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• ### Similar Content

• By fs1
I have been trying to see how the ID3DInclude, and how its methods Open and Close work.
I would like to add a custom path for the D3DCompile function to search for some of my includes.
I have not found any working example. Could someone point me on how to implement these functions? I would like D3DCompile to look at a custom C:\Folder path for some of the include files.
Thanks
• By stale
I'm continuing to learn more about terrain rendering, and so far I've managed to load in a heightmap and render it as a tessellated wireframe (following Frank Luna's DX11 book). However, I'm getting some really weird behavior where a large section of the wireframe is being rendered with a yellow color, even though my pixel shader is hard coded to output white.

The parts of the mesh that are discolored changes as well, as pictured below (mesh is being clipped by far plane).

Here is my pixel shader. As mentioned, I simply hard code it to output white:
float PS(DOUT pin) : SV_Target { return float4(1.0f, 1.0f, 1.0f, 1.0f); } I'm completely lost on what could be causing this, so any help in the right direction would be greatly appreciated. If I can help by providing more information please let me know.

• Hello,
i try to implement voxel cone tracing in my game engine.
At first step i try to emplement the easiest "poor mans" method
a.  my test scene "Sponza Atrium" is voxelized completetly in a static voxel grid 128^3 ( structured buffer contains albedo)
b. i dont care about "conservative rasterization" and dont use any sparse voxel access structure
c. every voxel does have the same color for every side ( top, bottom, front .. )
d.  one directional light injects light to the voxels ( another stuctured buffer )
I will try to say what i think is correct ( please correct me )
GI lighting a given vertecie  in a ideal method
A.  we would shoot many ( e.g. 1000 ) rays in the half hemisphere which is oriented according to the normal of that vertecie
B.  we would take into account every occluder ( which is very much work load) and sample the color from the hit point.
C. according to the angle between ray and the vertecie normal we would weigth ( cosin ) the color and sum up all samples and devide by the count of rays
Voxel GI lighting
In priciple we want to do the same thing with our voxel structure.
Even if we would know where the correct hit points of the vertecie are we would have the task to calculate the weighted sum of many voxels.
Saving time for weighted summing up of colors of each voxel
To save the time for weighted summing up of colors of each voxel we build bricks or clusters.
Every 8 neigbour voxels make a "cluster voxel" of level 1, ( this is done recursively for many levels ).
The color of a side of a "cluster voxel" is the average of the colors of the four containing voxels sides with the same orientation.

After having done this we can sample the far away parts just by sampling the coresponding "cluster voxel with the coresponding level" and get the summed up color.
Actually this process is done be mip mapping a texture that contains the colors of the voxels which places the color of the neighbouring voxels also near by in the texture.
Cone tracing, howto ??
Here my understanding is confus ?? How is the voxel structure efficiently traced.
I simply cannot understand how the occlusion problem is fastly solved so that we know which single voxel or "cluster voxel" of which level we have to sample.
Supposed,  i am in a dark room that is filled with many boxes of different kind of sizes an i have a pocket lamp e.g. with a pyramid formed light cone
- i would see some single voxels near or far
- i would also see many different kind of boxes "clustered voxels" of different sizes which are partly occluded
How do i make a weighted sum of this ligting area ??
e.g. if i want to sample a "clustered voxel level 4" i have to take into account how much per cent of the area of this "clustered voxel" is occluded.
Please be patient with me, i really try to understand but maybe i need some more explanation than others
best regards evelyn

• Hi guys, when I do picking followed by ray-plane intersection the results are all wrong. I am pretty sure my ray-plane intersection is correct so I'll just show the picking part. Please take a look:

