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    • By simco50
      I've stumbled upon Urho3D engine and found that it has a really nice and easy to read code structure.
      I think the graphics abstraction looks really interesting and I like the idea of how it defers pipeline state changes until just before the draw call to resolve redundant state changes.
      This is done by saving the state changes (blendEnabled/SRV changes/RTV changes) in member variables and just before the draw, apply the actual state changes using the graphics context.
      It looks something like this (pseudo):
      void PrepareDraw() { if(renderTargetsDirty) { pD3D11DeviceContext->OMSetRenderTarget(mCurrentRenderTargets); renderTargetsDirty = false } if(texturesDirty) { pD3D11DeviceContext->PSSetShaderResourceView(..., mCurrentSRVs); texturesDirty = false } .... //Some more state changes } This all looked like a great design at first but I've found that there is one big issue with this which I don't really understand how it is solved in their case and how I would tackle it.
      I'll explain it by example, imagine I have two rendertargets: my backbuffer RT and an offscreen RT.
      Say I want to render my backbuffer to the offscreen RT and then back to the backbuffer (Just for the sake of the example).
      You would do something like this:
      //Render to the offscreen RT pGraphics->SetRenderTarget(pOffscreenRT->GetRTV()); pGraphics->SetTexture(diffuseSlot, pDefaultRT->GetSRV()) pGraphics->DrawQuad() pGraphics->SetTexture(diffuseSlot, nullptr); //Remove the default RT from input //Render to the default (screen) RT pGraphics->SetRenderTarget(nullptr); //Default RT pGraphics->SetTexture(diffuseSlot, pOffscreenRT->GetSRV()) pGraphics->DrawQuad(); The problem here is that the second time the application loop comes around, the offscreen rendertarget is still bound as input ShaderResourceView when it gets set as a RenderTargetView because in Urho3D, the state of the RenderTargetView will always be changed before the ShaderResourceViews (see top code snippet) even when I set the SRV to nullptr before using it as a RTV like above causing errors because a resource can't be bound to both input and rendertarget.
      What is usually the solution to this?
    • By MehdiUBP
      I wrote a MatCap shader following this idea:
      Given the image representing the texture, we compute the sample point by taking the dot product of the vertex normal and the camera position and remapping this to [0,1].
      This seems to work well when I look straight at an object with this shader. However, in cases where the camera points slightly on the side, I can see the texture stretch a lot.
      Could anyone give me a hint as how to get a nice matcap shader ?
      Here's what I wrote:
      Shader "Unlit/Matcap"
              _MainTex ("Texture", 2D) = "white" {}
              Tags { "RenderType"="Opaque" }
              LOD 100
                  #pragma vertex vert
                  #pragma fragment frag
                  // make fog work
                  #include "UnityCG.cginc"
                  struct appdata
                      float4 vertex : POSITION;
                      float3 normal : NORMAL;
                  struct v2f
                      float2 worldNormal : TEXCOORD0;
                      float4 vertex : SV_POSITION;
                  sampler2D _MainTex;            
                  v2f vert (appdata v)
                      v2f o;
                      o.vertex = UnityObjectToClipPos(v.vertex);
                      o.worldNormal = mul((float3x3)UNITY_MATRIX_V, UnityObjectToWorldNormal(v.normal)).xy*0.3 + 0.5;  //UnityObjectToClipPos(v.normal)*0.5 + 0.5;
                      return o;
                  fixed4 frag (v2f i) : SV_Target
                      // sample the texture
                      fixed4 col = tex2D(_MainTex, i.worldNormal);
                      // apply fog
                      return col;
    • By DiligentDev
      I would like to introduce Diligent Engine, a project that I've been recently working on. Diligent Engine is a light-weight cross-platform abstraction layer between the application and the platform-specific graphics API. 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 front-end for all supported platforms and provides interoperability with underlying native API. Shader source code converter allows shaders authored in HLSL to be translated to GLSL and used on all platforms. Diligent Engine supports integration with Unity and is designed to be used as a graphics subsystem in a standalone game engine, Unity native plugin or any other 3D application. It is distributed under Apache 2.0 license and is free to use. Full source code is available for download on GitHub.
