Sign in to follow this  
Followers 0
BenS1

DX11
[DX11] Command Lists on a Single Threaded Renderer

12 posts in this topic

One of the new major features of DirectX 11 is its support for multithreaded rendering using Immediate and Deferred Contexts, however it seems to me that the ability to create a Command List would potentially be beneficial even for a single threaded renderer. Is this correct?

Basically a Command List is a more efficient way of submitting a number of state and draw commands than calling each API separately, so even if you do all your rendering on one thread it would still seem more efficient to use Command Lists to perform repeat lists of actions.

If this is correct, then why isn't this mentioned more? Why are Deferred Contexts pretty much exclusively documented as a multi threading feature?

Thanks
ben
0

Share this post


Link to post
Share on other sites
I'm pretty sure I remembered reading somewhere that the runtime/drivers weren't optimized for this case. However I still think it would be worth trying out, especially as the drivers get better support for deferred command list generation.
0

Share this post


Link to post
Share on other sites
[quote name='MJP' timestamp='1321297420' post='4883879']
I'm pretty sure I remembered reading somewhere that the runtime/drivers weren't optimized for this case. However I still think it would be worth trying out, especially as the drivers get better support for deferred command list generation.
[/quote]
You are right, I just ran a test on 10,000 cubes, single threaded:
[list][*]Immediate: 200 fps[*]Deferred: 150 fps[/list]So Deferred for single threaded application is slower (at least on my machine). Note that checking the threading support for command list for my graphics card (AMD 6970M) is returning false, so I assume that It is not supported natively by the driver but "emulated" by DX11...
0

Share this post


Link to post
Share on other sites
I'm not sure if the AMD GPU's support it yet, but my GTX 470 on latest drivers says that it does. I'll have to check on my HD 6970 when I get home.

If your test is easily packagable, I would be happy to try it out on my machine to see how it performs.
0

Share this post


Link to post
Share on other sites
[quote name='xoofx' timestamp='1321370413' post='4884183']
[quote name='MJP' timestamp='1321297420' post='4883879']
I'm pretty sure I remembered reading somewhere that the runtime/drivers weren't optimized for this case. However I still think it would be worth trying out, especially as the drivers get better support for deferred command list generation.
[/quote]
You are right, I just ran a test on 100,000 cubes, single threaded:
[list][*]Immediate: 200 fps[*]Deferred: 150 fps[/list]So Deferred for single threaded application is slower (at least on my machine). Note that checking the threading support for command list for my graphics card (AMD 6970M) is returning false, so I assume that It is not supported natively by the driver but "emulated" by DX11...
[/quote]
I would caution against making blanket statements about the performance of single vs. deferred rendering - it totally depends on what your renderer does when it is submitting work to the API. For example, if your engine does lots of work in between the API calls that it makes, then it would likely be beneficial to utilize multiple threads which could reduce the total time needed to process a rendering path. On the other hand, if your submission routines are very bare bones and only submits API calls, there could be some benefit to compiling a long list of commands into a command list and then reusing it from frame to frame. This will depend on the hardware, the driver, your engine, and the application that is using your engine - you need to profile and see if it is worth it in a given context. You could even dynamically test it out on the first startup of your application and then choose the appropriate rendering method.

To that end - I would suggest setting up your rendering code to not know if it is using a deferred or immediate context so that you can delay the decision as long as possible as to which method you will use. That is just my own suggestion though - I have found it to be useful, but your mileage may vary!
1

Share this post


Link to post
Share on other sites
[quote name='xoofx' timestamp='1321370413' post='4884183']
[quote name='MJP' timestamp='1321297420' post='4883879']
I'm pretty sure I remembered reading somewhere that the runtime/drivers weren't optimized for this case. However I still think it would be worth trying out, especially as the drivers get better support for deferred command list generation.
[/quote]
You are right, I just ran a test on 100,000 cubes, single threaded:
[list][*]Immediate: 200 fps[*]Deferred: 150 fps[/list]So Deferred for single threaded application is slower (at least on my machine). Note that checking the threading support for command list for my graphics card (AMD 6970M) is returning false, so I assume that It is not supported natively by the driver but "emulated" by DX11...
[/quote]

Thanks all

xoofx, in your test do you re-create the command list every frame, or do you create the command list once at startup and then just re-execute it every frame?

I'm amazed that AMD cards don't support multithreading at the driver level yet!

I'd be interested in seeing the results on a NVidia card too.

