目标:使用OpenSceneGraph(OSG)创建第三人称视图,其中包括控制模型。该模型可以使用WASD和鼠标移动。单击鼠标右键时,相机和视图应该更改。按住鼠标右键时,模型和相机的方向应相同。
我现在一直在研究这个问题,我可以同时改变模型和相机的方向,但我只能让相机显示自上而下的视图。我希望相机能够以其他角度渲染世界(距离世界平面0到90度)。
bool EventHandlerMouse::performMovementRightMouseButton(
const double eventTimeDelta,
const double dx,
const double dy
) {
// Read in the mouse movement to determine if the user is turning left
// or right. Then set the bool attribute of this->_screen_model to true
// for the direction that the user is moving and then sets the other to
// false. The else statement turns them both off.
if ( dx < -0.01 ) {
this->_screen_model->turn_left();
this->_screen_model->stop_turn_right();
}
else if ( dx > 0.01 ) {
this->_screen_model->turn_right();
this->_screen_model->stop_turn_left();
}
else {
this->_screen_model->stop_turn_right();
this->_screen_model->stop_turn_left();
}
// Get the model's orientation. Orientation is a float between 0.0 and
// 360.0 representing the models orientation. 0.0 and 360.0 are true
// north.
float local_o = this->_screen_model->get_orientation();
// Create the OSG variable to hold the camera manipulator's current and
// future rotation.
osg::Quat rotation, new_rotation;
osg::Vec3d eye;
// Retrieve the camera's current rotation and eye.
this->getTransformation( eye, rotation );
// Retrieve the camera's rotation matrix.
osg::Matrixd rotation_matrix;
rotation.get( rotation_matrix );
new_rotation = rotation_matrix.getRotate();
// I don't really know what makeRotate does. I couldn't find good
// documentation. From what I'm seeing, it takes the current attitude
// ( rotation ) and changes it to what you have specified. I think this
// is where my problem/solution will be. Here, I set the angle to the
// orientation of the model. I am then setting that angle to the z axis in
// the Vec3d. I think that this is what is giving me the top down view,
// but it does turn with the model. I don't know how I can change this so
// that it gives a view that would be at an over the shoulder type of
// angle similar to a typical 3rd person view.
new_rotation.makeRotate(
osg::DegreesToRadians( local_o ), Vec3d( 0.0, 0.0, 1.0 )
);
// Setting the camera's eye and rotation to the newly calculated
// perspective.
this->setTransformation( eye, new_rotation );
}
我仍然很擅长使用OSG。我正在阅读书籍并完成教程。我一直在寻找如何做我想做的事,但我没有成功。如有任何帮助,我将不胜感激。如果我可以从我初出茅庐的应用程序的任何其他部分提供代码片段,请告诉我您想要看到的内容。
答案 0 :(得分:1)
我最终通过一个相当简单的NodeTrackManipulator实现得到了理想的结果。我刚刚写了一些鼠标处理,它符合我的需要。
event_handler_mouse.hpp
#ifndef EVENT_HANDLER_MOUSE_H
#define EVENT_HANDLER_MOUSE_H
#include <osgGA/GUIEventHandler>
#include <osgGA/NodeTrackerManipulator>
#include <osgViewer/View>
#include <iostream>
#include "../headers/client_obj_char.hpp"
using std::cout;
using std::endl;
class EventHandlerMouse : public osgGA::NodeTrackerManipulator {
public:
virtual bool performMovementLeftMouseButton(
const double eventTimeDelta,
const double dx,
const double dy
);
virtual bool performMovementRightMouseButton(
const double eventTimeDelta,
const double dx,
const double dy
);
virtual bool performMovementMiddleMouseButton(
const double eventTimeDelta,
const double dx,
const double dy
);
EventHandlerMouse( ClientObjChar* sm ) :
_client_char( sm ),
_distance( 1.0 )
{}
protected:
virtual ~EventHandlerMouse() {}
osg::Vec3 _center;
double _distance;
ClientObjChar* _client_char;
osg::observer_ptr<osg::Node> _target;
};
#endif
event_handler_mouse.cpp
#include "../headers/event_handler_mouse.hpp"
bool EventHandlerMouse::performMovementLeftMouseButton(
const double eventTimeDelta,
const double dx,
const double dy
) {
rotateWithFixedVertical( dx, dy );
return true;
}
bool EventHandlerMouse::performMovementRightMouseButton(
const double eventTimeDelta,
const double dx,
const double dy
) {
if ( true ) {
if ( dx < -0.01 ) {
this->_client_char->turn_left();
this->_client_char->stop_turn_right();
}
else if ( dx > 0.01 ) {
this->_client_char->turn_right();
this->_client_char->stop_turn_left();
}
else {
this->_client_char->stop_turn_right();
this->_client_char->stop_turn_left();
}
}
return true;
}
bool EventHandlerMouse::performMovementMiddleMouseButton(
const double eventTimeDelta,
const double dx,
const double dy
) {
return false;
}