Snake V0.1

#include <Windows.h>
#include <time.h>
#include <malloc.h>
#include <stdio.h>
#include <stdlib.h>

#define TIMER_TIME 10
#define TIMER_ID 100
#define SPEED 1

HWND hwnd;

enum Vector { Left, Right, Up, Down };

struct Coin {
    int PosX, PosY;
    int Width, Height;
    COLORREF BorderColor, FillColor;
};

struct Snake {
    int PosX, PosY;
    int Width, Height;
    COLORREF BorderColor, FillColor;
    Vector vector ,PrevVector;
};

int Score =1;
PAINTSTRUCT PS;
RECT WndRect;
Snake snake;
Coin coin;

void SetNewCoinPos() {
    coin.PosX = (rand() % WndRect.right-50)+50;
    coin.PosY =( rand() % WndRect.bottom-50)+50;
}

void PrintScore(HDC &hdc) {
    char buff[255];
    sprintf_s(buff, "Wynik: %d", Score);
    TextOut(hdc, 0, 0, buff, strlen(buff));
}

void PrintSnake(Snake &snak,HDC &hdc) {
    HBRUSH Brush = CreateSolidBrush(snak.FillColor);
    HPEN Pen = CreatePen(PS_SOLID, 2, snak.BorderColor);

    HBRUSH OldBrush = (HBRUSH)SelectObject(hdc, Brush);
    HPEN OldPen = (HPEN)SelectObject(hdc, Pen);

    Rectangle(hdc, snak.PosX, snak.PosY, snak.PosX + snak.Width, snak.PosY + snak.Height);

    SelectObject(hdc, OldBrush);
    SelectObject(hdc, OldPen);

    DeleteObject(Brush);
    DeleteObject(Pen);
}

void PrintCoin(HDC &hdc) {
    HBRUSH Brush = CreateSolidBrush(coin.FillColor);
    HPEN Pen = CreatePen(PS_SOLID, 2, coin.BorderColor);

    HBRUSH OldBrush = (HBRUSH)SelectObject(hdc, Brush);
    HPEN OldPen = (HPEN)SelectObject(hdc, Pen);

    Ellipse(hdc, coin.PosX, coin.PosY, coin.PosX + coin.Width, coin.PosY + coin.Height);

    SelectObject(hdc, OldBrush);
    SelectObject(hdc, OldPen);

    DeleteObject(Brush);
    DeleteObject(Pen);
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
    switch (msg) {
    case WM_CREATE:break;
    case WM_COMMAND:break;
    case WM_TIMER: {
        GetClientRect(hwnd, &WndRect);

        // for 255 -> 0
        switch (snake.vector) {
        case Up:
            snake.PosY -= SPEED*Score;
            if (snake.PosY < WndRect.top) snake.PosY = WndRect.bottom - snake.Height;
            break;
        case Down:
            snake.PosY += SPEED*Score;
            if (snake.PosY + snake.Height > WndRect.bottom) snake.PosY = 0;
            break;
        case Left:
            snake.PosX -= SPEED*Score;
            if (snake.PosX < WndRect.left) snake.PosX = WndRect.right - snake.Width;
            break;
        case Right:
            snake.PosX += SPEED*Score;
            if (snake.PosX + snake.Width > WndRect.right) snake.PosX = 0;
            break;
        }

        if (snake.PosX >= coin.PosX-50 &&
            snake.PosY >= coin.PosY-50  &&

            snake.PosX + snake.Width <= (coin.PosX + coin.Width)+50  &&
            snake.PosY + snake.Height <= (coin.PosY + coin.Height)+50)

        {
            SetNewCoinPos();
            Score++;
        }

        InvalidateRect(hwnd, &WndRect, 1);
    }break;

    case WM_PAINT: {
        HDC hdc = BeginPaint(hwnd, &PS);
        PrintCoin(hdc);//[255]
        PrintSnake(snake,hdc);//[255]
        PrintScore(hdc);
        EndPaint(hwnd, &PS);;
    }break;

    case WM_KEYDOWN: {

        switch ((int)wParam) {
        case VK_UP:
            snake.PrevVector = snake.vector;
            if (snake.PrevVector != Down) {
                snake.vector = Up;
            }
            break;
        case VK_DOWN:
            snake.PrevVector = snake.vector;
            if (snake.PrevVector != Up) {
                snake.vector = Down;
            }
            break;
        case VK_RIGHT:
            snake.PrevVector = snake.vector;
            if (snake.PrevVector != Left) {
                snake.vector = Right;
            }
            break;
        case VK_LEFT:
            snake.PrevVector = snake.vector;
            if (snake.PrevVector != Right) {
                snake.vector = Left;
            }
            break;
        }
    }break;

    case WM_CLOSE:  DestroyWindow(hwnd);    break;
    case WM_DESTROY:PostQuitMessage(0);     break;
    default:    return DefWindowProc(hwnd, msg, wParam, lParam);
    }
    return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR ilCmdLine, int nCmdShow) {

    WNDCLASSEX window;
    MSG msg;
    TCHAR Class_Name[] = TEXT("OKNO_TEST"), Title[] = TEXT("Tytul");

    window.cbClsExtra = NULL;
    window.cbSize = sizeof(WNDCLASSEX);
    window.cbWndExtra = NULL;
    window.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    window.hCursor = LoadCursor(NULL, IDC_ARROW);
    window.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    window.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
    window.hInstance = hInstance;
    window.lpfnWndProc = WndProc;
    window.lpszClassName = Class_Name;
    window.lpszMenuName = 0;
    window.style = CS_VREDRAW | CS_HREDRAW;

    if (!RegisterClassEx(&window)) {
        MessageBox(NULL, TEXT("Błąd rejestracji okna"), TEXT("Błąd"), MB_ICONEXCLAMATION);
        return 0;
    }

    hwnd = CreateWindowEx(WS_EX_WINDOWEDGE, Class_Name, Title, WS_OVERLAPPEDWINDOW | WS_VISIBLE, CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, NULL, NULL, hInstance, NULL);

    if (hwnd == NULL) {
        MessageBox(NULL, TEXT("Błąd tworzenia okna"), TEXT("Błąd"), MB_ICONEXCLAMATION);
        return 0;
    }

    snake.BorderColor = RGB(0, 0, 0);
    snake.FillColor = RGB(255, 0, 255);
    snake.Width = 50;
    snake.Height = 50;
    snake.PosX = 100;
    snake.PosY = 100;
    snake.vector = Down;

    GetClientRect(hwnd, &WndRect);

    srand(time(NULL));
    coin.BorderColor = RGB(0, 0, 0);
    coin.FillColor = RGB(240, 240, 90);
    coin.Width = 50;
    coin.Height = 50;
    SetNewCoinPos();

    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);
    SetTimer(hwnd, TIMER_ID, TIMER_TIME, NULL);

    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    if (!UnregisterClass(Class_Name, hInstance)) {
        MessageBox(NULL, TEXT("Błąd niszczenia okna"), TEXT("Błąd"), MB_ICONEXCLAMATION);
        return 0;
    }
    return msg.wParam;
}