Unable to update window in consol application - c++

Question

I am extending an old console application. Trying to add a window( for an animation ). Are able to display first image, but unable to update the window with later images. Have created a minimum application to demonstrate the problem. In this app I have a red window that should change at each update of the window( it is not ). What am I doing wrong ?
#include "pch.h"
#include <iostream>
#include <Windows.h>
using namespace std;
HWND hWindow;
LRESULT __stdcall MyWindowProcedure(HWND hWnd, unsigned int msg, WPARAM wp, LPARAM lp)
{
PAINTSTRUCT ps;
HDC hdc;
HBITMAP hBitmap;
VOID * pvBits;
RGBQUAD *bmiColors;
static int j = 128;
HBITMAP hOldBmp;
BITMAPINFO MyBitmap;
BOOL qRetBlit;
switch (msg)
{
case WM_DESTROY:
std::cout << "\ndestroying window\n";
PostQuitMessage(0);
return 0L;
case WM_LBUTTONDOWN:
std::cout << "\nmouse left button down at (" << LOWORD(lp)
<< ',' << HIWORD(lp) << ")\n";
// fall thru
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
#if 1
// Create a device context that is compatible with the window
HDC hLocalDC;
hLocalDC = ::CreateCompatibleDC(hdc);
// Verify that the device context was created
if (hLocalDC == NULL) {
printf("CreateCompatibleDC Failed\n");
// return false;
break;
}
MyBitmap.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
MyBitmap.bmiHeader.biWidth = 256;
MyBitmap.bmiHeader.biHeight = -256;
MyBitmap.bmiHeader.biPlanes = 1;
MyBitmap.bmiHeader.biBitCount = 32;
MyBitmap.bmiHeader.biCompression = BI_RGB;
MyBitmap.bmiHeader.biSizeImage = 256 * 256 * 4;
MyBitmap.bmiHeader.biYPelsPerMeter = 1000;
MyBitmap.bmiHeader.biXPelsPerMeter = 1000;
MyBitmap.bmiHeader.biClrUsed = 0;
MyBitmap.bmiHeader.biClrImportant = 0;
hBitmap = CreateDIBSection(NULL, &MyBitmap, DIB_RGB_COLORS, &pvBits, NULL, NULL);
bmiColors = (RGBQUAD*)pvBits;
// note: BGR
for (int i = 0; i < 256 * 256; i++)
{
bmiColors[i].rgbBlue = 0;
bmiColors[i].rgbGreen = 0;
bmiColors[i].rgbRed = j % 256;
bmiColors[i].rgbReserved = 255;
}
j += 10;
bmiColors[1000].rgbRed;
// Select the bitmap into the device context
hOldBmp = (HBITMAP)::SelectObject(hLocalDC, hBitmap);
if (hOldBmp == NULL) {
printf("SelectObject Failed");
// return false;
break;
}
// Blit the dc which holds the bitmap onto the window's dc
qRetBlit = ::BitBlt(hdc, 0, 0, 256, 256, hLocalDC, 0, 0, SRCCOPY);
if (!qRetBlit) {
printf("Blit Failed");
// return false;
break;
}
// Unitialize and deallocate resources
SelectObject(hLocalDC, hOldBmp);
DeleteDC(hLocalDC);
DeleteObject(hBitmap);
#endif
EndPaint(hWnd, &ps);
break;
default:
std::cout << '.';
break;
}
return DefWindowProc(hWnd, msg, wp, lp);
}
int main()
{
WNDCLASSEX wndclass = { sizeof(WNDCLASSEX), CS_DBLCLKS | CS_HREDRAW, MyWindowProcedure,
0, 0, GetModuleHandle(0), LoadIcon(0,IDI_APPLICATION),
LoadCursor(0,IDC_ARROW), HBRUSH(COLOR_WINDOW + 1),
0, L"myclass", LoadIcon(0,IDI_APPLICATION) };
if (RegisterClassEx(&wndclass))
{
hWindow = CreateWindowEx(0, L"myclass", L"myclass", WS_OVERLAPPEDWINDOW, 1200, 600, 256 + 15, 256 + 38, 0, 0, GetModuleHandle(0), 0);
ShowWindow(hWindow, SW_SHOWDEFAULT);
UpdateWindow(hWindow);
MSG msg;
byte bRet;
while ((bRet = GetMessage(&msg, hWindow, 0, 0)) != 0)
{
if (bRet == -1)
{
return 1;
}
else
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
}
}

Answer 1

As pointed out. You do not want to call WM_PAINT your self. Let the system handle it. So in WM_LBUTTONDOWN do:
case WM_LBUTTONDOWN:
std::cout << "\nmouse left button down at (" << LOWORD(lp)
<< ',' << HIWORD(lp) << ")\n";
InvalidateRect(hWnd, nullptr, FALSE);
return 0;
Do not fall through. Wnen you call RedrawWindow the window is invalidated and then needs to be repainted. I just tested this, the window lightens up on each click.
UPDATE:
Thanks to Remy Lebeau
Difference between InvalidateRect and RedrawWindow
And yes, it is better to let windows use its own schedule for this kind of stuff.