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I think I understand the idea behind Shadow Mapping, however I'm having problems with implementation details.

In VS I need light position - but I don't have one! I only have light direction, what light position should I use?

I have working camera class, with Projection and View matrices and all - how can I reuse this? I should put camera position, but how to calculate "lookAt" parameter?

Is this suppose to be ortographic or perspective camera?

And one more thing - when in the 3D piplene is the actual write to the Depth Buffer? In PS or somewhere earlier?

Br.,BB

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37 minutes ago, Bartosz Boczula said:

In VS I need light position - but I don't have one! I only have light direction, what light position should I use?

I would recommend using the position of the light.  Unless the light is representing the sun, in which case just the direction can be used, you will need the light position.  But you didn't say if the light is a spotlight, point light, etc.  I'll assume spotlight.

53 minutes ago, Bartosz Boczula said:

I have working camera class, with Projection and View matrices and all - how can I reuse this? I should put camera position, but how to calculate "lookAt" parameter?

Create a new camera for the light if you want.  Though it's easy enough from the position/direction to create the ortho/projection matrix to pass to the shader.  I don't know what programming language or graphics API you're using so keeping this generic.  You shouldn't need to calculate the look at, you have the direction, just set the camera direction to the light direction.

55 minutes ago, Bartosz Boczula said:

Is this suppose to be ortographic or perspective camera?

Spotlight would use a perspective camera.  A point light might generate a cubemap.  A sun would use orthographic.  etc.  Depends completely on the type of light source.

57 minutes ago, Bartosz Boczula said:

And one more thing - when in the 3D piplene is the actual write to the Depth Buffer? In PS or somewhere earlier?

The pixel shader.   The vertex shader just multiplies the vertex by the mvp matrix you pass in.  The pixel shader writes depth information to the depth buffer.

1 hour ago, Bartosz Boczula said:

I think I understand the idea behind Shadow Mapping

I'm not trying to be mean, but I think you were using poor resources as all your questions should have been answered by whatever you were reading/watching to learn from.

These are OpenGL resources but the concepts are the same for D3D, the video is Java + OpenGL but again translating the concepts to C++/C# should be quite simple:

http://www.opengl-tutorial.org/intermediate-tutorials/tutorial-16-shadow-mapping/

The last video is one of like 8 that show different techniques.

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Thanks @Mike2343. Just for clarification, I'm writing in C++ with DX11. My current version has only Phong lighting, with one "sunlight" component, no point lights or spot lights. My camera component doesn't have "direction" property, only LookAt, Up and Position. For lighting calculations, I only needed sunlight direction and that was ok. So my question was - what sunlight position should I use? I mean, should I like pick whatever or there are some "guidelines"?

P.S. This was my first post, thank you for not dissing it and explaining instead :)

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I have only limited experience in this, so I really don't honestly know if there are any good tricks (I'm sure more experts will be along soon), but I believe the general idea is to try and include all the objects in your frame and those outside it that might be casting shadows into the frame. Roughly speaking you could start by taking a point in the 'centre' of your scene as seen by the camera, use that as your lookat point, then minus the light direction from this to get the 'shadow camera' position.

You can then widen the field of view of the shadow matrix / move shadow camera further back to try and get everything in. Of course the trick is to try and get everything in without losing shadow map resolution, and this will depend on the game. There are techniques to try and do this plus decrease the shadow map resolution further from the view camera. See:

https://developer.download.nvidia.com/SDK/10.5/opengl/src/cascaded_shadow_maps/doc/cascaded_shadow_maps.pdf

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10 hours ago, Bartosz Boczula said:

So my question was - what sunlight position should I use? I mean, should I like pick whatever or there are some "guidelines"?

The first video I posted is actually about only supporting sunlight.  Java is not that far from C++ and it's more about the concepts anyway so it should be a good video to watch.  You want large values anyway for the sun position and use an orthographic projection.  He explains and even shows the math for getting a bounding volume for the light which is handy.  I haven't used DX11 but again, this is fairly simple, I'm sure you can figure out the vertex/pixel shaders from the GLSL ones he makes as they're like ~8 lines each.

