// Note: I'm only posting the functions involved in this
// process, as well as any global variables/objects referenced
// by those functions. The program has no classes, so all objects
// and variables should be either local or global. Since the
// program runs fun until the WM_EXITSIZEMOVE message is sent,
// it seems safe to assume that all of these objects are
// initialized properly in the beginning and that the rest of the
// program runs fine.

LPDIRECT3DDEVICE9 pDevice = NULL;
D3DPRESENT_PARAMETERS params;
LPD3DXMESH pEarth = NULL;
LPD3DXEFFECT pEarthEffect = NULL;
IDirect3DTexture9 *pEarthDay = NULL, *pEarthNight = NULL;

void OnLostDevice();
void OnResetDevice();

LRESULT CALLBACK mainWindowProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	switch(msg)
	{
	case WM_CLOSE :
		DestroyWindow(hWnd);
		break;
	case WM_DESTROY :
		PostQuitMessage(0);
		break;
	case WM_EXITSIZEMOVE :
		RECT clientRect;
		GetClientRect(hWnd, &clientRect);
		params.BackBufferWidth = clientRect.right;
		params.BackBufferHeight = clientRect.bottom;
		OnLostDevice();
		HR(pDevice->Reset(&params));
		OnResetDevice();
		break;
	default :
		return DefWindowProc(hWnd, msg, wParam, lParam);
	}

	return 0;	
}

void OnLostDevice()
{
	// Earth Effect
	if(pEarthEffect)
	{
		pEarthEffect->Release();
		pEarthEffect = NULL;
	}

	// Earth Mesh
	if(pEarth)
	{
		pEarth->Release();
		pEarth = NULL;
	}

	// Earth Textures
	if(pEarthDay)
	{
		pEarthDay->Release();
		pEarthDay = NULL;
	}

	if(pEarthNight)
	{
		pEarthNight->Release();
		pEarthNight = NULL;
	}
}

void OnResetDevice()
{
	if(!pEarth)
		HR(D3DXCreateSphere(pDevice, 12.0f, NUM_SLICES, NUM_STACKS, &pEarth, NULL));

	if(!pEarthEffect)
		D3DXCreateEffectFromFile(pDevice, "C:\\_Programming Projects\\EarthNightDay\\EarthNightDay\\earth.fx", NULL, NULL, 0, NULL, &pEarthEffect, NULL);

	if(!pEarthDay)
		HR(D3DXCreateTextureFromFile(pDevice, "C:\\_Programming Projects\\EarthNightDay\\EarthNightDay\\earthmap1k.jpg", &pEarthDay));

	if(!pEarthNight)
		HR(D3DXCreateTextureFromFile(pDevice, "C:\\_Programming Projects\\EarthNightDay\\EarthNightDay\\earthlights1k.jpg", &pEarthNight));
}