Sign in to follow this  

DX11 D3D11 Constant Buffer not being sent correctly!

Recommended Posts

Hi guys,


this error has currently been a pain in the ass for me, but I haven't given up yet! So basically I have a constant buffer called UberData which contains loads of floats (code below). In my shader I have around 5 buffers and all have the correct size. So there is a float called _texture, when i debug the UberBuffer, _texture is ALWAYS 1, but in the shader it is 821371982 (basically unset). This float is used as a bool for now. So i tried to change the if statement (code in hlsl) from if (_texture == 1) to if (1) , so it will execute it, and the code inside the statement works perfectly, but the buffer somehow isn't being set correctly!


One thing that is irritating me is this message:


D3D11: WARNING: ID3D11DeviceContext::DrawIndexed: The size of the Constant Buffer at slot 2 of the Pixel Shader unit is too small (32 bytes provided, 208 bytes, at least, expected). This is OK, as out-of-bounds reads are defined to return 0. It is also possible the developer knows the missing data will not be used anyway. This is only a problem if the developer actually intended to bind a sufficiently large Constant Buffer for what the shader expects.  [ EXECUTION WARNING #351: DEVICE_DRAW_CONSTANT_BUFFER_TOO_SMALL ]


I perfectly understand this, but I don't see where (in my code) I'm doing it wrong, though it will probably be a simple mistake biggrin.png !




Creation of Uber Shader

BOOL UberShaderObject::Create( ID3D11Device *&dev )
	string finals = string(
		"C:\\Users\\Utilizador\\Documents\\Visual Studio 2012\\Projects\\Cube3D\\Product\\Bin32\\") + string("UberShader.hlsl").c_str();

	ID3D10Blob *vserrors;
	ID3D10Blob *pserrors;

	D3DX11CompileFromFile(finals.c_str(), 0, 0, "VShader", "vs_5_0", D3DCOMPILE_DEBUG, 0, 0, &VS, &vserrors, &HR);
	D3DX11CompileFromFile(finals.c_str(), 0, 0, "PShader", "ps_5_0", D3DCOMPILE_DEBUG, 0, 0, &PS, &pserrors, &HR);
	// create the shader objects
	if (!VS)

		MessageBoxA(NULL, "The uber vertex shader creation has failed, program will now exit!", "ERROR", 0);
	if (!PS)

		MessageBoxA(NULL, "The uber pixel shader creation has failed, program will now exit!", "ERROR", 0);
	dev->CreateVertexShader(VS->GetBufferPointer(), VS->GetBufferSize(), NULL, &pVS);
	dev->CreatePixelShader(PS->GetBufferPointer(), PS->GetBufferSize(), NULL, &pPS);

	if (dev->CreateInputLayout(ied, 4, VS->GetBufferPointer(), VS->GetBufferSize(), &pLayout) != S_OK)
		CE_WARNING("Input Layout Creation", "Input Layout creation in Uber Shader has failed!");

	pCBuffer = new ID3D11Buffer*[4]; // Object || Frame || Uber || Matrix || Fog

	// create the constant buffer
	ZeroMemory(&bd, sizeof(bd));
	bd.Usage = D3D11_USAGE_DEFAULT;


	bd.ByteWidth = 144; // Object
	if(dev->CreateBuffer(&bd, NULL, &pCBuffer[0]) != S_OK)
		CE_WARNING("Buffer Creation", "Object Buffer creation in Uber Shader has failed!");

    bd.ByteWidth = 32; // Frame
	if(dev->CreateBuffer(&bd, NULL, &pCBuffer[1]) != S_OK)
		CE_WARNING("Buffer Creation", "Frame Buffer creation in Uber Shader has failed!");

	bd.ByteWidth = 32; // Uber
	if(dev->CreateBuffer(&bd, NULL, &pCBuffer[2]) != S_OK)
		CE_WARNING("Buffer Creation", "Uber Buffer creation in Uber Shader has failed!");
	bd.ByteWidth = 224; // Matrix
	if(dev->CreateBuffer(&bd, NULL, &pCBuffer[3]) != S_OK)
		CE_WARNING("Buffer Creation", "Matrix Buffer creation in Uber Shader has failed!");
	bd.ByteWidth = 32; // Fog
	if(dev->CreateBuffer(&bd, NULL, &pCBuffer[4]) != S_OK)
		CE_WARNING("Buffer Creation", "Fog Buffer creation in Uber Shader has failed!");



