So my problem is kinda simple. I have a vertex buffer, I create it with
pDevice->CreateVertexBuffer(
m_dwCount * sizeof(CUSTOMVERTEX)),
0,
CUSTOMFVF,
D3DPOOL_MANAGED,
&m_pVB, NULL);
and then let's say for test purposes, I want to modify all of them and multiply them. How exactly can I lock all of them and then multiply them? I tried to lock it
CUSTOMVERTEX* pVoid;
pVB->Lock(0, 0, (void**)&pVoid, 0);
but that I assume doesn't lock the entire buffer. I'm kinda new to the DirectX so I'm sorry if the question is too stupid, however thanks anyone for help.
First create your multiplied vertices (for example called newVertices). Then you need to lock your vertex buffer and get the pointer to pointer of current vertices like this :
CUSTOMVERTEX* pVertices;
HRESULT hr = m_pVB->Lock(0, 0, reinterpret_cast<void**>(&pVertices), 0);
Then you can use memcpy to replace your new vertices into it like this :
if(hr == S_OK)
memcpy(pVertices, newVertices, num_of_vertices * sizeof(CUSTOMVERTEX));
Then unlock you vertex buffer like this :
hr = m_pVB->Unlock();
Related
So I'm trying to iron out kinks of how I'm rendering images with direct stuff. Right now it works as a DXGISwapchain with D3D11 and I make a ID2D1RenderTarget which I draw to using bitmaps. My issue is when I hit the maximize button on the window my images are off, or at least the ones using data from the window grabbed with GetClientRect (the others seem... close enough but probably still off and I want to be able to use the client space to scale and draw things later as well). I have a D2D1::RectF set with the top left at 0.0f and the bottom right as the window's height and width grabbed via GetClientRect (along with a few others just for additional fooling around). Looked around and it seems like I need to call recreate the ID2D1RenderTarget and/or resize the buffers. Calling a function to recreate the ID2D1RenderTarget before making objects which contain the bitmaps and the functions which draw them did not help with the issue at all. I tried resizing the buffers but I keep getting errors, first set were regarding parameters, but before fixing that I realized I needed to release the objects, but now my it seems since I have made the objects with ComPtr it seems how it deals with deleting them is having issues. client.h is calling an exception: "Access violation executing location " with the unsigned long InternalRelease() function. This occurs with the function to adjust the buffers and target. So right now I'm lost as to what to do in order to get the desired effect. Only other things to note is the ID3D11RenderTargetView I made is used to clear to a color since for I had errors with calling Clear(D2D1::ColorF(D2D1::ColorF::White)); on my ID2D1RenderTarget. I don't care if the solution to this resizes the ID3D11RenderTargetView unless it will improve speed for the program or prevent some sort of unforeseen issue elsewhere since I don't intend to use it aside for that. If I could call clear on the ID2D1RenderTarget and no longer need the ID311RenderTargetView and keep the swapchain while resolving the issue that would work too. Also I intend to work out fullscreen mode next so a method that works with that would also be very much desired. I'm also open to take any other advice here, while it's not polished and just in a form to get things working first, I probably will miss things even when tidying up. Anyway here's the code:
Here's the Graphics class where I make the swapchain, buffers and rendertargets and such and the function in which I try and reset the buffers. Side note I followed some tutorials on my way here to get me to understand enough of the direct stuff to get here and get to the point where I'm looking into to stuff on Microsoft and understanding it somewhat to solve problems I have. Anyway one of them went through making some exceptions and that is what stuff like Graphic_Throw_Failure() are for. (though I did it wrong or the errors are doing something and I can't see the pop up window half the time, sometimes it stops in the exception code but I can still read the message)
//not in the cpp file but just how some variables exist for clarity.