As for your camera not having a direction, you might want to add that, it's a fairly useful feature but not essential.  I think he covers using direction in the video also, been a while since I watched it and I was more using it for background noise than a lesson.  Let us/me know if you still have issues after watching/reading the links above. 

10 hours ago, Bartosz Boczula said:

P.S. This was my first post, thank you for not dissing it and explaining instead

No worries we all start someplace, no point in discouraging new blood into the game dev scene.  Nor did you copy and paste your non-functioning code and say, "fix this for me" :)

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Thank's guys, I'm making some good progress here. One question though - I changed my projection calculation from Perspective to Ortographic, but when I did that, it seems that camera position has no impact at all at the final image. I set (100.0f, -100.0f, 100.0f) and then (1.0f, -1.0f, 1.0f) and the result was exactly the same. The only way to change the output is to change viewWidth and viewHeight of this function:

DirectX::XMMatrixOrthographicLH(128.0f, 128.0f, 0.1f, 100.0f);

So when I set it to 1024x1024 the object gets really small, and when I set it to 128x128 the object gets bigger. Why is that?

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That is exactly what an orthographic camera does. If you hold the direction same, changing the position of the camera does not change the 'image', only where the view is centred. This is the closest I could find to an ortho depth map pulled off google.

If direction is the same and you move the camera position, you would just be scrolling up and down through a portion of e.g. the following image. If you move the camera further away, there is no effect, as the rays are parallel in an ortho camera.

I would encourage you to try moving an ortho camera in e.g. blender to see how it works, before trying to use it in shadow mapping. I'm guessing the 128x128 figure you are quoting is the scale of the camera, which determines how much is fitted into the view. Fit more in and each object is going to be smaller.

11244749674_9c21955ae4_b.thumb.jpg.fe40a829fbe7e635d78d5c1bb7ca3e0b.jpg

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@lawnjelly Ok, I decided to take a step back - I'm using my Perspective camera, the one that I know that works. I created a blitter render pass, which should render my already filled depth buffer on the screen, however the result is all red. I'm guessing this has something to do with the formats. My depth texture is in R16_TYPELESS format, Shader Resource View in R16_UNORM, but my Render Target is in R8G8B8A8_UNORM - how would 16-bit value will be written to a 32-bits slot?

 

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Hello Bartosz,

I am not a DX god but at the end this is how I understood it. You are wondering what is the position of the light because you want to position the camera correctly for the depth pass right? In my case I had to either assume the bounds of my scene or pre-calculate it. Knowing the bounds of my scene i was able to assume a position for my light that would make sure no 3D object are behind the projection. Knowing the bounds we are also able to calculate the minimum range of near/far values for our projection to keep an optimal depth precision while having all the scene objects inside the projection. With those bounds you can also figure out the left/top/right/bottom of your otho projection to cover the whole scene. Of course it requires some math to do.

 

Your lookAt can safely be the Position that you gave to the light minus the light direction. LookAt is always a position where your camera is pointing to relative to it's current position.

 

Also, as mentioned above, an orthographic projection should be used for directional lights as it is supposed to mimic a light that is so far away that all the rays appear to go in the same direction. The orthographic project does exactly that.

 

On 1/29/2018 at 8:09 AM, Bartosz Boczula said:

@lawnjelly Ok, I decided to take a step back - I'm using my Perspective camera, the one that I know that works. I created a blitter render pass, which should render my already filled depth buffer on the screen, however the result is all red. I'm guessing this has something to do with the formats. My depth texture is in R16_TYPELESS format, Shader Resource View in R16_UNORM, but my Render Target is in R8G8B8A8_UNORM - how would 16-bit value will be written to a 32-bits slot?

