ParticleCS.hlsl

//this shader handnles the movement of the particles

cbuffer Time
{
    float deltaTime;
    float random;
    float2 padding;
};

RWBuffer<float> particlePosition;
[numthreads(8, 1, 1)]
void main(uint3 dt_id : SV_DispatchThreadID)
{
    float3 currentPosition = float3(particlePosition[dt_id.x * 3 + 0], particlePosition[dt_id.x * 3 + 1], particlePosition[dt_id.x * 3 + 2]); 
    float3 output = currentPosition;
    
    output.y += 2 * deltaTime;  //movement, change the constant for faster/slower particles
    
    if (output.y > 10)  //if at a certain height
    {
        output.y = (random)-(float)dt_id.x;
        if (output.y < -10) //to not start too far below
        {
            output.y = -10;
        }
    }
    //set new position for particle
    particlePosition[dt_id.x * 3 + 0] = output.x;
    particlePosition[dt_id.x * 3 + 1] = output.y;
    particlePosition[dt_id.x * 3 + 2] = output.z;
}