void MQuaternion::setFromVectors(const MVector3 & source, const MVector3 & destination)
{
MVector3 axis=source.crossProduct(destination);
float angle = acosf(source.getNormalized().dotProduct(destination.getNormalized()));
setFromAngleAxis((float)(angle*RAD_TO_DEG), axis);
}
void MQuaternion::setFromAngleAxis(float angle, const MVector3 & axis)
{
const MVector3 normAxis = axis.getNormalized();
float sinHalfAngle = (float)sin((angle * DEG_TO_RAD) / 2.0);
float cosHalfAngle = (float)cos((angle * DEG_TO_RAD) / 2.0);
values[0] = sinHalfAngle * normAxis.x;
values[1] = sinHalfAngle * normAxis.y;
values[2] = sinHalfAngle * normAxis.z;
values[3] = cosHalfAngle;
normalize();
}
MVector3 computeTangent(
const MVector3 & P1, const MVector3 & P2, const MVector3 & P3,
const MVector2 & UV1, const MVector2 & UV2, const MVector2 & UV3)
{
MVector3 Edge1 = P2 - P1;
MVector3 Edge2 = P3 - P1;
MVector2 Edge1uv = UV2 - UV1;
MVector2 Edge2uv = UV3 - UV1;
float cp = Edge1uv.y * Edge2uv.x - Edge1uv.x * Edge2uv.y;
if(cp != 0.0f)
{
float mul = 1.0f / cp;
MVector3 tangent = (Edge1 * -Edge2uv.y + Edge2 * Edge1uv.y) * mul;
return tangent.getNormalized();
}
return MVector3(0.0f, 0.0f, 0.0f);
}
void MBLookAt::update(void)
{
MEngine * engine = MEngine::getInstance();
MLevel * level = engine->getLevel();
MScene * scene = level->getCurrentScene();
MObject3d * parent = getParentObject();
const char * targetName = m_targetName.getData();
if(strcmp(targetName, "none") == 0)
return;
// target object
MObject3d * object = scene->getObjectByName(targetName);
if(! object)
return;
// direction
MVector3 direction = object->getTransformedPosition() - parent->getTransformedPosition();
if(direction.x == 0 && direction.y == 0 && direction.z == 0)
return;
float angle;
float roll;
MVector3 axis;
// compute initial roll
MVector3 ZAxis = parent->getInverseRotatedVector(MVector3(0, 0, 1)).getNormalized();
ZAxis.z = 0;
ZAxis.normalize();
if(ZAxis.x == 0 && ZAxis.y == 0)
{
MVector3 YAxis = parent->getInverseRotatedVector(MVector3(0, 1, 0)).getNormalized();
YAxis.z = 0;
YAxis.normalize();
axis = MVector3(0, 1, 0).crossProduct(YAxis);
roll = acosf(MVector3(0, 1, 0).dotProduct(YAxis));
if(MVector3(0, 0, 1).dotProduct(axis) < 0)
roll = -roll;
}
else
{
axis = MVector3(0, 1, 0).crossProduct(ZAxis);
roll = acosf(MVector3(0, 1, 0).dotProduct(ZAxis));
if(MVector3(0, 0, 1).dotProduct(axis) < 0)
roll = -roll;
}
if(roll < 0.001f && roll > -0.001f) roll = 0;
// look-at
MVector3 cameraAxis = MVector3(0, 0, -1);
axis = cameraAxis.crossProduct(direction);
angle = acosf(cameraAxis.dotProduct(direction.getNormalized()));
parent->setAxisAngleRotation(axis, (float)(angle * RAD_TO_DEG));
parent->updateMatrix();
// set roll
ZAxis = parent->getInverseRotatedVector(MVector3(0, 0, 1)).getNormalized();;
ZAxis.z = 0;
ZAxis.normalize();
if(ZAxis.x == 0 && ZAxis.y == 0)
{
parent->addAxisAngleRotation(MVector3(0, 0, 1), (float)(-roll*RAD_TO_DEG));
}
else
{
axis = MVector3(0, 1, 0).crossProduct(ZAxis);
angle = acosf(MVector3(0, 1, 0).dotProduct(ZAxis));
if(angle < 0.001f && angle > -0.001f) angle = 0;
if(MVector3(0, 0, 1).dotProduct(axis) < 0)
angle = -angle;
parent->addAxisAngleRotation(MVector3(0, 0, 1), (float)((angle-roll)*RAD_TO_DEG));
}
}
