assimp/code/SkeletonMeshBuilder.cpp

269 lines
12 KiB
C++

/*
Open Asset Import Library (assimp)
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All rights reserved.
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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*/
/** @file SkeletonMeshBuilder.cpp
* @brief Implementation of a little class to construct a dummy mesh for a skeleton
*/
#include <assimp/scene.h>
#include "SkeletonMeshBuilder.h"
using namespace Assimp;
// ------------------------------------------------------------------------------------------------
// The constructor processes the given scene and adds a mesh there.
SkeletonMeshBuilder::SkeletonMeshBuilder( aiScene* pScene, aiNode* root, bool bKnobsOnly)
{
// nothing to do if there's mesh data already present at the scene
if( pScene->mNumMeshes > 0 || pScene->mRootNode == NULL)
return;
if (!root)
root = pScene->mRootNode;
mKnobsOnly = bKnobsOnly;
// build some faces around each node
CreateGeometry( root );
// create a mesh to hold all the generated faces
pScene->mNumMeshes = 1;
pScene->mMeshes = new aiMesh*[1];
pScene->mMeshes[0] = CreateMesh();
// and install it at the root node
root->mNumMeshes = 1;
root->mMeshes = new unsigned int[1];
root->mMeshes[0] = 0;
// create a dummy material for the mesh
if(pScene->mNumMaterials==0){
pScene->mNumMaterials = 1;
pScene->mMaterials = new aiMaterial*[1];
pScene->mMaterials[0] = CreateMaterial();
}
}
// ------------------------------------------------------------------------------------------------
// Recursively builds a simple mesh representation for the given node
void SkeletonMeshBuilder::CreateGeometry( const aiNode* pNode)
{
// add a joint entry for the node.
const unsigned int vertexStartIndex = mVertices.size();
// now build the geometry.
if( pNode->mNumChildren > 0 && !mKnobsOnly)
{
// If the node has children, we build little pointers to each of them
for( unsigned int a = 0; a < pNode->mNumChildren; a++)
{
// find a suitable coordinate system
const aiMatrix4x4& childTransform = pNode->mChildren[a]->mTransformation;
aiVector3D childpos( childTransform.a4, childTransform.b4, childTransform.c4);
ai_real distanceToChild = childpos.Length();
if( distanceToChild < 0.0001)
continue;
aiVector3D up = aiVector3D( childpos).Normalize();
aiVector3D orth( 1.0, 0.0, 0.0);
if( std::fabs( orth * up) > 0.99)
orth.Set( 0.0, 1.0, 0.0);
aiVector3D front = (up ^ orth).Normalize();
aiVector3D side = (front ^ up).Normalize();
unsigned int localVertexStart = mVertices.size();
mVertices.push_back( -front * distanceToChild * (ai_real)0.1);
mVertices.push_back( childpos);
mVertices.push_back( -side * distanceToChild * (ai_real)0.1);
mVertices.push_back( -side * distanceToChild * (ai_real)0.1);
mVertices.push_back( childpos);
mVertices.push_back( front * distanceToChild * (ai_real)0.1);
mVertices.push_back( front * distanceToChild * (ai_real)0.1);
mVertices.push_back( childpos);
mVertices.push_back( side * distanceToChild * (ai_real)0.1);
mVertices.push_back( side * distanceToChild * (ai_real)0.1);
mVertices.push_back( childpos);
mVertices.push_back( -front * distanceToChild * (ai_real)0.1);
mFaces.push_back( Face( localVertexStart + 0, localVertexStart + 1, localVertexStart + 2));
mFaces.push_back( Face( localVertexStart + 3, localVertexStart + 4, localVertexStart + 5));
mFaces.push_back( Face( localVertexStart + 6, localVertexStart + 7, localVertexStart + 8));
mFaces.push_back( Face( localVertexStart + 9, localVertexStart + 10, localVertexStart + 11));
}
}
else
{
// if the node has no children, it's an end node. Put a little knob there instead
aiVector3D ownpos( pNode->mTransformation.a4, pNode->mTransformation.b4, pNode->mTransformation.c4);
ai_real sizeEstimate = ownpos.Length() * ai_real( 0.18 );
mVertices.push_back( aiVector3D( -sizeEstimate, 0.0, 0.0));
mVertices.push_back( aiVector3D( 0.0, sizeEstimate, 0.0));
mVertices.push_back( aiVector3D( 0.0, 0.0, -sizeEstimate));
mVertices.push_back( aiVector3D( 0.0, sizeEstimate, 0.0));
mVertices.push_back( aiVector3D( sizeEstimate, 0.0, 0.0));
mVertices.push_back( aiVector3D( 0.0, 0.0, -sizeEstimate));
mVertices.push_back( aiVector3D( sizeEstimate, 0.0, 0.0));
mVertices.push_back( aiVector3D( 0.0, -sizeEstimate, 0.0));
mVertices.push_back( aiVector3D( 0.0, 0.0, -sizeEstimate));
mVertices.push_back( aiVector3D( 0.0, -sizeEstimate, 0.0));
mVertices.push_back( aiVector3D( -sizeEstimate, 0.0, 0.0));
mVertices.push_back( aiVector3D( 0.0, 0.0, -sizeEstimate));
mVertices.push_back( aiVector3D( -sizeEstimate, 0.0, 0.0));
mVertices.push_back( aiVector3D( 0.0, 0.0, sizeEstimate));
mVertices.push_back( aiVector3D( 0.0, sizeEstimate, 0.0));