Thanks
Ben
0

Share this post


Link to post
Share on other sites
If have released the executable test along some analysis about the results [url="http://code4k.blogspot.com/2011/11/direct3d11-multithreading-micro.html"]here[/url].

Of course, I agree with Jason.Z statements about taking carefully this kind of results, and the fact that a renderer can easily be built to switch transparently from a deferred context to an immediate context.

To respond to your initial question BenS1, It seems that hardware support for command list doesn't seems to change a lot (using a pre-prepared command list once and run it on an immediate context) compare to using the default Direct3D11 behavior.
0

Share this post


Link to post
Share on other sites
The problem with using a deferred context in a single threaded system is that you are doing more work per core in that situation; you have to prepare the CL, which takes some extra CPU overhead as the driver needs to do things and then you have to reaccess it again to send it to the card properly. Spread across multiple threads the cost-per-setup drops significantly and, if you batch them, your send arch will benifit greatly from code cache reuse (and depending on how it's stored maybe some data cache too).

Any speed gain also depends very much on what you are doing; in a test case at work which was setup to be heavily CPU bound, switching on mutli-threading CL support when NV's drivers were updated to fix it did give us a speed boost however it wasn't that much. I then spent some time playing with the test case and discovered that when we got over a certain threshold for data per CL we started spending more and more time in the buffer swapping function than anywhere else in the submission due to the driver having to do more. (I can't recall the specifics but from what I do recall drivers are limited memory wise or something like that... basically we blew a buffer right out).

However up until that point the MT CL rendering WAS making a significant difference with our CPU time usage and we had near perfect scaling [b]for the test case[/b].

The key point from all this; MT CL, if implimented by the drivers, will help but ONLY your CPU time.

I make a point of saying this because there is no 'hardware support' for CL; Command Lists are purely a CPU side thing, the difference is between letting the DX11 runtime cache the commands or letting the driver cache them and optimise them. (AMD still lacks support for this, although it is apprently 'coming soon')

(Also, as a side note, I do recall reading that 'create, store and reuse' isn't an optimal pattern for command lists. The runtime isn't really setup for this case and it assumes you'll be remaking them each frame, which is a fair assumption because as you can't chain them together to adjust each others state and most command lists will change each frame in a 'real world' situation it is best to test against this)
0

Share this post


Link to post
Share on other sites
[quote name='phantom' timestamp='1321785963' post='4885837']
I then spent some time playing with the test case and discovered that when we got over a certain threshold for data per CL we started spending more and more time in the buffer swapping function than anywhere else in the submission due to the driver having to do more. (I can't recall the specifics but from what I do recall drivers are limited memory wise or something like that... basically we blew a buffer right out).[/quote]
this could come from the Map/UnMap on command buffers, with an immediate context that is giving directly a kind of DMA to the GPU memory, but with a deferred context, it has to copy to a temporary buffer (which is probably on the RAM, but not sure it is on a shared memory on the GPU)...

[quote name='phantom' timestamp='1321785963' post='4885837']
I make a point of saying this because there is no 'hardware support' for CL; Command Lists are purely a CPU side thing, the difference is between letting the DX11 runtime cache the commands or letting the driver cache them and optimise them. (AMD still lacks support for this, although it is apprently 'coming soon')
[/quote]
Indeed, if it is natively supported by the driver, It can be optimized. A coworker found also on NVIDIA a performance boost when they introduced support for command list, though on AMD, It is already fine without the support from the driver... probably the command buffer on AMD is already layout in the same way DirectX11 command buffer is layout...
0

Share this post


Link to post
Share on other sites
[quote name='xoofx' timestamp='1321774033' post='4885817']
If have released the executable test along some analysis about the results [url="http://code4k.blogspot.com/2011/11/direct3d11-multithreading-micro.html"]here[/url].

Of course, I agree with Jason.Z statements about taking carefully this kind of results, and the fact that a renderer can easily be built to switch transparently from a deferred context to an immediate context.

To respond to your initial question BenS1, It seems that hardware support for command list doesn't seems to change a lot (using a pre-prepared command list once and run it on an immediate context) compare to using the default Direct3D11 behavior.
[/quote]

Wow, great article! Thanks.

Its a shame that the results show that command lists aren't really a faster way of repeating the same drawing commands over and over for a single threaded renderer.