      True cross-platform Exact same client code for all supported platforms and rendering backends No #if defined(_WIN32) ... #elif defined(LINUX) ... #elif defined(ANDROID) ... No #if defined(D3D11) ... #elif defined(D3D12) ... #elif defined(OPENGL) ... Exact same HLSL shaders run on all platforms and all backends Modular design Components are clearly separated logically and physically and can be used as needed Only take what you need for your project (do not want to keep samples and tutorials in your codebase? Simply remove Samples submodule. Only need core functionality? Use only Core submodule) No 15000 lines-of-code files Clear object-based interface No global states Key graphics features: Automatic shader resource binding designed to leverage the next-generation rendering APIs Multithreaded command buffer generation 50,000 draw calls at 300 fps with D3D12 backend Descriptor, memory and resource state management Modern c++ features to make code fast and reliable The following platforms and low-level APIs are currently supported:
      Windows Desktop: Direct3D11, Direct3D12, OpenGL Universal Windows: Direct3D11, Direct3D12 Linux: OpenGL Android: OpenGLES MacOS: OpenGL iOS: OpenGLES API Basics
      The engine can perform initialization of the API or attach to already existing D3D11/D3D12 device or OpenGL/GLES context. For instance, the following code shows how the engine can be initialized in D3D12 mode:
      #include "RenderDeviceFactoryD3D12.h" using namespace Diligent; // ...  GetEngineFactoryD3D12Type GetEngineFactoryD3D12 = nullptr; // Load the dll and import GetEngineFactoryD3D12() function LoadGraphicsEngineD3D12(GetEngineFactoryD3D12); auto *pFactoryD3D11 = GetEngineFactoryD3D12(); EngineD3D12Attribs EngD3D12Attribs; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[0] = 1024; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[1] = 32; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[2] = 16; EngD3D12Attribs.CPUDescriptorHeapAllocationSize[3] = 16; EngD3D12Attribs.NumCommandsToFlushCmdList = 64; RefCntAutoPtr<IRenderDevice> pRenderDevice; RefCntAutoPtr<IDeviceContext> pImmediateContext; SwapChainDesc SwapChainDesc; RefCntAutoPtr<ISwapChain> pSwapChain; pFactoryD3D11->CreateDeviceAndContextsD3D12( EngD3D12Attribs, &pRenderDevice, &pImmediateContext, 0 ); pFactoryD3D11->CreateSwapChainD3D12( pRenderDevice, pImmediateContext, SwapChainDesc, hWnd, &pSwapChain ); 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. To create a buffer, you need to populate BufferDesc structure and call IRenderDevice::CreateBuffer(). The following code creates a uniform (constant) buffer:
      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 ); Similar, to create a texture, populate TextureDesc structure and call IRenderDevice::CreateTexture() as in the following example:
      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 ); Initializing Pipeline State
      Diligent Engine follows Direct3D12 style 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.)
      Creating Shaders
      To create a shader, populate ShaderCreationAttribs structure. An important member is ShaderCreationAttribs::SourceLanguage. The following are valid values for this member:
      SHADER_SOURCE_LANGUAGE_DEFAULT  - The shader source format matches the underlying graphics API: HLSL for D3D11 or D3D12 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. See shader converter for details. SHADER_SOURCE_LANGUAGE_GLSL  - The shader source is in GLSL. There is currently no GLSL to HLSL converter. To allow grouping of resources based on the frequency of expected change, Diligent Engine introduces classification of shader variables:
      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. This post describes the resource binding model in Diligent Engine.
      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
      To create a pipeline state object, define instance of PipelineStateDesc structure. The structure defines the pipeline specifics such as if the pipeline is a compute pipeline, number and format of render targets as well as depth-stencil format:
