Meshes Part II. June 13, 2005

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1 Game Programming Meshes Part II June 13, 2005 Objectives To learn how to load the data of an XFile into an ID3DXMesh object To gain an understanding of the benefits of using progressive meshes and how to use the progressive mesh interface ID3DXPMesh To learn about bounding volume, why they are useful, and how to create them using the D3DX functions

ID3DXBuffer Generic data structure to store data in a contiguous block of memory Two methods ex) Must be released to avoid a memory leak ex) Creating an empty ID3DXBuffer LPVOID LPVOID

2 ID3DXBuffer Generic data structure to store data in a contiguous block of memory Two methods ex) Must be released to avoid a memory leak ex) Creating an empty ID3DXBuffer LPVOID LPVOID ID3DXBuffer::GetBufferPointer(VOID); DWORD DWORD ID3DXBuffer::GetBufferSize(VOID); DWORD* info = (DWORD*)adjacencyInfo->GetBufferPointer( ); D3DXMATERIAL *mtrls = (D3DXMATERIAL*)mtrlBuffer->GetBufferPointer( ); adjacencyinfo->release( ); mtrlbuffer->release( ); HRESULT HRESULT D3DXCreateBuffer ( DWORD DWORD NumBytes, NumBytes, LPD3DXBUFFER LPD3DXBUFFER *ppbuffer *ppbuffer ); ); ID3DXBuffer* buffer = 0; D3DXCreateBuffer( 4*sizeof(int), &buffer ); XFiles 3D modelers 3DS Max ( LightWave3D ( Maya ( export the created mesh data (geometry, materials, animations, and other possible useful data) to Xfiles

3 MSDN Exporter for 3DS MAX MSDN Exporter for Maya

4 Loading an XFile Creating an ID3DXMesh object and loading the geometric data of the XFile into it ex) HRESULT HRESULT D3DXLoadMeshFromX ( LPCSTR LPCSTR pfilename, pfilename, DWORD DWORD Options, Options, LPDIRECT3DDEVICE9 pdevice, pdevice, LPD3DXBUFFER* LPD3DXBUFFER* ppadjacency, ppadjacency, LPD3DXBUFFER* LPD3DXBUFFER* ppmaterials, ppmaterials, LPD3DXBUFFER* LPD3DXBUFFER* ppeffectinstances, PDWORD PDWORD pnummaterials, pnummaterials, LPD3DXMESH* LPD3DXMESH* ppmesh ppmesh ); ); HRESULT hr = 0; ID3DXBuffer* adjbuffer = 0; ID3DXBuffer* mtrlbuffer = 0; DWORD nummtrls = 0; hr = D3DXLoadMeshFromX( "bigship1.x", D3DXMESH_MANAGED, Device, &adjbuffer, &mtrlbuffer, 0, &nummtrls, &Mesh ); XFile Materials Array of D3DXMATERIAL structures containing the material data argument five of D3DXLoadMeshFromX function XFile doesn t embed the texture data Number of materials that mesh contains argument seven typedef typedef struct struct D3DXMATERIAL D3DXMATERIAL { D3DMATERIAL9 D3DMATERIAL9 MatD3D; MatD3D; LPSTR LPSTR ptexturefilename; } D3DXMATERIAL; D3DXMATERIAL; The ith entry in the returned D3DMATERIAL array corresponds with the ith subset

5 Sample: XFile Global Variables

6 Loading the XFile Extracting Materials & Loading Textures (1)

7 Extracting Materials & Loading Textures (2) Rotating the Mesh

Rendering the Mesh Generating Vertex Normals if XFile does not contain vertex normal data adjacency info to disregard duplicated vertices must have a D3DFVF_NORMAL in the vertex format ex) HRESULT

8 Rendering the Mesh Generating Vertex Normals if XFile does not contain vertex normal data adjacency info to disregard duplicated vertices must have a D3DFVF_NORMAL in the vertex format ex) HRESULT HRESULT D3DXComputeNormals ( LPD3DXBASEMESH LPD3DXBASEMESH pmesh, pmesh, CONST CONST DWORD DWORD *padjacency *padjacency ); ); if(!(pmesh->getfvf() & D3DFVF_NORMAL) ) { ID3DXMesh* ptempmesh = 0; pmesh->clonemeshfvf ( D3DXMESH_MANAGED, pmesh->getfvf() D3DFVF_NORMAL, Device, &ptempmesh ); D3DXComputeNormals( ptempmesh, 0 ); pmesh->release(); pmesh = ptempmesh; }

(ETC) Progressive Meshes (2) Edge collapse vs.

