void Arcball::cursorCallback( GLFWwindow *window, double x, double y ){
if( mouseEvent == 0 )
return;
else if( mouseEvent == 1 ) {
/* Start of trackball, remember the first position */
prevPos = toScreenCoord( x, y );
mouseEvent = 2;
return;
}
/* Tracking the subsequent */
currPos = toScreenCoord( x, y );
/* Calculate the angle in radians, and clamp it between 0 and 90 degrees */
angle = acos( std::min(1.0f, glm::dot(prevPos, currPos) ));
/* Cross product to get the rotation axis, but it's still in camera coordinate */
camAxis = glm::cross( prevPos, currPos );
}
/**
* Check whether we clicked in the window
*/
void Arcball::mouseButtonCallbackImpl(GLFWwindow * window, int button, int action, int mods)
{
processMouse(button, action);
double x, y;
glfwGetCursorPos(window, &x, &y);
m_clicked = m_mouse[GLFW_MOUSE_BUTTON_LEFT];
if(m_clicked){
m_prevPos = toScreenCoord(x, y);
} else {
m_dragging = false;
m_prevTrans = m_currTrans;
}
}
/*
* Check if the mouse moved in the window
*/
void Arcball::cursorCallbackImpl(GLFWwindow *window, double x, double y)
{
if (m_clicked) {
m_dragging = true;
m_currPos = toScreenCoord(x, y);
/* Calculate the angle in radians, and clamp it between 0 and pi/2 */
m_angle = acos(std::min(1.f, glm::dot(m_prevPos, m_currPos)));
//if angle really small then m_camAxis will be close to zero and may cause issue where model disappears from screen
if (m_angle > 0.01f ) {
/* Cross product to get the rotation axis in camera coordinate */
m_camAxis = glm::cross(m_prevPos, m_currPos);
}
} //else do nothing - mouse just moves over viewport
}
