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OpenGL Vulkan is Next-Gen OpenGL

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I was trying to bring up the fact that some people believe that Microsoft sabotaged the OpenGL implementation on Windows to increase DirectX adoption. And whether Microsoft will allow Vulkan and Mantle to be first-class citizens with DX12 (if it's even possible) and whether Microsoft will keep their open-source friendly ways up (like Promit mentioned).

 

IIRC, Apple has to explicitly allow support for new APIs because they write their own drivers. So "it just works" isn't always possible.

 

The story I heard was that the Windows NT team had OpenGL because they wanted to break into the CAD workstation market.  The Windows 95 team wanted OpenGL for games, the NT team wouldn't play ball, and hence DirectX (or more specifically Direct3D because DirectX already existed) was born.  If that was the case, any sabotage was internal.  If you've ever had to deal with Microsoft in a professional capacity that's perfectly believable.

 

As for open-source friendliness, it hardly seems relevant; it was never the case that OpenGL was open-source (it's not even software so it can't be).

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I was trying to bring up the fact that some people believe that Microsoft sabotaged the OpenGL implementation on Windows to increase DirectX adoption.


Yes, people do enjoy painting MS as the 'big bad' in all of this when, truth be told, 99% of OpenGL's problems were caused by ARB infighting and incompetence (see GL2.0 and Longs Peak/GL3.0) - the worst MS ever did was fix their software version back on GL1.1 and not ship GL drivers/dlls via Windows update for updated graphics drivers (which is a pain, but given they don't test that component I can see why), but they never actively sabotaged things.
(btw, if your source for this was the Wolfire blog from some time back then... well, forget you read it, it was trash frankly.)

The biggest tell in all of this is the utter amazement which has been expressed by many long time graphics programmers that Valkan seems, well, sane and well thought out.. I think many of us are still waiting for the other shoe to drop and won't be 100% convinced until we have working drivers in our hands to play with/test.

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I was trying to bring up the fact that some people believe that Microsoft sabotaged the OpenGL implementation on Windows to increase DirectX adoption.


Yes, people do enjoy painting MS as the 'big bad' in all of this when, truth be told, 99% of OpenGL's problems were caused by ARB infighting and incompetence (see GL2.0 and Longs Peak/GL3.0) - the worst MS ever did was fix their software version back on GL1.1 and not ship GL drivers/dlls via Windows update for updated graphics drivers (which is a pain, but given they don't test that component I can see why), but they never actively sabotaged things.

 

https://www.opengl.org/archives/about/arb/meeting_notes/

Go dig in there and see for yourself what Microsoft was doing back when they were part of the ARB.

 

For instance:

 

March 5, 2002
 
ARB_vertex_program:
"Microsoft wanted to alleviate concerns about their statement last week regarding possible claims on vertex program IP. Dave Aronson apologized for the perception that they aren't acting in good faith. They are trying to follow ARB regulations about stating IP as much as possible. When a vote was imminent, they reviewed and felt that they had patents or patents pending covering vertex programming. They do plan on coming up with licensing terms, and have set a hard deadline for themselves of 2 weeks before the June ARB meeting."
 
June 18, 2002
 
ARB_vertex_program:
"Microsoft believes they have patent rights relating to the ARB_vertex_program extension. They did not contribute to the extension, but are trying to be upfront about it. They're offering to license their IP under reasonable and nondiscriminatory terms; will license rights to the extent necessary, provided a reciprocal license is granted to MS. Granted on 1:1 basis for OpenGL 1.3, 1.4, and earlier versions. Contact Dave Aronson for more specifics. Suzy asked Dave to circulate his statement to the participants' list."
 
ARB_fragment_program:
"Microsoft does believe they have IP claims against fragment shaders, too."
"Bill asked about Microsoft's IP position on just the program management framework; Dave was unable to comment at this point."
"Suzy asked Microsoft to figure out their IP claims, if any, against just the program management stuff."
 
September 18, 2002
 
ARB_fragment_program:
"Microsoft noted their previously mentioned IP claim. They were asked if they could be at all more specific as to what their claim was, and will follow up with their lawyers to determine this."

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Remember, Vulkan is going to be a huge pain in the ass compared to GL. The Vulkan API is _much_ cleaner, yes, but it also eschews all the hand-holding and conveniences of GL and forces you to manage all kinds of hardware state and resource migration manually. Vulkan does not _replace_ OpenGL; it simply provides yet another alternative.

The same is true in Microsoft land: D3D11.3 is being released alongside D3D12, bringing the new hardware features to the older API because the newer API is significantly more complicated to use due to the greatly thinner abstractions; it's expected that the average non-AAA developer will want to stick with the older, easier APIs.

