• Advertisement
Sign in to follow this  

DX11 UV problem with FBX and DX11

This topic is 1548 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hello All!
Came by here today hoping somebody has some experience loading models into DX11 using the FBX SDK. I am
having a weird problem when I load in my texture coordinates. On some models, they render correctly while on others, they render with the "U" flipped. An example below:
uvissue.jpg

The space ship is rendered correctly, while the planet texture is flipped. Both are using the same code to load them in, the only difference is that I am sending in different strings for where to fetch the file from.

 

I load in the vertices from FBX in the following manner:

	int counter = 0;
	//Loop through the polygons
	for (int p = 0; p < fbxMesh->GetPolygonCount(); p++)
	{
		//Loop through the three vertices within each polygon
		for(int v = 0; v < fbxMesh->GetPolygonSize(p); v++)
		{

			const int controlPointIndex = fbxMesh->GetPolygonVertex(p, v);

			VertexStruct vS;
			vS.position = FBXD3DVector3(fbxMesh->GetControlPointAt(controlPointIndex));
			
			FbxVector2 tex;
			bool isMapped;
			fbxMesh->GetPolygonVertexUV(p, v, lUVSetName, tex, isMapped);
			vS.uv = D3DXVECTOR2(tex[0], -tex[1]);

			FbxVector4 norm;
			fbxMesh->GetPolygonVertexNormal(p, v, norm);
			vS.normal = D3DXVECTOR3(-norm[0], -norm[1], -norm[2]);

			m_Vertices.push_back(vS);

			m_Indices.push_back(static_cast<unsigned int>(counter));

			counter++;
		}
		
	}

Tried looking on the FBX forums but had no luck. I could hard code them individually but I was looking to create a system where all my resources are loaded. Any help would be greatly appreciated. Thanks!

Share this post


Link to post
Share on other sites
Advertisement

This is typical when using content from DCC packages in D3D. D3D specifies that V = 0 is the top of the texture and OpenGL specifies that V = 0 is the bottom, so you usually have to flip the V coordinates (and the bitangents!) when generating meshes for D3D.

Share this post


Link to post
Share on other sites

Thanks for the reply. Yes I understand that...however my problem seems to be with the 'U' coordinates. The planet is flipped ( so you have Asia on the western hemisphere and the Americas on the east.). The mesh was just a simple sphere that I exported from 3Ds Max, applied a mesh modifier, applied a texture to it and unwrapped it. The models I downloaded from TurboSquid. I tried 2 different artists and both loaded correctly. The same happened when I tried it on a cube.

Edited by JacobM

Share this post


Link to post
Share on other sites

Is your coordinate system handness coorect? 3DS Max is right-handed, while DX if left-handed.

If you export it as RHS, then in DX all of your triangles will be facing inward, causing back-face culling to cull the wrong triangles. Which means you are seeing the inside of the sphere, creating the apperance of U coordinate mirroring.

 

You can test this theory by rotating the sphere - if I'm correct, then it will appear to rotate in the wrong direction.

Share this post


Link to post
Share on other sites

Check you export settings. Probablly the problem is in the UVW mapping. Use the UVW modifination(if you're using 3ds max) and specify the mapping type. If you drag and drop the texture the default the mapping generated will be OGL style(not shure im always using UVW modifier). You can tell 3ds max to generate fliped UVs

Share this post


Link to post
Share on other sites

Thanks for the reply. Yes I understand that...however my problem seems to be with the 'U' coordinates. The planet is flipped ( so you have Asia on the western hemisphere and the Americas on the east.). The mesh was just a simple sphere that I exported from 3Ds Max, applied a mesh modifier, applied a texture to it and unwrapped it. The models I downloaded from TurboSquid. I tried 2 different artists and both loaded correctly. The same happened when I tried it on a cube.

 

Whoops, I mis-read your post. Sorry about that.

Share this post


Link to post
Share on other sites

Satanir:

This is what I originally thought as well. However culling was turned on and it was culling the correct triangles. i inverted the mesh in 3Ds max and it indeed fixed the texture. But now i was seeing inside of the sphere. Also, if that was the case then i assume the spaceships textures would have been inverted as well, but they come out just fine. 
But I am sure that the sphere is being drawn correctly so I am not understanding why I am getting such mixed results.

imoogiBG:
I have used the UV unwrap, and the UV Xform. i even tried the UV Map modifier as u suggested. And you're right I could just flip the texture backwards in 3Ds this way it comes out correctly when I load it, but I would really like to get to the source of this. Not sure what other problems I may run into down the line. But I just find it weird that complex objects come out correctly while standard primitives like cubes and spheres come out like this. I think that may play some kind of role in this.
 

