• Advertisement
  • Popular Tags

  • Popular Now

  • Advertisement
  • Similar Content

    • 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.
    • By evelyn4you
      Hello,
      i try to implement voxel cone tracing in my game engine.
      I have read many publications about this, but some crucial portions are still not clear to me.
      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
       
       
    • By Endemoniada

      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
      Please help. Thank you.
    • By turanszkij
      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.
    • By evelyn4you
      Hello,
      in my game engine i want to implement my own bone weight painting tool, so to say a virtual brush painting tool for a mesh.
      I have already implemented my own "dual quaternion skinning" animation system with "morphs" (=blend shapes)  and "bone driven"  "corrective morphs" (= morph is dependent from a bending or twisting bone)
      But now i have no idea which is the best method to implement a brush painting system.
      Just some proposals
      a.  i would build a kind of additional "vertecie structure", that can help me to find the surrounding (neighbours) vertecie indexes from a given "central vertecie" index
      b.  the structure should also give information about the distance from the neighbour vertecsies to the given "central vertecie" index
      c.  calculate the strength of the adding color to the "central vertecie" an the neighbour vertecies by a formula with linear or quadratic distance fall off
      d.  the central vertecie would be detected as that vertecie that is hit by a orthogonal projection from my cursor (=brush) in world space an the mesh
            but my problem is that there could be several  vertecies that can be hit simultaniously. e.g. i want to paint the inward side of the left leg. the right leg will also be hit.
      I think the given problem is quite typical an there are standard approaches that i dont know.
      Any help or tutorial are welcome
      P.S. I am working with SharpDX, DirectX11
        
  • Advertisement
  • Advertisement
Sign in to follow this  

DX11 Downsampling texture to half resolution

This topic is 707 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I decided to make SSAO in half resolution.

 

There are 2 input textures: Depth (DXGI_FORMAT_R24G8_TYPELESS) and Normal (DXGI_FORMAT_R10G10B10A2_UNORM)

Both textures may be noAA or MSAA.

 

I realized that I do a lot of sampling with the textures.

It seems for me that it’s better to downsample each texture to half resolution NO-AA texture before SSAO calculation and blurring.

After that just Load() data from them.

 

I need only one new LOD, that is 2x smaller that original texture.

 

The question is: what is the best way to do it in DX11?

I can imagine several solutions:

  1. Write full-quad pixel shader that will average each 2x2 values. In MSAA case it will average all subsamples.
  2. Write Compute shader that will do the same thing
  3. A better solution I am not aware of. :)

What would you recommend?

Edited by Happy SDE

Share this post


Link to post
Share on other sites
Advertisement
Yes 1/2 are the standard approaches. A single texture fetch with bilinear filtering will calculate the average for you :)

However, you can't average depth and normals... Well you can, but the results won't be sensible and won't produce a good result -- at the edges of objects, the averaging will take two discontinuous surfaces (e.g. a character and the background), and "invent" a new surface that's half-way between both (something floating half way between the character and the background).

In this case, you want to simply throw away 75% of your data when downsampling, and then use a bilateral depth/normal-aware upsampling feature when going back to full resolution.

Share this post


Link to post
Share on other sites

However, you can't average depth and normals... Well you can, but the results won't be sensible and won't produce a good result -- at the edges of objects, the averaging will take two discontinuous surfaces (e.g. a character and the background), and "invent" a new surface that's half-way between both (something floating half way between the character and the background).

In this case, you want to simply throw away 75% of your data when downsampling,

Thank you, Hodgman!

 

I just finished downsampling implementation on pixel shader and found the artifacts of depth averaging.

It's interesting, but throwing away 75% of data gives performance gain from 85 => 72 microsec for this pass (GPU time).

 

But I don't understand this statement:

...and then use a bilateral depth/normal-aware upsampling feature when going back to full resolution.

In my previous implementation without downsampling, I used 2-passes of bilateral depth/normal-aware (took from Luna book),

and after that just used the result on a lighting pass.

 

But you are suggesting bilateral upsampling?

Is it a different algorithm?

Edited by Happy SDE

Share this post


Link to post
Share on other sites

If you've already done bilateral blurring, then it should be pretty easy :D

To do depth-aware upsampling, when going from half-res to full-res, for each full-res pixel, point-sample the nearest 4 half-res pixels and generate standard bilinear weights for them.
Then, perform a depth/normal threshold test of some kind, to determine if each of those samples is 'valid' or not. If a sample is not valid, set its weight to zero.
Renormalize the weights so they sum to 1.0 (e.g. weights.xyzw /= dot(weights.xyzw, (float4)1))
-- But, take care to handle the case where all weights are zero: in that case, there's no valid low-res data that corresponds to your high res pixel, and the above code snippet will divide by zero! So, take the closest depth match, or average all 4 samples, or just use the initial bilinear weights, etc...
Combine the 4 samples using their new weights.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement