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OpenGL directx vs openGl

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i know there are a lot of topics in internet about which one is better or in which field which one is better, but i dont know the exact answer. i think these questions are mostly about exprience. and i want to know your exprience.

 

1) i read an article about valve engineers. it said opengl is faster than directx even on windows. is that true?

 

2) its said in directx programmer has more controll rather than opengl.

 

3) which one give better visuals about sahders or technology they use? is it make difference or that is all the same and depend only on programmer that work on them? what about built in effects, particles, lightening,...

4)as I searched in internet, there is no much difference between them, so why Microsoft introduced directx when there was opengl? or why is still developing it? a developer can use opengl for all platforms and forget pain of using a single platform api.

5) I see in engines like unity or unreal that says dx11 version or... it seems using new directx gives more important features. what are those features that can only be used on windows or xbox? are they just for editor or for last output game?

6) what is given in every update of those api,s? for example what is difference of dx10 and dx11? is this about new tools and functions or math or something else? so when in a graphic card is written it supports dx11 what does it mean?

thank you for helping

Edited by moeen k

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4)as I searched in internet, there is no much difference between them, so why Microsoft introduced directx when there was opengl? or why is still developing it? a developer can use opengl for all platforms and forget pain of using a single platform api.

I'm not the DX guy any more since changing to OpenGL in the early 2006's but OpenGL was intentially introduced as a graphics state machine a time when Microsoft was on the go for assimilating anything to force people using Windows and only Windows but that is an other story to tell. As far as I have read through the history of GL/DX, it was that GL was not made for high performance realtime graphics rather than be used as replacement for IrisGL from the Silicon Workstations in 1992. Its performance and capabilities were something of crappy and Microsoft decided itself to set a team for developing a counter product called Game SDK and later Direct X includign Direct 3D from version 3.0.

OpenGL itself was less standartised so anyone could develop its own extensions and platform/hardware specific functions for it. This and the lack of support on the early Microsoft Windows systems made developers go for Direct X instead even on the fact that Windows was the onlyx OS on Intel Computers that were much cheaper than Apples Macintosh.

OpenGL 2.0 got the shading model but also has had its fixed function pipeline when its legacy functions got depricated in version 3  and removed from 3.3 GL. When CX rises through its versions 7, 8 and 9 GL was fighting with its standards and extensions. In version 4.0 you have feeled 100 times more dynamic bound functions than core functions to use where DX takes this all for you into a code standard API.

 

1) i read an article about valve engineers. it said opengl is faster than directx even on windows. is that true?

Have read the same article but that anyways depends on hardware, what programs run in the background and how is the application coded. Using a wrapper library providing an avarage API for both may have one or the other be a bit faster

2) its said in directx programmer has more controll rather than opengl.

From my research this was true. When DX introduced command buffers for rendering OpenGL still seperates some management tasks from the user but Vulkan and DX 12 are now similar in there capabilities

3) which one give better visuals about sahders or technology they use? is it make difference or that is all the same and depend only on programmer that work on them? what about built in effects, particles, lightening

I think because of the history of both, DX hase more tutorials and books when some informations on GL are hard to find but on the other hand GL is a totally open standard when Microsoft dosent need to publish DX informations that go beyond how you use it

6) what is given in every update of those api,s? for example what is difference of dx10 and dx11? is this about new tools and functions or math or something else? so when in a graphic card is written it supports dx11 what does it mean?

Graphics cards are like CPUs, you need to know how to talkt to them on the software level. On newer DX versions may be new capabilities introduced that may for example be the command buffer. DX is like GL mostly a hardware driver talking to the GPU, managing memory and whatever so a graphics card that isnt DX11 ready may not understand and fail up to critically crash when instructions go wrong

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4) Win95 and WinNT both had their own graphics teams - one backed GL and one made their own API, and neither shared, so Windows ended up with both!


This is exactly what I understand the reason to have been from reading Alex St John's blog (http://www.alexstjohn.com/WP/2013/01/09/direct3d-vs-opengl/):

When Eric Engstrom approached the NT team about providing us with an OpenGL library to add 3D support to DirectX 2.0 we were turned down. The Windows NT team did not want Windows 95 to be competitive with Windows NT for professional graphics.