 

 

First of all I've never heard of a 16 bits depth format. I either use

DXGI_FORMAT_R32_FLOAT

for full depth precision or 

DXGI_FORMAT_R24_UNORM_X8_TYPELESS

in case I am using depth + stencil.

See this link : https://msdn.microsoft.com/en-us/library/windows/desktop/ff476464(v=vs.85).aspx

When you set your render target you specify both your render target AND the depth buffer to use. So your render target may be set to a R8G8B8A8_UNORM texture but your depth buffer must also be set to your R16_UNORM texture. The depth will be written to the depth buffer while your pixel shader will write colors to the R8G8B8A8_UNORM texture. Those are two completely different texture.

 

It is possible to ommit the render target and specify only a depth buffer in case you only want to do a depth pass with vertex shader which is what you should probably do when generating the depth map of your shadows.

Edited by ChuckNovice

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Hey guys, thanks for all the support, thanks to that I made some progress! My blitter shader looks like this:

float4 main(PS_INPUT input) : SV_TARGET
{
    float4 val = shaderTexture.Sample(sampleType, input.textureCoordinates);
    return float4(val.b, frac(val.g * 10), frac(val.r * 100), 1.0);
}

This seem to work, I'm now able to see my D16 texture as R8G8B8A8 Render Target. But of course, this can't be too easy, can it :)

This is my result:

image.thumb.png.d1876636cfade1b2472e3765b6b3f145.png

I might add that this looks normal with Perspective camera. @ChuckNovice did you have such issue?

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It is hard to tell what you got as a result. Could you modify your shader to output the actual texture data instead of those frac() operations. At the end your depth buffer is supposed to look something like this (the depth value is simply a shade of red) :

rendering-technologies-from-crysis-3-gdc

You can also use the visual studio graphic debugger tool to visualize the textures that you loaded so you don't need to write a shader and tons of code just to visualize your result.

 

Also be aware that since you used a perspective projection you are actually running a spot light and not a directional light.

 

