Matrix Rain

#include <iostream>
#include <string>
using namespace std;

#include "olcConsoleGameEngine.h"


class OneLoneCoder_Matrix : public olcConsoleGameEngine
{
public:
    OneLoneCoder_Matrix()
    {
        m_sAppName = L"Matrix";
    }

private:
    struct sStreamer
    {
        int nColumn = 0;
        float fPosition = 0;
        float fSpeed = 0;
        wstring sText;
    };

    list<sStreamer> listStreamers;

    int nMaxStreamers = 300;

    wchar_t RandomCharacter()
    {
        return (wchar_t)(rand() % 0x1EF + 0x00C0);
        return (wchar_t)(rand() % 93 + 33); // Random ASCII
    }

    void PrepareStreamer(sStreamer * s)
    {
        s->nColumn = rand() % ScreenWidth();
        s->fPosition = 0;
        s->fSpeed = rand() % 40 + 5;
        s->sText.clear();

        int nStreamerLength = rand() % 80 + 10;
        for (int i = 0; i < nStreamerLength; i++)
            s->sText.append(1, RandomCharacter());
    }


protected:
    virtual bool OnUserCreate()
    {
        for (int n = 0; n < nMaxStreamers; n++)
        {
            sStreamer s;
            PrepareStreamer(&s);
            listStreamers.push_back(s);
        }
        return true;
    }

    virtual bool OnUserUpdate(float fElapsedTime)
    {

        Fill(0, 0, ScreenWidth(), ScreenHeight(), PIXEL_SOLID, 0);

        for (auto& s : listStreamers)
        {
            s.fPosition += fElapsedTime * s.fSpeed;
            for (int i = 0; i < s.sText.size(); i++)
            {

                short col = s.fSpeed < 15.0f ? FG_DARK_GREEN : FG_GREEN; // ;-)
                if (i == 0)
                    col = FG_WHITE;
                else
                    if (i <= 3)
                        col = FG_GREY;

                int nCharIndex = (i - (int)s.fPosition) % s.sText.size();

                Draw(s.nColumn, (int)s.fPosition - i, s.sText[nCharIndex], col);

                if (rand() % 1000 < 5)
                    s.sText[i] = RandomCharacter();
            }

            if (s.fPosition - s.sText.size() >= ScreenHeight())
                PrepareStreamer(&s);

        }
        return true;
    }
};


int main()
{
    OneLoneCoder_Matrix game;
    game.ConstructConsole(128, 80, 12, 12);
    game.Start();
    return 0;
}