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DX11 DX11 - Preparing for Release Mode

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Hi guys,

 

a few weeks ago my computer went completely into a Blue Screen of Death, with the WHEA error (Windows Hardware Error Architecture, [that's bad]), but luckily, I kept a backup of everything.

 

Now as I'm writing, I'm porting my project to the new pc, and the repair shop managed to create a complete backup, but they switched two hard drives, so D:\ was now F:, which messed up some stuff. dry.png

 

Now, To the POINT!

 

I re-installed Visual Studio (IDE), but it somehow didn't support the debug version of the runtime c++, which I find wierd (notes obtained from external sources), so now I'm trying to make my Project work in the release mode, which is quite a pain in the ass... laugh.png

 

I managed to make it run, but at a certain point (found that 'point' by the way), it crashes the NVIDIA Kernel Driver, which isn't exactly what was supposed to happen, unless I was drunk making my application, but I don't remember so. huh.png

 

The crash seems to occur when I send some shader resources to the pixel shader, as so:

devcon->PSSetShaderResources(3, 1, &random);

The resource is created in a class called C3DEngineObject, which a member called PostProcess, which has a function called Render.

 

The function render has a paremeter called random, as seen above, but the wierd thing is that in debugging mode (in the dead pc), it worked fine! Perfect actually!

 

So why fail now? Does it have something to do with the release mode?

 

So my real question is, how can sending a resource to the pixel shader cause a Graphics Driver crash? ohmy.png

 

Thanks! 

 

PS. If you need more, please say so.

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I re-installed Visual Studio (IDE), but it somehow didn't support the debug version of the runtime c++, which I find wierd (notes obtained from external sources), so now I'm trying to make my Project work in the release mode, which is quite a pain in the ass... 

 

So your project can't compile and run in debug mode right now?

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Do you mean it doesn't cmpile in debug, or device creation fails when using the debug dx runtimes? If you mean the latter, and are using vs2010, you need to install the remove vs2012 debugging tools (free), and it will work again.

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It compiles fine, but when I run (in debug mode), this message arrives (From memory): The dll MMSVCP100d.dll could not be found. 

 

PS. I'm using VS 2012

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looks like the debug version has dependencies on a dll that's no longer installed. a Google search should tell you what package its from (earlier version of VS, some MS runtime of some sort, etc). then all you have to do is get the dll.

 

long ago i learned that games can behave differently in debug a release mode. stuff that works in debug doesn't in release (string pooling in my case - a long time ago). so i don't use debug at all anymore. haven't for years. i start a new project, set it to release mode, set my compiler options, and then code away with no worries.

 

when i need hardcore debugging i use trace variables and hi-rez timers. used to use trace files for debugging graphics when you can't display stuff on the screen easily, but i have't even needed that in years either. i think the last time i used trace files was when i was writing my own 3d p-correct t-mapped poly engine between the time that MS bought Brender (when i was about to license a copy) and the time they released it as DirectX v1.0 (with no retained mode!).

 

if you can live without the features of debug mode, you may want to just switch to release mode and be done with it. in the long run, debug mode is irrelevant to the final version of the game, its just a crutch to help get you there.

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Working in release mode may be a bit difficult especially if you're working on an experimental or unstable system. Because of the code optimizations, it is almost impossible to debug your code unless you disable those optimization in your project properties. The best way is to probably make sure you have a debug and release version of your application from time to time to make sure everything is working fine and immediately spot any problems that may cause a bigger problem later on.

 

I have encountered problems similar to that where it would run completely fine in debug but crash in release mode 3-4 times many years ago. Sadly i don't exactly remember what it was. But mine i think was more or uninitialized variables than missing libraries and or dlls.

 

@Migi0027: I don't really have any solutions but a few simple questions comes into mind:

 

* Are you sure your device context is a valid pointer? Your device context may be valid in debug mode but you might have a different setting in creating your device context in release mode.

 

* Is there a possibility of memory leaks? Are you constantly creating graphics resources and possibly not properly releasing or leaking them? I would sometimes do this and feel really stupid after realizing how simple the problem was but insanely hard to track down.

 

* If you're hundred percent sure your code should work then there may be a bug with your graphics driver. Try updating your graphics driver to the latest one.

 

* Based on your original post, i'm going to assume you've managed to recover the OS and use that existing OS for your new computer. I normally don't trust my OS after having a problem something like yours. Maybe some of your libraries were deleted or corrupted. Maybe try just to do a fresh install and see if that would work?

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 Norman: I agree with the information you gave, also because I have previous experience where the debugger automatically initialized variables for me, which, as in your case, was very hard to track down.

