[英]DirectX Partial Screen Capture
I am trying to create a program that will capture a full screen directx application, look for a specific set of pixels on the screen and if it finds it then draw an image on the screen. 我正在尝试创建一个程序来捕获全屏Directx应用程序,在屏幕上查找一组特定的像素,如果找到它,则在屏幕上绘制图像。
I have been able to set up the application to capture the screen the directx libraries using the code the answer for this question Capture screen using DirectX 我已经能够使用该代码来设置应用程序以捕获DirectX库的屏幕使用该问题的答案使用DirectX捕获屏幕
In this example the code saves to the harddrive using the IWIC libraries. 在此示例中,代码使用IWIC库保存到硬盘驱动器。 I would rather manipulate the pixels instead of saving it. 我宁愿操纵像素而不是保存像素。
After I have captured the screen and have a LPBYTE of the entire screen pixels I am unsure how to crop it to the region I want and then being able to manipulate the pixel array. 捕获屏幕并获得整个屏幕像素的LPBYTE后,我不确定如何将其裁剪到所需的区域,然后能够操纵像素阵列。 Is it just a multi dimensional byte array? 它只是一个多维字节数组吗?
The way I think I should do it is 我认为我应该做的方式是
Any help on any of this would be so much appreciated. 任何帮助,将不胜感激。
Here is a modified version of the original code that only captures a portion of the screen into a buffer, and also gives back the stride . 这是原始代码的修改版本,它仅将屏幕的一部分捕获到缓冲区中,并且还返回步幅 。 Then it browses all the pixels, dumps their colors as a sample usage of the returned buffer. 然后,它浏览所有像素,转储其颜色作为返回缓冲区的样本用法。
In this sample, the buffer is allocated by the function, so you must free it once you've used it: 在此示例中,缓冲区是由函数分配的,因此一旦使用它就必须释放它:
// sample usage
int main()
{
LONG left = 10;
LONG top = 10;
LONG width = 100;
LONG height = 100;
LPBYTE buffer;
UINT stride;
RECT rc = { left, top, left + width, top + height };
Direct3D9TakeScreenshot(D3DADAPTER_DEFAULT, &buffer, &stride, &rc);
// In 32bppPBGRA format, each pixel is represented by 4 bytes
// with one byte each for blue, green, red, and the alpha channel, in that order.
// But don't forget this is all modulo endianness ...
// So, on Intel architecture, if we read a pixel from memory
// as a DWORD, it's reversed (ARGB). The macros below handle that.
// browse every pixel by line
for (int h = 0; h < height; h++)
{
LPDWORD pixels = (LPDWORD)(buffer + h * stride);
for (int w = 0; w < width; w++)
{
DWORD pixel = pixels[w];
wprintf(L"#%02X#%02X#%02X#%02X\n", GetBGRAPixelAlpha(pixel), GetBGRAPixelRed(pixel), GetBGRAPixelGreen(pixel), GetBGRAPixelBlue(pixel));
}
}
// get pixel at 50, 50 in the buffer, as #ARGB
DWORD pixel = GetBGRAPixel(buffer, stride, 50, 50);
wprintf(L"#%02X#%02X#%02X#%02X\n", GetBGRAPixelAlpha(pixel), GetBGRAPixelRed(pixel), GetBGRAPixelGreen(pixel), GetBGRAPixelBlue(pixel));
SavePixelsToFile32bppPBGRA(width, height, stride, buffer, L"test.png", GUID_ContainerFormatPng);
LocalFree(buffer);
return 0;;
}
#define GetBGRAPixelBlue(p) (LOBYTE(p))
#define GetBGRAPixelGreen(p) (HIBYTE(p))
#define GetBGRAPixelRed(p) (LOBYTE(HIWORD(p)))
#define GetBGRAPixelAlpha(p) (HIBYTE(HIWORD(p)))
#define GetBGRAPixel(b,s,x,y) (((LPDWORD)(((LPBYTE)b) + y * s))[x])
int main()
HRESULT Direct3D9TakeScreenshot(UINT adapter, LPBYTE *pBuffer, UINT *pStride, const RECT *pInputRc = nullptr)
{
if (!pBuffer || !pStride) return E_INVALIDARG;
HRESULT hr = S_OK;
IDirect3D9 *d3d = nullptr;
IDirect3DDevice9 *device = nullptr;
IDirect3DSurface9 *surface = nullptr;
D3DPRESENT_PARAMETERS parameters = { 0 };
D3DDISPLAYMODE mode;
D3DLOCKED_RECT rc;
*pBuffer = NULL;
*pStride = 0;
// init D3D and get screen size
d3d = Direct3DCreate9(D3D_SDK_VERSION);
HRCHECK(d3d->GetAdapterDisplayMode(adapter, &mode));
LONG width = pInputRc ? (pInputRc->right - pInputRc->left) : mode.Width;
LONG height = pInputRc ? (pInputRc->bottom - pInputRc->top) : mode.Height;
parameters.Windowed = TRUE;
parameters.BackBufferCount = 1;
parameters.BackBufferHeight = height;
parameters.BackBufferWidth = width;
parameters.SwapEffect = D3DSWAPEFFECT_DISCARD;
parameters.hDeviceWindow = NULL;
// create device & capture surface (note it needs desktop size, not our capture size)
HRCHECK(d3d->CreateDevice(adapter, D3DDEVTYPE_HAL, NULL, D3DCREATE_SOFTWARE_VERTEXPROCESSING, ¶meters, &device));
HRCHECK(device->CreateOffscreenPlainSurface(mode.Width, mode.Height, D3DFMT_A8R8G8B8, D3DPOOL_SYSTEMMEM, &surface, nullptr));
// get pitch/stride to compute the required buffer size
HRCHECK(surface->LockRect(&rc, pInputRc, 0));
*pStride = rc.Pitch;
HRCHECK(surface->UnlockRect());
// allocate buffer
*pBuffer = (LPBYTE)LocalAlloc(0, *pStride * height);
if (!*pBuffer)
{
hr = E_OUTOFMEMORY;
goto cleanup;
}
// get the data
HRCHECK(device->GetFrontBufferData(0, surface));
// copy it into our buffer
HRCHECK(surface->LockRect(&rc, pInputRc, 0));
CopyMemory(*pBuffer, rc.pBits, rc.Pitch * height);
HRCHECK(surface->UnlockRect());
cleanup:
if (FAILED(hr))
{
if (*pBuffer)
{
LocalFree(*pBuffer);
*pBuffer = NULL;
}
*pStride = 0;
}
RELEASE(surface);
RELEASE(device);
RELEASE(d3d);
return hr;
}
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