3D D3D9 - How to linearize depth buffer obtained from closed source application

Recommended Posts

Hey guys, I hope for help on the following problem - hopefully an easy one for you, but I am an absolute beginner...

I want to simulate a Lidar in a closed source D3D9 game (ArmA2-based I think), meaning I want to get the pixel positions in view space. For that I intercept the D3D9 calls (via proxy dll) and retrieve the handle to the depth buffer texture (R32F) which I have identified .  I've attached an example of the contents of this depth buffer (just StretchRect'ed the contents to the back buffer) and the corresponding rendered image.

Now what I am trying to do is transform the depth buffer values to view space but I keep failing on this. I am trying to do it as described in this stackoverflow post (the only change I made after I saw that it does not work is to delete the first line 'z = depth*2.0 - 1.0' and instead directly using the depth value, because as far as I know the projection matrix(from MSDN: https://msdn.microsoft.com/de-de/library/windows/desktop/bb147302(v=vs.85).aspx,IC511470.png, Q = Zf/(Zf-Zn) )is already adjusted to output a depth in [0,1] - and thus should also be directly usable in inverted form for the transformatino from clip space to view space)

I should mention that I can query the game API for the view frustum values (left + right angle, top + bottom angle, near and far plane), but as you can see a large part of the depth buffer is black

So here are my questions:

1) What I don't quite understand is that apparently the whole depth buffer value interval is inverted, meaning far objects are dark (a color of (1,1,1,1) is white) . Are there any other projection matrices commonly used together with D3D9, that have this behavior and which I could try?

2) Is the approach shown in the mentioned stackoverflow post a valid one? Especially I'd really like to know if this division by w after applying the inverse projection matrix is correct - I thought, this division is necessary to get from clip space to normalized device coordinates. But why is it necessary here?

3) Is there any other approach I could use to get the pixel positions in view space?

Thanks in advance!



Edited by Apollo13

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Forum Statistics

    • Total Topics
    • Total Posts
  • Similar Content

    • By Rannion
      I'm trying to fill a win64 Console with ASCII char.
      At the moment I have 2 solutions: one using std::cout for each line, let's say 30 lines at once using std::endl at the end of each one.
      The second solution is using FillConsoleOutputCharacter. This method seems a lot more robust and with less flickering. But I'm guessing, internally it's using a different table than the one used by std::cout. I'm trying to fill the console with the unsigned char 0xB0 which is a sort of grey square when I use std::cout but when using FillConsoleOutputCharacter it is outputted as the UTF8 char '°'.
      I tried using SetConsoleOutputCP before but could not find a proper way to force it to only use the non-extended ASCII code page...
      Has anyone a hint on this one?
    • By Vortez
      Hi guys, i know this is stupid but i've been trying to convert this block of asm code in c++ for an hour or two and im stuck
      ////////////////////////////////////////////////////////////////////////////////////////////// /////// This routine write the value returned by GetProcAddress() at the address p /////////// ////////////////////////////////////////////////////////////////////////////////////////////// bool SetProcAddress(HINSTANCE dll, void *p, char *name) { UINT *res = (UINT*)ptr; void *f = GetProcAddress(dll, name); if(!f) return false; _asm { push ebx push edx mov ebx, f mov edx, p mov [ebx], edx // <--- put edx at the address pointed by ebx pop edx pop ebx } return res != 0; } ... // ie: SetProcAddress(hDll, &some_function, "function_name"); I tried:
      memcmp(p, f, sizeof(p)); and UINT *i1 = (*UINT)p; UINT *i2 = (*UINT)f; *f = *p; The first one dosent seem to give the right retult, and the second one won't compile.
      Any idea?
    • By adapelin
      I am a computer engineering student and i have the assignment below. İ only can write the 2D maze array and have no idea about creating car and time as well. Could anyone write and explain hot to do???
      Minimum Criteria: You are expected to design the game by using C ++ . Below are the minimal criteria: • You must create game board with 2 - Dimensional Matrix • Bonuses create with randomly in the game board • All bonuses have got the same value but different effect for car and score . These effects may be positive or negative . • You must use pointer for creating and using car . Some bonuses may be change car type. • When the game finish, you must show high - score. • For moving car , you need to create coordinate s randomly and you need to write proper control statements. • You must use functions for drawing game board and changing car type . If you need extra functions, you can use it. • If you cannot get out the maze when the time is up , the game is over and you need to show high score. In this project, you must do all minimum criteria. In the end, your program must be work without any errors. Bonus: • Save and load high score information to/from disk • Each bonus has got different random values. • You can create cheat codes for the game. • You can create alternative control for car . • Car can jump over the wall but may lose the score . When car exit the maze , game is over and you need to show high score.    
    • By pristondev
      Hey guys, Im getting bounding box of a mesh in my engine using D3DXComputeBoundingBox, but when I use this function, looks like the mesh is every on position (0,0,0), but it isn't.
      The bounding box should be in position of sphere, and dont (0,0,0)

      D3DXComputeBoundingBox getting wrong sMin and sMax (how we can see on the pic, it isnt a problem of render...)