 

Brent: One very important note that you told me (which I am going to experiment with), is to disable code optimization, just for testing, to track down the issue in a simpler manner.

 

Your Questions:

  1. I'm not sure how a device context can be created differently based on the mode, please tell me how.
  2. I actually haven't paid much attention in my code to this, so thanks for reminding me!
  3. I don't believe that that's the case, but I'll keep that in mind.
  4. I'll keep that in mind, but that will be my last decision.
Edited by Migi0027

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Ok, now I've figured out that it doesn't only crash in that function, but also when sending the constant buffers wacko.png

 

Is there a difference in how you initialize directx in debug and release mode?

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When you create your device context the D3D11CreateDevice(...) has a parameter that accepts a creation flag. I'm not really doing anything special but adding an extra flag whenever i'm in debug mode.

UINT createFlags = 0;
...

if ( pDesc->bDebug )
	createFlags |= D3D11_CREATE_DEVICE_DEBUG;
...

Having that flag, D3D gives me some additional debug info whenever there is something wrong or any warning messages that i may have. Try doing that in release mode and see if anything unusual shows up in visual studio's output window.

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That flag was removed when porting to the new pc.

 

Do you have any idea how you can get the inside information on what wen't wrong? If possible.

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If useful, here's how I initialize Directx:

#pragma region NativeDirectx
	HRESULT result;
	IDXGIFactory* factory;
	IDXGIAdapter* adapter;
	IDXGIOutput* adapterOutput;
	unsigned int numModes, i, numerator, denominator, stringLength;
	DXGI_MODE_DESC* displayModeList;
	DXGI_ADAPTER_DESC adapterDesc;
	int error;
	DXGI_SWAP_CHAIN_DESC swapChainDesc;
	D3D_FEATURE_LEVEL featureLevel;
	ID3D11Texture2D* backBufferPtr;
	D3D11_TEXTURE2D_DESC depthBufferDesc;
	D3D11_DEPTH_STENCIL_DESC depthStencilDesc;
	D3D11_DEPTH_STENCIL_VIEW_DESC depthStencilViewDesc;
	D3D11_RASTERIZER_DESC rasterDesc;
	D3D11_VIEWPORT viewport;
	float fieldOfView, screenAspect;


	// Store the vsync setting.
	bool m_vsync_enabled = false;

	// Create a DirectX graphics interface factory.
	result = CreateDXGIFactory(__uuidof(IDXGIFactory), (void**)&factory);
	if(FAILED(result))
	{
		CE_ERROR("Error in creating CESDK", "FATAL ERROR");
	}

	// Use the factory to create an adapter for the primary graphics interface (video card).
	result = factory->EnumAdapters(0, &adapter);
	if(FAILED(result))
	{
		CE_ERROR("Error in creating CESDK", "FATAL ERROR");
	}

	// Enumerate the primary adapter output (monitor).
	result = adapter->EnumOutputs(0, &adapterOutput);
	if(FAILED(result))
	{
		CE_ERROR("Error in creating CESDK", "FATAL ERROR");
	}

	// Get the number of modes that fit the DXGI_FORMAT_R8G8B8A8_UNORM display format for the adapter output (monitor).
	result = adapterOutput->GetDisplayModeList(DXGI_FORMAT_R8G8B8A8_UNORM, DXGI_ENUM_MODES_INTERLACED, &numModes, NULL);
	if(FAILED(result))
	{
		CE_ERROR("Error in creating CESDK", "FATAL ERROR");
	}

	// Create a list to hold all the possible display modes for this monitor/video card combination.
	displayModeList = new DXGI_MODE_DESC[numModes];
	if(!displayModeList)
	{
		CE_ERROR("Error in creating CESDK", "FATAL ERROR");
	}

	// Now fill the display mode list structures.
	result = adapterOutput->GetDisplayModeList(DXGI_FORMAT_R8G8B8A8_UNORM, DXGI_ENUM_MODES_INTERLACED, &numModes, displayModeList);
	if(FAILED(result))
	{
		CE_ERROR("Error in creating CESDK", "FATAL ERROR");
	}

	// Now go through all the display modes and find the one that matches the screen width and height.
	// When a match is found store the numerator and denominator of the refresh rate for that monitor.
	for(i=0; i<numModes; i++)
	{
		if(displayModeList[i].Width == (unsigned int)sw)
		{
			if(displayModeList[i].Height == (unsigned int)sh)
			{
				numerator = displayModeList[i].RefreshRate.Numerator;
				denominator = displayModeList[i].RefreshRate.Denominator;
			}
		}
	}