Edited by ChuckNovice

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      Static variables cannot be changed once a resource is bound to the variable. They are bound directly to the shader object. For instance, a shadow map texture is not expected to change after it is created, so it can be bound directly to the shader:
      PixelShader->GetShaderVariable( "g_tex2DShadowMap" )->Set( pShadowMapSRV ); Mutable and dynamic variables are bound via a new Shader Resource Binding object (SRB) that is created by the pipeline state (IPipelineState::CreateShaderResourceBinding()):
      m_pPSO->CreateShaderResourceBinding(&m_pSRB); Note that an SRB is only compatible with the pipeline state it was created from. SRB object inherits all static bindings from shaders in the pipeline, but is not allowed to change them.
      Mutable resources can only be set once for every instance of a shader resource binding. Such resources are intended to define specific material properties. For instance, a diffuse texture for a specific material is not expected to change once the material is defined and can be set right after the SRB object has been created:
      m_pSRB->GetVariable(SHADER_TYPE_PIXEL, "tex2DDiffuse")->Set(pDiffuseTexSRV); In some cases it is necessary to bind a new resource to a variable every time a draw command is invoked. Such variables should be labeled as dynamic, which will allow setting them multiple times through the same SRB object:
      m_pSRB->GetVariable(SHADER_TYPE_VERTEX, "cbRandomAttribs")->Set(pRandomAttrsCB); Under the hood, the engine pre-allocates descriptor tables for static and mutable resources when an SRB objcet is created. Space for dynamic resources is dynamically allocated at run time. Static and mutable resources are thus more efficient and should be used whenever possible.
      As you can see, Diligent Engine does not expose low-level details of how resources are bound to shader variables. One reason for this is that these details are very different for various APIs. The other reason is that using low-level binding methods is extremely error-prone: it is very easy to forget to bind some resource, or bind incorrect resource such as bind a buffer to the variable that is in fact a texture, especially during shader development when everything changes fast. Diligent Engine instead relies on shader reflection system to automatically query the list of all shader variables. Grouping variables based on three types mentioned above allows the engine to create optimized layout and take heavy lifting of matching resources to API-specific resource location, register or descriptor in the table.
      This post gives more details about the resource binding model in Diligent Engine.
      Setting the Pipeline State and Committing Shader Resources
      Before any draw or compute command can be invoked, the pipeline state needs to be bound to the context:
      m_pContext->SetPipelineState(m_pPSO); Under the hood, the engine sets the internal PSO object in the command list or calls all the required native API functions to properly configure all pipeline stages.
      The next step is to bind all required shader resources to the GPU pipeline, which is accomplished by IDeviceContext::CommitShaderResources() method:
      m_pContext->CommitShaderResources(m_pSRB, COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES); The method takes a pointer to the shader resource binding object and makes all resources the object holds available for the shaders. In the case of D3D12, this only requires setting appropriate descriptor tables in the command list. For older APIs, this typically requires setting all resources individually.
      Next-generation APIs require the application to track the state of every resource and explicitly inform the system about all state transitions. For instance, if a texture was used as render target before, while the next draw command is going to use it as shader resource, a transition barrier needs to be executed. Diligent Engine does the heavy lifting of state tracking.  When CommitShaderResources() method is called with COMMIT_SHADER_RESOURCES_FLAG_TRANSITION_RESOURCES flag, the engine commits and transitions resources to correct states at the same time. Note that transitioning resources does introduce some overhead. The engine tracks state of every resource and it will not issue the barrier if the state is already correct. But checking resource state is an overhead that can sometimes be avoided. The engine provides IDeviceContext::TransitionShaderResources() method that only transitions resources:
      m_pContext->TransitionShaderResources(m_pPSO, m_pSRB); In some scenarios it is more efficient to transition resources once and then only commit them.
      Invoking Draw Command
      The final step is to set states that are not part of the PSO, such as render targets, vertex and index buffers. Diligent Engine uses Direct3D11-syle API that is translated to other native API calls under the hood:
      ITextureView *pRTVs[] = {m_pRTV}; m_pContext->SetRenderTargets(_countof( pRTVs ), pRTVs, m_pDSV); // Clear render target and depth buffer const float zero[4] = {0, 0, 0, 0}; m_pContext->ClearRenderTarget(nullptr, zero); m_pContext->ClearDepthStencil(nullptr, CLEAR_DEPTH_FLAG, 1.f); // Set vertex and index buffers IBuffer *buffer[] = {m_pVertexBuffer}; Uint32 offsets[] = {0}; Uint32 strides[] = {sizeof(MyVertex)}; m_pContext->SetVertexBuffers(0, 1, buffer, strides, offsets, SET_VERTEX_BUFFERS_FLAG_RESET); m_pContext->SetIndexBuffer(m_pIndexBuffer, 0); Different native APIs use various set of function to execute draw commands depending on command details (if the command is indexed, instanced or both, what offsets in the source buffers are used etc.). For instance, there are 5 draw commands in Direct3D11 and more than 9 commands in OpenGL with something like glDrawElementsInstancedBaseVertexBaseInstance not uncommon. Diligent Engine hides all details with single IDeviceContext::Draw() method that takes takes DrawAttribs structure as an argument. The structure members define all attributes required to perform the command (primitive topology, number of vertices or indices, if draw call is indexed or not, if draw call is instanced or not, if draw call is indirect or not, etc.). For example:
      DrawAttribs attrs; attrs.IsIndexed = true; attrs.IndexType = VT_UINT16; attrs.NumIndices = 36; attrs.Topology = PRIMITIVE_TOPOLOGY_TRIANGLE_LIST; pContext->Draw(attrs); For compute commands, there is IDeviceContext::DispatchCompute() method that takes DispatchComputeAttribs structure that defines compute grid dimension.
      Source Code
      Full engine source code is available on GitHub and is free to use. The repository contains tutorials, sample applications, asteroids performance benchmark and an example Unity project that uses Diligent Engine in native plugin.
      Atmospheric scattering sample demonstrates how Diligent Engine can be used to implement various rendering tasks: loading textures from files, using complex shaders, rendering to multiple render targets, using compute shaders and unordered access views, etc.

