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DX11 Texture close view looks pixelated

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Good day,
i have some problem with my textures in my directx 11 app.
In the distance the texture filtering seems to work like it should.
But they look very pixelated when iam very close to it.
 
See this picture:
98555950.jpg
 
And this one:
 
70372621.jpg
 
Iam using "D3D11_FILTER_MIN_MAG_MIP_LINEAR" to create the texture sampler.
 
//Code for sampler creation
D3D11_SAMPLER_DESC SamDesc;
ZeroMemory(&SamDesc, sizeof(D3D11_SAMPLER_DESC));
SamDesc.Filter		= D3D11_FILTER_MIN_MAG_MIP_LINEAR;
SamDesc.AddressU	= D3D11_TEXTURE_ADDRESS_WRAP;
SamDesc.AddressV	= D3D11_TEXTURE_ADDRESS_WRAP;
SamDesc.AddressW	= D3D11_TEXTURE_ADDRESS_WRAP;
SamDesc.MipLODBias	= 0.0f;
SamDesc.MaxAnisotropy	= 1;
SamDesc.ComparisonFunc	= D3D11_COMPARISON_NEVER;
SamDesc.BorderColor[0]	= SamDesc.BorderColor[1] = SamDesc.BorderColor[2] = SamDesc.BorderColor[3] = 0;
SamDesc.MinLOD		= 0;
SamDesc.MaxLOD		= D3D11_FLOAT32_MAX;

 

 

I tested it by using the filter "D3D11_FILTER_ANISOTROPIC" with MaxAnisotropy of 4 or 8 and the texture still looks pixelated at very close view.
The texture loading is done with "D3DX11CreateShaderResourceViewFromFile".
 
//Code for texture loading
D3DX11_IMAGE_LOAD_INFO imageInfo;
imageInfo.Width		= D3DX11_DEFAULT;
imageInfo.Height	= D3DX11_DEFAULT;
imageInfo.Depth		= D3DX11_DEFAULT;
imageInfo.FirstMipLevel	= D3DX11_DEFAULT;
imageInfo.MipLevels	= D3DX11_DEFAULT;
imageInfo.Usage		= D3D11_USAGE_DEFAULT;
imageInfo.BindFlags	= D3D11_BIND_SHADER_RESOURCE;
imageInfo.Format	= DXGI_FORMAT_R8G8B8A8_UNORM;
imageInfo.MipFilter	= D3DX11_FILTER_LINEAR;
imageInfo.Filter	= D3DX11_FILTER_LINEAR;

D3DX11CreateShaderResourceViewFromFile(..)

 

 

It doesnt matter what kind of Filter i set or using default values for the 'D3DX11_IMAGE_LOAD_INFO' structure it still pixelated at close view.
 
First of all i tested if swapchain, backbuffer, depth texture are the same size as the window creation.
They where all matching.
 
//Code window creation
RECT rc = { 0, 0, 1600, 960 };
AdjustWindowRect( &rc, WS_OVERLAPPEDWINDOW, FALSE );

hWnd = CreateWindow(L"myclass", L"myapp", WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, CW_USEDEFAULT, rc.right - rc.left, rc.bottom - rc.top, NULL, NULL, hInstance, NULL);

if (!hWnd)
    return FALSE;

g_WindowHWND = hWnd;
ShowWindow(g_WindowHWND, nCmdShow);

//Code buffer creation after window is created
m_hWndMainRenderTarget = hwnd;

// Create a Direct2D render target			
RECT rcRenderTarget;
GetClientRect( hwnd, &rcRenderTarget);
m_uiRenderTargetWidth	= rcRenderTarget.right-rcRenderTarget.left;
m_uiRenderTargetHeight	= rcRenderTarget.bottom-rcRenderTarget.top;


// Create swapchain settings
DXGI_SWAP_CHAIN_DESC sSwapChainDesc;
ZeroMemory( &sSwapChainDesc, sizeof( sSwapChainDesc ) );

sSwapChainDesc.BufferCount		= 1;
sSwapChainDesc.BufferDesc.Width		= m_uiRenderTargetWidth;
sSwapChainDesc.BufferDesc.Height	= m_uiRenderTargetHeight;
sSwapChainDesc.BufferDesc.Format	= DXGI_FORMAT_R8G8B8A8_UNORM;
sSwapChainDesc.BufferUsage		= DXGI_USAGE_RENDER_TARGET_OUTPUT;
sSwapChainDesc.OutputWindow		= m_hWndMainRenderTarget;
sSwapChainDesc.SampleDesc.Count		= 1;
sSwapChainDesc.SampleDesc.Quality	= 0;
sSwapChainDesc.Windowed			= m_bWindowed;
sSwapChainDesc.SwapEffect		= DXGI_SWAP_EFFECT_DISCARD;