private:
Microsoft::WRL::ComPtr<ID3D11Device> pDevice = nullptr;
Microsoft::WRL::ComPtr < IDXGISwapChain> pSwapChain = nullptr;
Microsoft::WRL::ComPtr < ID3D11DeviceContext> pContext = nullptr;
Microsoft::WRL::ComPtr < ID3D11RenderTargetView> pRTarget = nullptr;
ID2D1RenderTarget* p2dRenderTarget = nullptr;
ID2D1Factory* p2DFactory = nullptr;
Graphics::Graphics(HWND hwnd) {
DXGI_SWAP_CHAIN_DESC swapchainDesc = {};
ZeroMemory(&swapchainDesc, sizeof(DXGI_SWAP_CHAIN_DESC));
swapchainDesc.Windowed = true;
swapchainDesc.BufferCount = 1;
swapchainDesc.BufferDesc.Height = 0;
swapchainDesc.BufferDesc.Width = 0;
swapchainDesc.BufferDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
swapchainDesc.SampleDesc.Count = 1;
swapchainDesc.SampleDesc.Quality = 0;
swapchainDesc.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;
swapchainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
swapchainDesc.BufferDesc.RefreshRate.Numerator = 1;
swapchainDesc.BufferDesc.RefreshRate.Denominator = 60;
swapchainDesc.OutputWindow = hwnd;
HRESULT hre;
Graphic_Throw_Failure(D3D11CreateDeviceAndSwapChain(
nullptr,
D3D_DRIVER_TYPE_HARDWARE,
nullptr,
D3D11_CREATE_DEVICE_BGRA_SUPPORT,
levels,
4,
D3D11_SDK_VERSION,
&swapchainDesc,
&pSwapChain,
&pDevice,
nullptr,
&pContext
));
//3Dbuffer setup
wrl::ComPtr<ID3D11Resource> p3dbuffer = nullptr;
Graphic_Throw_Failure(pSwapChain->GetBuffer(0, __uuidof(ID3D11Resource), &p3dbuffer));
Graphic_Throw_Failure(pDevice->CreateRenderTargetView(p3dbuffer.Get(), nullptr, &pRTarget));
//2D buffer Setup
IDXGISurface* pBackBuffer = nullptr;
Graphic_Throw_Failure(pSwapChain->GetBuffer(0,IID_PPV_ARGS(&pBackBuffer)));
//makes 2d Factory
Graphic_Throw_Failure(D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED, &p2DFactory));
//sets up DXGI buffer for 2d
FLOAT dpi;
dpi = GetDpiForWindow(hwnd);
//p2DFactory->GetDesktopDpi(&dpiX, &dpiY);
D2D1_RENDER_TARGET_PROPERTIES p2dRTprops =
D2D1::RenderTargetProperties(
D2D1_RENDER_TARGET_TYPE_DEFAULT,
D2D1::PixelFormat(DXGI_FORMAT_UNKNOWN, D2D1_ALPHA_MODE_PREMULTIPLIED),
dpi,
dpi
);
Graphic_Throw_Failure(p2DFactory->CreateDxgiSurfaceRenderTarget(
pBackBuffer, &p2dRTprops, &p2dRenderTarget
));
if(pBackBuffer!=nullptr)
pBackBuffer->Release();
}
//the adjusting function I failed to make. could also be missing somethings I need to clear before
//calling ResizeBuffers
void Graphics::adjustRenderTargets(HWND hwnd) {
HRESULT hre;
pContext->ClearState();
p2dRenderTarget->Release();
pRTarget->Release();
//3Dbuffer setup
wrl::ComPtr<ID3D11Resource> p3dbuffer = nullptr;
Graphic_Throw_Failure(pSwapChain->GetBuffer(0, __uuidof(ID3D11Resource), &p3dbuffer));
Graphic_Throw_Failure(pDevice->CreateRenderTargetView(p3dbuffer.Get(), nullptr, &pRTarget));
//2D buffer Setup
IDXGISurface* pBackBuffer = nullptr;
Graphic_Throw_Failure(pSwapChain->GetBuffer(0, IID_PPV_ARGS(&pBackBuffer)));
//makes 2d Factory
Graphic_Throw_Failure(D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED, &p2DFactory));
//sets up DXGI buffer for 2d
FLOAT dpi;
dpi = GetDpiForWindow(hwnd);
//p2DFactory->GetDesktopDpi(&dpiX, &dpiY);
D2D1_RENDER_TARGET_PROPERTIES p2dRTprops =
D2D1::RenderTargetProperties(
D2D1_RENDER_TARGET_TYPE_DEFAULT,
D2D1::PixelFormat(DXGI_FORMAT_UNKNOWN, D2D1_ALPHA_MODE_PREMULTIPLIED),
dpi,
dpi
);
Graphic_Throw_Failure(p2DFactory->CreateDxgiSurfaceRenderTarget(
pBackBuffer, &p2dRTprops, &p2dRenderTarget
));
if (pBackBuffer != nullptr)
pBackBuffer->Release();
};
//and the destructor in case there is something still wrong there though
//currently not giving me issues since I set the objects in it to nullptr after releasing it.
//didn't work for the ComPtr.