      Asteroids performance benchmark is based on this demo developed by Intel. It renders 50,000 unique textured asteroids and allows comparing performance of Direct3D11 and Direct3D12 implementations. Every asteroid is a combination of one of 1000 unique meshes and one of 10 unique textures.

      Finally, there is an example project that shows how Diligent Engine can be integrated with Unity.

      Future Work
      The engine is under active development. It currently supports Windows desktop, Universal Windows, Linux, Android, MacOS, and iOS platforms. Direct3D11, Direct3D12, OpenGL/GLES backends are now feature complete. Vulkan backend is coming next, and Metal backend is in the plan.
    • By francoisdiy
      So I wrote a programming language called C-Lesh to program games for my game maker Platformisis. It is a scripting language which tiles into the JavaScript game engine via a memory mapper using memory mapped I/O. Currently, I am porting the language as a standalone interpreter to be able to run on the PC and possibly other devices excluding the phone. The interpreter is being written in C++ so for those of you who are C++ fans you can see the different components implemented. Some background of the language and how to program in C-Lesh can be found here:

      http://www.codeloader.net/readme.html
      As I program this thing I will post code from different components and explain.
    • By trojanfoe
      I hope this is the right place to ask questions about DirectXTK which aren't really about graphics, if not please let me know a better place.
      Can anyone tell me why I cannot do this:
      DirectX::SimpleMath::Rectangle rectangle = {...}; RECT rect = rectangle; or
      RECT rect = static_cast<RECT>(rectangle); or
      const RECT rect(m_textureRect); despite Rectangle having the following operator RECT:
      operator RECT() { RECT rct; rct.left = x; rct.top = y; rct.right = (x + width); rct.bottom = (y + height); return rct; } VS2017 tells me:
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    • By isu diss
      I'm trying to duplicate vertices using std::map to be used in a vertex buffer. I don't get the correct index buffer(myInds) or vertex buffer(myVerts). I can get the index array from FBX but it differs from what I get in the following std::map code. Any help is much appreciated.
      struct FBXVTX { XMFLOAT3 Position; XMFLOAT2 TextureCoord; XMFLOAT3 Normal; }; std::map< FBXVTX, int > myVertsMap; std::vector<FBXVTX> myVerts; std::vector<int> myInds; HRESULT FBXLoader::Open(HWND hWnd, char* Filename, bool UsePositionOnly) { HRESULT hr = S_OK; if (FBXM) { FBXIOS = FbxIOSettings::Create(FBXM, IOSROOT); FBXM->SetIOSettings(FBXIOS); FBXI = FbxImporter::Create(FBXM, ""); if (!(FBXI->Initialize(Filename, -1, FBXIOS))) { hr = E_FAIL; MessageBox(hWnd, (wchar_t*)FBXI->GetStatus().GetErrorString(), TEXT("ALM"), MB_OK); } FBXS = FbxScene::Create(FBXM, "REALMS"); if (!FBXS) { hr = E_FAIL; MessageBox(hWnd, TEXT("Failed to create the scene"), TEXT("ALM"), MB_OK); } if (!