// get projection_matrix DirectX::XMFLOAT4X4 mat; DirectX::XMStoreFloat4x4(&mat, projection_matrix); float2 v; v.x = (((2.0f * (float)mouse_x) / (float)screen_width) - 1.0f) / mat._11; v.y = -(((2.0f * (float)mouse_y) / (float)screen_height) - 1.0f) / mat._22; // get inverse of view_matrix DirectX::XMMATRIX inv_view = DirectX::XMMatrixInverse(nullptr, view_matrix); DirectX::XMStoreFloat4x4(&mat, inv_view); // create ray origin (camera position) float3 ray_origin; ray_origin.x = mat._41; ray_origin.y = mat._42; ray_origin.z = mat._43; // create ray direction float3 ray_dir; ray_dir.x = v.x * mat._11 + v.y * mat._21 + mat._31; ray_dir.y = v.x * mat._12 + v.y * mat._22 + mat._32; ray_dir.z = v.x * mat._13 + v.y * mat._23 + mat._33;
That should give me a ray origin and direction in world space but when I do the ray-plane intersection the results are all wrong.
If I click on the bottom half of the screen ray_dir.z becomes negative (more so as I click lower). I don't understand how that can be, shouldn't it always be pointing down the z-axis ?
I had this working in the past but I can't find my old code

• Hi,
I finally managed to get the DX11 emulating Vulkan device working but everything is flipped vertically now because Vulkan has a different clipping space. What are the best practices out there to keep these implementation consistent? I tried using a vertically flipped viewport, and while it works on Nvidia 1050, the Vulkan debug layer is throwing error messages that this is not supported in the spec so it might not work on others. There is also the possibility to flip the clip scpace position Y coordinate before writing out with vertex shader, but that requires changing and recompiling every shader. I could also bake it into the camera projection matrices, though I want to avoid that because then I need to track down for the whole engine where I upload matrices... Any chance of an easy extension or something? If not, I will probably go with changing the vertex shaders.

# DX11 Reading one texel from depthbuffer

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I was trying to find something similiar to glReadPixel() and stumbled upon this post: https://www.gamedev.net/topic/594722-reading-one-pixel-from-texture-to-cpu-in-dx11/

Seemed reasonable, tried it but lo and behold didnt work.

Sample code;

{
mContext(context),
mDepthbuffer(depthBuffer),
mStaging1x1(nullptr)
{
D3D11_TEXTURE2D_DESC depthTextureDesc;
ZeroMemory(&depthTextureDesc, sizeof(depthTextureDesc));
depthBuffer->GetDesc(&depthTextureDesc);

depthTextureDesc.Usage = D3D11_USAGE_STAGING;
depthTextureDesc.BindFlags = 0;
device->CreateTexture2D(&depthTextureDesc, NULL, &mStaging1x1);
}

{
D3D11_BOX box;
ZeroMemory(&box, sizeof(box));
box.left = position.x;
box.right = box.left + 1;
box.top = position.y;
box.bottom = box.top + 1;
box.front = 0;
box.back = 1;

mContext->CopySubresourceRegion(mStaging1x1, 0, 0, 0, 0, mDepthbuffer, 0, &box);

D3D11_MAPPED_SUBRESOURCE mappedRes;
float depth = *static_cast<float*>(mappedRes.pData);
mContext->Unmap(mStaging1x1, 0);

return depth;
}
}


This is the debug ouput I get:

D3D11 ERROR: ID3D11DeviceContext::CopySubresourceRegion: If CopySubresourceRegion is used with Multisampled or D3D11_BIND_DEPTH_STENCIL Resources, then the whole Subresource must be copied. DstX, DstY, and DstZ must all be 0, while pSrcBox must be NULL. [ RESOURCE_MANIPULATION ERROR #280: COPYSUBRESOURCEREGION_INVALIDSOURCEBOX]


So this dosn't seem to work. Is there any similiarly easy/straight forward solution that works?

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You could write a single-thread, single-wave Compute Shader that reads a single sample from the texel you're interested in and writes that to a USAGE_DEFAULT buffer. You can then issue a CopySubresourceRegion to copy the single float from a USAGE_DEFAULT buffer to a USAGE_STAGING buffer and map that for readback instead. You can't call ResourceSubresource on an MSAA depth buffer, so you'll need to use a shader (CS or PS) to extract the data you're interested in and write that to another resource. If you'd like to avoid Compute Shaders you could write the extracted depth value to a 1x1 R32_FLOAT render target and copy that texture instead to a STAGING resource.

