5 replies to this topic

[sunnysideup]

I've programmed a simple little app that renders a triangle to the screen. Whenever I maximize the screen or drag the resize bars the triangle squishes and stretches along with the window. I wrote a function that uses IDXGISwapChain::ResizeBuffers() to resize the swap chain's buffers in response to a WM_SIZE message but it doesn't seem to fix the distortion. Am I misunderstanding the purpose of IDXGISwapChain::ResizeBuffers()?

Here's my OnResize() function. I'm either doing something wrong, or ResizeBuffers doesn't do what I though it did. Sorry if this is a dumb question

[source lang="cpp"]HRESULT OnResize(LPARAM lParam){ g_pImmediateContext->OMSetRenderTargets(0, 0, 0); // Release any extraneous instances of swap chain's buffers. The render // target view typically holds references to swap chain's buffers. g_pRenderTargetView->Release(); UINT width = LOWORD(lParam); UINT height = HIWORD(lParam); // Resize swap chain's buffers. HRESULT hr = g_pSwapChain->ResizeBuffers(1, width, height, DXGI_FORMAT_R8G8B8A8_UNORM, 0);   if(FAILED(hr)) { MessageBox(NULL, "[ERROR] Failed to resize buffers.\nOnResize() in rederer.cpp", "ERROR", MB_ICONERROR | MB_OK); return hr; } // Get buffer and create render target view. ID3D11Texture2D* pBackBuffer = nullptr; hr = g_pSwapChain->GetBuffer(0, __uuidof(ID3D11Texture2D), (void**)&pBackBuffer); if(FAILED(hr)) { MessageBox(NULL, "[ERROR] Failed to get back buffer.\nOnResize() in renderer.cpp", "ERROR", MB_ICONERROR | MB_OK); return hr; } hr = g_pD3DDevice->CreateRenderTargetView(pBackBuffer, NULL, &g_pRenderTargetView); pBackBuffer->Release(); if(FAILED(hr)) { MessageBox(NULL, "[ERROR] Failed to create render target view." "\nOnResize() in renderer.cpp", "ERROR", MB_ICONERROR | MB_OK); return hr; } g_pImmediateContext->OMSetRenderTargets(1, &g_pRenderTargetView, NULL); // Set up viewport. D3D11_VIEWPORT vp; vp.Width = (float)width; vp.Height = (float)height; vp.MinDepth = 0.0f; vp.MaxDepth = 1.0f; vp.TopLeftX = 0; vp.TopLeftY = 0; g_pImmediateContext->RSSetViewports(1, &vp); return S_OK;}[/source]


And here's the little snippet inside of WndProc() where I call it.

[source lang="cpp"]case WM_SIZE:  if(g_pSwapChain)  {   OnResize(lParam);  }  return 0;[/source]


Thanks for the help.

[sunnysideup]

Eeek. It doesn't look like the code hilighting came out right. Sorry about that guys :/

[sunnysideup]

I think I might be able to better clarify what I'm getting at. I've rendered an equalateral trianlge with vertices (0.0, 0.5, 0.5), (0.5, -0.5, 0.5), and (-0.5, -0.5, 0.5) without any projection transformation. How can I make it so that the the triangle remains equalateral whenever the user resizes the window? Isn't this what ResizeBuffers() is supposed to do or would this require a projection transformation or something like that?

Edited by sunnysideup, 06 November 2012 - 01:08 AM.

[NumberXaero]

Are you updating your projection matrix?

Edited by NumberXaero, 06 November 2012 - 02:00 AM.

[sunnysideup]

Are you updating your projection matrix?

There's no projection transformation. This is actually just a slightly modified version of the triangle tutorial in the SDK docs. I (perhaps stupidly) thought that resizing the swap chain's buffers would cause the triangle to retain it's shape when the window is resized. I'm guessing that would require a projection transformation? If I wanted to make a 2D game for example where the sprites were rendered to a square, would I need to do a projection transformation on the square. Pardon my ignorance.

Edited by sunnysideup, 06 November 2012 - 02:20 AM.

[Gavin Williams]

I'd say you are working in clip space, which is -1 to 1 in x & y, and that space will stretch. So you will need to use world / view / projection matrices for getting everything the way you want it.