// Retrive device, adapter and factory that was created with the device
IDXGIDevice * pDXGIDevice;
hr = m_pDevice->QueryInterface(__uuidof(IDXGIDevice), (void **)&pDXGIDevice);

IDXGIAdapter * pDXGIAdapter;
hr = pDXGIDevice->GetParent(__uuidof(IDXGIAdapter), (void **)&pDXGIAdapter);

IDXGIFactory * pIDXGIFactory;
pDXGIAdapter->GetParent(__uuidof(IDXGIFactory), (void **)&pIDXGIFactory);

// Create swap chain seperate	
if(FAILED( hr = pIDXGIFactory->CreateSwapChain( pDXGIDevice, &sSwapChainDesc, &m_pSwapChain ) ))
{
         return hr;
}
// Get a pointer to the back buffer
if(FAILED( hr = m_pSwapChain->GetBuffer( 0, __uuidof( ID3D11Texture2D ), ( LPVOID* )&m_pBackBuffer )))
{
	return hr;
}

// Create a render-target view
if(FAILED( hr = m_pDevice->CreateRenderTargetView( m_pBackBuffer, NULL, &m_pRenderTargetView )))
{
	return hr;
}

D3D11_TEXTURE2D_DESC	sDepthStencilTextureDesc;

// Create depth stencil texture etc..
sDepthStencilTextureDesc.Width			= m_uiRenderTargetWidth;
sDepthStencilTextureDesc.Height			= m_uiRenderTargetHeight;
sDepthStencilTextureDesc.MipLevels		= 1;
sDepthStencilTextureDesc.ArraySize		= 1;
sDepthStencilTextureDesc.Format			= DXGI_FORMAT_D24_UNORM_S8_UINT;
sDepthStencilTextureDesc.SampleDesc.Count	= 1;
sDepthStencilTextureDesc.SampleDesc.Quality	= 0;
sDepthStencilTextureDesc.Usage			= D3D11_USAGE_DEFAULT;
sDepthStencilTextureDesc.BindFlags		= D3D11_BIND_DEPTH_STENCIL;
sDepthStencilTextureDesc.CPUAccessFlags		= 0;
sDepthStencilTextureDesc.MiscFlags		= 0;

if(FAILED( hr = m_pDevice->CreateTexture2D( &sDepthStencilTextureDesc, NULL, &m_pDepthStencilTexture )))
{
	return hr;
}
	
D3D11_DEPTH_STENCIL_VIEW_DESC	sDepthStencilViewDesc;

// Depth stencil view desc...
ZeroMemory( &sDepthStencilViewDesc, sizeof( sDepthStencilViewDesc ) );
sDepthStencilViewDesc.Format			= DXGI_FORMAT_D24_UNORM_S8_UINT;
sDepthStencilViewDesc.ViewDimension		= D3D11_DSV_DIMENSION_TEXTURE2D;
sDepthStencilViewDesc.Texture2D.MipSlice	= 0;
sDepthStencilViewDesc.Flags			= 0;

if(FAILED( hr = m_pDevice->CreateDepthStencilView( m_pDepthStencilTexture, &sDepthStencilViewDesc,&m_pDepthStencilView )))
{
	return hr;
}

// Bind the view
m_pDeviceContext->OMSetRenderTargets( 1, &m_pRenderTargetView, m_pDepthStencilView );

D3D11_VIEWPORT sViewPort;

// Setup the viewport
sViewPort.Width		= (FLOAT)m_uiRenderTargetWidth;
sViewPort.Height	= (FLOAT)m_uiRenderTargetHeight;
sViewPort.MinDepth	= 0.0f;
sViewPort.MaxDepth	= 1.0f;
sViewPort.TopLeftX	= 0;
sViewPort.TopLeftY	= 0;

m_pDeviceContext->RSSetViewports( 1, &sViewPort );

 

 

 

 

During some debug session i tested if all the dimension of the created buffers match up with the window client rect.
Every created buffer has the same size as the client area of the created window.
The window istself is very basic. No menu, bars or anything. Just a simply titlebar.
Text displayed on the screen done with my font engine are pixel perfect so i think the buffers size match up with the window client area size.
At this point i have to say that other application like the samples from the Microsoft sdk works like accepted.
 