I suspect they have the potential to be faster if the driver developers had sufficient motivation to optimise this area of their code, especially if they optimised the command list when you call FinishCommandList. I guess the problem is that the driver has no idea if you're only going to use the command list once and throw it away (In which case the act of optimising the command list may cost more than the potential gains), if if you're going to create the comand list once and execute it many times (In which case optimisng the list may be beneficial).

I guess we'd need a tweak to the API so that you can either pass in a boolean to FinishCommandList to tell the driver whether the command list should be optimised or not, or maybe there could be a separate explicit OptimizeCommandList method.

Thanks again for your detailed analysis.

Thanks
Ben
0

Share this post


Link to post
Share on other sites
[quote name='phantom' timestamp='1321785963' post='4885837']
The problem with using a deferred context in a single threaded system is that you are doing more work per core in that situation; you have to prepare the CL, which takes some extra CPU overhead as the driver needs to do things and then you have to reaccess it again to send it to the card properly. Spread across multiple threads the cost-per-setup drops significantly and, if you batch them, your send arch will benifit greatly from code cache reuse (and depending on how it's stored maybe some data cache too).

<snip>

(Also, as a side note, I do recall reading that 'create, store and reuse' isn't an optimal pattern for command lists. The runtime isn't really setup for this case and it assumes you'll be remaking them each frame, which is a fair assumption because as you can't chain them together to adjust each others state and most command lists will change each frame in a 'real world' situation it is best to test against this)
[/quote]

Thanks Phantom, but in my case I was thinking of creating the command list once and then executing it for each frame.

As I'm sure you know, a command list containing a constant buffer will only contain references (Or pointers) to the constant buffer and not the actual data containined int he buffer itself, so an app can still change the data in the constant buffer from frame to frame without having to create a new command list.

So for example I was thinking:
1. At startup create a command list (DrawTankCL) that draws a Tank at a position defined in a Contant Buffer ("TankCB")
2. Update TankCB.position on the CPU based on user input, physics etc
3. ExecuteCommandList(DrawTankCL)
4. Repeat from step 2.

As you can see the command list is created once and executed over and over, and yet the tanks posiiton is still dynamic.

Its a shame that this "create, store, reuse" pattern is not optimised int he drivers.

Anyway, at least now I know the answer so I code my game accordingly.

Thanks for your help
Ben
0

Share this post


Link to post
Share on other sites
There are two problems with your idea.

Firstly, you are being too fine grain with your CL for it to really be useful. There is a good PDF from GDC2011 which covers some of this (google: Jon Jansen DX11 Performance Gems, that should get you it). The main thing is that a CL has overhead, apprently a few dozen API calls so doing too little work in one is going to be a problem as it will just get swamped with overhead. Depending on your setup scenes or material groups are better fits for CL building and execution.

Secondly; you run the risk of suffering a stall at step 2. The driver buffers commands and the GPU should be working at the same time as you execute other work, so there is a chance that when you come to update in step 2 you could be waiting a 'significant' amount of time for the GPU to be done with your buffer and release it so that you can update it again. Discard/lock or other update [i]might[/i] avoid the problem, I've not tried it myself, but it still presents an issue.
0

Share this post


Link to post
Share on other sites
[quote name='xoofx' timestamp='1321790455' post='4885852']
Indeed, if it is natively supported by the driver, It can be optimized. A coworker found also on NVIDIA a performance boost when they introduced support for command list, though on AMD, It is already fine without the support from the driver... probably the command buffer on AMD is already layout in the same way DirectX11 command buffer is layout...
[/quote]

NV is a strange beast; before they had 'proper' support they kinda emulated it by spinning up a 'server' thread and serialising the CL creation via that. Amusingly if any of your active threads ended up on the same core as the server thread it tended to murder performance but by staying clear you could get a small improvement. Once the drivers came out which did the work correctly this problem went away.

In our test NV with proper support soundly beat AMD without it; this was a 470GTX vs 5870 on otherwise basically identical hardware (i7 CPUs, the NV one had a few hundred Mhz over the AMD one, but not enough for the performance delta seen). AMD's performance was more in line with the single thread version. However our test was a very heavy CPU bound one; 15,000 draw calls spread over 6 cores each one drawing a single flat shaded cube. Basically an API worse nightmare ;)

(Amusing side note; the same test/code on an X360 @ 720p could render at a solid 60fps with a solid 16.6ms frame time. That's command lists being generated each frame over 6 cores; shows just how much CPU overhead/performance loss you take when running on Windows :( )
0