	// Get the adapter (video card) description.
	result = adapter->GetDesc(&adapterDesc);
	if(FAILED(result))
	{
		CE_ERROR("Error in creating CESDK", "FATAL ERROR");
	}

	// Store the dedicated video card memory in megabytes.
	m_videoCardMemory = (int)(adapterDesc.DedicatedVideoMemory / 1024 / 1024);

	// Convert the name of the video card to a character array and store it.
	error = wcstombs_s(&stringLength, m_videoCardDescription, 128, adapterDesc.Description, 128);
	if(error != 0)
	{
		CE_ERROR("Error in creating CESDK", "FATAL ERROR");
	}

	// Release the display mode list.
	delete [] displayModeList;
	displayModeList = 0;

	// Release the adapter output.
	adapterOutput->Release();
	adapterOutput = 0;

	// Release the adapter.
	adapter->Release();
	adapter = 0;

	// Release the factory.
	factory->Release();
	factory = 0;

	// Initialize the swap chain description.
	ZeroMemory(&swapChainDesc, sizeof(swapChainDesc));

	// Set to a single back buffer.
	swapChainDesc.BufferCount = 1;

	// Set the width and height of the back buffer.
	swapChainDesc.BufferDesc.Width = sw;
	swapChainDesc.BufferDesc.Height = sh;

	// Set regular 32-bit surface for the back buffer.
	swapChainDesc.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;

	// Set the refresh rate of the back buffer.
	if(m_vsync_enabled)
	{
		swapChainDesc.BufferDesc.RefreshRate.Numerator = numerator;
		swapChainDesc.BufferDesc.RefreshRate.Denominator = denominator;
	}
	else
	{
		swapChainDesc.BufferDesc.RefreshRate.Numerator = 0;
		swapChainDesc.BufferDesc.RefreshRate.Denominator = 1;
	}

	// Set the usage of the back buffer.
	swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;

	// Set the handle for the window to render to.
	swapChainDesc.OutputWindow = hWnd;

	// Turn multi sampling off.
	swapChainDesc.SampleDesc.Count = 1;
	swapChainDesc.SampleDesc.Quality = 0;

	// Set to full screen or windowed mode.
	if(windowed)
	{
		swapChainDesc.Windowed = true;
	}
	else
	{
		swapChainDesc.Windowed = false;
	}

	// Set the scan line ordering and scaling to unspecified.
	swapChainDesc.BufferDesc.ScanlineOrdering = DXGI_MODE_SCANLINE_ORDER_UNSPECIFIED;
	swapChainDesc.BufferDesc.Scaling = DXGI_MODE_SCALING_UNSPECIFIED;

	// Discard the back buffer contents after presenting.
	swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;

	// Don't set the advanced flags.
	swapChainDesc.Flags = 0;

	// Set the feature level to DirectX 11.
	featureLevel = D3D_FEATURE_LEVEL_11_0;

	// Create the swap chain, Direct3D device, and Direct3D device context.
	result = D3D11CreateDeviceAndSwapChain(NULL, D3D_DRIVER_TYPE_HARDWARE, NULL, 0, &featureLevel, 1, 
		D3D11_SDK_VERSION, &swapChainDesc, &swapchain, &dev, NULL, &devcon);
	if(FAILED(result))
	{
		CE_ERROR("Error in creating CESDK", "FATAL ERROR");
	}

	ZeroMemory(&texd, sizeof(texd));

	texd.Width = sw;
	texd.Height = sh;
	texd.ArraySize = 1;
	texd.MipLevels = 1;
	texd.SampleDesc.Count = 1;	
	texd.SampleDesc.Quality = 0;
	texd.Format = DXGI_FORMAT_D32_FLOAT;
	texd.BindFlags = D3D11_BIND_DEPTH_STENCIL;

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

	ZeroMemory(&dsvd, sizeof(dsvd));

	dsvd.Format = DXGI_FORMAT_D32_FLOAT;
	dsvd.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;

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

	if (pDepthBuffer != nullptr)
		pDepthBuffer->Release();

	// 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);

	if (pBackBuffer != nullptr)
		pBackBuffer->Release();

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


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

	viewport.TopLeftX = 0;    // set the left to 0
	viewport.TopLeftY = 0;    // set the top to 0
	viewport.Width = sw;    // set the width to the window's width
	viewport.Height = sh;    // 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);
	#pragma endregion

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A quick look at your code seems to have enough security checks to catch if there's anything wrong with the device creation and setup process. I'm afraid i have no more suggestions to your problem. sad.png

 

The worse bug that i can actually think of is if somewhere in your code is doing a buffer overflow and overwrites your graphics device context. I'm not sure if this can be detected with the use of _CrtSetDbgFlag() and _CrtDumpMemoryLeaks() but with those security checks that you have above i doubt you're doing this mistake somewhere in your code.