Since iam running out of ideas i can post here some more code that could be relevant.
 
//Code projection matrx creation. zNear = 1.0f and zFar = 12000.0f
int width	= g_CDevice.GetRenderTargetWidth();
int height	= g_CDevice.GetRenderTargetHeight();
float fov	= 0.785398163f;
float aspectRatio = width / (float)height;
D3DXMatrixPerspectiveFovLH(&g_mProjection, fov, aspectRatio, g_fZNear, g_fZFar);

 

 

The pixelated effect normaly starts when iam comming close to the zNear value.
Something like 2 units above the zNear settings.
 
 
Here is the pixelshader iam using.
It is a combination of some detail textures with slope based texturing and some blending of mixed uv values for the detail textures.
They are also combined via a noise blending map for mixing the slope based texture values to get ride of the repeat effect of detail textures.
All textures used here are 512x512.
The texture are loaded all the same way like described at the beginning of this post and using the same texture sampler.
 
//Code pixelshader
Texture2D txColorMap_1 : register( t0 ); // grass
Texture2D txColorMap_2 : register( t1 ); // dirt
Texture2D txColorMap_3 : register( t2 ); // rock
Texture2D txColorMap_4 : register( t3 ); // rgba random blend map
Texture2D txColorMap_5 : register( t4 ); // noisy normal map

// Texture sampler - D3D11_FILTER_MIN_MAG_MIP_LINEAR / ADRESS: D3D11_TEXTURE_ADDRESS_WRAP
SamplerState samLinear2D_1 : register( s0 );

struct PixelInputType
{
    float4 position : SV_POSITION;
    float3 normal   : TEXCOORD0;
    float2 tex_1    : TEXCOORD1; // uv for detail
    float2 tex_2    : TEXCOORD2; // uv for noise map
};


float4 PSMain(PixelInputType input) : SV_Target
{
	const float uvDetail = 32.0f; // detail uv in the range of 0.125f - 0.25f
	const float4 vLightDir = float4(-0.5f, 1.0f, 1.0f, 1.0f); // Directional light for testing
	const float4 vLightColor = float4(0.8f, 0.8f, 0.8f, 1.0f);
	const float4 vAmbientColor = float4(0.2f, 0.2f, 0.2f, 1.0f);

	float4 finalColor;
	float blendAmount;
	
	float4 t_1 =  txColorMap_4.Sample( samLinear2D_1, input.tex_2 * 0.125f);// random map blend values
	float4 col;

	// Read detail texture
	float4 c1 = txColorMap_1.Sample( samLinear2D_1, input.tex_1 * uvDetail);
	float4 c2 = txColorMap_2.Sample( samLinear2D_1, input.tex_1 * uvDetail);
	float4 c3 = txColorMap_3.Sample( samLinear2D_1, input.tex_1 * uvDetail);
	
	// Read detail texture with lower uv values for mixing
	float4 c4 = txColorMap_1.Sample( samLinear2D_1, input.tex_1 * uvDetail * 0.25f);
	float4 c5 = txColorMap_2.Sample( samLinear2D_1, input.tex_1 * uvDetail * 0.125f);
	float4 c6 = txColorMap_3.Sample( samLinear2D_1, input.tex_1 * uvDetail * 0.125f);
	
	// lerp the values with the blend values of the 
	c1 = lerp(c1*c4, c2, t_1.r);
	c2 = lerp(c2*c5, c3, t_1.g);
	c3 = lerp(c3,c6, t_1.b);

	//  Slope calculation based on rastertek tutorial
	float slope = 1.0f - input.normal.y;

    if(slope < 0.2)
    {
        blendAmount = slope / 0.2f;
        col = lerp(c1, c2, blendAmount);
    }
	
    if((slope < 0.7) && (slope >= 0.2f))
    {
        blendAmount = (slope - 0.2f) * (1.0f / (0.7f - 0.2f));
        col = lerp(c2, c3, blendAmount);
    }

    if(slope >= 0.7) 
    {
        col = c3;
    }
	
	// add normal map noise values for some cheap bump effect
	float3 n1 = txColorMap_5.Sample(samLinear2D_1, input.tex_1 * uvDetail);
	float3 n2 = txColorMap_5.Sample(samLinear2D_1, input.tex_1 * uvDetail * 0.25f);
	n1 = lerp(n1, n2, t_1.r);
	float  d = dot((float3)vLightDir,n1);
	col *= d;
	
	// calculate directional lighting
	finalColor = saturate( dot( (float3)vLightDir,input.normal) * vLightColor) * col;
	finalColor += col * vAmbientColor;

	return finalColor;
}

 

 

 

Thats all the code that could be relevant to guess what kind of bug i have.
Thanks in advance to anyone here.
Edited by dxdude

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The one thing I can't see mentioned here is the UV coordinates you are using, which may mean you are trying to debug code that doesn't actually need to be debugged. Have a look (if you haven't already) to see if the UV coords you are using use the full resolution of the texture.