      // This is a graphics pipeline PSODesc.IsComputePipeline = false; PSODesc.GraphicsPipeline.NumRenderTargets = 1; PSODesc.GraphicsPipeline.RTVFormats[0] = TEX_FORMAT_RGBA8_UNORM_SRGB; PSODesc.GraphicsPipeline.DSVFormat = TEX_FORMAT_D32_FLOAT; The structure also defines depth-stencil, rasterizer, blend state, input layout and other parameters. For instance, rasterizer state can be defined as in the code snippet below:
      // Init rasterizer state RasterizerStateDesc &RasterizerDesc = PSODesc.GraphicsPipeline.RasterizerDesc; RasterizerDesc.FillMode = FILL_MODE_SOLID; RasterizerDesc.CullMode = CULL_MODE_NONE; RasterizerDesc.FrontCounterClockwise = True; RasterizerDesc.ScissorEnable = True; //RSDesc.MultisampleEnable = false; // do not allow msaa (fonts would be degraded) RasterizerDesc.AntialiasedLineEnable = False; When all fields are populated, call IRenderDevice::CreatePipelineState() to create the PSO:
      m_pDev->CreatePipelineState(PSODesc, &m_pPSO); Binding Shader Resources
      Shader resource binding in Diligent Engine is based on grouping variables in 3 different groups (static, mutable and dynamic). Static variables 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. They are bound directly to the shader object:
      PixelShader->GetShaderVariable( "g_tex2DShadowMap" )->Set( pShadowMapSRV ); Mutable and dynamic variables are bound via a new object called Shader Resource Binding (SRB), which is created by the pipeline state:
      m_pPSO->CreateShaderResourceBinding(&m_pSRB); Dynamic and mutable resources are then bound through SRB object:
      m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "tex2DDiffuse")->Set(pDiffuseTexSRV); m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "cbRandomAttribs")->Set(pRandomAttrsCB); The difference between mutable and dynamic resources is that mutable ones can only be set once for every instance of a shader resource binding. Dynamic resources can be set multiple times. It is important to properly set the variable type as this may affect performance. Static variables are generally most efficient, followed by mutable. Dynamic variables are most expensive from performance point of view. This post explains shader resource binding in more details.
      Setting the Pipeline State and Invoking Draw Command
      Before any draw command can be invoked, all required vertex and index buffers as well as the pipeline state should be bound to the device context:
      // Clear render target const float zero[4] = {0, 0, 0, 0}; m_pContext->ClearRenderTarget(nullptr, zero); // 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); m_pContext->SetPipelineState(m_pPSO); Also, all shader resources must be committed to the device context:
      m_pContext->CommitShaderResources(m_pSRB, COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES); When all required states and resources are bound, IDeviceContext::Draw() can be used to execute draw command or IDeviceContext::DispatchCompute() can be used to execute compute command. Note that for a draw command, graphics pipeline must be bound, and for dispatch command, compute pipeline must be bound. Draw() 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); Tutorials and Samples
      The GitHub repository contains a number of tutorials and sample applications that demonstrate the API usage.
      Tutorial 01 - Hello Triangle This tutorial shows how to render a simple triangle using Diligent Engine API.   Tutorial 02 - Cube This tutorial demonstrates how to render an actual 3D object, a cube. It shows how to load shaders from files, create and use vertex, index and uniform buffers.   Tutorial 03 - Texturing This tutorial demonstrates how to apply a texture to a 3D object. It shows how to load a texture from file, create shader resource binding object and how to sample a texture in the shader.   Tutorial 04 - Instancing This tutorial demonstrates how to use instancing to render multiple copies of one object using unique transformation matrix for every copy.   Tutorial 05 - Texture Array This tutorial demonstrates how to combine instancing with texture arrays to use unique texture for every instance.   Tutorial 06 - Multithreading This tutorial shows how to generate command lists in parallel from multiple threads.   Tutorial 07 - Geometry Shader This tutorial shows how to use geometry shader to render smooth wireframe.   Tutorial 08 - Tessellation This tutorial shows how to use hardware tessellation to implement simple adaptive terrain rendering algorithm.   Tutorial_09 - Quads This tutorial shows how to render multiple 2D quads, frequently swithcing textures and blend modes.
      AntTweakBar sample demonstrates how to use AntTweakBar library to create simple user interface.

