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Dirext3D 11 bloom/glow/blur and textures

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catman77    104

Can someone be kind enough to walk me through the (basic) steps in applying a glow/bloom/blur to a sphere? I'm using Visual C++ 2012 and DirectX 11. I have a created a sphere(s) and applied a texture to it and it renders fine, but I would like to apply bloom to it. Using ideas from and other sites I have managed to apply blur, but it only blurs the texture on the sphere, not outside the sphere. I guess this is to expected since there is currently no way of knowing which pixels are adjacent to the sphere, since it's drawn to the backbuffer.
From what I can read around the web, mostly forums, one has to create a quad on a separate texture, draw the sphere on that quad/texture to create a bloom around the sphere. There are other spheres in my program that shouldn't have a bloom applied to.

I lack an understanding on how one can use an "off-screen" texture and, draw a sphere with texture, on to that texture and then combine it with what is already on the back buffer before calling swapchain->Present(0, 0);

How does one make the quad to fill the whole screen? From what I can understand, one has to use devcon->OMSetRenderTargets to switch between the backbuffer and the render texture, but the whole procedure is something I do not currently understand. The code at is great but not so good from a tutorial perspective, so many classes with so many function calls it's very hard to follow.



This is how I create my back buffer:

	// create a struct to hold information about the swap chain

	// clear out the struct for use
	ZeroMemory(&scd, sizeof(DXGI_SWAP_CHAIN_DESC));

	// fill the swap chain description struct
	scd.BufferCount = 1;                                   // one back buffer
	scd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;    // use 32-bit color
	scd.BufferDesc.Width = SCREEN_WIDTH;                   // set the back buffer width
	scd.BufferDesc.Height = SCREEN_HEIGHT;                 // set the back buffer height
	scd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;     // how swap chain is to be used
	scd.OutputWindow = hWnd;                               // the window to be used
	scd.SampleDesc.Count = 4;                              // how many multisamples
	scd.Windowed = TRUE;                                   // windowed/full-screen mode
	scd.Flags = DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH;    // allow full-screen switching

	// create a device, device context and swap chain using the information in the scd struct

	// create the depth buffer texture
	ZeroMemory(&texd, sizeof(texd));

	texd.Width = SCREEN_WIDTH;
	texd.Height = SCREEN_HEIGHT;
	texd.ArraySize = 1;
	texd.MipLevels = 1;
	texd.SampleDesc.Count = 4;
	texd.Format = DXGI_FORMAT_D32_FLOAT;
	texd.BindFlags = D3D11_BIND_DEPTH_STENCIL;

	ID3D11Texture2D *pDepthBuffer;
	dev->CreateTexture2D(&texd, NULL, &pDepthBuffer);

	// create the depth buffer
	ZeroMemory(&dsvd, sizeof(dsvd));

	dsvd.Format = DXGI_FORMAT_D32_FLOAT;
	dsvd.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2DMS;

	dev->CreateDepthStencilView(pDepthBuffer, &dsvd, &zbuffer);

	// get the address of the back buffer
	ID3D11Texture2D *pBackBuffer;
	swapchain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer);

	// use the back buffer address to create the render target
	dev->CreateRenderTargetView(pBackBuffer, NULL, &backbuffer);

	// set the render target as the back buffer
	devcon->OMSetRenderTargets(1, &backbuffer, zbuffer);

	// Set the viewport
	D3D11_VIEWPORT viewport;
	ZeroMemory(&viewport, sizeof(D3D11_VIEWPORT));

	viewport.TopLeftX = 0;    // set the left to 0
	viewport.TopLeftY = 0;    // set the top to 0
	viewport.Width = SCREEN_WIDTH;    // set the width to the window's width
	viewport.Height = SCREEN_HEIGHT;    // set the height to the window's height
	viewport.MinDepth = 0;    // the closest an object can be on the depth buffer is 0.0
	viewport.MaxDepth = 1;    // the farthest an object can be on the depth buffer is 1.0

	devcon->RSSetViewports(1, &viewport);

Load my texture:

	D3DX11CreateShaderResourceViewFromFile(dev,        // the Direct3D device
		L"sun.png",    // load  in the local folder
		NULL,           // no additional information
		NULL,           // no multithreading
		&pTextureSun,      // address of the shader-resource-view
		NULL);          // no multithreading

Create the texture to render to:

	D3D11_TEXTURE2D_DESC textureDesc;
	D3D11_RENDER_TARGET_VIEW_DESC renderTargetViewDesc;
	D3D11_SHADER_RESOURCE_VIEW_DESC shaderResourceViewDesc;

	// Initialize the render target texture description.
	ZeroMemory(&textureDesc, sizeof(textureDesc));

	// Setup the render target texture description.
	textureDesc.Width = SCREEN_WIDTH;
	textureDesc.Height = SCREEN_HEIGHT;
	textureDesc.MipLevels = 1;
	textureDesc.ArraySize = 1;
	textureDesc.Format = DXGI_FORMAT_R32G32B32A32_FLOAT;
	textureDesc.SampleDesc.Count = 1;
	textureDesc.Usage = D3D11_USAGE_DEFAULT;
	textureDesc.CPUAccessFlags = 0;
    textureDesc.MiscFlags = 0;
	ID3D11Texture2D *renderTargetTexture;
	swapchain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&renderTargetTexture);
	dev->CreateTexture2D(&textureDesc, NULL, &renderTargetTexture);
	// Setup the description of the render target view.
	renderTargetViewDesc.Format = textureDesc.Format;
	renderTargetViewDesc.ViewDimension = D3D11_RTV_DIMENSION_TEXTURE2D;
	renderTargetViewDesc.Texture2D.MipSlice = 0;

	dev->CreateRenderTargetView(renderTargetTexture, &renderTargetViewDesc, &renderTargetView);

	// Setup the description of the shader resource view.
	shaderResourceViewDesc.Format = textureDesc.Format;
	shaderResourceViewDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
	shaderResourceViewDesc.Texture2D.MostDetailedMip = 0;
	shaderResourceViewDesc.Texture2D.MipLevels = 1;

	// Create the shader resource view.
	dev->CreateShaderResourceView(renderTargetTexture, &shaderResourceViewDesc, &shaderResourceView);

Thanks for reading.

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