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You could write a single-thread, single-wave Compute Shader that reads a single sample from the texel you're interested in and writes that to a USAGE_DEFAULT buffer. You can then issue a CopySubresourceRegion to copy the single float from a USAGE_DEFAULT buffer to a USAGE_STAGING buffer and map that for readback instead. You can't call ResourceSubresource on an MSAA depth buffer, so you'll need to use a shader (CS or PS) to extract the data you're interested in and write that to another resource. If you'd like to avoid Compute Shaders you could write the extracted depth value to a 1x1 R32_FLOAT render target and copy that texture instead to a STAGING resource.

This is my depthbuffer, also used for my staging texture except for cpuAccess, usage and bindflags:

// create depth buffer
D3D11_TEXTURE2D_DESC depthStencilBufferDesc;
ZeroMemory(&depthStencilBufferDesc, sizeof(D3D11_TEXTURE2D_DESC));
depthStencilBufferDesc.ArraySize = 1;
depthStencilBufferDesc.Format = DXGI_FORMAT_R24G8_TYPELESS;
depthStencilBufferDesc.Width = backbufferTextureDesc.Width;
depthStencilBufferDesc.Height = backbufferTextureDesc.Height;
depthStencilBufferDesc.MipLevels = 1;
depthStencilBufferDesc.SampleDesc.Count = 1;
depthStencilBufferDesc.Usage = D3D11_USAGE_DEFAULT;


depthStencilBufferDesc.SampleDesc.Count = 1 is not multisampled right? (i.e it should work?)

Edited by KaiserJohan

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Correct, but the error message also says you can't copy just a sub-region of the depth buffer, you have to copy it at all. You appear to be trying to copy a 1x1 region.

You can either copy the entire thing back to system memory and just read the texel you're interested in, or you can extract the relevant texel on the GPU and just copy that back.

I'm not sure whether you might encounter difficulty copying back D24S8 too, I've never tried that. Given that some hardware doesn't pack D24 and S8 together into a single DWORD I don't know what the memory layout of the system memory copy of this surface would look like. It wouldn't surprise me if you encounter further validation errors.

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Correct, but the error message also says you can't copy just a sub-region of the depth buffer, you have to copy it at all. You appear to be trying to copy a 1x1 region.

You can either copy the entire thing back to system memory and just read the texel you're interested in, or you can extract the relevant texel on the GPU and just copy that back.

I'm not sure whether you might encounter difficulty copying back D24S8 too, I've never tried that. Given that some hardware doesn't pack D24 and S8 together into a single DWORD I don't know what the memory layout of the system memory copy of this surface would look like. It wouldn't surprise me if you encounter further validation errors.

What do you estimate would be the most efficient way of doing it (copy entire depthbuffer and read one texel -VS- use a CS/PS to output to a 1x1 staging texture and read that?)

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There's only limited bandwidth back across the PCI-E bus, so ideally you'd be copying as little data as possible over that (which favours the CS/PS approach). A 1080p depth buffer is at least 8MB, heading up to 32MB by the time your resolution is 4K. With the single texel extraction you can copy back a fixed amount (4 bytes) irrespective of your resolution.

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I would suggest don't do it at all.  Aside from bandwidth, even a single pixel readback will cause the GPU and CPU to synchronize, potentially cutting your performance by up to two-thirds.  Think about what you want to do rather than how you want to do it - is there an alternative approach that doesn't involve a readback?

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Copying back the texel on a one frame delay shouldn't do much to impact the frame rate. So long as there's latency tolerance built into the system there's nothing particularly harmful about a small readback.

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I am doing this in my editor to raise/lower terrain (i.e increment/decrement values in a heightmap). To do that I first need to reconstruct the 3d point from 2d screen coords and for that I need depth for that pixel (afaik) and then somehow go from that 3d point to modify the correct hieghtmap texel (but that is a later problem).

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... If CopySubresourceRegion is used with Multisampled or D3D11_BIND_DEPTH_STENCIL Resources ...

Do you have a need for a stencil buffer? If not, try changing DXGI_FORMAT_R24G8_TYPELESS to DXGI_FORMAT_R32_TYPELESS (and no D3D11_BIND_DEPTH_STENCIL) and see if it works..?