Share this post


Link to post
Share on other sites

Satanir, I guess u you were right, feel like a dunce now.

After a little reading I found all I had to do was switch the position Y and position Z of the verts like so:

FbxVector4 position = fbxMesh->GetControlPointAt(controlPointIndex);
vS.position = D3DXVECTOR3(position[0], position[2], position[1]); 
			
FbxVector2 tex;
bool isMapped;
fbxMesh->GetPolygonVertexUV(p, v, lUVSetName, tex, isMapped);
vS.uv = D3DXVECTOR2(tex[0], -tex[1]);

FbxVector4 norm;
fbxMesh->GetPolygonVertexNormal(p, v, norm);
vS.normal = D3DXVECTOR3(-norm[0], -norm[2], -norm[1]);

Thanks for the help. Hopefully this will also help someone else with the same issue.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
  • Advertisement
  • Popular Tags

  • Advertisement
  • Popular Now

  • Similar Content

    • By AxeGuywithanAxe
      I wanted to see how others are currently handling descriptor heap updates and management.
      I've read a few articles and there tends to be three major strategies :
      1 ) You split up descriptor heaps per shader stage ( i.e one for vertex shader , pixel , hull, etc)
      2) You have one descriptor heap for an entire pipeline
      3) You split up descriptor heaps for update each update frequency (i.e EResourceSet_PerInstance , EResourceSet_PerPass , EResourceSet_PerMaterial, etc)
      The benefits of the first two approaches is that it makes it easier to port current code, and descriptor / resource descriptor management and updating tends to be easier to manage, but it seems to be not as efficient.
      The benefits of the third approach seems to be that it's the most efficient because you only manage and update objects when they change.
    • By evelyn4you
      hi,
      until now i use typical vertexshader approach for skinning with a Constantbuffer containing the transform matrix for the bones and an the vertexbuffer containing bone index and bone weight.
      Now i have implemented realtime environment  probe cubemaping so i have to render my scene from many point of views and the time for skinning takes too long because it is recalculated for every side of the cubemap.
      For Info i am working on Win7 an therefore use one Shadermodel 5.0 not 5.x that have more options, or is there a way to use 5.x in Win 7
      My Graphic Card is Directx 12 compatible NVidia GTX 960
      the member turanszkij has posted a good for me understandable compute shader. ( for Info: in his engine he uses an optimized version of it )
      https://turanszkij.wordpress.com/2017/09/09/skinning-in-compute-shader/
      Now my questions
       is it possible to feed the compute shader with my orignial vertexbuffer or do i have to copy it in several ByteAdressBuffers as implemented in the following code ?
        the same question is about the constant buffer of the matrixes
       my more urgent question is how do i feed my normal pipeline with the result of the compute Shader which are 2 RWByteAddressBuffers that contain position an normal
      for example i could use 2 vertexbuffer bindings
      1 containing only the uv coordinates
      2.containing position and normal
      How do i copy from the RWByteAddressBuffers to the vertexbuffer ?
       