 

Aimee

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Thank you for the answer AmzBee.

I cant test any code here at work atm so will do it when iam back home later.

The UV are generated inside my vertex shader.

 

Can very low uv coodinates make problems?

So when mapping from 0 to 1 and the uv for it are like 0,0078125 - 0,01..... ?

 

But ill check my vertex shader later.

Thank you very much.

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The one thing I can't see mentioned here is the UV coordinates you are using, which may mean you are trying to debug code that doesn't actually need to be debugged. Have a look (if you haven't already) to see if the UV coords you are using use the full resolution of the texture.

 

Aimee

 

Woot i solved it now.

There was a bug in the uv generation in the vertex shader process.

Thank you very much.

And sorry for the big post :)

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Can very low uv coodinates make problems?
So when mapping from 0 to 1 and the uv for it are like 0,0078125 - 0,01..... ?
 
I don't do shaders, but i follow pretty much everything you're doing.
 
looks like you might have a classic case of "5 foot texture, 10 foot rock" as i call it.   IE your texture is not high rez enough for the size of the mesh its mapped onto.
 
when this occurs, you can get very small u,v coords for a given tri, such as you mention. 
 
that and your first image (a classic case of low rez texture) are what make me suspect "5 foot texture, 10 foot rock", or "1 meter texture, 2 meter rock" if you prefer.
 
if thats the case, then the image in your texture is a picture of a piece of land thats not as big as the area it gets mapped onto in your world. so it gets stretched. instead of vertex coords 0 to 1 mapping to UVs  0 to 1, you get UVs 0 to 0.1 or .01, etc.
 
so, you can do one or a combo of things:
1. increase texture rez.   i run 256x256 for speed, but have tested up to 4096x4096 on the exact same case you're working (ground textures). i saw that first image of yours, and i was like "yeah, been there, done that, i remember that, walking up to rocks and ground that sticks up, and figuring out how to get high enough rez with the lowest rez textures possible, while tweaking texture wrap, quad size, and seamless textures.   increasing texture size costs memory.   bigger textures run slower (at least in fixed function pipeline).
 
2. decrease quad/triangle size.  1/2 as big with same mapping means twice the resolution from the same texture.  seamless textures may be required.
 
3. repeat the texture more than once across a quad - usually requires seamless texture. this gets you the high rez of a high rez texture without the memory hit, and doesn't increase your triangle count. the downside is possible moire' patterns from repeating the same texture 2 or more times across a surface.
 
here's the load code for the texture:
 
// load texture - creates mipmaps. no image filtering, box filtering for mipmaps. 
void Zloadtex(char *s)
{
HRESULT h;
char s2[100];
h=D3DXCreateTextureFromFileExA(Zd3d_device_ptr,s,D3DX_DEFAULT,  // widtth
                                                D3DX_DEFAULT,   // height 
                                                D3DX_DEFAULT,      // miplvls ( default = complete chain ) 
                                                0,                 // usage (0=not render & not dynamic)
                                                D3DFMT_A8R8G8B8,
                                                mempool,                         // memory pool of your choice - managed, most likely.
                                                D3DX_FILTER_NONE,      //   image filter   ( default = tri + dither )
                                                D3DX_DEFAULT,      // mip filter ( default = box )  
                                                0,     // color key (0=none)
                                                NULL,NULL,&(Ztex[numtextures].tex));
if (h != D3D_OK) { strcpy_s(s2,100,"Error loading "); strcat_s(s2,100,s); Zmsg2(s2); exit(1); }
strcpy_s(Ztex[numtextures].name,s);
numtextures++;
}
 
 
and here are the states of the pipeline when drawing:
 