THIS. A lot of people don't seem to get these are very low level APIs with a focus on raw memory manipulation and baking of objects/commands that are needed very frequently. You destroyed a texture while it was still in use? BAM! Graphics corruption (or worse, BSOD). You wrote to a constant buffer while it was still in use? Let the random jumping of objects begin! You manipulated the driver buffers and had an off-by-1 error? BAM! Crash or BSOD. Your shader has a loop and is reading the count from unitialized memory? BAM! TDR kicks in or system becomes highly unresponsive.
You need to change certain states more frequently than you thought? Too bad, turns out you need to make some architectural modifications to do what you want efficiently.

It's hard. But I love it, with great power comes great responsability. None of this is a show-stopper for people used to low level programming. But it is certainly not newbie friendly like D3D11 or GL were (if you considered those newbie friendly). Anyway, a lot of people learned hardcore programming back in the DOS days when it was a wild west. So may be this is a good thing. Edited by Matias Goldberg

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Remember, Vulkan is going to be a huge pain in the ass compared to GL. The Vulkan API is _much_ cleaner, yes, but it also eschews all the hand-holding and conveniences of GL and forces you to manage all kinds of hardware state and resource migration manually. Vulkan does not _replace_ OpenGL; it simply provides yet another alternative.

I started my engine with OGL1.2 and being at OGL2.1 + extensions now,I have removed a lot of this convenience OGL over time. I'm currently at the state of handling many things by buffers and in the application itself and that with OGL2.1 (allocate buffer, manage double/triple buffering yourself, handling buffer sync yourself etc.). Most likely I use only a few % of the API at all. I think that a modern OGL architecture (AZDO, using buffers everywhere including UBOs etc) will be close to what you could expect from vulkan and that if they expose some vulkan features as extensions (command buffer), then switching over to vulkan will not be a pain in the ass.

Edited by Ashaman73

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THIS. A lot of people don't seem to get these are very low level APIs with a focus on raw memory manipulation and baking of objects/commands that are needed very frequently. You destroyed a texture while it was still in use?

Come on, time has changed. Current game engines uses multithreading and multithreading is one of the best ways to kill your game project, still people are able to code games smile.png And as game-dev you just can't take all the easy to use OS multithreading support features (mutex, critical sections, synchronise language features etc.).

For rookie coders there will be still comfortable libs around and for professional coders this should not be a problem (thought some headache might be included). On the other hand, the other modern APIs will not take this burden from the developers too.

Edited by Ashaman73

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THIS. A lot of people don't seem to get these are very low level APIs with a focus on raw memory manipulation and baking of objects/commands that are needed very frequently. You destroyed a texture while it was still in use?

Come on, time has changed. Current game engines uses multithreading and multithreading is one of the best ways to kill your game project, still people are able to code games smile.png

It's not really the same. Multithreading problems can be debugged and there's a lot of literature and tools to understand them.
It's much harder to debug a problem that locks up your entire system every time you try to analyze it.
 

I'm currently at the state of handling many things by buffers and in the application itself and that with OGL2.1 (allocate buffer, manage double/triple buffering yourself, handling buffer sync yourself etc.). Most likely I use only a few % of the API at all. I think that a modern OGL architecture (AZDO, using buffers everywhere including UBOs etc) will be close to what you could expect from vulkan and that if they expose some vulkan features as extensions (command buffer), then switching over to vulkan will not be a pain in the ass.

If you're already doing AZDO with explicit synchronization then you will find these new APIs pleasing indeed. However there are breaking changes like how textures are being loaded and bound. Since there's no hazard tracking, you can't issue a draw call that uses a texture until the it is actually in GPU memory. Drivers were also handling residency for you, but since now they don't, out of GPU errors can be much more common unless you write your own residency solution. Also how textures are bound is going to change.
Then, in the case of D3D12, there's PSOs, which fortunately you should be already emulating them for forward compatibility.

Indeed, professional developers won't have much problems; whatever annoyance they may have is obliterated by the happiness from the performance gains. I'm talking from a rookie perspective. Edited by Matias Goldberg

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Hopefully Vulkan "drivers" won't exclude each other so that concurrently using gpus from multiple vendors is possible.

I even wonder how feasible it would be to use igpu (since they are common) for coarse depth rasterization for occlusion culling instead of course.


Hopefully Vulkan could also be used to write an opengl implementation on top of it. With such a standard implementation a lot of non conformity troubles would come to an end.

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I'd be excited to see the possibilities of using an HSA chip (APU) for compute and leaving the dedicated GPU for graphics.  Hopefully with AMD having a big stake in Vulkan and OpenCL 2.1 this will be possible.