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  
Followers 0

  • Similar Content

    • By AxeGuywithanAxe
      So I wanted to ask a question pertaining to rendering thread architecture. I currently know of two main designs.
      One approach is where visibility , drawcall logic, and gpu submission are all done on the rendering thread and render related game data is sent to the rendering thread at the end of the frame. 
      The second approach is where the sole responsibility of the rendering thread is to send gpu commands to the api. Engine abstacted Command Buffers will be generated in parallel or on the game thread, and sent to the rendering thread to be translated into gpu commands.
      I know that Engines such as Unreal Engine use the first approach, while Unity / Source use the second approach , and Cryengine uses a hybrid of both. I wanted to see if anyone could give some advice, I know some of the benefits of both approaches , but wanted to get more incite on the architecture.
    • By Cyndanera
      I new here, anyways how would I load a b3d model? three files mesh,animation,skeleton
      and play animation from model, new to directx.
      b3d format was created by blitzbasic.
      https://www.blitzbasic.com/sdkspecs/sdkspecs/b3dfile_specs.txt
    • By Enitalp
      Hi all.
      I have a direct2d1 application with all my UI. And now i'm trying to insert 3d rendering in my UI. I tried a lot of thing as i'm new to that. and failed....
      So my UI contain a control that is a 3d render. so stupidly i was thinking of making a 3d rendertarget, get the bitmap of that. and draw it at the place of my control.
      So i created this function
      public Bitmap1 CreateTarget(int i_Width, int i_Height) { Texture2DDescription l_Description = new Texture2DDescription(); l_Description.BindFlags = BindFlags.RenderTarget; l_Description.Format = m_BackBuffer.Description.Format; l_Description.Width = i_Width; l_Description.Height = i_Height; l_Description.Usage = ResourceUsage.Default; l_Description.ArraySize = 1; l_Description.MipLevels = 1; l_Description.SampleDescription = new SampleDescription(1, 0); l_Description.CpuAccessFlags = CpuAccessFlags.None; l_Description.OptionFlags = ResourceOptionFlags.None; Texture2D l_RenderTarget = new Texture2D(m_Device, l_Description); BitmapProperties1 properties = new BitmapProperties1() { PixelFormat = new PixelFormat(l_Description.Format, SharpDX.Direct2D1.AlphaMode.Premultiplied), BitmapOptions = BitmapOptions.Target, DpiX=96, DpiY = 96 }; Bitmap1 m_OffscreenBitmap; using (Surface l_Surface = l_RenderTarget.QueryInterface<Surface>()) { m_OffscreenBitmap = new Bitmap1(m_2DContext, l_Surface, properties); } return m_OffscreenBitmap; }  
      And my control does a simple :
      if (m_OldSize != Size) { m_OldSize = Size; if (m_OffscreenBitmap != null) { m_OffscreenBitmap.Dispose(); } m_OffscreenBitmap = i_Param.CurrentWindow.CreateTarget(Size.Width, Size.Height); } i_Context.DrawContext2D.DrawBitmap(m_OffscreenBitmap, m_Rect, 1.0f, BitmapInterpolationMode.Linear);  
      Here is my problem, if BitmapOptions is different from BitmapOptions = BitmapOptions.Target | BitmapOptions.CannotDraw
      i crash when creating my new Bitmap1 because of invalid params.
      and if i let it, i crash at present because :
      Additional information: HRESULT: [0x88990021], Module: [SharpDX.Direct2D1], ApiCode: [D2DERR_BITMAP_CANNOT_DRAW/BitmapCannotDraw], Message: Impossible de dessiner avec une bitmap qui a l’option D2D1_BITMAP_OPTIONS_CANNOT_DRAW.
       
      I must admit i'm out of idea. and i'm stuck. Please help.
      Does my method is totally wrong ?
      I tried to make my control owning is own 3d device so i can render that at a different pace than the 2d and did get the same result
       
       
       
