot;
float4 FluidDim;
int flipX;
int NumKinects;

[numthreads(512,1,1)]
void CSMain (uint3 id : SV_DispatchThreadID)
{
	uint2 tex_coord = uint2(id.x % HEIGHT, id.x / HEIGHT);

	for (int i = 0; i < NumKinects; i++)
	{
		float4 pos = float4(MotionTexture[tex_coord].xyz, 1);
		pos = float4(MotionTextureArray[uint3(tex_coord, i)].xyz, 1);
		//pos.y *= -1;
		pos.z *= -1;
		pos.x = lerp(pos.x, -pos.x, flipX);

		float pos_mag = length(pos.xyz);

		{
			pos = mul(pos, ModelMatrix);

			float4 vel = MotionTexture[tex_coord + uint2(WIDTH, 0)];
			vel = MotionTextureArray[uint3(tex_coord, i) + uint3(WIDTH, 0, 0)];
			//vel.y *= -1;
			vel.z *= -1;
			vel.x = lerp(vel.x, -vel.x, flipX);

			float3 grid_pos = (pos.xyz - FluidRoot.xyz) / FluidSize.xyz;
			int grid_index = -1;
			if (grid_pos.x > 0 && grid_pos.x < 1 &&
				grid_pos.y > 0 && grid_pos.y < 1 &&
				grid_pos.z > 0 && grid_pos.z < 1 &&
				pos_mag > 0.0f)// && length(pos) > 10.0f)
			{
				grid_pos *= FluidDim.xyz;
				grid_index = (int)grid_pos.x + (int)grid_pos.y * FluidDim.x + (int)grid_pos.z * FluidDim.x * FluidDim.y;
				KinectGridBuffer[grid_index] += float4(vel.xyz, 1);

				if (pos_mag > 0.1f)// && pos.y < 0.5f)
				{
					//pos.y = 0.0f;
					//vel.xyz = float3(0, 0, 0);

					HomePositionBuffer.Append(float4(pos.xyz, 0));
					HomeVelocityBuffer.Append(float4(vel.xyz, 0));
				}
					
			}

			KinectPositionBuffer[id.x] = float4(pos.xyz, grid_index);
			KinectVelocityBuffer[id.x] = float4((pos_mag == 0.0f) ? float3(0, 0, 0) : vel.xyz, 0);

		}
	}

}