// no blending, turn on gouraud shading
Zd3d_device_ptr->SetTextureStageState( 0, D3DTSS_COLOROP, D3DTOP_MODULATE );
Zd3d_device_ptr->SetTextureStageState( 0, D3DTSS_COLORARG1, D3DTA_TEXTURE );
Zd3d_device_ptr->SetTextureStageState( 0, D3DTSS_COLORARG2, D3DTA_DIFFUSE );
Zd3d_device_ptr->SetRenderState(D3DRS_SHADEMODE,D3DSHADE_GOURAUD);
Zmipmaps(1);         //  Zd3d_device_ptr->SetSamplerState(0,D3DSAMP_MIPFILTER,D3DTEXF_LINEAR);
Zminmagfilter(2);   // 0=point, 1=linear, 2=aniso min and magnification
Zambient(255,255,255);  //  i control ambient with materials
Znormalize(1);                // normalize normals on.   i do scaling of meshes on the fly.
Zspecular(1);                  // turn on specular
Zalphablend(0);             // alpha blend off
 
 
and heres the results with 256x256 texture on a 10x10 quad.    when i get up close and personal like in your first image, i get about 4x the rez you are getting (IE just slightly pixelated).
 
well, i was going to post an image, but the image button doesn't work. i have a couple screenshots in my gallery if you want to check them out. not sure how well they show the ground though.
 
 

It is a combination of some detail textures with slope based texturing and some blending of mixed uv values for the detail textures.
They are also combined via a noise blending map for mixing the slope based texture values to get ride of the repeat effect of detail textures.

 
i believe this is the only place where we're doing things differently. i do a simple aniso tmapping of a seamless texture onto a height mapped quad.
 
as i said, i'm using 256x256 tex on a 10x10 quad. based on you first image, if you're using a 512x512 texture, it looks like you're mapping it onto a quad size of about 80x80, whereas 512x512 mapped onto 20x20 would be the equivalent of what i'm doing (4 times the rez).   
 
from my testing, i found i couldn't go bigger than a 10x10 with a 256x256 texture, without unacceptable levels of pixelation at closest ranges. this would be the equivalent of a 20x20 quad using 512x512 textures.
 
don't forget that the size of the image in the texture can be a factor too.
 
if your mapping a 512x512 tex onto a 20x20 quad, at 1 meter per d3d or Ogl unit, and your image on your texture is only a section of land 5 meters across, you'll also get similar results to your first image.

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The one thing I can't see mentioned here is the UV coordinates you are using, which may mean you are trying to debug code that doesn't actually need to be debugged. Have a look (if you haven't already) to see if the UV coords you are using use the full resolution of the texture.

 

Aimee

 

Woot i solved it now.

There was a bug in the uv generation in the vertex shader process.

Thank you very much.

And sorry for the big post smile.png

no worries, sometimes the biggest problem can be solved with the smallest fix lol :P

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There was a bug in the uv generation in the vertex shader process.

 

uv coords too small , eh?

 

Nice info Norman.

There where not to small but i did a small mistake.

Since i update a small constant buffer for each patch that get rendered i also supplied sector data from the patch.

The sector data was used to generate continuous uv coordinates.

But i got a small bug in the update process for the constant buffer.

 

Nice info you supplied. Thank you very much.

Edited by dxdude

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But i got a small bug in the update process for the constant buffer.

 

its always the little stuff, isn't it?

 

i was working on blending height map edges the other day.   it helps if you calculate the average height at an edge as (h1+h2)/2 as opposed to h1 + h2/2. i forgot the parentheses. that one took a few hours to find, tracing up and down the call stack (so to speak, purely by code inspection).