       
    • By ErnieDingo
      Before you read, apologies for the wall of text!  
      I'm looking to leverage efficiencies in DirectX 11 calls, to improve performance and throughput of my game.  I have a number of bad decisions I am going to remedy, but before I do, I am just wanting to get input into I should put effort into doing these.
      I've been running for a while with a high frame rate in my game, but as I add assets, its obviously dipping (its a bit of an n squared issue).  I'm fully aware of the current architecture, and I'm looking to take care of some severe vertex buffer thrashing i'm doing at the moment. 
      Keep in mind, the game engine has evolved over the past year so some decisions made at that time in hindsight are considered bad, but were logical at the time.
      The scenarios:
      Current: my game world is broken up by quad tree.  I'm rendering the terrain geometry and water geometry separately and in different vertex buffers.   Currently I am using Raw Draw Calls which means that I am very wasteful on computational power.  
      Goal: Use Index buffers to reduce vertices by 80%, compress my index buffers and vertex buffers into one index buffer and vertex buffer.  I can't reduce the number of draw calls as its per leaf.
      Current: Static assets such as trees etc are bound to each leaf of my quad tree, as I traverse the tree to see whats in view/out of view, I trim the leaf which in turn trims all the static assets.  This means there is an instance buffer for each node AND for each mesh.  
      Goal: Compress the instance Buffers into one instance buffer per mesh (Ie, even if 10 meshes are in 1 vertex buffer, I need 10 instance buffers), for all meshes, compress the meshes into 1 index buffer and 1 vertex buffer.  I can not reduce the number of draw calls.
      Current: My unlimited sea function reuses the same tile mesh and just remaps with a constant buffer.  This means, if there are 10 tiles, there are 10 draw calls and 10 constant buffer updates.
      Goal: Simple, Use an instance buffer and remove the constant buffer updates (I was lazy and wanted to do this quick :)).  Reduces it to 1 draw call, 1 instance buffer bind and 1 vertex buffer bind.
      Current: Each shader, i'm rebinding the same constant buffers, these buffers only change at the start of a new scene (shadow AND rendered).  
      Goal: Create a map of buffers to be bound once per context, use consistent registers.   Combine wasteful buffer structures into 1 buffer.  Reduce number of constant changes.  More negligible for deferred contexts but still worth it.
      All these changes are not difficult as I have layered my graphics engine in such a way that it doesn't disturb the lower levels.  Ie. Instance management is not bound to mesh directly, mesh management allows for compression easily.    All static buffers are set immutable in my game, so vertex, index and most index buffers are immutable.
      So the questions: 
      - Are some or all changes worth it?  Or am I going to just suffer from draw calls?  
      - I am assuming at the moment that Setting vertex buffers, index buffers, instance buffers are part of the command buffer?  Is this correct, i'm looking to reduce the number of calls pushed through it.
      - I assume in a deferred context world, that constant buffers when set are not persistent across contexts when I execute command lists.
      - Lastly, should I look into Draw Indexed instanced indirect to accumulate draw calls?  And would I get any benefit from the GPU side doing this?
       
       
       