 

I hope someone here can help you out and i'm also eager to learn what exactly is the problem with your code and its fix.

Edited by BrentChua

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Do you think using a copy pasted DX11 SDK folder could cause this problem?

 

(I didn't download the sdk again... too lazy... laugh.png )

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I'm not sure... I don't exactly know the exact content of the SDK installer but i'm guessing besides the API it installs some additional DX runtimes in your systems folder as well. That may be a reason to have a crash like a wrong version of the runtime libraries? But then again it should cause an error message just before your app runs instead of having a weird crash.

 

Is the crash a BSOD?

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It even fails when sending the shader: (Though, here it doesn't crash, but it sends an exception [ Access violation reading location 0xBAADF015. ] )

 

devcon->VSSetShader(pVS, 0, 0);

 

, and the shader is created and validated, no errors!

 

This is really wierd.

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Ok, just tweaking, looking and stuff. 

 

And it finally ran! (... in debug mode happy.png ) 

 

But black...

 

So I ran PIX, and found out that the full screen quad was being rendered, with color. So looking over the code again, the stencils weren't being restored properly.

 

But I guess the next goal is to make it run in Release Mode, but for now, I'm just going to play around a bit.

 

Just one question: Can Directx 11 with c++ corrupt the system, or cause BSOD, even if the system is healthy?

 

Thanks for your help! wink.png

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Ok, just tweaking, looking and stuff. 

 

And it finally ran! (... in debug mode happy.png ) 

 

But black...

 

So I ran PIX, and found out that the full screen quad was being rendered, with color. So looking over the code again, the stencils weren't being restored properly.

 

But I guess the next goal is to make it run in Release Mode, but for now, I'm just going to play around a bit.

 

Just one question: Can Directx 11 with c++ corrupt the system, or cause BSOD, even if the system is healthy?

 

Thanks for your help! wink.png

The code itself shouldn't cause BSOD or other "enjoyable" Windows hangs and crashes... 

Any crashes/hangs/BSOD/nuclear disaster/celin dion song/zombie pandemic/etc. caused by a direct3d application are related with the quality of the video drivers only; with the introduction of WDDM (since Vista), most of problems appear as driver crashes with reset to desktop (or just with some seconds of hangs without the application crash if you are lucky)...

Edited by Alessio1989

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Ok, just tweaking, looking and stuff. 

 

And it finally ran! (... in debug mode happy.png ) 

 

But black...

 

So I ran PIX, and found out that the full screen quad was being rendered, with color. So looking over the code again, the stencils weren't being restored properly.

 

But I guess the next goal is to make it run in Release Mode, but for now, I'm just going to play around a bit.

 

Just one question: Can Directx 11 with c++ corrupt the system, or cause BSOD, even if the system is healthy?

 

Thanks for your help! wink.png

The code itself shouldn't cause BSOD or other "enjoyable" Windows hangs and crashes... 

Any crashes/hangs/BSOD/nuclear disaster/celin dion song/zombie pandemic/etc. caused by a direct3d application are related with the quality of the video drivers only; with the introduction of WDDM (since Vista), most of problems appear as driver crashes with reset to desktop (or just with some seconds of hangs without the application crash if you are lucky)...

 

 

Phew.. happy.png

 

Ok, thanks!