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Explicit multi-device capabilities should be a standard part of all these next-gen APIs. Allowing dev's to implement SLI/Crossfire style Alternate Frame Rendering, split frame rendering, or other kind of workload splits, such as moving shadows or post-processing to another GPU, with the developer in control of synchronization and cross-GPU data transfers.

It also opens up the ability for one device to be used for graphics and another purely for compute, with different latencies on each device.

 

If Vulkan doesn't support this, I'll be quite surprised.

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Hopefully Vulkan could also be used to write an opengl implementation on top of it.

That might be fun as a pet project but otherwise I don’t see the point in subjecting yourself to the tortures that OpenGL driver writers had to endure for so long (and still will unless they got promoted).
The OpenGL API is significantly flawed, which is specifically why these kinds of major upgrades have been requested for so long(’s Peak).

 

It may be a fun and novel project to make a Nintendo Entertainment System® emulator, but since OpenGL still exists and will continue to exist and be maintained there’s no novelty in making an OpenGL API rewrite using Vulkan.

 

 

L. Spiro

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This will be quite interesting as it could potentially mean that a Crossfire/SLI system can accumulate VRAM instead of having to keep each card in a similar state.

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Ashaman73, on 04 Mar 2015 - 07:01 AM, said:

Matias Goldberg, on 04 Mar 2015 - 06:03 AM, said:

THIS. A lot of people don't seem to get these are very low level APIs with a focus on raw memory manipulation and baking of objects/commands that are needed very frequently. You destroyed a texture while it was still in use?

Come on, time has changed. Current game engines uses multithreading and multithreading is one of the best ways to kill your game project, still people are able to code games smile.png

It's not really the same. Multithreading problems can be debugged and there's a lot of literature and tools to understand them.
It's much harder to debug a problem that locks up your entire system every time you try to analyze it.


Ashaman73, on 04 Mar 2015 - 06:48 AM, said:

I'm currently at the state of handling many things by buffers and in the application itself and that with OGL2.1 (allocate buffer, manage double/triple buffering yourself, handling buffer sync yourself etc.). Most likely I use only a few % of the API at all. I think that a modern OGL architecture (AZDO, using buffers everywhere including UBOs etc) will be close to what you could expect from vulkan and that if they expose some vulkan features as extensions (command buffer), then switching over to vulkan will not be a pain in the ass.

If you're already doing AZDO with explicit synchronization then you will find these new APIs pleasing indeed. However there are breaking changes like how textures are being loaded and bound. Since there's no hazard tracking, you can't issue a draw call that uses a texture until the it is actually in GPU memory. Drivers were also handling residency for you, but since now they don't, out of GPU errors can be much more common unless you write your own residency solution. Also how textures are bound is going to change.
Then, in the case of D3D12, there's PSOs, which fortunately you should be already emulating them for forward compatibility.

Indeed, professional developers won't have much problems; whatever annoyance they may have is obliterated by the happiness from the performance gains. I'm talking from a rookie perspective.

I'm still not seeing a lot of issues here. Multithreading debugging is as hard as visual debugging. Most rookie coders will have a hard time using some profiler or debugger nevertheless and reproducing a multithreading issue only occuring in a fast environment (release mode) which can't be reproduced easily in a slower environment (debug mode) will drive many rookies crazy.

So, my point is just, that the new APIs, much like multithreading, will be not suited to beginners, but they are neither hard nor extensive difficult.

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That might be fun as a pet project but otherwise I don’t see the point in subjecting yourself to the tortures that OpenGL driver writers had to endure for so long (and still will unless they got promoted).
The OpenGL API is significantly flawed, which is specifically why these kinds of major upgrades have been requested for so long(’s Peak).

Yet it already happened more or less. As the shader languages came up most IHV removed the fix-pipeline and exchanged it with internal shaders. This could work for OpenGL too, everything got compiled to the intermediate language and delegated to the vulkan driver, why not ?

 

It would be interesting if only the shader code will use the intermediate language or all commands ?

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If Vulkan doesn't support this, I'll be quite surprised.


Well, it is based on Mantle and Mantle had that so I'm hoping they would have left that ability intact; the ImgTech blog example code has a 'graphicsQueue' variable in it which implies there are separate queues which can be made so I'm hoping this means the preservation of per-device queues and separate graphics and compute queues even if the memory transfer one has gone away (although I'd prefer if they kept all 3 but I could live with just the first chunk).