Sending Buffers:

void UberShaderObject::SendObjectBuffer(CBUFFER_PEROBJECT &bff, ID3D11DeviceContext *&devcon)
	devcon->UpdateSubresource(pCBuffer[0], 0, 0, &bff, NULL, NULL);

void UberShaderObject::SendFrameBuffer(CBUFFER_PERFRAME &bff, ID3D11DeviceContext *&devcon)
	devcon->UpdateSubresource(pCBuffer[1], 0, 0, &bff, NULL, NULL);

void UberShaderObject::SendUberBuffer(CBUFFER_UBERDATA &bff, ID3D11DeviceContext *&devcon)
	devcon->UpdateSubresource(pCBuffer[2], 0, 0, &bff, NULL, NULL);

void UberShaderObject::SendMatrixBuffer(CBUFFER_MATRIX &bff, ID3D11DeviceContext *&devcon)
	devcon->UpdateSubresource(pCBuffer[3], 0, 0, &bff, NULL, NULL);

void UberShaderObject::SendFogBuffer(CBUFFER_FOG &bff, ID3D11DeviceContext *&devcon)
	devcon->UpdateSubresource(pCBuffer[4], 0, 0, &bff, NULL, NULL);



Buffers in C++:

	D3DXVECTOR4 LightVector;
	D3DXCOLOR LightColor;

	D3DXMATRIX Rotation;
	D3DXCOLOR AmbientColor;

	float _diffuse;
	float _texture;
	float _directionall;
	float _bumpmap;

	float _fog;
	D3DXVECTOR3 space5;

	D3DXMATRIX world;
	D3DXMATRIX projection;
	D3DXVECTOR4 EyePosition;
	D3DXVECTOR3 Forward;
	float space;

	float FogStart;
	float FogEnd;
	D3DXVECTOR2 __space;
	D3DXVECTOR3 FogColor;
	float __space2;



Shader (Some code like bump mapping probably isn't working yet biggrin.png , the important part is the buffers!)

cbuffer ConstantObjectBuffer
	float4x4 final;
	float4x4 rotation;
	float4 ambientcol;

cbuffer ConstantFrameBuffer
	float4 lightvec;
	float4 lightcol;

cbuffer UberData
	float _diffuse;
	float _texture;
	float _directionall;
	float _bumpmap;

	float _fog;
	float3 space5;

cbuffer ConstantMatrixBuffer
	float4x4 world;
	float4x4 view;
	float4x4 projection;
	float4 eyepos;
	float3 cforward;
	float _space;

cbuffer ConstantFogBuffer
	float FogStart;
	float FogEnd;
	float2 __space;
	float3 FogColor;
	float __space2;

Texture2D txt;
Texture2D txt2;

SamplerState ss;

struct VOut
    float4 position : SV_POSITION;
    float4 worldPos : POSITION;
    float2 texcoord : TEXCOORD;
	float4 normal : NORMAL;
	float4 tangent : TANGENT;
	float Depth : FOG;
    float4 color : COLOR;

VOut VShader(float4 position : POSITION, float4 normal : NORMAL, float2 texcoord : TEXCOORD, float4 tangent : TANGENT)
    VOut output;
    output.position = mul(final, position);
    output.worldPos = mul(position, final);

	output.color = float4(0,0,0,1);

    // set the ambient light
	if (_diffuse == 1)
		output.color += ambientcol;

	if (_texture == 1)
		output.texcoord = texcoord;

	// Stuff for dir and bump
	if (_directionall == 1)
		float4 norm = normalize(mul(rotation, normal));
		float diffusebrightness = saturate(dot(norm, lightvec));
		output.color += lightcol * diffusebrightness;

	if (_bumpmap)
		output.normal = normal;
		output.tangent = tangent;

