16
votes
What's the main difference of pipeline process between Vulkan and DX12?
D3D12 has 4 separate kinds of command lists: direct, bundle, compute, and copy.
Vulkan has similar concepts, but they happen in a different way. Command buffers are allocated from command pools. And ...
- 9,997
7
votes
Accepted
What mechanisms are being used by Directx12 and Vulkan APIs in order to communicate with graphic card drivers internally?
It's very different between the Khronos standards (including Vulkan) and DirectX.
In DirectX, Microsoft implements the API, but they publish to GPU vendors a HAL API. There's actually two HALs: one ...
- 6,880
5
votes
Accepted
How much does driver quality affect Vulkan and DX12 compared to OpenGL and DX11?
TL;DR: There's some room for optimization in Vulkan drivers, but not nearly to the degree that there is in GL / DX11 drivers.
how much do drivers affect performance?
It depends a great deal on ...
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4
votes
Accepted
mipmap selection process
Mipmap selection is done by looking at adjacent pixels on the screen, and finding how far apart their texture samples fall. The mip level is chosen so as to make the space between adjacent texture ...
- 25.3k
4
votes
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Path tracing - cannot converge diffuse sampling + oversaturation
One point: the Lambert BRDF is not $N\cdot L$, it's just the albedo divided by pi. The $N \cdot L$ factor comes from the $\cos \theta$ in the rendering equation. So, when sampling with a cosine-...
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4
votes
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How does ID3D12Resource::Map work?
There are two general ways the graphics driver can implement Map().
One way is to set up a virtual memory mapping that makes the resource's actual memory (could be ...
- 25.3k
4
votes
Accepted
Do we really need a fence event?
In your first example, the call to WaitForSingleObject blocks the thread. This puts it into a waiting state, which takes it off the run queue and allows other ...
- 6,880
3
votes
Accepted
Can D3D12 resource barriers be used to synchronize between the compute and 3D engine?
My understanding would be that resource barriers are not at all about synchronization. They are about memory ordering, which is a related but separate concern. Basically, synchronization is about ...
- 533
2
votes
DX12 compute signature
You're trying to map all three UAVs to the same descriptor slot (slot 0).
...
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2
votes
Compute Shader PSO Dx12
If I understand you correctly, you've added a new compute shader. In DX12, you'll need at least one separate PSO for each shader, since the shader code is part of the PSO.
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2
votes
Accepted
How can I control memory for command allocators and command queues in D3D12?
You don't.
These objects typically work with CPU memory, not device memory. And to the extent that they involve device memory, such allocations tend to be rare and/or fixed in size (a queue may have ...
- 9,997
2
votes
Accepted
Is there an analogue of OpenGL's ImageLoadStore in DirectX 12?
You should be able to use RWTexture3D.
The hlsl documentation page about RWTexture2D also has sample code that you might find useful.
- 1,871
2
votes
Accepted
Using array of textures in DX12
I think what you want for this is to create a descriptor table which lists your textures. The individual textures would be created and uploaded as ordinary Texture2Ds. You'd set up the root signature ...
- 25.3k
2
votes
Accepted
DXC error when compiling PSO
This can be caused by the compiler creating unsigned bytecode. For the compiler to sign the bytecode, you have to have a copy of dxil.dll in the same folder as the dxcompiler.dll at runtime. See Using ...
- 25.3k
2
votes
Accepted
Objects in depth buffer are always black (0.0)
That's how I used to initialize viewport (CD3DX12_VIEWPORT). But I didn't realize that there are two additional fields minDepth and maxDepth. Therefore, I have min/max depth set to 0.0 and objects ...
2
votes
What's different between D3D12_CPU_PAGE_PROPERTY_WRITE_COMBINE and D3D12_CPU_PAGE_PROPERTY_WRITE_BACK, and why they're named like that?
These are names for certain kinds of strategies for how the CPU gets to write to certain more CPU-distant memories.
Most CPU memory writes are cached; they're bundled together with other writes to ...
- 9,997
1
vote
How to orbit rotate a camera from a C++ program?
In order to orbit the camera around a specific point, you need to have that point available to the function that's doing the orbiting. So lets have the signatures reflect that...
...
- 556
1
vote
Accepted
Mesh-Shader and layered rendering
In accord with the GLSL extension, gl_Layer in a mesh shader is part of the predefined gl_MeshPerPrimitiveNV output interface ...
- 9,997
1
vote
Accepted
Generate Hi-Z buffer using single PSO and single UAV
The code for mip1 and mip2 (and higher mips if you have them—SSR ray marching can benefit a lot from higher mips) is identical except for which mip is being read and written; you don't need separate ...
- 25.3k
1
vote
what is the range for NDC coordinates to be visible in directx
Like you said... When using a perspective projection, your 'w' can be !=1.
Between the vertex pocess stages (Vertex, Tessellation control, Tessellation evaluation, geometry) and the Fragment shader, ...
- 1,366
1
vote
What causes buffer access to be significantly slower in DXIL than SPIR-V?
Are you sure the buffer isn't just defined as a host visible buffer? If you allocate it in CPU space it might have to transfer it a lot, I use ByteAddressBuffer a lot and it's not that slow for me. So ...
1
vote
Accepted
How Anisotropic filtering works
Anisotropic filtering (and any other filtering process) will respect the base/max level settings for the texture they're fetching from. So as long as those settings are properly provided, it will ...
- 9,997
1
vote
Accepted
what is the output from rasterizer
You are correct in your understanding that the rasterizer produces fragments. Each fragment can be thought of as a quasi-pixel, in that geometry may generate more than one fragment for the same pixel (...
- 126
1
vote
Accepted
Unbound descriptor tables and descriptors for fat root signatures
Everything is allowed to be left unbound / invalid / uninitialized as long as the shader doesn't try to look at it. However, if the shader does try to look at it, it could trigger a GPU crash / TDR.
...
- 25.3k
1
vote
Accepted
Worsening sampling quality of raytracing with increasing distance from world origin
Problem was that perspective matrix had very short Z_NEAR and Z_FAR values (0.01f and 200.0f). By changing it to much higher range (10.0f, 20000.0f), problem with jaggies and artifacts disappears.
1
vote
Is it possible to bind dynamic texture samplers to a shader in DX12?
Yes it is possible by putting Samplers in descriptor tables to dynamically assign and index into them. Source: https://youtu.be/Wbnw87tYqVg?t=754
Here's an example that uses the HLSL root signature ...
- 301
1
vote
Writing data to a shader resource at runtime in DX12
So, I figured it out.
While UAV will be necessary when I start manipulating data in Compute Shaders, for the time being, SRV works fine provided the resource is read-only from the fragment shader.
...
- 21
1
vote
How does ID3D12Resource::Map work?
First you may want to take a look at the doc.
Map basically allows you to retrieve a CPU pointer of a GPU resource. It performs a few operations on the background so the data is up to date. ...
- 110
1
vote
Accepted
Readback Data through Buffers
Ok, so I made little example of how to do this.
Short version
You need to allocate additional buffer with heap type D3D12_HEAP_TYPE_READBACK and resource state ...
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