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That might be fun as a pet project but otherwise I don’t see the point in subjecting yourself to the tortures that OpenGL driver writers had to endure for so long (and still will unless they got promoted).
The OpenGL API is significantly flawed, which is specifically why these kinds of major upgrades have been requested for so long(’s Peak).

NVidia has solid GL drivers... but AMD/Intel could probably save themselves a lot of time and money if they could just completely scrap their own GL drivers and just make Vulkan drivers instead. A reliable, open-source GL->Vulkan layer would be very handy for them smile.png

 

It even makes a lot of sense for nVidia. This is a rather high-level thing (compared to a "real" OpenGL implementation) that you write once and never touch again afterwards, and pronto you have backwards compatibility for every card that you sold during the last 10 years, with no weird quirks and very little room for card-driver-combo specific bugs. Plus, every customer can trivially use old OpenGL programs on every new card that you sell in the future.

 

That's an immense advantage if you ask me. If nothing else, it's great for marketing.

 

There exist games that ask for OpenGL 3 or 4, and people will be playing them for another 10 years (fewer people every year, but there are people who still want to play DX9 games nowadays, so why not).

 

Customers who don't want to yank out another few ten thousands for new versions of their CAD software come to mind. They'd probably stick with their hardware (which is totally sufficient as it is, if you're being honest!) for another few years rather than having to update the hardware and the software. So, an IHV interested in selling hardware is somewhat forced to provide OpenGL too, just so the old software keeps working. Now you can let Vulkan do the heavy lifting, and it will run on your new cards on the unmodified OpenGL layer.

Edited by samoth

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NVidia has solid GL drivers... but AMD/Intel could probably save themselves a lot of time and money if they could just completely scrap their own GL drivers and just make Vulkan drivers instead.

That definitely was the case once, but I don't think I've had real trouble with an AMD or Intel driver in the past 5 years...

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I've read somewhere about also Intel already having a Vulkan demo but I forgot the link.

 

Personally Vulkan might save me the next PC update. I usually get a new PC every 5 years or so to keep up with games demands foremost X-Plane and FSX.

Now I should be able to keep my PC some years longer. wub.png

Curious about GDC Valve news coming today.

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NVidia has solid GL drivers... but AMD/Intel could probably save themselves a lot of time and money if they could just completely scrap their own GL drivers and just make Vulkan drivers instead.

That definitely was the case once, but I don't think I've had real trouble with an AMD or Intel driver in the past 5 years...
performance wise, NV still has a huge edge.
I don't imagine NV supporting an open source GL implementation, as it would mean giving up this advantage.

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      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 reenigne
      For those that don't know me. I am the individual who's two videos are listed here under setup for https://wiki.libsdl.org/Tutorials
      I also run grhmedia.com where I host the projects and code for the tutorials I have online.
      Recently, I received a notice from youtube they will be implementing their new policy in protecting video content as of which I won't be monetized till I meat there required number of viewers and views each month.

      Frankly, I'm pretty sick of youtube. I put up a video and someone else learns from it and puts up another video and because of the way youtube does their placement they end up with more views.
      Even guys that clearly post false information such as one individual who said GLEW 2.0 was broken because he didn't know how to compile it. He in short didn't know how to modify the script he used because he didn't understand make files and how the requirements of the compiler and library changes needed some different flags.

      At the end of the month when they implement this I will take down the content and host on my own server purely and it will be a paid system and or patreon. 

      I get my videos may be a bit dry, I generally figure people are there to learn how to do something and I rather not waste their time. 
      I used to also help people for free even those coming from the other videos. That won't be the case any more. I used to just take anyone emails and work with them my email is posted on the site.

      I don't expect to get the required number of subscribers in that time or increased views. Even if I did well it wouldn't take care of each reoccurring month.
      I figure this is simpler and I don't plan on putting some sort of exorbitant fee for a monthly subscription or the like.
      I was thinking on the lines of a few dollars 1,2, and 3 and the larger subscription gets you assistance with the content in the tutorials if needed that month.
      Maybe another fee if it is related but not directly in the content. 
      The fees would serve to cut down on the number of people who ask for help and maybe encourage some of the people to actually pay attention to what is said rather than do their own thing. That actually turns out to be 90% of the issues. I spent 6 hours helping one individual last week I must have asked him 20 times did you do exactly like I said in the video even pointed directly to the section. When he finally sent me a copy of the what he entered I knew then and there he had not. I circled it and I pointed out that wasn't what I said to do in the video. I didn't tell him what was wrong and how I knew that way he would go back and actually follow what it said to do. He then reported it worked. Yea, no kidding following directions works. But hey isn't alone and well its part of the learning process.

