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• 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.

• 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

• Hi, I'm implementing a simple 3D engine based on DirectX11. I'm trying to render a skybox with a cubemap on it and to do so I'm using DDS Texture Loader from DirectXTex library. I use texassemble to generate the cubemap (texture array of 6 textures) into a DDS file that I load at runtime. I generated a cube "dome" and sample the texture using the position vector of the vertex as the sample coordinates (so far so good), but I always get the same face of the cubemap mapped on the sky. As I look around I always get the same face (and it wobbles a bit if I move the camera). My code:
//Texture.cpp:         Texture::Texture(const wchar_t *textureFilePath, const std::string &textureType) : mType(textureType)         {             //CreateDDSTextureFromFile(Game::GetInstance()->GetDevice(), Game::GetInstance()->GetDeviceContext(), textureFilePath, &mResource, &mShaderResourceView);             CreateDDSTextureFromFileEx(Game::GetInstance()->GetDevice(), Game::GetInstance()->GetDeviceContext(), textureFilePath, 0, D3D11_USAGE_DEFAULT, D3D11_BIND_SHADER_RESOURCE, 0, D3D11_RESOURCE_MISC_TEXTURECUBE, false, &mResource, &mShaderResourceView);         }     // SkyBox.cpp:          void SkyBox::Draw()     {         // set cube map         ID3D11ShaderResourceView *resource = mTexture.GetResource();         Game::GetInstance()->GetDeviceContext()->PSSetShaderResources(0, 1, &resource);              // set primitive topology         Game::GetInstance()->GetDeviceContext()->IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);              mMesh.Bind();         mMesh.Draw();     }     // Vertex Shader:     cbuffer Transform : register(b0)     {         float4x4 viewProjectionMatrix;     };          float4 main(inout float3 pos : POSITION) : SV_POSITION     {         return mul(float4(pos, 1.0f), viewProjectionMatrix);     }     // Pixel Shader:     SamplerState cubeSampler;     TextureCube cubeMap;          float4 main(in float3 pos : POSITION) : SV_TARGET     {         float4 color = cubeMap.Sample(cubeSampler, pos.xyz);         return color;     } I tried both functions grom DDS loader but I keep getting the same result. All results I found on the web are about the old SDK toolkits, but I'm using the new DirectXTex lib.
• By B. /
Hi Guys,
i want to draw shadows of a direction light but the shadows always disappear, if i translate my mesh (cube) in the world to far of the bounds of my orthographic projection matrix.
That my code (Based of an XNA sample i recode for my project):
// Matrix with that will rotate in points the direction of the light Matrix lightRotation = Matrix.LookAtLH(Vector3.Zero, lightDir, Vector3.Up); BoundingFrustum cameraFrustum = new BoundingFrustum(Matrix.Identity); // Get the corners of the frustum Vector3[] frustumCorners = cameraFrustum.GetCorners(); // Transform the positions of the corners into the direction of the light for (int i = 0; i < frustumCorners.Length; i++) frustumCorners[i] = Vector4F.ToVector3(Vector3.Transform(frustumCorners[i], lightRotation)); // Find the smallest box around the points BoundingBox lightBox = BoundingBox.FromPoints(frustumCorners); Vector3 boxSize = lightBox.Maximum - lightBox.Minimum; Vector3 halfBoxSize = boxSize * 0.5f; // The position of the light should be in the center of the back pannel of the box. Vector3 lightPosition = lightBox.Minimum + halfBoxSize; lightPosition.Z = lightBox.Minimum.Z; // We need the position back in world coordinates so we transform // the light position by the inverse of the lights rotation lightPosition = Vector4F.ToVector3(Vector3.Transform(lightPosition, Matrix.Invert(lightRotation))); // Create the view matrix for the light this.view = Matrix.LookAtLH(lightPosition, lightPosition + lightDir, Vector3.Up); // Create the projection matrix for the light // The projection is orthographic since we are using a directional light int amount = 25; this.projection = Matrix.OrthoOffCenterLH(boxSize.X - amount, boxSize.X + amount, boxSize.Y + amount, boxSize.Y - amount, -boxSize.Z - amount, boxSize.Z + amount); I believe the bug is by cameraFrustum to set a Matrix Idetity. I also tried with a Translation Matrix of my Camera Position and also the View Matrix of my Camera, but without success
Can anyone tell me, how to draw shadows of my direction light always where my camera is current in my scene?
Greets
Benjamin

# DX11 DX11 Update textures every frame

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Hi,

I am trying to upload multiple (say n) textures (BC7) to the gpu each frame (there's data every frame read from CPU; there is no way around this), and I am trying to minimize this time as much as possible, was wondering if anyone has any insights other than what I've done:

- each texture is dynamic, have 2 copies (total 2n textures) and interchange between a cpu mapped (D3D11_MAP_WRITE_DISCARD) version to copy data into and gpu unmapped to use for render

- each texture has 2 corresponding resources, a default & a staging version (2n staging, 2n default), map with D3D11_MAP_WRITE and CopyResource (n times each) to default from staging

- have a staging & default texture2darray (array size = n, 2 staging, 2 default), call map D3D11_MAP_WRITE once per frame on staging, CopyResource once to copy and unmap once.