Summary is: Microsoft wanted to break into the professional graphics workstation market with Windows NT and they needed OpenGL in order to do that. So it was very much in Microsoft's best interest - strategically, financially, etc - to have solid OpenGL support.
Their consumer division also needed a 3D API (the first versions of DirectX didn't have a 3D API) but the NT team didn't wish to share, so the consumer team ended up buying up RenderMorphics and basing the first version of Direct3D on their Reality Lab API.
If two divisions of the same company not cooperating in this manner seems surprising, remember: this is Microsoft. If you've ever dealt with them in a professional capacity you'll know that this is exactly how they work.
If you look back at the history of the so-called "API war" all the evidence either supports or - at worst - doesn't contradict this version of events, so it certainly seems credible enough.
Some specific examples.
The first version of Windows 95 didn't have OpenGL; Windows NT 4 didn't have Direct3D.
Microsoft's positioning of OpenGL as a "CAD API" and Direct3D as a "games API".
Microsoft's maneuvering with the OpenGL MCD vs ICD driver model.
It can be popular in some quarters to make claims such as "Microsoft tried to kill OpenGL because they wanted a monopoly over 3D APIs" but the sequence of events as they happened just don't really support that.
-------
Finally, the statement that "a developer can use OpenGL on all platforms" just isn't true anyway. A developer cannot use OpenGL on the major console platforms. A developer can use OpenGL ES on Android (and ES doesn't support all OpenGL features so it's not the same API). OpenGL is a second-class citizen on Apple platforms. So the cross-platform advantage of using OpenGL just isn't actually there.

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Don't let GL's "portability" argument fool you.

I have to respectfully disagree here.  Every device with a GPU supports OpenGL.  DX is only supported on Windows and XBox.  OpenGL wins portability by a country mile.  Sure, different platforms and different manufacturers implement OpenGL differently, but I've been able to port my OpenGL engine between Objective-C, C#, Java, and Javascript/HTML5 in about a day per platform.

Otherwise, as you noted, they are the same.  For me, it comes down to this : If you are developing only for Windows platforms you should use DX.  Otherwise, you pretty much HAVE to use OpenGL.

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I have to respectfully disagree here.  Every device with a GPU supports OpenGL.

 

Be very careful. Several people who post on this forum actually have worked with major console devkits and on AAA titles - they have actual hands-on experience of which APIs are used and know what they're talking about.  Others are well-known and well-respected industry figures.  So when one of these people says "not every device supports OpenGL" - they're probably right.

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Every device with a GPU supports OpenGL.

PS4s contain a GPU, but doesn't support OpenGL natively.

 

its psgl but its said basically its some modification of opengl. portability is most obvois difference of dx and opengl. my question was mostly based on performance, quality and ease of use.

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its psgl but its said basically its some modification of opengl. portability is most obvois difference of dx and opengl. my question was mostly based on performance, quality and ease of use.


PSGL existed on PS3 only (its not on PS4) and was a sub-ES 1.0 (or maybe 1.1) implementation that was a wrapper built on top of it's native API but which nobody used because it's performance and functionality were dreadful.

That's basically where the "PS supports OpenGL" mythology came from.

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It is strictly insane to force OpenGL onto a console because there hardware is made for much more specific use than OpenGL is and vendor SDKs should know there hardware best

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Another point is that having a cross-platform graphics API is not actually as important as people think it is.

Graphics is after all only a small part of a game engine. A cross-platform graphics API won't get you sound, input, networking, memory management, file access, etc. Just using OpenGL won't magically make a game engine be cross-platform; you still have to deal with all of these other areas (and even something like SDL has platform-specific quirks once you go beyond trivial programs).

If you're targetting multiple platforms you're probably already using multiple graphics APIs anyway. If you're targetting PC, XBox and PS you're already using 3. Having to support multiple graphics APIs is a solved problem, so rather than ask "why wouldn't you use OpenGL?" you should be asking "why wouldn't you use the best API for each platform?" That's a much more interesting and useful question.

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as i searched i found some interesting info on wikipedia:

 

The PlayStation 4 features two graphics APIs, a low level API named GNM and a high level API named GNMX. Most people start with the GNMX API which wraps around GNM and manages the more esoteric GPU details in a way that's a lot more familiar if users are used to platforms like Direct3D 11. The developers of The Crew put a lot of work into the move to the lower-level GNM, and in the process the tech team found out just how much work DirectX does in the background in terms of memory allocation and resource management.[8]

Another key area of the game is its programmable pixel shaders.[8] Sony's own PlayStation Shader Language (PSSL) was introduced on the PlayStation 4.[9] It has been suggested[by whom?] that the PlayStation Shader Language is very similar indeed to the HLSL standard in DirectX 11, with just subtle differences that were eliminated for the most part through preprocessor macros

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Part of the problem with OpenGL is that design by committee just doesn't work.

Let's say there's a new feature that is proposed for a new version of the spec.  Vendors A and B would like to get it in, but vendor C's hardware doesn't support it.