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      Graphics APIs have come a long way from small set of basic commands allowing limited control of configurable stages of early 3D accelerators to very low-level programming interfaces exposing almost every aspect of the underlying graphics hardware. Next-generation APIs, Direct3D12 by Microsoft and Vulkan by Khronos are relatively new and have only started getting widespread adoption and support from hardware vendors, while Direct3D11 and OpenGL are still considered industry standard. New APIs can provide substantial performance and functional improvements, but may not be supported by older hardware. An application targeting wide range of platforms needs to support Direct3D11 and OpenGL. New APIs will not give any advantage when used with old paradigms. It is totally possible to add Direct3D12 support to an existing renderer by implementing Direct3D11 interface through Direct3D12, but this will give zero benefits. Instead, new approaches and rendering architectures that leverage flexibility provided by the next-generation APIs are expected to be developed.
      There are at least four APIs (Direct3D11, Direct3D12, OpenGL/GLES, Vulkan, plus Apple's Metal for iOS and osX platforms) that a cross-platform 3D application may need to support. Writing separate code paths for all APIs is clearly not an option for any real-world application and the need for a cross-platform graphics abstraction layer is evident. The following is the list of requirements that I believe such layer needs to satisfy:
      Lightweight abstractions: the API should be as close to the underlying native APIs as possible to allow an application leverage all available low-level functionality. In many cases this requirement is difficult to achieve because specific features exposed by different APIs may vary considerably. Low performance overhead: the abstraction layer needs to be efficient from performance point of view. If it introduces considerable amount of overhead, there is no point in using it. Convenience: the API needs to be convenient to use. It needs to assist developers in achieving their goals not limiting their control of the graphics hardware. Multithreading: ability to efficiently parallelize work is in the core of Direct3D12 and Vulkan and one of the main selling points of the new APIs. Support for multithreading in a cross-platform layer is a must. Extensibility: no matter how well the API is designed, it still introduces some level of abstraction. In some cases the most efficient way to implement certain functionality is to directly use native API. The abstraction layer needs to provide seamless interoperability with the underlying native APIs to provide a way for the app to add features that may be missing. Diligent Engine is designed to solve these problems. Its main goal is to take advantages of the next-generation APIs such as Direct3D12 and Vulkan, but at the same time provide support for older platforms via Direct3D11, OpenGL and OpenGLES. Diligent Engine exposes common C++ front-end for all supported platforms and provides interoperability with underlying native APIs. It also supports integration with Unity and is designed to be used as graphics subsystem in a standalone game engine, Unity native plugin or any other 3D application. Full source code is available for download at GitHub and is free to use.
      Overview
      Diligent Engine API takes some features from Direct3D11 and Direct3D12 as well as introduces new concepts to hide certain platform-specific details and make the system easy to use. It contains the following main components:
      Render device (IRenderDevice  interface) is responsible for creating all other objects (textures, buffers, shaders, pipeline states, etc.).
      Device context (IDeviceContext interface) is the main interface for recording rendering commands. Similar to Direct3D11, there are immediate context and deferred contexts (which in Direct3D11 implementation map directly to the corresponding context types). Immediate context combines command queue and command list recording functionality. It records commands and submits the command list for execution when it contains sufficient number of commands. Deferred contexts are designed to only record command lists that can be submitted for execution through the immediate context.
      An alternative way to design the API would be to expose command queue and command lists directly. This approach however does not map well to Direct3D11 and OpenGL. Besides, some functionality (such as dynamic descriptor allocation) can be much more efficiently implemented when it is known that a command list is recorded by a certain deferred context from some thread.
      The approach taken in the engine does not limit scalability as the application is expected to create one deferred context per thread, and internally every deferred context records a command list in lock-free fashion. At the same time this approach maps well to older APIs.
      In current implementation, only one immediate context that uses default graphics command queue is created. To support multiple GPUs or multiple command queue types (compute, copy, etc.), it is natural to have one immediate contexts per queue. Cross-context synchronization utilities will be necessary.
      Swap Chain (ISwapChain interface). Swap chain interface represents a chain of back buffers and is responsible for showing the final rendered image on the screen.
      Render device, device contexts and swap chain are created during the engine initialization.
      Resources (ITexture and IBuffer interfaces). There are two types of resources - textures and buffers. There are many different texture types (2D textures, 3D textures, texture array, cubmepas, etc.) that can all be represented by ITexture interface.
      Resources Views (ITextureView and IBufferView interfaces). While textures and buffers are mere data containers, texture views and buffer views describe how the data should be interpreted. For instance, a 2D texture can be used as a render target for rendering commands or as a shader resource.
      Pipeline State (IPipelineState interface). GPU pipeline contains many configurable stages (depth-stencil, rasterizer and blend states, different shader stage, etc.). Direct3D11 uses coarse-grain objects to set all stage parameters at once (for instance, a rasterizer object encompasses all rasterizer attributes), while OpenGL contains myriad functions to fine-grain control every individual attribute of every stage. Both methods do not map very well to modern graphics hardware that combines all states into one monolithic state under the hood. Direct3D12 directly exposes pipeline state object in the API, and Diligent Engine uses the same approach.
      Shader Resource Binding (IShaderResourceBinding interface). Shaders are programs that run on the GPU. Shaders may access various resources (textures and buffers), and setting correspondence between shader variables and actual resources is called resource binding. Resource binding implementation varies considerably between different API. Diligent Engine introduces a new object called shader resource binding that encompasses all resources needed by all shaders in a certain pipeline state.
      API Basics
      Creating Resources
      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.
       
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