      (Code from turanszkij )
      Here is my shader implementation for skinning a mesh in a compute shader:
      1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 struct Bone { float4x4 pose; }; StructuredBuffer<Bone> boneBuffer;   ByteAddressBuffer vertexBuffer_POS; // T-Pose pos ByteAddressBuffer vertexBuffer_NOR; // T-Pose normal ByteAddressBuffer vertexBuffer_WEI; // bone weights ByteAddressBuffer vertexBuffer_BON; // bone indices   RWByteAddressBuffer streamoutBuffer_POS; // skinned pos RWByteAddressBuffer streamoutBuffer_NOR; // skinned normal RWByteAddressBuffer streamoutBuffer_PRE; // previous frame skinned pos   inline void Skinning(inout float4 pos, inout float4 nor, in float4 inBon, in float4 inWei) {  float4 p = 0, pp = 0;  float3 n = 0;  float4x4 m;  float3x3 m3;  float weisum = 0;   // force loop to reduce register pressure  // though this way we can not interleave TEX - ALU operations  [loop]  for (uint i = 0; ((i &lt; 4) &amp;&amp; (weisum&lt;1.0f)); ++i)  {  m = boneBuffer[(uint)inBon].pose;  m3 = (float3x3)m;   p += mul(float4(pos.xyz, 1), m)*inWei;  n += mul(nor.xyz, m3)*inWei;   weisum += inWei;  }   bool w = any(inWei);  pos.xyz = w ? p.xyz : pos.xyz;  nor.xyz = w ? n : nor.xyz; }   [numthreads(1024, 1, 1)] void main( uint3 DTid : SV_DispatchThreadID ) {  const uint fetchAddress = DTid.x * 16; // stride is 16 bytes for each vertex buffer now...   uint4 pos_u = vertexBuffer_POS.Load4(fetchAddress);  uint4 nor_u = vertexBuffer_NOR.Load4(fetchAddress);  uint4 wei_u = vertexBuffer_WEI.Load4(fetchAddress);  uint4 bon_u = vertexBuffer_BON.Load4(fetchAddress);   float4 pos = asfloat(pos_u);  float4 nor = asfloat(nor_u);  float4 wei = asfloat(wei_u);  float4 bon = asfloat(bon_u);   Skinning(pos, nor, bon, wei);   pos_u = asuint(pos);  nor_u = asuint(nor);   // copy prev frame current pos to current frame prev pos streamoutBuffer_PRE.Store4(fetchAddress, streamoutBuffer_POS.Load4(fetchAddress)); // write out skinned props:  streamoutBuffer_POS.Store4(fetchAddress, pos_u);  streamoutBuffer_NOR.Store4(fetchAddress, nor_u); }  
    • By mister345
      Hi, can someone please explain why this is giving an assertion EyePosition!=0 exception?
       
      _lightBufferVS->viewMatrix = DirectX::XMMatrixLookAtLH(XMLoadFloat3(&_lightBufferVS->position), XMLoadFloat3(&_lookAt), XMLoadFloat3(&up));
      It looks like DirectX doesnt want the 2nd parameter to be a zero vector in the assertion, but I passed in a zero vector with this exact same code in another program and it ran just fine. (Here is the version of the code that worked - note XMLoadFloat3(&m_lookAt) parameter value is (0,0,0) at runtime - I debugged it - but it throws no exceptions.
          m_viewMatrix = DirectX::XMMatrixLookAtLH(XMLoadFloat3(&m_position), XMLoadFloat3(&m_lookAt), XMLoadFloat3(&up)); Here is the repo for the broken code (See LightClass) https://github.com/mister51213/DirectX11Engine/blob/master/DirectX11Engine/LightClass.cpp
      and here is the repo with the alternative version of the code that is working with a value of (0,0,0) for the second parameter.
      https://github.com/mister51213/DX11Port_SoftShadows/blob/master/Engine/lightclass.cpp
    • By mister345
      Hi, can somebody please tell me in clear simple steps how to debug and step through an hlsl shader file?
      I already did Debug > Start Graphics Debugging > then captured some frames from Visual Studio and
      double clicked on the frame to open it, but no idea where to go from there.
       
      I've been searching for hours and there's no information on this, not even on the Microsoft Website!
      They say "open the  Graphics Pixel History window" but there is no such window!
      Then they say, in the "Pipeline Stages choose Start Debugging"  but the Start Debugging option is nowhere to be found in the whole interface.
      Also, how do I even open the hlsl file that I want to set a break point in from inside the Graphics Debugger?
       
      All I want to do is set a break point in a specific hlsl file, step thru it, and see the data, but this is so unbelievably complicated
      and Microsoft's instructions are horrible! Somebody please, please help.
       
       
       

    • By mister345
      I finally ported Rastertek's tutorial # 42 on soft shadows and blur shading. This tutorial has a ton of really useful effects and there's no working version anywhere online.
      Unfortunately it just draws a black screen. Not sure what's causing it. I'm guessing the camera or ortho matrix transforms are wrong, light directions, or maybe texture resources not being properly initialized.  I didnt change any of the variables though, only upgraded all types and functions DirectX3DVector3 to XMFLOAT3, and used DirectXTK for texture loading. If anyone is willing to take a look at what might be causing the black screen, maybe something pops out to you, let me know, thanks.
      https://github.com/mister51213/DX11Port_SoftShadows
       
      Also, for reference, here's tutorial #40 which has normal shadows but no blur, which I also ported, and it works perfectly.
      https://github.com/mister51213/DX11Port_ShadowMapping
       
  • Advertisement