(FBXI->Import(FBXS))) { hr = E_FAIL; MessageBox(hWnd, TEXT("Failed to import fbx file content into the scene"), TEXT("ALM"), MB_OK); } FbxAxisSystem OurAxisSystem = FbxAxisSystem::DirectX; FbxAxisSystem SceneAxisSystem = FBXS->GetGlobalSettings().GetAxisSystem(); if(SceneAxisSystem != OurAxisSystem) { FbxAxisSystem::DirectX.ConvertScene(FBXS); } FbxSystemUnit SceneSystemUnit = FBXS->GetGlobalSettings().GetSystemUnit(); if( SceneSystemUnit.GetScaleFactor() != 1.0 ) { FbxSystemUnit::cm.ConvertScene( FBXS ); } if (FBXI) FBXI->Destroy(); FbxNode* MainNode = FBXS->GetRootNode(); int NumKids = MainNode->GetChildCount(); FbxNode* ChildNode = NULL; for (int i=0; i<NumKids; i++) { ChildNode = MainNode->GetChild(i); FbxNodeAttribute* NodeAttribute = ChildNode->GetNodeAttribute(); if (NodeAttribute->GetAttributeType() == FbxNodeAttribute::eMesh) { FbxMesh* Mesh = ChildNode->GetMesh(); if (UsePositionOnly) { NumVertices = Mesh->GetControlPointsCount();//number of vertices MyV = new XMFLOAT3[NumVertices]; for (DWORD j = 0; j < NumVertices; j++) { FbxVector4 Vertex = Mesh->GetControlPointAt(j);//Gets the control point at the specified index. MyV[j] = XMFLOAT3((float)Vertex.mData[0], (float)Vertex.mData[1], (float)Vertex.mData[2]); } NumIndices = Mesh->GetPolygonVertexCount();//number of indices MyI = (DWORD*)Mesh->GetPolygonVertices();//index array } else { FbxLayerElementArrayTemplate<FbxVector2>* uvVertices = NULL; Mesh->GetTextureUV(&uvVertices); int idx = 0; for (int i = 0; i < Mesh->GetPolygonCount(); i++)//polygon(=mostly triangle) count { for (int j = 0; j < Mesh->GetPolygonSize(i); j++)//retrieves number of vertices in a polygon { FBXVTX myVert; int p_index = 3*i+j; int t_index = Mesh->GetTextureUVIndex(i, j); FbxVector4 Vertex = Mesh->GetControlPointAt(p_index);//Gets the control point at the specified index. myVert.Position = XMFLOAT3((float)Vertex.mData[0], (float)Vertex.mData[1], (float)Vertex.mData[2]); FbxVector4 Normal; Mesh->GetPolygonVertexNormal(i, j, Normal); myVert.Normal = XMFLOAT3((float)Normal.mData[0], (float)Normal.mData[1], (float)Normal.mData[2]); FbxVector2 uv = uvVertices->GetAt(t_index); myVert.TextureCoord = XMFLOAT2((float)uv.mData[0], (float)uv.mData[1]); if ( myVertsMap.find( myVert ) != myVertsMap.end() ) myInds.push_back( myVertsMap[ myVert ]); else { myVertsMap.insert( std::pair<FBXVTX, int> (myVert, idx ) ); myVerts.push_back(myVert); myInds.push_back(idx); idx++; } } } } } } } else { hr = E_FAIL; MessageBox(hWnd, TEXT("Failed to create the FBX Manager"), TEXT("ALM"), MB_OK); } return hr; } bool operator < ( const FBXVTX &lValue, const FBXVTX &rValue) { if (lValue.Position.x != rValue.Position.x) return(lValue.Position.x < rValue.Position.x); if (lValue.Position.y != rValue.Position.y) return(lValue.Position.y < rValue.Position.y); if (lValue.Position.z != rValue.Position.z) return(lValue.Position.z < rValue.Position.z); if (lValue.TextureCoord.x != rValue.TextureCoord.x) return(lValue.TextureCoord.x < rValue.TextureCoord.x); if (lValue.TextureCoord.y != rValue.TextureCoord.y) return(lValue.TextureCoord.y < rValue.TextureCoord.y); if (lValue.Normal.x != rValue.Normal.x) return(lValue.Normal.x < rValue.Normal.x); if (lValue.Normal.y != rValue.Normal.y) return(lValue.Normal.y < rValue.Normal.y); return(lValue.Normal.z < rValue.Normal.z); }  
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