Background image fails to get set for a window in WinApi - c

Question

I am learning to how to set a background image for a window in C.
Here is my code:
#include <stdio.h>
#include <windows.h>
char* window_name = "Window";
char* window_title = "Window Title";
char* background_name = "test.bmp";
int window_width = 600;
int window_height = 400;
HBITMAP hbackground_image;
WNDCLASSEX wc;
HWND hwnd, hbackground;
MSG msg;
LRESULT CALLBACK WindowProcedure(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
{
switch (msg)
{
case WM_CREATE:
hbackground = CreateWindow("STATIC", "background", SS_BITMAP | WS_CHILD | WS_VISIBLE, 0, 0, 300, 300, hwnd,
NULL, NULL, NULL);
hbackground_image = (HBITMAP)LoadImage(NULL, background_name, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
SendMessage(hbackground, STM_SETIMAGE, (WPARAM)IMAGE_BITMAP, (LPARAM)hbackground_image);
break;
default:
return DefWindowProc(hwnd, msg, wp, lp);
}
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = DefWindowProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(hInstance, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.lpszMenuName = NULL;
wc.hIconSm = LoadIcon(hInstance, IDI_APPLICATION);
wc.lpszClassName = window_name;
if (!RegisterClassEx(&wc))
{
MessageBox(NULL, "Windows registration failure", NULL, MB_RETRYCANCEL);
return 1;
}
hwnd = CreateWindowEx(WS_EX_OVERLAPPEDWINDOW, window_name, window_title, WS_OVERLAPPEDWINDOW, CW_USEDEFAULT,
CW_USEDEFAULT, window_width, window_height, NULL, NULL, hInstance, NULL);
// hwnd = CreateWindow("test", "test title", WS_OVERLAPPED | WS_VISIBLE, 100, 100, 500, 500, NULL, NULL, NULL, NULL); // This fails
if (!hwnd) // If fails
{
MessageBox(NULL, "Window creation failed :(", NULL, MB_RETRYCANCEL);
return 2;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
while (GetMessage(&msg, NULL, 0, 0) > 0)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
However, the background image doesn't get set even though there is a bitmap in the same folder as the .exe. I also tried different bitmaps from the internet, and one I made in paint. Any help would be appreciated.

Answer 1

This line is wrong:
wc.lpfnWndProc = DefWindowProc;
You are not seeing your background image because you are not using your WindowProcedure() with the window class, and thus it is never called to load/display the bitmap.
That line needs to be this instead:
wc.lpfnWndProc = WindowProcedure;
Also, when processing WM_CREATE, you are not return'ing any value, so the result is indeterminate, which is undefined behavior. You need to return 0; for that message:
LRESULT CALLBACK WindowProcedure(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
{
switch (msg)
{
case WM_CREATE:
...
return 0;
...
}
return DefWindowProc(hwnd, msg, wp, lp);
}