- I also want to try 3d textures, but the limitation of 2048x2048x2048 means i can't use it.

All of these are approximately the same times. Does anyone have thoughts on how I can hide/reduce this time?

I am aware GPU has compute/copy/3d engines (exposed in D12), but is there anyway to parallelize whatever unmap/copyresource is doing to a separate engine from the 3d engine on D11? If not any suggestions/thoughts?

Thanks

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Copying textures every frame from CPU to GPU memory will be bottlenecked by the bus-bandwidth, so, check out your target platform (e.g. PCI-E) bandwidth and do some theo-crafting about how many times you would be theoretically able to transfer your textures from CPU memory to GPU memory. If this would be an issue, try to re-think your approach.

Data transfer will use DMA most of the time, so you can hide this transfer costs (aka avoid stalling your pipeline) if you can get along with one or two frames delay. If this is the case, look into double/triple buffering.

Eventually try to reduce the transfered data, either update only parts, use some compression or do even packing/unpacking.

Why are 2048x2048x2048 limiting ? Do you need larger textures ? I mean, 2k^3 ~ 32GB for an RGBA texture without mipmaps.

Edited by Ashaman73

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I am not sure if PCIe is the problem, I have maybe 40MB per frame (with PCIe3.0 x16 for 32GB/s), and I am already double buffering (with a frame delay) to hide the memcpy operation. However, I was thinking earlier, it seems using staging/default approach, the time is not in the unmap, but copyresource. Does D11's CopyResource automatically use the Copy Engine and not stall the 3D Engine (if there is no dependency)? Or would I have to use D12 for that? I'll have to test that out with triple buffering and 2 frames delay I guess. :D

2048^3 is limiting cause my widths are > 2048 (height and depth are fine).

Edited by hiya83

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D3D11 has no concept of a "copy engine", and so the driver is free to implement CopyResource however it wants as long as it has the correct behavior. It might implement it with an asynchronous DMA. it might not. It might even be doing the same thing for all 3 of your approaches.

When you say that all of your approaches are "approximately the same times", what do you mean by that? Are you measuring CPU timing? GPU timing?

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I am measuring GPU times.

- in dynamic case, I put gpu ticks around unmap

- in default & staging case, unmap doesn't take time, but CopyResource is where the time is

- in default/staging with texture2darray, same as 2nd case.

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- in default & staging case, unmap doesn't take time, but CopyResource is where the time is

Unmap will only trigger the upload, which, when done with DMA, will not involve the GPU. But CopyResource, when you try to access the memory block, will spent time in

To measure the first delay try to use some fence and try to measure the time spend in waiting for the fence:

unmap buffer A -> fence A ->... -> start GPU timer -> wait for fence B -> end GPU timer -> CopyResource ->... ->  unmap buffer B -> fence B ->...

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I also want to try 3d textures, but the limitation of 2048x2048x2048 means i can't use it

Perhaps this is not a relevant suggestion, but is it possible to use a texture array instead of one big volume texture?

Edited by vanka78bg

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How much time exactly is your 40MiB copy operation currently taking with any of your methods?

2048^3 is limiting cause my widths are > 2048 (height and depth are fine).

Well, another limit is that you'd need a video card with over 8GiB of RAM, which pretty much limits your min-spec hardware to the US$999 GeForce GTX Titan X :wink: :lol: #### Share this post ##### Link to post ##### Share on other sites Unmap will only trigger the upload, which, when done with DMA, will not involve the GPU. But CopyResource, when you try to access the memory block, will spent time in To measure the first delay try to use some fence and try to measure the time spend in waiting for the fence: Does that mean unmap for Dynamic Textures triggers some sort of copy from cpu-accessible gpu memory to default gpu memory internally since that takes about same time as unmap/copyresource for staging/default textures. Also possibly dumb question, how would you setup a memory fence on DX from the CPU?? There is no query for that, and everything seems to be implicit... Perhaps this is not a relevant suggestion, but is it possible to use a texture array instead of one big volume texture? I did try texture arrays already, that was the 3rd thing I tried in my original post.. sorry if it was misleading. How much time exactly is your 40MiB copy operation currently taking with any of your methods? Well, another limit is that you'd need a video card with over 8GiB of RAM, which pretty much limits your min-spec hardware to the US$999 GeForce GTX Titan X :wink: :lol:

Hey sorry but not sure what you meant by how long 40MB copy operation is taking? If you mean the methods I've tried above, they are all in the upper 3 ms ballpark (3.6 - 3.9).

Yea I am aware of the large memory video card, I am working on other forms of compression as well, but just want to get this down with BC7 for now :D

Edited by hiya83

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So tried the triple buffering approach hoping CopyResource is async dma, but it still stalls the gpu command. :(

Also since d11 device is free threaded, I tried to do something real "dumb" of creating another thread and just keep deleting old/creating new textures (with new content) on this other thread, hoping the texture creation/deletion is async from the gpu graphics engine, and that plan fell flat as well. Even though device is free threaded from the context, apparently creating/deleting resources still runs in same pipeline as the context commands. :(

Any other thoughts/ideas would be appreciated.