Graphics::~Graphics() {
if (p2DFactory != nullptr) {
p2DFactory->Release();
}
if (p2dRenderTarget != nullptr) {
p2dRenderTarget->Release();
}
}
This is the class which holds the bitmaps and deals with them and drawing them. Once again I made some exceptions for this class
//some variables in the header file
ID2D1Bitmap* Bittmap=nullptr;
Graphics* GFX;
Sprites::Sprites(const wchar_t* filename, Graphics* gfx) {
HRESULT hre;
GFX = gfx;
//makes WIC Factory
IWICImagingFactory* WICfactory = NULL;
Sprite_Throw_Failure(CoCreateInstance(
CLSID_WICImagingFactory,
NULL,
CLSCTX_INPROC_SERVER,
IID_IWICImagingFactory,
(LPVOID*)&WICfactory
));
//Makes the Decoder
IWICBitmapDecoder* WICdecode = NULL;
Sprite_Throw_Failure(WICfactory->CreateDecoderFromFilename(
filename,
NULL,
GENERIC_READ,
WICDecodeMetadataCacheOnLoad,
&WICdecode
));
//Read the frame (should be only one so read the image)
IWICBitmapFrameDecode* WICframe = NULL;
Sprite_Throw_Failure(WICdecode->GetFrame(0, &WICframe));
//Format converter
IWICFormatConverter* WICconverter = NULL;
Sprite_Throw_Failure(WICfactory->CreateFormatConverter(&WICconverter));
//makes the converter set up to create a 32bpp BGRA bitmap
Sprite_Throw_Failure(WICconverter->Initialize(
WICframe,
GUID_WICPixelFormat32bppPBGRA,
WICBitmapDitherTypeNone,
NULL,
0.0,
WICBitmapPaletteTypeCustom
));
//makes the bitmap
Sprite_Throw_Failure(GFX->Get2DRenderTarget()->CreateBitmapFromWicBitmap(
WICconverter,
NULL,
&Bittmap
));
if (WICfactory) WICfactory->Release();
if (WICdecode) WICdecode->Release();
if (WICconverter)WICconverter->Release();
if (WICframe)WICframe->Release();
}
//draws the sprites
void Sprites::Draw(D2D1_RECT_F location) {
HRESULT hre;
GFX->Get2DRenderTarget()->BeginDraw();
GFX->Get2DRenderTarget()->DrawBitmap(
Bittmap,
location, //destination rect
1.0f, //opacity
D2D1_BITMAP_INTERPOLATION_MODE::D2D1_BITMAP_INTERPOLATION_MODE_NEAREST_NEIGHBOR,
D2D1::RectF(
1980.0f, 2850.0f, 3000.0f,
3600.0f) //source rect
);
Sprite_Throw_Failure(GFX->Get2DRenderTarget()-> EndDraw());
}
Sprites::~Sprites() {
//bitmapsheet.clear();
if (Bittmap != nullptr) {
Bittmap->Release();
}
}
This is the class which the main loop is handled wnd is the windowclass I made which makes and manages the window. I use it here to get the graphics object the window uses which has all the direct stuff. here are some variables that appear, forgive the name bob.
//in header file
private:
Window wnd;
//in cpp file
Sprites* testsprite;
Sprites* testsprite2;
D2D1_RECT_F bob;
within the function that calls over and over for the duration of the program at the part where I render:
//inefficient constant adjusting of rendering just so I can quickly assess
//the change and make sure it works so when I implement how I intend the windows to be scaled it
//will already be done
wnd.GFX().adjustRenderTargets(wnd.getwindowhandle());
//clearing the ID3D11RenderTargetView to a color
wnd.GFX().ClearBuffer(0.3f, 0.5f, 1.0f);
//drawing calls
const wchar_t* filename = L"\environmentsketches 02.png";
//this creates a Sprites object getGraphix returns the a pointer to the graphics object
//only really used to get the ID2D1RenderTarget but I may use it for other things, will
//remove later if not needed and just pass the render target unless issues arise.
testsprite = new Sprites(filename, wnd.GFX().getGraphix());
bob = D2D1::RectF(
0.0f, 0.0f, wnd.getwindowWidth(),
wnd.getwindowHeight());
//This draws the bitmap of a predetermined portion of the image but uses bob to
// to determine where to draw the bitmap
testsprite->Draw(bob);
bob = D2D1::RectF(
0.0f, 0.0f, wnd.getwindowWidth()/(16.0f/9.0f),
wnd.getwindowHeight());
testsprite->Draw(bob);
filename= L"\envrioment sketch march 1.png";
bob = D2D1::RectF(
100.0f, 100.0f, 600.f,
300.f);
testsprite2 = new Sprites(filename, wnd.GFX().getGraphix());
testsprite2->Draw(bob);
//EndFrame just calls present on the IDXGISwapChain
wnd.GFX().EndFrame();
testsprite->~Sprites();
testsprite2->~Sprites();
If you read through this thank you and thank you for any advice you have to offer.
Don't code late or tired. So first thing I realized is one when posting the code here I forgot to include the call for SwapChain->ResizeBuffers(0,width,height, DXGI_FORMAT_UNKNOWN, 0)) which is where the mistake was. I changed my pointers from smart to regular to manage their release manually for this, but the issue was more so that the last parameter wasn't 0, it was D3D11_CREATE_DEVICE_BGRA_SUPPORT instead of a proper swapchain flag and was reading as another (I believe DXGI_SWAP_CHAIN_FLAG_DISPLAY_ONLY) which I couldn't use because of how I made my swapchain resulting in an error and it just not running.
In all the solution to my problem was to release my render targets (I already released by buffers after I made the targets), resize the buffers and then remake the ID2D1RenderTarget. Just don't put a wrong flag in, (or make sure the call is in when posting it for feedback to the mistake might be caught by others.)
I am trying to load a grass texture onto my game with the function DirectX::CreateWICTextureFromFile but everytime I do, the function won't seem to actually load anything, it just loads a black texture. The function successfully returns S_OK, and i've also called the CoInitialize(NULL) before I actually call the function. But it still doesn't work.
Down below is my usage of the function
// This is where i load the texture
void Load_Texture_for_Ground()
{
HRESULT status;
ID3D11ShaderResourceView * Texture;
CoInitialize(NULL);
status = DirectX::CreateWICTextureFromFile(device, L"AmazingGrass.jpg", NULL, &Texture);
if (Texture != NULL) // This returns true
{
MessageBox(MainWindow, L"The pointer points to the texture", L"MessageBox", MB_OK);
}
if (status == S_OK) //This returns true
{
MessageBox(MainWindow, L"The function succeeded", L"MessageBox", MB_OK);
}
CoUninitialize();
}
// This is where i actually load the texture onto an object, assuming i already declared all the variables in this function
void DrawTheGround ()
{
DevContext->VSSetShader(VS, 0, 0);
DevContext->PSSetShader(PS, 0, 0);
DevContext->IASetVertexBuffers(
0,
1,
&GroundVertexBuffer,
&strides,
&offset
);
DevContext->IASetIndexBuffer(
IndexBuffer,
DXGI_FORMAT_R32_UINT,
0
);
/* Transforming the matrices*/
TransformedMatrix = GroundWorld * CameraView * CameraProjection ;
Data.WORLDSPACE = XMMatrixTranspose(GroundWorld);
Data.TRANSFORMEDMATRIX = XMMatrixTranspose(TransformedMatrix);
/* Updating the matrix in application's Constant Buffer*/
DevContext->UpdateSubresource(
ConstantBuffer,
0,
NULL,
&Data,
0,
0
);
DevContext->VSSetConstantBuffers(0, 1, &ConstantBuffer);
DevContext->PSSetShaderResources(0, 1, &Texture);
DevContext->PSSetSamplers(0, 1, &TextureSamplerState);
DevContext->DrawIndexed(6, 0, 0);
}
What could be wrong here? Why won't the function load the texture?
A quick way to test if you have loaded the texture data correctly is to use SaveWICTextureToFile in the ScreenGrab module right after loading it. You'd only do this for debugging of course.
#include <wincodec.h>
#include <wrl/cient.h>
using Microsoft::WRL::ComPtr;
ComPtr<ID3D11Resource> Res;
ComPtr<ID3D11ShaderResourceView> Texture;
HRESULT status = DirectX::CreateWICTextureFromFile(device, L"AmazingGrass.jpg", &Res, &Texture);
if (FAILED(status))
// Error handling
#ifdef _DEBUG
status = SaveWICTextureToFile( DevContext, Res.Get(),
GUID_ContainerFormatBmp, L"SCREENSHOT.BMP" );
#endif
Then you can run the code and check that SCREENSHOT.BMP is not all black.
I strongly suggest you adopt the ComPtr smart pointer and the FAILED / SUCCEEDED macros in your coding style. Raw pointers and directly comparing HRESULT to S_OK is setting yourself up for a lot of bugs.
