Files
OpenSpace/modules/touch/src/directinputsolver.cpp
2020-02-10 21:51:01 +01:00

269 lines
10 KiB
C++

/*****************************************************************************************
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* OpenSpace *
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* Copyright (c) 2014-2020 *
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#include <modules/touch/include/touchinteraction.h>
#include <openspace/scene/scenegraphnode.h>
#include <openspace/util/camera.h>
namespace {
// Used in the LM algorithm
struct FunctionData {
std::vector<glm::dvec3> selectedPoints;
std::vector<glm::dvec2> screenPoints;
int nDOF;
const openspace::Camera* camera;
openspace::SceneGraphNode* node;
LMstat stats;
};
} // namespace
namespace openspace {
DirectInputSolver::DirectInputSolver() {
levmarq_init(&_lmstat);
}
// project back a 3D point in model view to clip space [-1,1] coordinates on the view
// plane
glm::dvec2 castToNDC(const glm::dvec3& vec, Camera& camera, SceneGraphNode* node) {
glm::dvec3 posInCamSpace = glm::inverse(camera.rotationQuaternion()) *
(node->worldRotationMatrix() * vec +
(node->worldPosition() - camera.positionVec3()));
glm::dvec4 clipspace = camera.projectionMatrix() * glm::dvec4(posInCamSpace, 1.0);
return (glm::dvec2(clipspace) / clipspace.w);
}
// Returns the screen point s(xi,par) dependent the transform M(par) and object point xi
double distToMinimize(double* par, int x, void* fdata, LMstat* lmstat) {
FunctionData* ptr = reinterpret_cast<FunctionData*>(fdata);
// Apply transform to camera and find the new screen point of the updated camera state
// { vec2 globalRot, zoom, roll, vec2 localRot }
double q[6] = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 };
for (int i = 0; i < ptr->nDOF; ++i) {
q[i] = par[i];
}
using namespace glm;
// Create variables from current state
dvec3 camPos = ptr->camera->positionVec3();
dvec3 centerPos = ptr->node->worldPosition();
dvec3 directionToCenter = normalize(centerPos - camPos);
dvec3 lookUp = ptr->camera->lookUpVectorWorldSpace();
dvec3 camDirection = ptr->camera->viewDirectionWorldSpace();
// Make a representation of the rotation quaternion with local and global
// rotations
dmat4 lookAtMat = lookAt(
dvec3(0, 0, 0),
directionToCenter,
// To avoid problem with lookup in up direction
normalize(camDirection + lookUp)
);
dquat globalCamRot = normalize(quat_cast(inverse(lookAtMat)));
dquat localCamRot = inverse(globalCamRot) * ptr->camera->rotationQuaternion();
{
// Roll
dquat rollRot = angleAxis(q[3], dvec3(0.0, 0.0, 1.0));
localCamRot = localCamRot * rollRot;
}
{
// Panning (local rotation)
dvec3 eulerAngles(q[5], q[4], 0);
dquat panRot = dquat(eulerAngles);
localCamRot = localCamRot * panRot;
}
{
// Orbit (global rotation)
dvec3 eulerAngles(q[1], q[0], 0);
dquat rotationDiffCamSpace = dquat(eulerAngles);
dvec3 centerToCamera = camPos - centerPos;
dquat rotationDiffWorldSpace =
globalCamRot * rotationDiffCamSpace * inverse(globalCamRot);
dvec3 rotationDiffVec3 = centerToCamera * rotationDiffWorldSpace - centerToCamera;
camPos += rotationDiffVec3;
centerToCamera = camPos - centerPos;
directionToCenter = normalize(-centerToCamera);
dvec3 lookUpWhenFacingCenter =
globalCamRot * dvec3(ptr->camera->lookUpVectorCameraSpace());
lookAtMat = lookAt(
dvec3(0, 0, 0),
directionToCenter,
lookUpWhenFacingCenter
);
globalCamRot = normalize(quat_cast(inverse(lookAtMat)));
}
{ // Zooming
camPos += directionToCenter * q[2];
}
// Update the camera state