mVertices.push_back( aiVector3D( 0.0, sizeEstimate, 0.0));
mVertices.push_back( aiVector3D( 0.0, 0.0, sizeEstimate));
mVertices.push_back( aiVector3D( sizeEstimate, 0.0, 0.0));
mVertices.push_back( aiVector3D( sizeEstimate, 0.0, 0.0));
mVertices.push_back( aiVector3D( 0.0, 0.0, sizeEstimate));
mVertices.push_back( aiVector3D( 0.0, -sizeEstimate, 0.0));
mVertices.push_back( aiVector3D( 0.0, -sizeEstimate, 0.0));
mVertices.push_back( aiVector3D( 0.0, 0.0, sizeEstimate));
mVertices.push_back( aiVector3D( -sizeEstimate, 0.0, 0.0));
mFaces.push_back( Face( vertexStartIndex + 0, vertexStartIndex + 1, vertexStartIndex + 2));
mFaces.push_back( Face( vertexStartIndex + 3, vertexStartIndex + 4, vertexStartIndex + 5));
mFaces.push_back( Face( vertexStartIndex + 6, vertexStartIndex + 7, vertexStartIndex + 8));
mFaces.push_back( Face( vertexStartIndex + 9, vertexStartIndex + 10, vertexStartIndex + 11));
mFaces.push_back( Face( vertexStartIndex + 12, vertexStartIndex + 13, vertexStartIndex + 14));
mFaces.push_back( Face( vertexStartIndex + 15, vertexStartIndex + 16, vertexStartIndex + 17));
mFaces.push_back( Face( vertexStartIndex + 18, vertexStartIndex + 19, vertexStartIndex + 20));
mFaces.push_back( Face( vertexStartIndex + 21, vertexStartIndex + 22, vertexStartIndex + 23));
}
unsigned int numVertices = mVertices.size() - vertexStartIndex;
if( numVertices > 0)
{
// create a bone affecting all the newly created vertices
aiBone* bone = new aiBone;
mBones.push_back( bone);
bone->mName = pNode->mName;
// calculate the bone offset matrix by concatenating the inverse transformations of all parents
bone->mOffsetMatrix = aiMatrix4x4( pNode->mTransformation).Inverse();
for( aiNode* parent = pNode->mParent; parent != NULL; parent = parent->mParent)
bone->mOffsetMatrix = aiMatrix4x4( parent->mTransformation).Inverse() * bone->mOffsetMatrix;
// add all the vertices to the bone's influences
bone->mNumWeights = numVertices;
bone->mWeights = new aiVertexWeight[numVertices];
for( unsigned int a = 0; a < numVertices; a++)
bone->mWeights[a] = aiVertexWeight( vertexStartIndex + a, 1.0);
// HACK: (thom) transform all vertices to the bone's local space. Should be done before adding
// them to the array, but I'm tired now and I'm annoyed.
aiMatrix4x4 boneToMeshTransform = aiMatrix4x4( bone->mOffsetMatrix).Inverse();
for( unsigned int a = vertexStartIndex; a < mVertices.size(); a++)
mVertices[a] = boneToMeshTransform * mVertices[a];
}
// and finally recurse into the children list
for( unsigned int a = 0; a < pNode->mNumChildren; a++)
CreateGeometry( pNode->mChildren[a]);
}
// ------------------------------------------------------------------------------------------------
// Creates the mesh from the internally accumulated stuff and returns it.
aiMesh* SkeletonMeshBuilder::CreateMesh()
{
aiMesh* mesh = new aiMesh();
// add points
mesh->mNumVertices = mVertices.size();
mesh->mVertices = new aiVector3D[mesh->mNumVertices];
std::copy( mVertices.begin(), mVertices.end(), mesh->mVertices);
mesh->mNormals = new aiVector3D[mesh->mNumVertices];
// add faces
mesh->mNumFaces = mFaces.size();
mesh->mFaces = new aiFace[mesh->mNumFaces];
for( unsigned int a = 0; a < mesh->mNumFaces; a++)
{
const Face& inface = mFaces[a];
aiFace& outface = mesh->mFaces[a];
outface.mNumIndices = 3;
outface.mIndices = new unsigned int[3];
outface.mIndices[0] = inface.mIndices[0];
outface.mIndices[1] = inface.mIndices[1];
outface.mIndices[2] = inface.mIndices[2];
// Compute per-face normals ... we don't want the bones to be smoothed ... they're built to visualize
// the skeleton, so it's good if there's a visual difference to the rest of the geometry
aiVector3D nor = ((mVertices[inface.mIndices[2]] - mVertices[inface.mIndices[0]]) ^
(mVertices[inface.mIndices[1]] - mVertices[inface.mIndices[0]]));
if (nor.Length() < 1e-5) /* ensure that FindInvalidData won't remove us ...*/
nor = aiVector3D(1.0,0.0,0.0);
for (unsigned int n = 0; n < 3; ++n)
mesh->mNormals[inface.mIndices[n]] = nor;
}
// add the bones
mesh->mNumBones = mBones.size();
mesh->mBones = new aiBone*[mesh->mNumBones];
std::copy( mBones.begin(), mBones.end(), mesh->mBones);
// default
mesh->mMaterialIndex = 0;
return mesh;
}
// ------------------------------------------------------------------------------------------------
// Creates a dummy material and returns it.
aiMaterial* SkeletonMeshBuilder::CreateMaterial()
{
aiMaterial* matHelper = new aiMaterial;
// Name
aiString matName( std::string( "SkeletonMaterial"));
matHelper->AddProperty( &matName, AI_MATKEY_NAME);
// Prevent backface culling
const int no_cull = 1;
matHelper->AddProperty(&no_cull,1,AI_MATKEY_TWOSIDED);
return matHelper;
}