	// Final stuff
	output.Depth = output.position.z;
	output.color.a = 1;

    return output;

float4 PShader(VOut input) : SV_TARGET
	float4 color = input.color;

	float4 spec = float4(0,0,0, 1);
	float4 tex = float4(0,0,0, 1);
	float4 bump = float4(0,0,0, 1);

	if (_texture == 1)
		color *= txt.Sample(ss, input.texcoord);

	if (_directionall == 1)
		float3 h = normalize(normalize(eyepos - input.position) - lightvec);
		float specLighting = pow(saturate(dot(h, input.normal)), 200);

		color += saturate(float4(1, 1, 1, 1) * float4(1, 1, 1, 1) * specLighting * 0.5);

	if (_bumpmap== 1)
		float4 light = normalize(input.position-lightvec);
		float4 eye = normalize(eyepos-light);
		float4 vhalf = normalize(eye-lightvec);

		float4 Normal = txt2.Sample(ss, input.texcoord);
		color *= dot(2.0*(Normal-0.5), 2.0*(color-0.5));

		input.tangent = mul(float4(,0.0),final);
		input.normal = mul(float4(,0.0),final);
		float3 binormal = cross(,;

		float3 L = float3(dot(input.tangent, light), dot(binormal,, dot(input.normal, light));
		float3 H = float3(dot(input.tangent, vhalf), dot(binormal,, dot(input.normal, vhalf));

		float diffuse = dot(input.normal, L);
		float specular = dot(input.normal, H);
		specular = pow(specular, 2);

		bump = 2.0*(diffuse + specular);

	color = saturate(color + spec);;
	if (_fog == 1)
		float l = saturate((input.Depth - FogStart) / (FogEnd - FogStart));
		color = float4(lerp(color,FogColor, l), 1);

	color.a = 1;

    return color;



Sorry for such a long post, but i kinda see you people as a last hope for this wink.png !


Thank You!

Share this post

Link to post
Share on other sites

You don't specify registers for your buffers so they might be different order than you expect.


Error message says it expects 208 bytes, which is 64 + 64 + 16 = float4x4 + float4x4 + float4 = ConstantObjectBuffer. This buffer has index 2 for some reason, you probably thought it's going to be 0.

Share this post

Link to post
Share on other sites

didn't go through all the code... so this may not be applicable

  • this is HLSL code as far as i can tell... use fxc.exe  to test your shader code explicitly without having to feed it any the top of the output it gives you info of what sizes the shader expects for all your constant buffers. fxc.exe is part of the directx sdk for windows 7 and below, and (afaik) part of the windows sdk as of windows 8.
  • make sure the sizes of your constant buffers in C++ match the sizes of the shaders'. easily done by making your struct mirror the cbuffer, and using sizeof() when mapping the memory.
  • make sure all your buffers are multiples of 16 (in bytes that is). i always found this restriction to be stupid, but probably has some performance reason.
  • make sure all buffers are actually created and mapped, send in dummy values if you have to.
  • make sure slot numbers are passed in correctly when calling the XXSetConstantBuffer() method, where XX is the appropriate shader stage.
  • make sure you set the buffers for the correct shader stage. (see your fxc output to find out what is expected where)

well this is a very general troubleshooting list, but running through these i usually solve all my constant buffer issues.

good luck,

   Tasche =)