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      Device resources are created by the render device. The two main resource types are buffers, which represent linear memory, and textures, which use memory layouts optimized for fast filtering. Graphics APIs usually have a native object that represents linear buffer. Diligent Engine uses IBuffer interface as an abstraction for a native buffer. To create a buffer, one needs to populate BufferDesc structure and call IRenderDevice::CreateBuffer() method as in the following example:
      BufferDesc BuffDesc; BufferDesc.Name = "Uniform buffer"; BuffDesc.BindFlags = BIND_UNIFORM_BUFFER; BuffDesc.Usage = USAGE_DYNAMIC; BuffDesc.uiSizeInBytes = sizeof(ShaderConstants); BuffDesc.CPUAccessFlags = CPU_ACCESS_WRITE; m_pDevice->CreateBuffer( BuffDesc, BufferData(), &m_pConstantBuffer ); While there is usually just one buffer object, different APIs use very different approaches to represent textures. For instance, in Direct3D11, there are ID3D11Texture1D, ID3D11Texture2D, and ID3D11Texture3D objects. In OpenGL, there is individual object for every texture dimension (1D, 2D, 3D, Cube), which may be a texture array, which may also be multisampled (i.e. GL_TEXTURE_2D_MULTISAMPLE_ARRAY). As a result there are nine different GL texture types that Diligent Engine may create under the hood. In Direct3D12, there is only one resource interface. Diligent Engine hides all these details in ITexture interface. There is only one  IRenderDevice::CreateTexture() method that is capable of creating all texture types. Dimension, format, array size and all other parameters are specified by the members of the TextureDesc structure:
      TextureDesc TexDesc; TexDesc.Name = "My texture 2D"; TexDesc.Type = TEXTURE_TYPE_2D; TexDesc.Width = 1024; TexDesc.Height = 1024; TexDesc.Format = TEX_FORMAT_RGBA8_UNORM; TexDesc.Usage = USAGE_DEFAULT; TexDesc.BindFlags = BIND_SHADER_RESOURCE | BIND_RENDER_TARGET | BIND_UNORDERED_ACCESS; TexDesc.Name = "Sample 2D Texture"; m_pRenderDevice->CreateTexture( TexDesc, TextureData(), &m_pTestTex ); If native API supports multithreaded resource creation, textures and buffers can be created by multiple threads simultaneously.
      Interoperability with native API provides access to the native buffer/texture objects and also allows creating Diligent Engine objects from native handles. It allows applications seamlessly integrate native API-specific code with Diligent Engine.
      Next-generation APIs allow fine level-control over how resources are allocated. Diligent Engine does not currently expose this functionality, but it can be added by implementing IResourceAllocator interface that encapsulates specifics of resource allocation and providing this interface to CreateBuffer() or CreateTexture() methods. If null is provided, default allocator should be used.
      Initializing the Pipeline State
      As it was mentioned earlier, Diligent Engine follows next-gen APIs to configure the graphics/compute pipeline. One big Pipelines State Object (PSO) encompasses all required states (all shader stages, input layout description, depth stencil, rasterizer and blend state descriptions etc.). This approach maps directly to Direct3D12/Vulkan, but is also beneficial for older APIs as it eliminates pipeline misconfiguration errors. With many individual calls tweaking various GPU pipeline settings it is very easy to forget to set one of the states or assume the stage is already properly configured when in fact it is not. Using pipeline state object helps avoid these problems as all stages are configured at once.
      Creating Shaders
      While in earlier APIs shaders were bound separately, in the next-generation APIs as well as in Diligent Engine shaders are part of the pipeline state object. The biggest challenge when authoring shaders is that Direct3D and OpenGL/Vulkan use different shader languages (while Apple uses yet another language in their Metal API). Maintaining two versions of every shader is not an option for real applications and Diligent Engine implements shader source code converter that allows shaders authored in HLSL to be translated to GLSL. To create a shader, one needs to populate ShaderCreationAttribs structure. SourceLanguage member of this structure tells the system which language the shader is authored in:
      SHADER_SOURCE_LANGUAGE_DEFAULT - The shader source language matches the underlying graphics API: HLSL for Direct3D11/Direct3D12 mode, and GLSL for OpenGL and OpenGLES modes. SHADER_SOURCE_LANGUAGE_HLSL - The shader source is in HLSL. For OpenGL and OpenGLES modes, the source code will be converted to GLSL. SHADER_SOURCE_LANGUAGE_GLSL - The shader source is in GLSL. There is currently no GLSL to HLSL converter, so this value should only be used for OpenGL and OpenGLES modes. There are two ways to provide the shader source code. The first way is to use Source member. The second way is to provide a file path in FilePath member. Since the engine is entirely decoupled from the platform and the host file system is platform-dependent, the structure exposes pShaderSourceStreamFactory member that is intended to provide the engine access to the file system. If FilePath is provided, shader source factory must also be provided. If the shader source contains any #include directives, the source stream factory will also be used to load these files. The engine provides default implementation for every supported platform that should be sufficient in most cases. Custom implementation can be provided when needed.
      When sampling a texture in a shader, the texture sampler was traditionally specified as separate object that was bound to the pipeline at run time or set as part of the texture object itself. However, in most cases it is known beforehand what kind of sampler will be used in the shader. Next-generation APIs expose new type of sampler called static sampler that can be initialized directly in the pipeline state. Diligent Engine exposes this functionality: when creating a shader, textures can be assigned static samplers. If static sampler is assigned, it will always be used instead of the one initialized in the texture shader resource view. To initialize static samplers, prepare an array of StaticSamplerDesc structures and initialize StaticSamplers and NumStaticSamplers members. Static samplers are more efficient and it is highly recommended to use them whenever possible. On older APIs, static samplers are emulated via generic sampler objects.