    • By Zototh
      I am using slimDX and am having a problem with a shader. I have an instance Shader that works perfect but I needed one for drawing fonts manually. The idea is to create the plane and simple instance it with separate position color and texture coordinates for each char.  I know this post is terribly long but any help would be appreciated. I tried to provide everything needed but if you need more I will be glad to post it.
      This is the shader. the only difference between it and the working one is the instance texture coordinates. I was able to render 4,000 spheres with 30,000 faces with the original and still maintain a 100+ framerate. I don't know if that is a lot but it looked like it to me.
      cbuffer cbVSPerFrame:register(b0) { row_major matrix world; row_major matrix viewProj; }; Texture2D g_Tex; SamplerState g_Sampler; struct VSInstance { float4 Pos : POSITION; float3 Normal : NORMAL; float2 Texcoord : TEXCOORD0; float4 model_matrix0 : TEXCOORD1; float4 model_matrix1 : TEXCOORD2; float4 model_matrix2 : TEXCOORD3; float4 model_matrix3 : TEXCOORD4; // this is the only addition float2 instanceCoord:TEXCOORD5; float4 Color:COLOR; }; struct PSInput { float4 Pos : SV_Position; float3 Normal : NORMAL; float4 Color:COLOR; float2 Texcoord : TEXCOORD0; }; PSInput Instancing(VSInstance In) { PSInput Out; // construct the model matrix row_major float4x4 modelMatrix = { In.model_matrix0, In.model_matrix1, In.model_matrix2, In.model_matrix3 }; Out.Normal = mul(In.Normal, (row_major float3x3)modelMatrix); float4 WorldPos = mul(In.Pos, modelMatrix); Out.Pos = mul(WorldPos, viewProj); Out.Texcoord = In.instanceCoord; Out.Color = In.Color; return Out; } float4 PS(PSInput In) : SV_Target { return g_Tex.Sample(g_Sampler, In.Texcoord); } technique11 HWInstancing { pass P0 { SetGeometryShader(0); SetVertexShader(CompileShader(vs_4_0, Instancing())); SetPixelShader(CompileShader(ps_4_0, PS())); } } this is the input elements for the 2 buffers
      private static readonly InputElement[] TextInstance = { new InputElement("POSITION", 0, Format.R32G32B32_Float, 0, 0, InputClassification.PerVertexData, 0), new InputElement("NORMAL", 0, Format.R32G32B32_Float, InputElement.AppendAligned, 0, InputClassification.PerVertexData, 0), new InputElement("TEXCOORD", 0, Format.R32G32_Float, InputElement.AppendAligned, 0, InputClassification.PerVertexData, 0), new InputElement("TEXCOORD", 1, Format.R32G32B32A32_Float, 0, 1, InputClassification.PerInstanceData, 1 ), new InputElement("TEXCOORD", 2, Format.R32G32B32A32_Float, InputElement.AppendAligned, 1, InputClassification.PerInstanceData, 1 ), new InputElement("TEXCOORD", 3, Format.R32G32B32A32_Float, InputElement.AppendAligned, 1, InputClassification.PerInstanceData, 1 ), new InputElement("TEXCOORD", 4, Format.R32G32B32A32_Float, InputElement.AppendAligned, 1, InputClassification.PerInstanceData, 1 ), new InputElement("TEXCOORD", 5, Format.R32G32_Float, InputElement.AppendAligned, 1, InputClassification.PerInstanceData, 1 ), new InputElement("COLOR", 0, Format.R32G32B32A32_Float, InputElement.AppendAligned, 1, InputClassification.PerInstanceData, 1 ) }; the struct for holding instance data. 
      [StructLayout(LayoutKind.Sequential)] public struct InstancedText { public Matrix InstancePosition; public Vector2 InstanceCoords; public Color4 Color; }; instanceData buffer creation. Instance Positions is a simple List<InstancedText> above
      DataStream ds = new DataStream(InstancePositions.ToArray(), true, true); BufferDescription vbDesc = new BufferDescription(); vbDesc.BindFlags = BindFlags.VertexBuffer; vbDesc.CpuAccessFlags = CpuAccessFlags.None; vbDesc.OptionFlags = ResourceOptionFlags.None; vbDesc.Usage = ResourceUsage.Default; vbDesc.SizeInBytes = InstancePositions.Count * Marshal.SizeOf<InstancedText>(); vbDesc.StructureByteStride = Marshal.SizeOf<InstancedText>(); ds.Position = 0; instanceData = new Buffer(renderer.Device, vbDesc);  
      and finally the render code.
      the mesh is a model class that contains the plane's data. PositionNormalTexture is just a struct for those elements.
      renderer.Context.InputAssembler.InputLayout = new InputLayout(renderer.Device, effect.GetTechniqueByName("HWInstancing").GetPassByIndex(0).Description.Signature, TextInstance); renderer.Context.InputAssembler.PrimitiveTopology = PrimitiveTopology.TriangleList; renderer.Context.InputAssembler.SetVertexBuffers(0, new VertexBufferBinding(mesh.VertexBuffer, Marshal.SizeOf<PositionNormalTexture>(), 0)); renderer.Context.InputAssembler.SetIndexBuffer(mesh.IndexBuffer, SlimDX.DXGI.Format.R32_UInt, 0); renderer.Context.InputAssembler.SetVertexBuffers(1, new VertexBufferBinding(instanceData, Marshal.SizeOf<InstancedText>(), 0)); effect.GetVariableByName("g_Tex").AsResource().SetResource(textures[fonts[name].Name]); EffectTechnique currentTechnique = effect.GetTechniqueByName("HWInstancing"); for (int pass = 0; pass < currentTechnique.Description.PassCount; ++pass) { EffectPass Pass = currentTechnique.GetPassByIndex(pass); System.Diagnostics.Debug.Assert(Pass.IsValid, "Invalid EffectPass"); Pass.Apply(renderer.Context); renderer.Context.DrawIndexedInstanced(mesh.IndexCount, InstancePositions.Count, 0, 0, 0); }; I have been over everything I can think of to find the problem but I can't seem to locate it.
      my best guess is the instance data buffer is wrong somehow since VS graphics debugger shows no output from vertex shader stage
       but I just can't see where.
  • Popular Now