      So the point of this isn't to be a gripe session. I'm just looking for a bit of feed back. Do you think the fees are unreasonable?
      Should I keep the youtube channel and do just the fees with patreon or do you think locking the content to my site and require a subscription is an idea.

      I'm just looking at the fact it is unrealistic to think youtube/google will actually get stuff right or that youtube viewers will actually bother to start looking for more accurate videos. 
    • By Balma Alparisi
      i got error 1282 in my code.
      sf::ContextSettings settings; settings.majorVersion = 4; settings.minorVersion = 5; settings.attributeFlags = settings.Core; sf::Window window; window.create(sf::VideoMode(1600, 900), "Texture Unit Rectangle", sf::Style::Close, settings); window.setActive(true); window.setVerticalSyncEnabled(true); glewInit(); GLuint shaderProgram = createShaderProgram("FX/Rectangle.vss", "FX/Rectangle.fss"); float vertex[] = { -0.5f,0.5f,0.0f, 0.0f,0.0f, -0.5f,-0.5f,0.0f, 0.0f,1.0f, 0.5f,0.5f,0.0f, 1.0f,0.0f, 0.5,-0.5f,0.0f, 1.0f,1.0f, }; GLuint indices[] = { 0,1,2, 1,2,3, }; GLuint vao; glGenVertexArrays(1, &vao); glBindVertexArray(vao); GLuint vbo; glGenBuffers(1, &vbo); glBindBuffer(GL_ARRAY_BUFFER, vbo); glBufferData(GL_ARRAY_BUFFER, sizeof(vertex), vertex, GL_STATIC_DRAW); GLuint ebo; glGenBuffers(1, &ebo); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,GL_STATIC_DRAW); glVertexAttribPointer(0, 3, GL_FLOAT, false, sizeof(float) * 5, (void*)0); glEnableVertexAttribArray(0); glVertexAttribPointer(1, 2, GL_FLOAT, false, sizeof(float) * 5, (void*)(sizeof(float) * 3)); glEnableVertexAttribArray(1); GLuint texture[2]; glGenTextures(2, texture); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture[0]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); sf::Image* imageOne = new sf::Image; bool isImageOneLoaded = imageOne->loadFromFile("Texture/container.jpg"); if (isImageOneLoaded) { glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageOne->getSize().x, imageOne->getSize().y, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageOne->getPixelsPtr()); glGenerateMipmap(GL_TEXTURE_2D); } delete imageOne; glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texture[1]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); sf::Image* imageTwo = new sf::Image; bool isImageTwoLoaded = imageTwo->loadFromFile("Texture/awesomeface.png"); if (isImageTwoLoaded) { glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageTwo->getSize().x, imageTwo->getSize().y, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageTwo->getPixelsPtr()); glGenerateMipmap(GL_TEXTURE_2D); } delete imageTwo; glUniform1i(glGetUniformLocation(shaderProgram, "inTextureOne"), 0); glUniform1i(glGetUniformLocation(shaderProgram, "inTextureTwo"), 1); GLenum error = glGetError(); std::cout << error << std::endl; sf::Event event; bool isRunning = true; while (isRunning) { while (window.pollEvent(event)) { if (event.type == event.Closed) { isRunning = false; } } glClear(GL_COLOR_BUFFER_BIT); if (isImageOneLoaded && isImageTwoLoaded) { glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture[0]); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texture[1]); glUseProgram(shaderProgram); } glBindVertexArray(vao); glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr); glBindVertexArray(0); window.display(); } glDeleteVertexArrays(1, &vao); glDeleteBuffers(1, &vbo); glDeleteBuffers(1, &ebo); glDeleteProgram(shaderProgram); glDeleteTextures(2,texture); return 0; } and this is the vertex shader
      #version 450 core layout(location=0) in vec3 inPos; layout(location=1) in vec2 inTexCoord; out vec2 TexCoord; void main() { gl_Position=vec4(inPos,1.0); TexCoord=inTexCoord; } and the fragment shader
      #version 450 core in vec2 TexCoord; uniform sampler2D inTextureOne; uniform sampler2D inTextureTwo; out vec4 FragmentColor; void main() { FragmentColor=mix(texture(inTextureOne,TexCoord),texture(inTextureTwo,TexCoord),0.2); } I was expecting awesomeface.png on top of container.jpg

    • By khawk
      We've just released all of the source code for the NeHe OpenGL lessons on our Github page at https://github.com/gamedev-net/nehe-opengl. code - 43 total platforms, configurations, and languages are included.
      Now operated by GameDev.net, NeHe is located at http://nehe.gamedev.net where it has been a valuable resource for developers wanting to learn OpenGL and graphics programming.

      View full story
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