      How it should be:

      The code im using to get bounding box:
      BYTE * pData; pMeshContainer->MeshData.pMesh->LockVertexBuffer( D3DLOCK_READONLY, (void**)&pData ); //Compute Bounding Box D3DXComputeBoundingBox( (const D3DXVECTOR3*)(pData), pMeshContainer->MeshData.pMesh->GetNumVertices(), pMeshContainer->MeshData.pMesh->GetNumBytesPerVertex(), &pMeshContainer->cBoundingBox.sMin, &pMeshContainer->cBoundingBox.sMax ); pMeshContainer->cBoundingBox.sMid = (pMeshContainer->cBoundingBox.sMax - pMeshContainer->cBoundingBox.sMin) * 0.5f; pMeshContainer->cBoundingBox.sCenter = (pMeshContainer->cBoundingBox.sMax + pMeshContainer->cBoundingBox.sMin) * 0.5f; //Compute Bounding Sphere D3DXComputeBoundingSphere( (const D3DXVECTOR3*)(pData), pMeshContainer->MeshData.pMesh->GetNumVertices(), pMeshContainer->MeshData.pMesh->GetNumBytesPerVertex(), &pMeshContainer->cBoundingSphere.sCenter, &pMeshContainer->cBoundingSphere.fRadius ); pMeshContainer->MeshData.pMesh->UnlockVertexBuffer(); //We have min and max values, use these to get the 8 corners of the bounding box pMeshContainer->cBoundingBox.sBoxPoints[0] = D3DXVECTOR3( pMeshContainer->cBoundingBox.sMin.x, pMeshContainer->cBoundingBox.sMin.y, pMeshContainer->cBoundingBox.sMin.z ); //xyz pMeshContainer->cBoundingBox.sBoxPoints[1] = D3DXVECTOR3( pMeshContainer->cBoundingBox.sMax.x, pMeshContainer->cBoundingBox.sMin.y, pMeshContainer->cBoundingBox.sMin.z ); //Xyz pMeshContainer->cBoundingBox.sBoxPoints[2] = D3DXVECTOR3( pMeshContainer->cBoundingBox.sMin.x, pMeshContainer->cBoundingBox.sMax.y, pMeshContainer->cBoundingBox.sMin.z ); //xYz pMeshContainer->cBoundingBox.sBoxPoints[3] = D3DXVECTOR3( pMeshContainer->cBoundingBox.sMax.x, pMeshContainer->cBoundingBox.sMax.y, pMeshContainer->cBoundingBox.sMin.z ); //XYz pMeshContainer->cBoundingBox.sBoxPoints[4] = D3DXVECTOR3( pMeshContainer->cBoundingBox.sMin.x, pMeshContainer->cBoundingBox.sMin.y, pMeshContainer->cBoundingBox.sMax.z ); //xyZ pMeshContainer->cBoundingBox.sBoxPoints[5] = D3DXVECTOR3( pMeshContainer->cBoundingBox.sMax.x, pMeshContainer->cBoundingBox.sMin.y, pMeshContainer->cBoundingBox.sMax.z ); //XyZ pMeshContainer->cBoundingBox.sBoxPoints[6] = D3DXVECTOR3( pMeshContainer->cBoundingBox.sMin.x, pMeshContainer->cBoundingBox.sMax.y, pMeshContainer->cBoundingBox.sMax.z ); //xYZ pMeshContainer->cBoundingBox.sBoxPoints[7] = D3DXVECTOR3( pMeshContainer->cBoundingBox.sMax.x, pMeshContainer->cBoundingBox.sMax.y, pMeshContainer->cBoundingBox.sMax.z ); //XYZ SAFE_RELEASE( pMeshContainer->lpBoundingBoxMesh ); SAFE_RELEASE( pMeshContainer->lpBoundingSphereMesh ); //Create Bounding Sphere Mesh D3DXCreateSphere( lpDevice, pMeshContainer->cBoundingSphere.fRadius, 15, 10, &pMeshContainer->lpBoundingSphereMesh, NULL ); //Create Bounding Box Mesh float fWidth = pMeshContainer->cBoundingBox.sMax.x - pMeshContainer->cBoundingBox.sMin.x; float fHeight = pMeshContainer->cBoundingBox.sMax.y - pMeshContainer->cBoundingBox.sMin.y; float fDepth = pMeshContainer->cBoundingBox.sMax.z - pMeshContainer->cBoundingBox.sMin.z; D3DXCreateBox( lpDevice, fWidth, fHeight, fDepth, &pMeshContainer->lpBoundingBoxMesh, NULL ); Im not using any World transform on the mesh or bounding box...
    • By Yarden2JR
      Hi there everyone! I'm trying to implement SPH using CPU single core. I'm having troubles in making it stable. I'd like some help in order to understand what is wrong and how could I fix it. Please, take a look at the following videos:
      Water inside sphere using Kelager's parameters
      Water inside big box
      Water inside thinner box
      I've already tried using XSPH, the hash method to find the neighbors (now I'm using the regular grid, because the hash method didn't work for me) and two different ways of calculating the pressure force.
      I'm using mostly the following articles:
      Particle-Based Fluid Simulation for Interactive Applications, Matthias Müller, David Charypar and Markus Gross
      Lagrangian Fluid Dynamics Using Smoothed Particle Hydrodynamics, Micky Kelager
      Smoothed Particle Hydrodynamics Real-Time Fluid Simulation Approach, David Staubach
      Fluid Simulation using Smoothed Particle Hydrodynamics, Burak Ertekin
      3D Langrangian Fluid Solver using SPH approximations, Chris Priscott
      Any ideas? Thanks!
  • Popular Now