You should not call CoInitialize every frame. You should call it once as part of your application's initialization.
You should not be creating a new instance of SpriteBatch and SpriteFont every frame. Just create them after you create your device and hold on to them.
I am trying to access the screen data from backbuffer using directx. However with the code below, the pointer to the pixel data has all 0.
I am really not sure if I am checking the data correctly. I am running this on Visual studio 2013, and using break points to check the pointer b. And its value is 0, all the time.
I am aware that I am not using IDirect3DDevice9::GetRenderTargetData method. This cause me to try to access the data in the device's memory I suppose. Would it prevent me from getting correct pixel data ?
d3dManager = new D3DManager(NULL, 600, 600);
IDirect3DDevice9 *device = d3dManager->getDevice();
IDirect3DSurface9 *ppBackBuffer = NULL;
HRESULT result = device->GetBackBuffer(
0,
0,
D3DBACKBUFFER_TYPE_MONO,
&ppBackBuffer
);
if (FAILED(result))
{
printf("vuhu");
return 1;
}
D3DSURFACE_DESC pDesc;
ppBackBuffer->GetDesc(&pDesc);
HANDLE *handle = NULL;
device->CreateOffscreenPlainSurface(pDesc.Width, pDesc.Height, pDesc.Format, D3DPOOL_SYSTEMMEM, &ppBackBuffer, handle);
D3DLOCKED_RECT lockedRectangle;
ppBackBuffer->LockRect(&lockedRectangle, NULL, D3DLOCK_DONOTWAIT);
void* bits = lockedRectangle.pBits;
int *a = (int*)(bits);
int *b = a + 120;
When you call CreateOffscreenPlainSurface here, and you pass in ppBackBuffer, it gets overwritten because it's creating new surface that's empty by default. In fact, you just leaked your reference to the backbuffer you obtained from GetBackBuffer.
D3DSURFACE_DESC pDesc;
ppBackBuffer->GetDesc(&pDesc);
HANDLE *handle = NULL;
device->CreateOffscreenPlainSurface(pDesc.Width, pDesc.Height, pDesc.Format, D3DPOOL_SYSTEMMEM, &ppBackBuffer, handle);
You need to actually call GetRenderTargetData to copy the data from the backbuffer (which is likely in video memory that is completely inaccessible to the CPU) to a surface you can read from the CPU.
BTW, check the HRESULTs of your calls, particularly CreateOffscreenPlainSurface and LockRect.
EDIT: If what you mean to do is create a new surface with the same properties as the backbuffer, then you should do:
D3DSURFACE_DESC pDesc;
ppBackBuffer->GetDesc(&pDesc);
ppBackBuffer->Release(); // <--- Let go of our reference to the back buffer surface
HANDLE *handle = NULL;
device->CreateOffscreenPlainSurface(pDesc.Width, pDesc.Height, pDesc.Format, D3DPOOL_SYSTEMMEM, &ppBackBuffer, handle);
There's nothing at all in your code that is actually moving the contents of the back buffer into the new surface. You are just reusing the variable IDirect3DSurface9 *ppBackBuffer.
Whenever I try to render a custom model in my program the program crashes
When I try to run it in debug mode it points me to
deviceContext->IASetVertexBuffers(0, 1, &m_vertexBuffer, &stride, &offset);
The odd thing is that I have two different models stored in two different files.
The first model renders all file with no problems this is also the more "advanced" model, but now I'm trying to render a box, a very simple box.
But whenever I try to render this box my programs crashes and ends up on that line.
And I dont know what I'm doing wrong, or what can cause it.
I whould like to know what could make this
"IASetVertexBuffers(0, 1, &m_vertexBuffer, &stride, &offset);"
crash
First of all, Make sure you have initialized DirectX properly. If you have done that and the ID3D11DeviceContext works properly I use this folowing code.
