assimp/code/ConvertToLHProcess.cpp

195 lines
6.4 KiB
C++

/** @file Implementation of the post processing step to convert all imported data
* to a left-handed coordinate system.
*/
#include "ConvertToLHProcess.h"
#include "../include/DefaultLogger.h"
#include "../include/aiPostProcess.h"
#include "../include/aiMesh.h"
#include "../include/aiAnim.h"
#include "../include/aiScene.h"
using namespace Assimp;
// The transformation matrix to convert from DirectX coordinates to OpenGL coordinates.
const aiMatrix3x3 Assimp::ConvertToLHProcess::sToOGLTransform(
1.0f, 0.0f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f, 0.0f
);
// The transformation matrix to convert from OpenGL coordinates to DirectX coordinates.
const aiMatrix3x3 Assimp::ConvertToLHProcess::sToDXTransform(
1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, -1.0f, 0.0f
);
// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
ConvertToLHProcess::ConvertToLHProcess()
{
bTransformVertices = false;
}
// ------------------------------------------------------------------------------------------------
// Destructor, private as well
ConvertToLHProcess::~ConvertToLHProcess()
{
// nothing to do here
}
// ------------------------------------------------------------------------------------------------
// Returns whether the processing step is present in the given flag field.
bool ConvertToLHProcess::IsActive( unsigned int pFlags) const
{
if (pFlags & aiProcess_ConvertToLeftHanded)
{
if (pFlags & aiProcess_PreTransformVertices)
this->bTransformVertices = true;
return true;
}
return false;
}
// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void ConvertToLHProcess::Execute( aiScene* pScene)
{
// Check for an existent root node to proceed
if (NULL == pScene->mRootNode)
{
DefaultLogger::get()->error("ConvertToLHProcess fails, there is no root node");
return;
}
DefaultLogger::get()->debug("ConvertToLHProcess begin");
// transform vertex by vertex or change the root transform?
if (this->bTransformVertices)
{
this->bTransformVertices = false;
aiMatrix4x4 mTransform;
this->ConvertToDX(mTransform);
for (unsigned int i = 0; i < pScene->mNumMeshes;++i)
{
aiMesh* pcMesh = pScene->mMeshes[i];
for (unsigned int n = 0; n < pcMesh->mNumVertices;++n)
{
pcMesh->mVertices[n] = mTransform * pcMesh->mVertices[n];
}
if (pcMesh->HasNormals())
{
mTransform.Inverse().Transpose();
for (unsigned int n = 0; n < pcMesh->mNumVertices;++n)
{
pcMesh->mNormals[n] = mTransform * pcMesh->mNormals[n];
}
}
}
}
else
{
// transform the root node of the scene, the other nodes will follow then
ConvertToDX( pScene->mRootNode->mTransformation);
}
// transform all meshes accordingly
for( unsigned int a = 0; a < pScene->mNumMeshes; a++)
ProcessMesh( pScene->mMeshes[a]);
// transform all animation channels affecting the root node as well
for( unsigned int a = 0; a < pScene->mNumAnimations; a++)
{
aiAnimation* anim = pScene->mAnimations[a];
for( unsigned int b = 0; b < anim->mNumBones; b++)
{
aiBoneAnim* boneAnim = anim->mBones[b];
if( strcmp( boneAnim->mBoneName.data, pScene->mRootNode->mName.data) == 0)
ProcessAnimation( boneAnim);
}
}
DefaultLogger::get()->debug("ConvertToLHProcess finished");
}
// ------------------------------------------------------------------------------------------------
// Converts a single mesh to left handed coordinates.
void ConvertToLHProcess::ProcessMesh( aiMesh* pMesh)
{
// invert the order of all faces in this mesh
for( unsigned int a = 0; a < pMesh->mNumFaces; a++)
{
aiFace& face = pMesh->mFaces[a];
for( unsigned int b = 0; b < face.mNumIndices / 2; b++)
std::swap( face.mIndices[b], face.mIndices[ face.mNumIndices - 1 - b]);
}
// mirror texture y coordinate
for( unsigned int a = 0; a < AI_MAX_NUMBER_OF_TEXTURECOORDS; a++)
{
if( pMesh->HasTextureCoords( a))
{
for( unsigned int b = 0; b < pMesh->mNumVertices; b++)
pMesh->mTextureCoords[a][b].y = 1.0f - pMesh->mTextureCoords[a][b].y;
}
}
// mirror bitangents as well as they're derived from the texture coords
if( pMesh->HasTangentsAndBitangents())
{
for( unsigned int a = 0; a < pMesh->mNumVertices; a++)
pMesh->mBitangents[a] = -pMesh->mBitangents[a];
}
}
// ------------------------------------------------------------------------------------------------
// Converts the given animation to LH coordinates.
void ConvertToLHProcess::ProcessAnimation( aiBoneAnim* pAnim)
{
// position keys
for( unsigned int a = 0; a < pAnim->mNumPositionKeys; a++)
ConvertToDX( pAnim->mPositionKeys[a].mValue);
// rotation keys
for( unsigned int a = 0; a < pAnim->mNumRotationKeys; a++)
{
aiMatrix3x3 rotmat = pAnim->mRotationKeys[a].mValue.GetMatrix();
ConvertToDX( rotmat);
pAnim->mRotationKeys[a].mValue = aiQuaternion( rotmat);
}
}
// ------------------------------------------------------------------------------------------------
// Static helper function to convert a vector/matrix from DX to OGL coords
void ConvertToLHProcess::ConvertToOGL( aiVector3D& poVector)
{
poVector = sToOGLTransform * poVector;
}
// ------------------------------------------------------------------------------------------------
void ConvertToLHProcess::ConvertToOGL( aiMatrix3x3& poMatrix)
{
poMatrix *= sToOGLTransform;
}
// ------------------------------------------------------------------------------------------------
void ConvertToLHProcess::ConvertToOGL( aiMatrix4x4& poMatrix)
{
poMatrix *= aiMatrix4x4( sToOGLTransform);
}
// ------------------------------------------------------------------------------------------------
// Static helper function to convert a vector/matrix from OGL back to DX coords
void ConvertToLHProcess::ConvertToDX( aiVector3D& poVector)
{
poVector = sToDXTransform * poVector;
}
// ------------------------------------------------------------------------------------------------
void ConvertToLHProcess::ConvertToDX( aiMatrix3x3& poMatrix)
{
poMatrix *= sToDXTransform;
}
// ------------------------------------------------------------------------------------------------
void ConvertToLHProcess::ConvertToDX( aiMatrix4x4& poMatrix)
{
aiMatrix4x4 temp(sToDXTransform);
poMatrix *= temp;
}