      The following is an example of shader initialization:
      ShaderCreationAttribs Attrs; Attrs.Desc.Name = "MyPixelShader"; Attrs.FilePath = "MyShaderFile.fx"; Attrs.SearchDirectories = "shaders;shaders\\inc;"; Attrs.EntryPoint = "MyPixelShader"; Attrs.Desc.ShaderType = SHADER_TYPE_PIXEL; Attrs.SourceLanguage = SHADER_SOURCE_LANGUAGE_HLSL; BasicShaderSourceStreamFactory BasicSSSFactory(Attrs.SearchDirectories); Attrs.pShaderSourceStreamFactory = &BasicSSSFactory; ShaderVariableDesc ShaderVars[] = {     {"g_StaticTexture", SHADER_VARIABLE_TYPE_STATIC},     {"g_MutableTexture", SHADER_VARIABLE_TYPE_MUTABLE},     {"g_DynamicTexture", SHADER_VARIABLE_TYPE_DYNAMIC} }; Attrs.Desc.VariableDesc = ShaderVars; Attrs.Desc.NumVariables = _countof(ShaderVars); Attrs.Desc.DefaultVariableType = SHADER_VARIABLE_TYPE_STATIC; StaticSamplerDesc StaticSampler; StaticSampler.Desc.MinFilter = FILTER_TYPE_LINEAR; StaticSampler.Desc.MagFilter = FILTER_TYPE_LINEAR; StaticSampler.Desc.MipFilter = FILTER_TYPE_LINEAR; StaticSampler.TextureName = "g_MutableTexture"; Attrs.Desc.NumStaticSamplers = 1; Attrs.Desc.StaticSamplers = &StaticSampler; ShaderMacroHelper Macros; Macros.AddShaderMacro("USE_SHADOWS", 1); Macros.AddShaderMacro("NUM_SHADOW_SAMPLES", 4); Macros.Finalize(); Attrs.Macros = Macros; RefCntAutoPtr<IShader> pShader; m_pDevice->CreateShader( Attrs, &pShader );
      Creating the Pipeline State Object
      After all required shaders are created, the rest of the fields of the PipelineStateDesc structure provide depth-stencil, rasterizer, and blend state descriptions, the number and format of render targets, input layout format, etc. For instance, rasterizer state can be described as follows:
      PipelineStateDesc PSODesc; RasterizerStateDesc &RasterizerDesc = PSODesc.GraphicsPipeline.RasterizerDesc; RasterizerDesc.FillMode = FILL_MODE_SOLID; RasterizerDesc.CullMode = CULL_MODE_NONE; RasterizerDesc.FrontCounterClockwise = True; RasterizerDesc.ScissorEnable = True; RasterizerDesc.AntialiasedLineEnable = False; Depth-stencil and blend states are defined in a similar fashion.
      Another important thing that pipeline state object encompasses is the input layout description that defines how inputs to the vertex shader, which is the very first shader stage, should be read from the memory. Input layout may define several vertex streams that contain values of different formats and sizes:
      // Define input layout InputLayoutDesc &Layout = PSODesc.GraphicsPipeline.InputLayout; LayoutElement TextLayoutElems[] = {     LayoutElement( 0, 0, 3, VT_FLOAT32, False ),     LayoutElement( 1, 0, 4, VT_UINT8, True ),     LayoutElement( 2, 0, 2, VT_FLOAT32, False ), }; Layout.LayoutElements = TextLayoutElems; Layout.NumElements = _countof( TextLayoutElems ); Finally, pipeline state defines primitive topology type. When all required members are initialized, a pipeline state object can be created by IRenderDevice::CreatePipelineState() method:
      // Define shader and primitive topology PSODesc.GraphicsPipeline.PrimitiveTopologyType = PRIMITIVE_TOPOLOGY_TYPE_TRIANGLE; PSODesc.GraphicsPipeline.pVS = pVertexShader; PSODesc.GraphicsPipeline.pPS = pPixelShader; PSODesc.Name = "My pipeline state"; m_pDev->CreatePipelineState(PSODesc, &m_pPSO); When PSO object is bound to the pipeline, the engine invokes all API-specific commands to set all states specified by the object. In case of Direct3D12 this maps directly to setting the D3D12 PSO object. In case of Direct3D11, this involves setting individual state objects (such as rasterizer and blend states), shaders, input layout etc. In case of OpenGL, this requires a number of fine-grain state tweaking calls. Diligent Engine keeps track of currently bound states and only calls functions to update these states that have actually changed.
      Binding Shader Resources
      Direct3D11 and OpenGL utilize fine-grain resource binding models, where an application binds individual buffers and textures to certain shader or program resource binding slots. Direct3D12 uses a very different approach, where resource descriptors are grouped into tables, and an application can bind all resources in the table at once by setting the table in the command list. Resource binding model in Diligent Engine is designed to leverage this new method. It introduces a new object called shader resource binding that encapsulates all resource bindings required for all shaders in a certain pipeline state. It also introduces the classification of shader variables based on the frequency of expected change that helps the engine group them into tables under the hood:
      Static variables (SHADER_VARIABLE_TYPE_STATIC) are variables that are expected to be set only once. They may not be changed once a resource is bound to the variable. Such variables are intended to hold global constants such as camera attributes or global light attributes constant buffers. Mutable variables (SHADER_VARIABLE_TYPE_MUTABLE) define resources that are expected to change on a per-material frequency. Examples may include diffuse textures, normal maps etc. Dynamic variables (SHADER_VARIABLE_TYPE_DYNAMIC) are expected to change frequently and randomly. Shader variable type must be specified during shader creation by populating an array of ShaderVariableDesc structures and initializing ShaderCreationAttribs::Desc::VariableDesc and ShaderCreationAttribs::Desc::NumVariables members (see example of shader creation above).
      Static variables cannot be changed once a resource is bound to the variable. They are bound directly to the shader object. For instance, a shadow map texture is not expected to change after it is created, so it can be bound directly to the shader:
      PixelShader->GetShaderVariable( "g_tex2DShadowMap" )->Set( pShadowMapSRV ); Mutable and dynamic variables are bound via a new Shader Resource Binding object (SRB) that is created by the pipeline state (IPipelineState::CreateShaderResourceBinding()):