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

Sign in to follow this  

  • Forum Statistics

    • Total Topics
    • Total Posts
  • Similar Content

    • By mellinoe
      Hi all,
      First time poster here, although I've been reading posts here for quite a while. This place has been invaluable for learning graphics programming -- thanks for a great resource!
      Right now, I'm working on a graphics abstraction layer for .NET which supports D3D11, Vulkan, and OpenGL at the moment. I have implemented most of my planned features already, and things are working well. Some remaining features that I am planning are Compute Shaders, and some flavor of read-write shader resources. At the moment, my shaders can just get simple read-only access to a uniform (or constant) buffer, a texture, or a sampler. Unfortunately, I'm having a tough time grasping the distinctions between all of the different kinds of read-write resources that are available. In D3D alone, there seem to be 5 or 6 different kinds of resources with similar but different characteristics. On top of that, I get the impression that some of them are more or less "obsoleted" by the newer kinds, and don't have much of a place in modern code. There seem to be a few pivots:
      The data source/destination (buffer or texture) Read-write or read-only Structured or unstructured (?) Ordered vs unordered (?) These are just my observations based on a lot of MSDN and OpenGL doc reading. For my library, I'm not interested in exposing every possibility to the user -- just trying to find a good "middle-ground" that can be represented cleanly across API's which is good enough for common scenarios.
      Can anyone give a sort of "overview" of the different options, and perhaps compare/contrast the concepts between Direct3D, OpenGL, and Vulkan? I'd also be very interested in hearing how other folks have abstracted these concepts in their libraries.
    • By turanszkij
      If I do a buffer update with MAP_NO_OVERWRITE or MAP_DISCARD, can I just write to the buffer after I called Unmap() on the buffer? It seems to work fine for me (Nvidia driver), but is it actually legal to do so? I have a graphics device wrapper and I don't want to expose Map/Unmap, but just have a function like void* AllocateFromRingBuffer(GPUBuffer* buffer, uint size, uint& offset); This function would just call Map on the buffer, then Unmap immediately and then return the address of the buffer. It usually does a MAP_NO_OVERWRITE, but sometimes it is a WRITE_DISCARD (when the buffer wraps around). Previously I have been using it so that the function expected the data upfront and would copy to the buffer between Map/Unmap, but now I want to extend functionality of it so that it would just return an address to write to.
    • By mister345
      Trying to write a multitexturing shader in DirectX11 - 3 textures work fine, but adding 4th gets sampled as black!
      Could you please look at the textureClass.cpp line 79? - I'm guess its D3D11_TEXTURE2D_DESC settings are wrong, 
      but no idea how to set it up right. I tried changing ArraySize from 1 to 4, but does nothing. If thats not the issue, please look
      at the LightShader_ps - maybe doing something wrong there? Otherwise, no idea.
          // Setup the description of the texture.
          textureDesc.Height = height;
          textureDesc.Width = width;
          textureDesc.MipLevels = 0;
          textureDesc.ArraySize = 1;
          textureDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
          textureDesc.SampleDesc.Count = 1;
          textureDesc.SampleDesc.Quality = 0;
          textureDesc.Usage = D3D11_USAGE_DEFAULT;
          textureDesc.BindFlags = D3D11_BIND_SHADER_RESOURCE | D3D11_BIND_RENDER_TARGET;
          textureDesc.CPUAccessFlags = 0;
          textureDesc.MiscFlags = D3D11_RESOURCE_MISC_GENERATE_MIPS;
      Please help, thanks.
    • By GameDevCoder
      I have to learn DirectX for a course I am studying. This book I felt would be great for me to learn from.
      The trouble is the examples which are all offered here . They do not work for me. This is a known issue as there is a link on the examples page saying how to fix it. I'm having difficulty with doing this though. This is the page with the solution
      The reason why this problem is happening, the book was released before Windows 10 was released. Now when the examples are run they need slight fixes in order for them to even work. I just can't get these examples working at all.
      Would anyone be able to help me get the examples working please. I am running Windows 10 also just to make this clear, so this is why the examples are experiencing the not so desired behaviour. I just wish they would work straight away but there seems to be issues with the examples from this book mainly because of it trying to run from a Windows 10 OS.
      On top of this, if anyone has any suggestions with how I can learn DirectX 11 i would be most grateful. Thanks very much. I really would like to get them examples working to though from the book I mentioned.
      Look forward to reading any replies this thread receives.

      PS - If anyone has noticed. I asked this about 1 year ago also but this was when I was dabbling in it. Now I am actually needing to produce some stuff with DirectX so I have to get my head round this now. I felt at the time that I sort of understood what was being written to me in response to my thread back then. I had always been a little unsure though of being absolutely sure of what was happening with these troublesome examples. So I am really just trying to get to the bottom of this now. If anyone can help me work these examples out so I can see them working then hopefully I can learn DirectX 11 from them.
      *SOLUTION* - I was able to get the examples running thanks to the community. Great work guys. I'm so please now that I can learn from this book now I have the examples running.
    • 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. It also 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. The engine contains shader source code converter that allows shaders authored in HLSL to be translated to GLSL.
      The engine currently supports Direct3D11, Direct3D12, and OpenGL/GLES on Win32, Universal Windows and Android platforms.
      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); Build Instructions
      Please visit this page for detailed build instructions.
      The engine contains two graphics samples that demonstrate how the API can be used.
      AntTweakBar sample demonstrates how to use AntTweakBar library to create simple user interface. It can also be thought of as Diligent Engine’s “Hello World” example.

      Atmospheric scattering sample is a more advanced one. 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 engine also 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.

  • Popular Now