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• 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.

• 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.

# DX11 DirectX C++ DLL for C# Problem?

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## Recommended Posts

I am currently trying to use my DirectX C++ engine in a C# project to develop a level editor. Based on the advice I was given I have decided to write my engine in a DLL and use p/invoke in C#. http://gamedev.stackexchange.com/questions/124249/how-do-i-render-my-directx-c-engine-to-a-c-panel

An unhandled exception of type 'System.BadImageFormatException' occurred in DirectXinForms.exe

I don't know what the problem is but can someone help me fix this? Maybe there's an issue with the DLL aswell. Here is my code for the C++ DLL & C# Windows Forms project. I am also unable to directly add a reference to the DLL in C# but using

[DLLImport]

seemed to work.

#pragma once

#define DllExport __declspec(dllexport)

#include <windows.h>
#include <windowsx.h>
#include <d3d11.h>
#include <d3dx11.h>
#include <d3dx10.h>
#include <DirectXMath.h>

using namespace DirectX;

// include the Direct3D Library file
#pragma comment (lib, "d3d11.lib")
#pragma comment (lib, "d3dx11.lib")
#pragma comment (lib, "d3dx10.lib")

// global declarations
IDXGISwapChain *swapchain;             // the pointer to the swap chain interface
ID3D11Device *dev;                     // the pointer to our Direct3D device interface
ID3D11DeviceContext *devcon;           // the pointer to our Direct3D device context
ID3D11RenderTargetView *backbuffer;    // the pointer to our back buffer

extern "C"
{
__declspec(dllexport) void InitD3D(HWND hWnd, int Width, int Height);    // sets up and initializes Direct3D
}

extern "C"
{
__declspec(dllexport) void RenderFrame(void);     // renders a single frame
}

extern "C"
{
__declspec(dllexport) void CleanD3D(void);        // closes Direct3D and releases memory
}


DLL Main.cpp

#include "Header.h"

void InitD3D(HWND hWnd, int Width, int Height)
{
// create a struct to hold information about the swap chain
DXGI_SWAP_CHAIN_DESC scd;

// clear out the struct for use
ZeroMemory(&scd, sizeof(DXGI_SWAP_CHAIN_DESC));

HRESULT hr = S_OK;

// fill the swap chain description struct
scd.BufferCount = 2;                                    // one back buffer
scd.BufferDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;     // use 32-bit color
scd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;      // how swap chain is to be used
scd.OutputWindow = hWnd;                                // the window to be used
scd.SampleDesc.Count = 8;                               // how many multisamples
scd.SampleDesc.Quality = 1;
scd.Windowed = TRUE;
scd.Flags = DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH;     // allow full-screen switching// windowed/full-screen mode
// create a device, device context and swap chain using the information in the scd struct

hr = D3D11CreateDeviceAndSwapChain(NULL,
D3D_DRIVER_TYPE_HARDWARE,
NULL,
NULL,
NULL,
NULL,
D3D11_SDK_VERSION,
&scd,
&swapchain,
&dev,
NULL,
&devcon);

// get the address of the back buffer
ID3D11Texture2D *pBackBuffer;
swapchain->GetBuffer(0, __uuidof(ID3D11Texture2D), (LPVOID*)&pBackBuffer);

// use the back buffer address to create the render target
dev->CreateRenderTargetView(pBackBuffer, NULL, &backbuffer);
pBackBuffer->Release();

// set the render target as the back buffer
devcon->OMSetRenderTargets(1, &backbuffer, NULL);

// Set the viewport
D3D11_VIEWPORT viewport;
ZeroMemory(&viewport, sizeof(D3D11_VIEWPORT));

viewport.TopLeftX = 0;
viewport.TopLeftY = 0;
viewport.Width = Width;
viewport.Height = Width;

}

void RenderFrame(void)
{
// clear the back buffer to a deep blue
devcon->ClearRenderTargetView(backbuffer, D3DXCOLOR(0.0f, 0.2f, 0.4f, 1.0f));

// do 3D rendering on the back buffer here

// switch the back buffer and the front buffer
swapchain->Present(0, 0);
}

void CleanD3D(void)
{
// close and release all existing COM objects
swapchain->Release();
backbuffer->Release();
dev->Release();
devcon->Release();
}

C# Project:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms;

namespace DirectXinForms
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
Dengine.Initialize(panel1.Handle, panel1.Width, panel1.Height);
Dengine.RenderFrame();
}

private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
Dengine.CleanD3D();
}
}

public class Dengine
{
[DllImport("DirectXENGINEDLL.dll")]
public static extern void Initialize(IntPtr window, int Width, int Height);

[DllImport("DirectXENGINEDLL.dll")]
public static extern void RenderFrame();

[DllImport("DirectXENGINEDLL.dll")]
public static extern void CleanD3D();
}

}

Edited by arjansingh00

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BadImageFormatException tends to mean you are trying to load a 32-bit dll from a 64-bit process or the other way around, so start by making sure you are not doing that. For example, using Any CPU in your C# project means your process might be 32-bits, it might be 64 bits. If you need to use Any Cpu, you'll need to compile your native dll for both 32 and 64 bits, then use the one that makes sense at runtime.

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Thanks, this fixed it :)

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Funnily enough communication between C# and C++ is something I was just looking in to this morning.

As an alternative to p/invoke have you considered using managed c++? If you compile your C++ project with /clr and link it as a reference to you C# project it makes the whole process much cleaner.

On the C++ side of things you can have a singleton interface to your engine:

namespace CPlusPlusLib
{
public ref class SomeCPlusPlusInterface
{
...

static property SomeCPlusPlusInterface^ Instance
{
SomeCPlusPlusInterface^ get()
{
if( ourInstance == nullptr )
{
ourInstance = gcnew SomeCPlusPlusInterface();
}

return ourInstance;
}
}

...

String^ GetString()
{
return "Hello from C++";
}

...

static SomeCPlusPlusInterface^ ourInstance = nullptr;
}
}


Then in C#:

using CPlusPlusLib;

...

private void SomeFunction()
{
String cPlusPlusString = SomeCPlusPlusInterface.Instance.GetString();

...
}


Not sure about the overhead that you incur by using managed c++, but I really like that you don't have to explicitly declare everything from the DLL that you want to use.