      m_pPSO->CreateShaderResourceBinding(&m_pSRB); Note that an SRB is only compatible with the pipeline state it was created from. SRB object inherits all static bindings from shaders in the pipeline, but is not allowed to change them.
      Mutable resources can only be set once for every instance of a shader resource binding. Such resources are intended to define specific material properties. For instance, a diffuse texture for a specific material is not expected to change once the material is defined and can be set right after the SRB object has been created:
      m_pSRB->GetVariable(SHADER_TYPE_PIXEL, "tex2DDiffuse")->Set(pDiffuseTexSRV); In some cases it is necessary to bind a new resource to a variable every time a draw command is invoked. Such variables should be labeled as dynamic, which will allow setting them multiple times through the same SRB object:
      m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "cbRandomAttribs")->Set(pRandomAttrsCB); Under the hood, the engine pre-allocates descriptor tables for static and mutable resources when an SRB objcet is created. Space for dynamic resources is dynamically allocated at run time. Static and mutable resources are thus more efficient and should be used whenever possible.
      As you can see, Diligent Engine does not expose low-level details of how resources are bound to shader variables. One reason for this is that these details are very different for various APIs. The other reason is that using low-level binding methods is extremely error-prone: it is very easy to forget to bind some resource, or bind incorrect resource such as bind a buffer to the variable that is in fact a texture, especially during shader development when everything changes fast. Diligent Engine instead relies on shader reflection system to automatically query the list of all shader variables. Grouping variables based on three types mentioned above allows the engine to create optimized layout and take heavy lifting of matching resources to API-specific resource location, register or descriptor in the table.
      This post gives more details about the resource binding model in Diligent Engine.
      Setting the Pipeline State and Committing Shader Resources
      Before any draw or compute command can be invoked, the pipeline state needs to be bound to the context:
      m_pContext->SetPipelineState(m_pPSO); Under the hood, the engine sets the internal PSO object in the command list or calls all the required native API functions to properly configure all pipeline stages.
      The next step is to bind all required shader resources to the GPU pipeline, which is accomplished by IDeviceContext::CommitShaderResources() method:
      m_pContext->CommitShaderResources(m_pSRB, COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES); The method takes a pointer to the shader resource binding object and makes all resources the object holds available for the shaders. In the case of D3D12, this only requires setting appropriate descriptor tables in the command list. For older APIs, this typically requires setting all resources individually.
      Next-generation APIs require the application to track the state of every resource and explicitly inform the system about all state transitions. For instance, if a texture was used as render target before, while the next draw command is going to use it as shader resource, a transition barrier needs to be executed. Diligent Engine does the heavy lifting of state tracking.  When CommitShaderResources() method is called with COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES flag, the engine commits and transitions resources to correct states at the same time. Note that transitioning resources does introduce some overhead. The engine tracks state of every resource and it will not issue the barrier if the state is already correct. But checking resource state is an overhead that can sometimes be avoided. The engine provides IDeviceContext::TransitionShaderResources() method that only transitions resources:
      m_pContext->TransitionShaderResources(m_pPSO, m_pSRB); In some scenarios it is more efficient to transition resources once and then only commit them.
      Invoking Draw Command
      The final step is to set states that are not part of the PSO, such as render targets, vertex and index buffers. Diligent Engine uses Direct3D11-syle API that is translated to other native API calls under the hood:
      ITextureView *pRTVs[] = {m_pRTV}; m_pContext->SetRenderTargets(_countof( pRTVs ), pRTVs, m_pDSV); // Clear render target and depth buffer const float zero[4] = {0, 0, 0, 0}; m_pContext->ClearRenderTarget(nullptr, zero); m_pContext->ClearDepthStencil(nullptr, CLEAR_DEPTH_FLAG, 1.f); // Set vertex and index buffers IBuffer *buffer[] = {m_pVertexBuffer}; Uint32 offsets[] = {0}; Uint32 strides[] = {sizeof(MyVertex)}; m_pContext->SetVertexBuffers(0, 1, buffer, strides, offsets, SET_VERTEX_BUFFERS_FLAG_RESET); m_pContext->SetIndexBuffer(m_pIndexBuffer, 0); Different native APIs use various set of function to execute draw commands depending on command details (if the command is indexed, instanced or both, what offsets in the source buffers are used etc.). For instance, there are 5 draw commands in Direct3D11 and more than 9 commands in OpenGL with something like glDrawElementsInstancedBaseVertexBaseInstance not uncommon. Diligent Engine hides all details with single IDeviceContext::Draw() method that takes takes DrawAttribs structure as an argument. The structure members define all attributes required to perform the command (primitive topology, number of vertices or indices, if draw call is indexed or not, if draw call is instanced or not, if draw call is indirect or not, etc.). For example:
      DrawAttribs attrs; attrs.IsIndexed = true; attrs.IndexType = VT_UINT16; attrs.NumIndices = 36; attrs.Topology = PRIMITIVE_TOPOLOGY_TRIANGLE_LIST; pContext->Draw(attrs); For compute commands, there is IDeviceContext::DispatchCompute() method that takes DispatchComputeAttribs structure that defines compute grid dimension.
      Source Code
      Full engine source code is available on GitHub and is free to use. The repository contains two samples, asteroids performance benchmark and example Unity project that uses Diligent Engine in native plugin.
      AntTweakBar sample is Diligent Engine’s “Hello World” example.

