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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] InterlockedMin works wrong?

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hello,

[size=2]code snippet from Compute Shader 5.0:
 groupshared int3 sMin; ... InterlockedMin(sMin.x, asint(viewPosition.x)); ... 
In code snippet above there is groupshared variable that holds minimum position value across the thread group. I noticed the case that the InterlockedMin works wrong when sMin.x == 0 and viewPosition == some_negaive_sign_value. After the operation sMin.x == 0.

Question: why negative value doesn't take as minimal value? In documentation mentioned that uint and int types are supported by InterlockedMin, so the sine should takes in account in case of int type.

I use nSight to profiler via network to debug shaders. The graphics adapter on target PC is GeForce GTX 460.

Any help would be appreciated.. Edited by user88

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I found work around simply inverting sign bit. For those who are interested:
 groupshared uint3 sMin; ... uint3 InvertSignBit(uint3 value) { return ((~value) &amp;amp; uint3(0x80000000, 0x80000000, 0x80000000)) | (value &amp;amp; uint3(0x7FFFFFFF, 0x7FFFFFFF, 0x7FFFFFFF)); } ... InterlockedMin(sMin.x, InvertSignBit(asint(viewPosition).x); ... GroupMemoryBarrierWithGroupSync(); uint3 signedSMin = InvertSignBit(sMin); float3 minViewPosition = asfloat(signedSMin); 

Edit:
No.. Unfortunately this is not a solution. Min for values with negative sing is wrong. Edited by user88

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InterlockedMin takes a uint parameter, hence it only works with unsigned integers. If you pass it an int, it will treat it as an unsigned integer which will cause negative numbers to be treated as greater than positive numbers.

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Ok, thanks for answer MJP. Strange why Microsoft didn't noticed it in MSDN?..

For those who are interested in work around, i use two functions for signed values (this time the code is working &lt;_&lt;) :
 uint IntToUIntInRange(uint value) { if ((value & 0x80000000) == 0) { return 0x80000000 | value; } else { return ~value; } } uint UIntToIntInRange(uint value) { if ((value & 0x80000000) != 0) { return 0x7FFFFFFF & value; } else { return ~value; } }