9 Progressive Meshes (1) New representation for storing and transmitting arbitrary triangle meshes (H. Hoppe, SIGGRAPH 96) ID3DXPMesh interface simplify a mesh by applying a sequence of edge collapse transformations (ETC) Progressive Meshes (2) Edge collapse vs. vertex split v u ecollapse(v u,v t,v s ) v l v r v l v r v t vsplit(vs,v v s l,v r,v u,v t ) Base mesh + sequence of vertex splits M 0 M 175 M 425 M n = M org vsplit 0 vsplit 174 vsplit i vsplit n-1 PM

Progressive Meshes (3) LOD (level of detail) High Resolution Medium Resolution Low Resolution a small, far-away mesh does not need as high a triangle count as a large, close-up mesh to adjust the LOD

10 Progressive Meshes (3) LOD (level of detail) High Resolution Medium Resolution Low Resolution a small, far-away mesh does not need as high a triangle count as a large, close-up mesh to adjust the LOD of a mesh based on its distance from the camera Generating a Progressive Mesh Creating an ID3DXPMesh object HRESULT HRESULT D3DXGeneratePMesh ( LPD3DXMESH LPD3DXMESH pmesh, pmesh, CONST CONST DWORD DWORD *padjacency, *padjacency, CONST CONST LPD3DXATTRIBUTEWEIGHTS pvertexattributeweights, CONST CONST FLOAT FLOAT *pvertexweights, DWORD DWORD MinValues, MinValues, DWORD DWORD Options, Options, LPD3DXPMESH LPD3DXPMESH *pppmesh *pppmesh ); ); pvertexattributeweights pointer to a D3DXATTRIBUTEWEIGHTS array of size pmesh- >GetNumVertices() pvertexweights pointer to a float array of size pmesh->getnumvertices() MinValue the minimum vertices or faces Options D3DXMESHSIMP_VERTEX, D3DXMESHSIMP_FACE

11 Vertex Attribute Weights to specify a weight for each possible component of a vertex the default weights are recommended typedef typedef struct struct _D3DXATTRIBUTEWEIGHTS { FLOAT FLOAT Position; Position; FLOAT FLOAT Boundary; Boundary; FLOAT FLOAT Normal; Normal; FLOAT FLOAT Diffuse; Diffuse; FLOAT FLOAT Specular; Specular; FLOAT FLOAT Texcoord[8]; Texcoord[8]; FLOAT FLOAT Tangent; Tangent; FLOAT FLOAT Binormal; Binormal; } D3DXATTRIBUTEWEIGHTS; D3DXATTRIBUTEWEIGHTS AttributeWeights; AttributeWeights.Position = 1.0; AttributeWeights.Boundary = 1.0; AttributeWeights.Normal = 1.0; AttributeWeights.Diffuse = 0.0; AttributeWeights.Specular = 0.0; AttributeWeights.Texcoord[8] = { 0, 0, 0, 0, 0, 0, 0, 0 }; ID3DXPMesh Methods (1) ID3DXPMesh interface inherits from the ID3DXBaseMesh interface ID3DXBaseMesh Adjust LOD Additional methods ID3DXPMesh DWORD ID3DXPMesh::GetMaxFaces(VOID); DWORD ID3DXPMesh::GetMaxVertices(VOID); DWORD ID3DXPMesh::GetMinFaces(VOID); DWORD ID3DXPMesh::GetMinVertices(VOID); HRESULT ID3DXPMesh::SetNumFaces(DWORD Faces); HRESULT ID3DXPMesh::SetNumVertices(DWORD Vertices);

12 ID3DXPMesh Methods (2) Additional methods (cont.) HRESULT ID3DXPMesh::TrimByFaces ( DWORD NewFacesMin, DWORD NewFacesMax, DWORD *rgifaceremap, DWORD *rgivertremap ); HRESULT ID3DXPMesh::TrimByVertices ( DWORD NewVerticesMin, DWORD NewVerticesMax, DWORD *rgifaceremap, DWORD *rgivertremap ); Sample: Progressive Mesh