       
      Atmospheric scattering sample is a more advanced example. It demonstrates how Diligent Engine can be used to implement various rendering tasks: loading textures from files, using complex shaders, rendering to multiple render targets, using compute shaders and unordered access views, etc.

      Asteroids performance benchmark is based on this demo developed by Intel. It renders 50,000 unique textured asteroids and allows comparing performance of Direct3D11 and Direct3D12 implementations. Every asteroid is a combination of one of 1000 unique meshes and one of 10 unique textures.

      Finally, there is an example project that shows how Diligent Engine can be integrated with Unity.

      Future Work
      The engine is under active development. It currently supports Windows desktop, Universal Windows and Android platforms. Direct3D11, Direct3D12, OpenGL/GLES backends are now feature complete. Vulkan backend is coming next, and support for more platforms is planned.
    • By kan123
      Hello,
      DX9Ex. I have the problem with driver stability in time of serial renderings, which i try to use for image processing in memory with fragment shaders. For big bitmaps the video driver sometimes becomes unstable ("Display driver stopped responding and has recovered") and, for instance, if the media player runs video in background, it sometimes freezes and distorts. I tried to use next methods of IDirect3DDevice9Ex:
      SetGPUThreadPriority(-7);
      WaitForVBlank(0);
      EvictManagedResources();
      with purpose to give some time for GPU between scenes, but it seems to be has not notable effect in this case. I don't want to reinitilialize subsystem for every step to avoid performance loss.
      So, my question is next: does some common practice exists to avoid overloading of GPU by running tasks? Many thanks in advance.
       
    • By AxeGuywithanAxe
      I wanted to see how others are currently handling descriptor heap updates and management.
      I've read a few articles and there tends to be three major strategies :
      1 ) You split up descriptor heaps per shader stage ( i.e one for vertex shader , pixel , hull, etc)
      2) You have one descriptor heap for an entire pipeline
      3) You split up descriptor heaps for update each update frequency (i.e EResourceSet_PerInstance , EResourceSet_PerPass , EResourceSet_PerMaterial, etc)
      The benefits of the first two approaches is that it makes it easier to port current code, and descriptor / resource descriptor management and updating tends to be easier to manage, but it seems to be not as efficient.
      The benefits of the third approach seems to be that it's the most efficient because you only manage and update objects when they change.
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