Option 1 is that it goes in; vendor C are now in a position where they can't claim support for the new version but vendors A and B are happy.

Option 2 is that it doesn't go in; vendor C can now claim support for the new version but vendors A and B aren't happy.

Or we could do it the OpenGL way and massage the spec a little to allow vendor C to claim support for it but in a way that allows them to not actually support it, thereby keeping all of the vendors happy.  But now of course the poor programmer has to be aware of edge cases such as this.

The end result is that in the absence of a central controlling body putting a stop to this kind of nonsense, vendor-specific behaviour bubbles up into the core specification (let's look for how many times the term "implementation dependent" occurs in the GL spec) and the programmers and end-users are the ones who take the hit.

And just in case you're interested - the example I gave wasn't a contrived example to make OpenGL look bad: it actually happened.

How to try and get this into the core? Seems too small to do as an optional subset. Called a straw poll contingent on someone coming up with a "caps-bit like" interface that would let Intel claim to support it. Rob then suggested that we could change the spec to allow supporting counters with zero bits and calling out in the spec that query functionality should not be used in this case.

Edited by mhagain

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let me ask another question. there are some other available API,s like mantle and vulkan. what about them? are there replacements or additive stuff? is opengl being deprecated because of vulkan? is coding much the same or compeletly different? its said mantle has less overhead than both opengl and directx. 

can you give some explanation?

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as i searched a bit, mantle is implemented by AMD but after that AMD has helped kronos to make vulkan as a low overhead API with more controll over graphic card. its said API like GNM and GNMX and vulkan has coding style more like dx rather than opengl and vulkan supports many platforms like win lin and android. for some one in the middle of way of learning graphics proggraming, it seems better to concentrate more on directx. am i right?

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Microsoft had said that D3D11 was "mature" and was hinting that it could be the final version of the API. Khronos were similarly hinting about OpenGL4... But gamedevs wanted a PC API similar to the console API's (e.g. GCM, GNM), so AMD created Mantle as an example of what we could have, and then gave it to Khronos for free to force them to act (if you don't make a new API, we will replace you)... and they did, adopting Mantle and rebranding it as Vulkan faster than any of their previous API designs. Meanwhile, MS needed a console style API for the XboxOne, so AMD worked closely with them in the design of Direct3D12, which is very similar to Vulkan/Mantle.

So now we have:
D3D9 / GL2 -- legacy crap.
D3D11-feature-level-10 / GL3 -- legacy.
D3D11 / GL4 -- current "high level" APIs.
D3D12 / Vulkan -- current "low level" APIs.

D3D11 / GL will still stick around because they're EXTREMELY easier to use than the new low level APIs.
D3D12 / Vulkan move a lot of responsibilities out of the driver and into your game engine, so to use these APIs, you basically have to be able to write a GPU driver too :o

Khronos have hinted that they will develop a GL5 and a Vulkan2 in the future, as they're targeted at a different set of users each.

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      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 tutorials, sample applications, asteroids performance benchmark and an example Unity project that uses Diligent Engine in native plugin.
      Atmospheric scattering sample 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, Linux, Android, MacOS, and iOS platforms. Direct3D11, Direct3D12, OpenGL/GLES backends are now feature complete. Vulkan backend is coming next, and Metal backend is in the plan.
    • By LifeArtist
      Good Evening,
      I want to make a 2D game which involves displaying some debug information. Especially for collision, enemy sights and so on ...
      First of I was thinking about all those shapes which I need will need for debugging purposes: circles, rectangles, lines, polygons.
      I am really stucked right now because of the fundamental question:
      Where do I store my vertices positions for each line (object)? Currently I am not using a model matrix because I am using orthographic projection and set the final position within the VBO. That means that if I add a new line I would have to expand the "points" array and re-upload (recall glBufferData) it every time. The other method would be to use a model matrix and a fixed vbo for a line but it would be also messy to exactly create a line from (0,0) to (100,20) calculating the rotation and scale to make it fit.
      If I proceed with option 1 "updating the array each frame" I was thinking of having 4 draw calls every frame for the lines vao, polygons vao and so on. 
      In addition to that I am planning to use some sort of ECS based architecture. So the other question would be:
      Should I treat those debug objects as entities/components?
      For me it would make sense to treat them as entities but that's creates a new issue with the previous array approach because it would have for example a transform and render component. A special render component for debug objects (no texture etc) ... For me the transform component is also just a matrix but how would I then define a line?
      Treating them as components would'nt be a good idea in my eyes because then I would always need an entity. Well entity is just an id !? So maybe its a component?
      Regards,
      LifeArtist
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