[Solved]How can I operate the model in the scene through c++ call Unigine API?

[jiangqiu]

Hi ,

    I'm a fresh Unigine learner. I have a question about operate the model in the scene. The total function I wanna realize is that :

 

a. I can import a model(.obj) though the C++ call Unigine API(I've realized this function).

b. I can pick one of the models in scene.

c. I can move the model I picked in the scene.

d. I can rotate the model I picked in the scene.

e. I can zoom out and zoom in the model i picked in the scene.

 

please tell me which class can help me to realize those function, Or can you give me some samples?

 

 

Thanks.

Ivy.

 

[maxi]

Hi,

 

b. To get a node, that mouse cursor points to, you need to get world intersection by mouse direction. Check out WorldIntersection usage example https://developer.unigine.com/en/docs/future/api/library/worlds/class.worldintersection?rlang=usc.

This sample is in unigine script. The main issue here, that in C++ API there is no "getPlayerMouseDirection" method.

 

He have added corresponding functionality to Unigine::Camera class (method Camera::getDirectionFromScreen), it will be available in the next release. You can use the following function so far:

bool getPlayerMouseDirection(Vec3 *p0, Vec3 *p1)
{
	PlayerPtr player = Unigine::Game::get()->getPlayer();
	float mouse_x = Unigine::App::get()->getMouseX();
	float mouse_y = Unigine::App::get()->getMouseY();
	float width = Unigine::App::get()->getWidth();
	float height = Unigine::App::get()->getHeight();
	
	if (player.get() == NULL)
		return false;
	
	mat4 projection = player->getProjection();
	Mat4 imodelview = player->getWorldTransform();

	projection.m00 *= height / width;
	float x = -(mouse_x / width * 2.0f - 1.0f + projection.m02) / projection.m00;
	float y = (mouse_y / height * 2.0f - 1.0f + projection.m12) / projection.m11;

	if (projection.m32 == 0.0f)
	{
		*p0 = imodelview * Vec3(-x, -y, -1.0f);
		*p1 = imodelview * Vec3(-x, -y, 1.0f);
	} else
	{
		*p0 = Vec3(imodelview.m03, imodelview.m13, imodelview.m23);
		*p1 = imodelview * Vec3(x, y, 1.0f);
	}

	*p1 = *p0 - normalize(*p1 - *p0) * player->getZFar();

	return true;
}

Sorry for inconvenience caused.

 

c,d. When you get your NodePtr you can move and rotate it using transformation matrix and methods Node::(set/get)Transform and Node::(set/get)WorldTransform, the difference here, that world transform operates in global space coordinates, while other in local.

 

e. To zoom in/out (and also to rotate camera around node) you can create PlayerPersecutor, assign it to node by PlayerPersecutor::setTarget, and set it as a game player by Game::setPlayer. Now you can rotate camera by mouse. For changing distances there are corresponding methods setMinDistance, setMaxDistance, setDistance.

[jiangqiu]

Hi maxi,

    Thank you very much for your particular suggestion. 

    About my needs, I wanna explain the last item : "e. I can zoom out and zoom in the model i picked in the scene."    This function I wanna realize is that I can chose one model in the scene(there are many models in the scene) and only zoom in/out the model I selected instead of all models in the scene. so I think I can't rotate camera directly. 

[silent]

jiangqiu

 

For that use-case just modify selected object's scale like we suggested in c and d item. You also can check basic matrix operations in that article: https://developer.unigine.com/en/docs/2.2.1/code/uniginescript/usage/matrix/

 

Thanks!

[jiangqiu]

Hi,
    Now I can't chose the model I've load in my code, because I can't remove it's ownnership form code to the editor. I have consulted the UnigineScript's code, but I can't use it in C++ code.

    I saw that UnigineScript realize that by this:

Source code(UnigineScript)
/* declare ObjectMeshStatic objects for nodes 
*/
ObjectMeshStatic box_1;
ObjectMeshStatic box_2;

/* add a mesh as a node to the editor
 */
Node add_editor(Node node) {
	engine.editor.addNode(node);
	return node_remove(node);
}

/* the init() function of the world script file
 */
int init() {
	/* create a camera and add it to the world
	 */
	Player player = new PlayerSpectator();
	player.setDirection(Vec3(0.755f,-1.0f,0.25f));
	engine.game.setPlayer(player);

	// add the box mesh to the editor
	box_1 = add_editor(new ObjectMeshStatic("matrix_project/meshes/box.mesh"));

	// set the transformation and the material for the first box mesh
	mat4 transform = translate(vec3(0.0f,0.0f,0.0f));
	box_1.setWorldTransform(mat4(transform));
	box_1.setMaterial("mesh_base", "*");

	// add the second box mesh to the editor
	box_2 = add_editor(new ObjectMeshStatic("matrix_project/meshes/box.mesh"));
	
	// set the transformation and the material for the second box mesh
	mat4 transform1 = translate(vec3(0.0f,2.0f,1.0f));
	box_2.setWorldTransform(Mat4(transform1));
	box_2.setMaterial("mesh_base", "*");
	
	// add the second box mesh as a child to the first box mesh
	box_1.addChild(box_2);

	// show the transformation matrix and the world transformation matrix of the child node
	log.message("transformation matrix of the child node: %s\n", typeinfo(box_2.getTransform()));
	log.message("world transformation matrix of the child node: %s\n", typeinfo(box_2.getWorldTransform()));

	return 1;
}

He use  

engine.editor.addNode(node)

function and put a ObjectMeshStatic object as the function's argument, so that he add the ObjectMeshStatic object he creat in code to the editor, so that he can operate the object. so how can I turn an ObjectMeshStaticPtr model into NodePtr so that I can remove code's ownnership and add it to editor by use of some function like "node_remove()" and "addNode()" function in the UnigieScript?

 

 

Sorry for my question, I'm a new girl for Unigine Engine.

Thanks.

jiangqiu

[maxi]

Hi, 

 

The owning model is a little bit different in c++. You have smart pointers, that have an owner flag. If owner == 1, pointer deletes node on destruction. When you create an object using create method, an owner pointer is returned, in other cases pointer will not be an owner. Node::grab - takes ownership, node::release - set owner to 0, and node::isOwner returned owner flag.

This is how your code snippet can look like in c++:

Source code(c++)

// private class members
ObjectMeshStaticPtr box_1;
ObjectMeshStaticPtr box_2;

int init() {
	/* create a camera and add it to the world
	 */
	PlayerSpectatorPtr player_spectator = PlayerSpectator::create();
        // player_spectator is an owner pointer here and will be deleted in out of scope, so release it
        player_spectator->release();
	player_spectator->setDirection(Vec3(0.755f,-1.0f,0.25f));

        // get base class player pointer, it will not be an owner
        PlayerPtr player = player_spectator->getPlayer();
	engine.game.setPlayer(player);

	// add the box mesh to the editor
	box_1 = ObjectMeshStatic::create("matrix_project/meshes/box.mesh");
        // box_1 is owner and if you want to add it to editor, release it
        box_1->release();
        Unigine::Editor::get()->addNode(box_1);
        
        // for example we don't add box_2 to editor so owner is fine here
        box_2 = ObjectMeshStatic::create("matrix_project/meshes/box.mesh");

	return 1;
}

[jiangqiu]

Hi,

     I did it ! :D  Thank you so much ! :wub:   Now I'm gonna to realize my b c d e function.