Camera cam = *(ptr->camera);
cam.setPositionVec3(camPos);
cam.setRotation(globalCamRot * localCamRot);
// we now have a new position and orientation of camera, project surfacePoint to
// the new screen to get distance to minimize
glm::dvec2 newScreenPoint = castToNDC(
ptr->selectedPoints.at(x),
cam,
ptr->node
);
lmstat->pos.push_back(newScreenPoint);
return glm::length(ptr->screenPoints.at(x) - newScreenPoint);
}
// Gradient of distToMinimize w.r.t par (using forward difference)
void gradient(double* g, double* par, int x, void* fdata, LMstat* lmstat) {
FunctionData* ptr = reinterpret_cast<FunctionData*>(fdata);
double f0 = distToMinimize(par, x, fdata, lmstat);
// scale value to find minimum step size h, dependant on planet size
double scale = log10(ptr->node->boundingSphere());
std::vector<double> dPar(ptr->nDOF, 0.0);
dPar.assign(par, par + ptr->nDOF);
for (int i = 0; i < ptr->nDOF; ++i) {
// Initial values
double h = 1e-8;
double lastG = 1;
dPar.at(i) += h;
double f1 = distToMinimize(dPar.data(), x, fdata, lmstat);
dPar.at(i) = par[i];
// Iterative process to find the minimum step h that gives a good gradient
for (int j = 0; j < 100; ++j) {
if ((f1 - f0) != 0 && lastG == 0) { // found minimum step size h
// scale up to get a good initial guess value
h *= scale * scale * scale;
// clamp min step size to a fraction of the incoming parameter
if (i == 2) {
double epsilon = 1e-3;
// make sure incoming parameter is larger than 0
h = std::max(std::max(std::abs(dPar.at(i)), epsilon) * 0.001, h);
}
else if (ptr->nDOF == 2) {
h = std::max(std::abs(dPar.at(i)) * 0.001, h);
}
// calculate f1 with good h for finite difference
dPar[i] += h;
f1 = distToMinimize(dPar.data(), x, fdata, lmstat);
dPar[i] = par[i];
break;
}
else if ((f1 - f0) != 0 && lastG != 0) {
// h too big
h /= scale;
}
else if ((f1 - f0) == 0) {
// h too small
h *= scale;
}
lastG = f1 - f0;
dPar.at(i) += h;
f1 = distToMinimize(dPar.data(), x, fdata, lmstat);
dPar.at(i) = par[i];
}
g[i] = (f1 - f0) / h;
}
if (ptr->nDOF == 2) {
// normalize on 1 finger case to allow for horizontal/vertical movement
for (int i = 0; i < 2; ++i) {
g[i] = g[i] / std::abs(g[i]);
}
}
else if (ptr->nDOF == 6) {
for (int i = 0; i < ptr->nDOF; ++i) {
// lock to only pan and zoom on 3 finger case, no roll/orbit
g[i] = (i == 2) ? g[i] : g[i] / std::abs(g[i]);
}
}
}
bool DirectInputSolver::solve(const std::vector<TouchInputHolder>& list,
const std::vector<SelectedBody>& selectedBodies,
std::vector<double>* parameters, const Camera& camera)
{
int nFingers = std::min(static_cast<int>(list.size()), 3);
_nDof = std::min(nFingers * 2, 6);
// Parse input data to be used in the LM algorithm
std::vector<glm::dvec3> selectedPoints;
std::vector<glm::dvec2> screenPoints;
for (int i = 0; i < nFingers; ++i) {
const SelectedBody& sb = selectedBodies.at(i);
selectedPoints.push_back(sb.coordinates);
screenPoints.emplace_back(
2.0 * (list[i].latestInput().x - 0.5),
-2.0 * (list[i].latestInput().y - 0.5)
);
}
FunctionData fData = {
selectedPoints,
screenPoints,
_nDof,
&camera,
selectedBodies.at(0).node,
_lmstat
};
void* dataPtr = reinterpret_cast<void*>(&fData);
bool result = levmarq(
_nDof,
parameters->data(),
static_cast<int>(screenPoints.size()),
nullptr,
distToMinimize,
gradient,
dataPtr,
&_lmstat
);
return result;
}
int DirectInputSolver::nDof() const {
return _nDof;
}
const LMstat& DirectInputSolver::levMarqStat() {
return _lmstat;
}
void DirectInputSolver::setLevMarqVerbosity(bool verbose) {
_lmstat.verbose = verbose;
}
} // openspace namespace