This code is a simulation of what you should have.. It shows that the backbuffer is actually being captured. I created the device the exact same way you did. I capture the back-buffer the same way..
To test if the back-buffer is actually captured, I have set the window background to a navy-blue colour. Then when I call the capture function, I compare all the colours in the buffer to the original background colour.. This lets me know if a single pixel is different than the background..
If it is different, we "possibly" failed to capture the background. Otherwise, we are good..
I've tested the below and it indeed captures the backbuffer perfectly fine.. I even saved the backbuffer to a bitmap to see if it captures it and it does..
All in all, there's nothing wrong with your code, but I cannot guarantee that you are using it correctly.. In other words, you haven't shown me where you call your back-buffer capture code.. There are many places it can be called, but the best places are either in a hook to EndScene or a hook to Present. If you are using this on your own application, then call it in your onDraw/onUpdate function..
#include <tchar.h>
#include <windows.h>
#include <d3d9.h>
#include <d3dx9.h>
#include <iostream>
HRESULT capture(IDirect3DDevice9* m_d3ddev, void* buffer, int& width, int& height, D3DFORMAT format);
void onUpdate(HWND hwnd, IDirect3D9* d3d9, IDirect3DDevice9* d3ddev9, D3DFORMAT format)
{
d3ddev9->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 40, 100), 1.0f, 0);
d3ddev9->BeginScene();
//All drawing goes here..
d3ddev9->EndScene();
d3ddev9->Present(NULL, NULL, NULL, NULL); //Swaps the back and front buffers. Displays all drawing on the screen..
RECT rect;
GetClientRect(hwnd, &rect);
int width = rect.right - rect.left, height = rect.bottom - rect.top;
unsigned char* buffer = new unsigned char[width * height * 4];
capture(d3ddev9, buffer, width, height, format);
unsigned char* px = buffer;
for(int i = 0; i < height; ++i)
{
for(int j = 0; j < width; ++j)
{
unsigned char B = *px++;
unsigned char G = *px++;
unsigned char R = *px++;
unsigned char A = *px++;
if(D3DCOLOR_XRGB(R, G, B) != D3DCOLOR_XRGB(0, 40, 100))
{
MessageBox(NULL, "FAILED.. Colour differs from original background..", NULL, 0);
}
}
}
delete[] buffer;
}
int onDisplay(HWND hwnd)
{
IDirect3D9* d3d9 = NULL;
IDirect3DDevice9* d3ddev9 = NULL;
D3DPRESENT_PARAMETERS Parameters = {0};
d3d9 = Direct3DCreate9(D3D_SDK_VERSION);
D3DDISPLAYMODE* dispMode = new D3DDISPLAYMODE();
d3d9->GetAdapterDisplayMode(D3DADAPTER_DEFAULT, dispMode);
Parameters.Windowed = true;
Parameters.SwapEffect = D3DSWAPEFFECT_DISCARD;
Parameters.hDeviceWindow = hwnd;
Parameters.BackBufferFormat = dispMode->Format;
d3d9->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hwnd, D3DCREATE_SOFTWARE_VERTEXPROCESSING, &Parameters, &d3ddev9);
delete dispMode;
MSG messages;
ShowWindow(hwnd, SW_SHOW);
while(true)
{
if(PeekMessage(&messages, NULL, 0, 0, PM_REMOVE) > 0)
{
if(messages.message != WM_QUIT)
{
TranslateMessage(&messages);
DispatchMessageW(&messages);
continue;
}
break;
}
else
{
onUpdate(hwnd, d3d9, d3ddev9, Parameters.BackBufferFormat);
}
}
if(d3ddev9) d3ddev9->Release();
if(d3d9) d3d9->Release();
return messages.wParam;
}
LRESULT CALLBACK WindowProcedure(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch(message)
{
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, message, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hThisInstance, HINSTANCE hPrevInstance, LPSTR lpszArgument, int nCmdShow)
{
WNDCLASSEX wincl;
wincl.hInstance = hThisInstance;
wincl.lpszClassName = "D3DWindow";
wincl.lpfnWndProc = WindowProcedure;
wincl.style = CS_DBLCLKS;
wincl.cbSize = sizeof(WNDCLASSEX);
wincl.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wincl.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
wincl.hCursor = LoadCursor(NULL, IDC_ARROW);
wincl.lpszMenuName = NULL;
wincl.cbClsExtra = 0;
wincl.cbWndExtra = 0;
wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;
if(!RegisterClassEx(&wincl)) return 0;
HWND hwnd = CreateWindowEx(0, "D3DWindow", "D3D9: Window", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 544, 375, HWND_DESKTOP, NULL, hThisInstance, NULL);
return onDisplay(hwnd);
}
HRESULT capture(IDirect3DDevice9* m_d3ddev, void* buffer, int& width, int& height, D3DFORMAT format)
{
IDirect3DSurface9 *renderTarget= NULL;
IDirect3DSurface9 *destTarget = NULL;
HRESULT hr = m_d3ddev->GetRenderTarget(0, &renderTarget);
hr = m_d3ddev->CreateOffscreenPlainSurface(width, height, format, D3DPOOL_SYSTEMMEM, &destTarget, NULL);
if(FAILED(hr))
{
printf("Failed CreateOffscreenPlainSurface!");
}
hr = m_d3ddev->GetRenderTargetData(renderTarget, destTarget);
if(FAILED(hr))
{
printf("Failed GetRenderTargetData!");
}
D3DLOCKED_RECT lr;
ZeroMemory(&lr, sizeof(D3DLOCKED_RECT));
hr = destTarget->LockRect(&lr, 0, D3DLOCK_READONLY);
if(FAILED(hr))
{
printf("Cannot lock rect!");
}
if(lr.pBits)
{
memcpy(buffer, lr.pBits, width * height * 4);
}
hr = destTarget->UnlockRect();
if(FAILED(hr))
{
printf("Cannot unlock rect!");
}
renderTarget->Release();
destTarget->Release();
return hr;
}