13 Global Variables Loading the XFile data

14 Extracting Materials & Loading Textures Optimizing the Mesh

15 Generating the Progressive Mesh Setting the Resolution

16 Adjusting the LOD Rendering the Progressive Mesh

Bounding Volumes (1) Common example spheres and boxes Others cylinders, ellipsoids, lozenges, capsules max center radius min to speed up visibility tests and collision tests Bounding Volumes

dwstride, dwstride, D3DXVECTOR3* D3DXVECTOR3* pcenter, pcenter, FLOAT* FLOAT* pradius pradius ); ); HRESULT HRESULT D3DXComputeBoundingBox ( LPD3DXVECTOR3 LPD3DXVECTOR3 pfirstposition,

17 Bounding Volumes (1) Common example spheres and boxes Others cylinders, ellipsoids, lozenges, capsules max center radius min to speed up visibility tests and collision tests Bounding Volumes (2) D3DX library provides functions HRESULT HRESULT D3DXComputeBoundingSphere ( LPD3DXVECTOR3 LPD3DXVECTOR3 pfirstposition, pfirstposition, DWORD DWORD NumVertices, NumVertices, DWORD DWORD dwstride, dwstride, D3DXVECTOR3* D3DXVECTOR3* pcenter, pcenter, FLOAT* FLOAT* pradius pradius ); ); HRESULT HRESULT D3DXComputeBoundingBox ( LPD3DXVECTOR3 LPD3DXVECTOR3 pfirstposition, pfirstposition, DWORD DWORD NumVertices, NumVertices, DWORD DWORD dwstride, dwstride, D3DXVECTOR3* D3DXVECTOR3* pmin, pmin, D3DXVECTOR3* D3DXVECTOR3* pmax pmax ); ); dwstride the size of each vertex in bytes

18 Sample: Bounding Volumes Some New Special Constants Floating Point Imprecision

19 Bounding Volume Types (1) Bounding Volume Types (2)

20 Global Variables Computing Bounding Volumes

21 Cleanup Rendering Bounding Volumes

22 Window Procedure Computing Bounding Sphere

23 Computing Bounding Box Vertex Hierarchy (1) vsplit v s v u v t

11 v 4 v 5 v 8 v 9 M n v 12 v 13 v 6 v 7 v 14 v 15 Selective

24 Vertex Hierarchy (2) PM : M 0 M0 M 0 vsplit 0 vsplit 0 1 vsplit 1 2 vsplit 2 3 vsplit 3 4 vsplit v 0 v 0 v1 v 1 v2 v 2 v 10 v 11 v 4 v 5 v 8 v 9 M n v 12 v 13 v 6 v 7 v 14 v 15 Selective Refinement (1/2) M0 M 0 vsplit 00 vsplit 11 vsplit i i vsplit n-1 n-1

25 Selective Refinement (2/2) PM : M 0 M0 M 0 vsplit 0 0 vsplit 1 21 vsplit 2 2 vsplit 3 3 vsplit 4 4 vsplit 5 v1 v2 v 0 v 1 v2 v 2 v 10 v 11 v 4 v 5 v 8 v 9 v 12 v 13 v 6 v 7 v 14 v 15 Selectively Refined Mesh Construction of PM Mesh Optimization modify the energy function with respect to the original E ( M ) = E ( M ) + E ( M ) + E ( M ) E ( M ) dist spring scalar + Distance energy Spring energy dist Preserving scalar attributes E E spring n 2 ( K, V ) = d ( xi, φv ( K )) ( K V ) Escalar V = cscalar xi φv bk Preserving discontinuity curves: disallow i or penalize i= 1, = κ v v { j, k} K j k 2 disc 2 ( ) ( ) ( ) 2

26 Simplification of PM Minimizing E scalar original (200x200 vertices) simplified mesh (400 vertices) LOD of PM Dragon model

Meshes. 9 th Week, To gain an understanding of the internal data organization of an ID3DXMesh object

Meshes. 9 th Week, To gain an understanding of the internal data organization of an ID3DXMesh object Meshes 9 th Week, 2009 Objectives To gain an understanding of the internal data organization of an ID3DXMesh object To find out how to create, optimize, i and render an ID3DXMesh object To learn how to