      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 textures, using compute shaders and unordered access views, etc. 

      The repository includes Asteroids performance benchmark based on this demo developed by Intel. It renders 50,000 unique textured asteroids and lets compare performance of D3D11 and D3D12 implementations. Every asteroid is a combination of one of 1000 unique meshes and one of 10 unique textures. 

      Integration with Unity
      Diligent Engine supports integration with Unity through Unity low-level native plugin interface. The engine relies on Native API Interoperability to attach to the graphics API initialized by Unity. After Diligent Engine device and context are created, they can be used us usual to create resources and issue rendering commands. GhostCubePlugin shows an example how Diligent Engine can be used to render a ghost cube only visible as a reflection in a mirror.

    • By tedyage
         I want to output the Image file from the shaderresourceview of the rendertexture, so I have to transfer the shaderresourceview into a image object, and I don't know how to do this. Could you help me with it? 
         PS:I am using SharpDx to develop my program. So it's better be coding by C#. Many thanks.
    • By isu diss
      I decided to implement light shafts using http://sirkan.iit.bme.hu/~szirmay/lightshaft_link.htm So far I've only managed to implement the shadow map. Can anyone help me to implement this in D3D11? (I mean steps, I can do the rest). I'm new to all these shadow maps and etc.
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DX11 Antialiasing artifacts with render targets (or something else)

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I'm developing with flash stage3d api, so I can't say for sure what's going on, but it seems that I have antialiasing artifact.




It appears only when I render to texture with any antialiasing. On movement everything much worse - this broken pixels randomly appears on the edge of a sphere. I tried to debug with renderdoc (stage3d api uses dx11 under the hood), but this great tool shows me wrong results. So I'll listen for more experienced guys with pleasure - is it trully problems with antialiased render target or somethinf else? And I'll check my shader more carefully.

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Can you post your shader? Is it possible that the values are not clamped and are overflowing?

Also does it do this at all AA levels, i.e. 2 4, 8 and 16?

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What wrong results are you getting in renderdoc? Something completely crazy, or just the bug has gone away?


One thing that sometimes causes differences between program & capture is that renderdoc by default doesn't save render target contents at the start of the frame if it thinks they'll be overwritten. Try enabling 'save all initials' in the capture window to see if that changes anything.

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like bwhiting, I would guess that something is going wrong in your pixel shader. One thing to watch out for with MSAA is extrapolation. When you have attributes from your vertex shader that are passed to the pixel shader (positions, texture coordinates, colors, etc.) they will typically get interpolated to the center point of a pixel. With MSAA you will get edge pixels don't cover the center point but do cover 1 or more sub-sample points inside the pixel. In those cases you will get vertex attributes that are actually interpolated outside of your triangle. To help account for this, GPU's support centroid sampling. Centroid sampling causes attributes to be interpolated to the centroid of all covered sub-sample positions, which prevents extrapolation.

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Thank you everyone,

I didn't post my shader because I don't want to scare people - stage3d shaders are assembler like code. I double checked it and it seems correct - I even don't have divisions. And the main thing - without antialiasing I don't have artifacts. So MJP's answer is the explanation I searched for. Unfortunatelly, stage3d doesn't allow to setup sampling or anything like that.


@bwhiiting, for render target AA levels are 0, 1, 2, 3, 4.


@baldurk, I have wrong results in fragment shader. For example in vertex shader I have a varing (vi0) and I can see it's value, but in fragment shader I suddenly have vi1 (not vi0) value filled with zeroes only. So I can't step through the code and check intermediate results (and output color actually is wrong too, although on the screen it's ok). But as you say it can be problem with render target - flash internally draws to some texture and internally draws it to back buffer in the end. And I tried to turn on every option.


Upd.: I checked on different machine and I can't see this artifacts, so I assume that this is my hardware's fault.

Edited by Volgogradetzzz

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If you're willing to share it or email to me, I'd be interested to run the program myself or look at a capture. I don't mind assembly shaders :). Getting the wrong inputs in the pixel shader means a bug in renderdoc and I'd like to fix it if I can!

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