MyStructure:
struct D3D11TextureVertexType
{
XMFLOAT3 Position;
XMFLOAT2 TX;
};
Part of my Function that uses deviceContext->IASetVertexBuffers..
hr = m_pd3dImmediateContext->Map(MyID3D11Buffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
if (FAILED(hr)) return hr;
pData = (D3D11TextureVertexType*)mappedResource.pData;
memcpy(pData, MYOBJECTVERTICES/*this is D3D11TextureVertexType*/, sizeof(D3D11TextureVertexType) * VertexCount);
m_pd3dImmediateContext->Unmap(MyID3D11Buffer, 0);
stride = sizeof(D3D11TextureVertexType);
offset = 0;
m_pd3dImmediateContext->IASetVertexBuffers(0, 1, &MyID3D11Buffer, &stride, &offset);
m_pd3dImmediateContext->IASetIndexBuffer(m_AdjRectangleIBuffer, DXGI_FORMAT_R32_UINT, 0);
m_pd3dImmediateContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
result = m_TextureShader->Render(m_pd3dImmediateContext, 6, worldMatrix, viewMatrix, orthoMatrix, m_Textures[Q.textureID]->pSRV); if (!result)
{
return S_FALSE;
}
So I've found a lot of code samples, guides, and answers on SO about drawing an image to a layered window. I've tried using pure HBITMAPS and the WIC libs to draw, and now I'm on to GDI+ to draw (which is much simpler and is seemingly easier to use, and thus far it has solved a lot of errors that were caused by faulty WIC code).
I'm currently stuck on UpdateLayeredWindow. No matter what I try I can't get it to work. Right now, it's returning 87, or ERROR_INVALID_PARAMETER. The question is, which one is incorrect? I'm stumped! The below code seems to be the solution other than the fact that UpdateLayeredWindow is refusing to work.
What am I doing wrong?
Here is the code that sets up the HDC/bitmap information/graphics object.
// Create DC
_oGrphInf.canvasHDC = GetDC(_hwndWindow);
// Create drawing 'canvas'
_oGrphInf.lpBits = NULL;
_oGrphInf.bmpCanvas = CreateDIBSection(_oGrphInf.canvasHDC,
&_oGrphInf.bmpWinInformation, DIB_RGB_COLORS,
&_oGrphInf.lpBits, NULL, 0);
// Create graphics object
_oGrphInf.graphics = new Gdiplus::Graphics(_oGrphInf.canvasHDC);
The above works fine - I step through it and all of the pointers work.
And here is the method that draws the PNG.
void Splash::DrawPNG(PNG* lpPNG, int x, int y)
{
LOGD("Drawing bitmap!");
HDC hdcMem = CreateCompatibleDC(_oGrphInf.canvasHDC);
// Select
HBITMAP bmpOld = (HBITMAP)SelectObject(hdcMem, _oGrphInf.bmpCanvas);
Gdiplus::Color trans(0, 0, 0, 0);
_oGrphInf.graphics->Clear(trans);
_oGrphInf.graphics->DrawImage(lpPNG->GetImage(), x, y);
_oGrphInf.graphics->Flush();
SIZE szSize = {_oGrphInf.bmpWinInformation.bmiHeader.biWidth,
_oGrphInf.bmpWinInformation.bmiHeader.biHeight};
// Setup drawing location
POINT ptLoc = {0, 0};
POINT ptSrc = {0, 0};
// Set up alpha blending
BLENDFUNCTION blend = {0};
blend.BlendOp = AC_SRC_OVER;
blend.SourceConstantAlpha = 255;
blend.AlphaFormat = AC_SRC_ALPHA;
blend.BlendFlags = 0;
// Update
if(UpdateLayeredWindow(_hwndWindow, _oGrphInf.canvasHDC, &ptLoc,
&szSize, hdcMem, &ptSrc,
(COLORREF)RGB(0, 0, 0),
&blend, ULW_ALPHA) == FALSE)
LOGE("Could not update layered window: %u", GetLastError());
// Delete temp objects
SelectObject(hdcMem, bmpOld);
DeleteObject(hdcMem);
DeleteDC(hdcMem);
}
Pulling my hair out! Help?
EDIT: I just decided to re-write the call to UpdateLayeredWindow function, which solved the incorrect parameter issue. Here is what I came up with. However, it still does not work. What am I doing wrong?
UpdateLayeredWindow(_hwndWindow, _oGrphInf.canvasHDC,
NULL, NULL, hdcMem, &ptLoc,
RGB(0, 0, 0), &blend, ULW_ALPHA)
For alpha information to be preserved in drawing operations, you have to make your Graphics object based on a memory-backed Bitmap object, not an HDC, and of course your Bitmap needs to be in a format with an alpha channel.
You'll need to use this Bitmap constructor: http://msdn.microsoft.com/en-us/library/ms536315%28v=vs.85%29.aspx
Just give that a stride of 0, a pointer to your DIB's bits, and PixelFormat32bppPARGB.
Then use Graphics::FromImage to create your Graphics object.
I've never used UpdateLayeredWindow, so I can't verify that that side of it is correct.