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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 ID3dX11Effect constant buffer

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Hey.

I am investigating the use of constant buffers in effect files. Say, my effect file had buffer declarations like this:

 cbuffer cbPerViewBuffer { matrix viewMatrix; }; 

When initializing my shader, i would get a pointer to this effect variable by name, and store it in my object:

 ID3DX11EffectMatrixVariable *p_view; ID3DX11Effect* p_effect; //... Compiling effect ...// p_view = p_effect->GetVariableByName("viewMatrix")->AsMatrix(); 

On rendering, I do

 D3DXMATRIX v; //... doing the math on v ...// p_view->SetMatrix( v); 

There is no buffer mapping or else involved. So my question is, is this even using the advantages of constant buffers, or is this an absurdely abuse of mentioned features?
Should I instead create a custom buffer type, create a buffer of this type, bind it as dynamic to the effect, and use map on each render call?
Can the view buffer even be updated, I have seen no flag specifying it as DYNAMIC?

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The effects framework does a Map or UpdateResource behind the scenes. It's been a while since I looked at the effect code, but it should flag a variable as "dirty" and only update the constant buffer if one of the values changed. So it is not really an abuse.

However, one example of an improvement is your "per-frame" constant buffer. You only need one of these and all your effects can share it. I use a header and always put the per-frame cb in slot 0. Then I use ID3DX11Effect::GetConstantBufferByName and set the per-frame CB for each effect; this is just a bind operation (when Apply() is called), as the per-frame CB is only updated once per-frame.

If you don't do this, then each effect will maintain its own per-frame cbuffer. This is still not likely to make a performance impact, but still.

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This is how it's done:

[source] // Retrieve the handles to the constant buffers
//
m_pD3DXEffectEveryFrameConstBuffer = m_pD3DXEffect->GetConstantBufferByName("CBEveryFrame"); // Constant buffer that changes every frame
if(!m_pD3DXEffectEveryFrameConstBuffer->IsValid())
return E_FAIL;
update constant buffer:
D3D11_MAPPED_SUBRESOURCE oD3DMappedSubresource;
CHECK_COM(pD3DDeviceContext->Map(m_pD3DMaterialConstbuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &oD3DMappedSubresource)); // Get a pointer to the data in the constant buffer
::memcpy(oD3DMappedSubresource.pData, pMaterialConstantBuffer, sizeof(SMaterialConstantBuffer)); // Copy the constant buffers
pD3DDeviceContext->Unmap(m_pD3DMaterialConstbuffer, 0);
CHECK_COM(m_pD3DXEffectMaterialConstBuffer->SetConstantBuffer(m_pD3DMaterialConstbuffer)); // Set material constant buffer in the shader
Assuming the constant buffer was created dynamic usage flag. If it's created with default usage flag then you have to use UpdateSubresource method to do so[/source]

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@ Quat: Your answer sounds good: it's easy, would not require me to do too much changes, and would not need me to do obscure things.

@ Asesh: It's quite the opposite to what Quat suggested: You tell me to actually take everything in my own responsibility, and actually mapping the buffer. In this case, would I have to create the buffers myself? As I see it, the effect creates the declared buffers within it on compilation(?) and I can just access it with the GetConstantBufferFunction. Where can I make it's usage DYNAMIC? Do I have to create the buffer myself and replace it with the one the shader generated?

Actually, now I'm as wise as before: It seems to me I have two concurring opinions on this topic, and (of course I am tempted to use the easier one for the time being) still can't decide which option to settle with.
Are there any more opinions?