奇怪的if语句导致计时器关闭

所以我一直在尝试计算以下内容：

LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC hDC;                // Display context handle
    PAINTSTRUCT PaintSt;    // Structure defining area to be drawn
    RECT aRect;             // A working rectangle
    HPEN hPen;              // A working pen
    HBRUSH hBrush;          // A working brush
    switch(message)
    {
        case WM_TIMER:
            switch(wParam)
            {
            case IDT_TIMER1: 
                    redraw = true;
                InvalidateRect(hWnd, NULL, TRUE);
            case IDT_TIMER2:
                if(keys[UP])
            {
                rect2.bottom -= 5;
                rect2.top -= 5;
            }
            if(keys[DOWN])
            {
                rect2.bottom += 5;
                rect2.top += 5;
            }
            if(keys[RIGHT])
            {
                rect2.left += 5;
                rect2.right += 5;
            }
            if(keys[LEFT])
            {
                rect2.left -= 5;
                rect2.right -= 5;
            }
        }
        return 0;
    case WM_PAINT:
            //if(redraw)
            {
                redraw = false;
                render_frame();
            }
        return 0;
    case WM_KEYDOWN:
            switch(wParam)
            {
            case VK_UP:
                keys[UP] = true;
                break;
            case VK_DOWN:
                keys[DOWN] = true;
                break;
            case VK_LEFT:
                keys[LEFT] = true;
                break;
            case VK_RIGHT:
                keys[RIGHT] = true;
                break;
            default:
                break;
            }
        return 0;
    case WM_KEYUP:
        switch(wParam)
        {
        case VK_UP:
            keys[UP] = false;
            break;
        case VK_DOWN:
            keys[DOWN] = false;
            break;
        case VK_LEFT:
            keys[LEFT] = false;
            break;
        case VK_RIGHT:
            keys[RIGHT] = false;
            break;
        default:
                break;
        }
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);    // default message processing
    }
}

所以问题来了：在的情况下，WM_PAINT:，当我取消对if语句的注释时，由于某种原因，时间停止了计时。我不知道为什么，也不知道如何将其与任何事情联系起来。因此，如果我取消注释它，它将不会渲染，也不会从另一个计时器（有两个计时器）接收信息。请帮帮我，如果这很傻，请不要笑。