moving a character from a point to another

[pyandrea]

I know that many similar questions have been already posted on the forum, but I can't find a clear, 'universal' answer to the problem of character movement.

The queston is: What is the best way to move a character from a point (P1) to another (P2) so that he faces the direction of movement?

In other words, the character is at position X1, Y1 (point P1) and he should move to position X2, Y2 (point P2), facing the direction between P1 and P2. The idea is similar to the controller movement of World of Warcraft 3 / Baldur's Gate / Heroes of Might and Magic V.

[Seven]

I hope I understand the question

if the player is at position1 and and looking direction2, then you can simply use the 'in' vector of the scenenode to move in that direction.

Code: Select all

 
        virtual vector3df getIn()
        {
            if (getPrimarySceneNode())
            {
                matrix4 mat = getPrimarySceneNode()->getRelativeTransformation();
                vector3df in(mat[8], mat[9], mat[10]);
                in.normalize();
                return in;
            }
            else return vector3df(0, 0, 0);
        }
 

and you would use it like this.........

playerSceneNode->setPosition(getIn() * movement speed);

this would move the player 'forward' by some amount

if you wanted to strafe left you could use

Code: Select all

 
        virtual vector3df getLeft()
        {
            if (getPrimarySceneNode())
            {
                matrix4 mat = getPrimarySceneNode()->getRelativeTransformation();
                vector3df left(mat[0], mat[1], mat[2]);
                left.normalize();
                return left;
            }
            else return vector3df(0, 0, 0);
        }
 

and use it like this.......

playerSceneNode->setPosition(getLeft() * movement speed);

which would strafe the player to the left.

it would be better to use the elapedtime of the frame to make for smoother movement though

playerSceneNode->setPosition(getIn() * movement speed * elapsedtime);
playerSceneNode->setPosition(getLeft() * movement speed * elapsedtime);

let me know if you need more info.

[Seven]

of course, this is for my own framework, you would rewrite the code to something like this......

Code: Select all

 
vector3df getLeft(ISceneNode* node)
        {
            if (node)
            {
                matrix4 mat = node->getRelativeTransformation();
                vector3df left(mat[0], mat[1], mat[2]);
                left.normalize();
                return left;
            }
            else return vector3df(0, 0, 0);
        }
 

[Seven]

if you are wnating to 'face' towards the position2 then you could use this

Code: Select all

 
    void lookAt(ISceneNode* node, vector3df pos)
    {
        // rotate to face target pos
        vector3df nodePos = node->getAbsolutePosition();
        vector3df targetPos = pos;
        vector3df diff = targetPos - nodePos;
        node->setRotation(diff.getHorizontalAngle());
    }
 

which will abruptly turn the player and face him towards the position, and used like this.....

Code: Select all

 
// look at the enemy
lookAt(playerSceneNode, enemySceneNode->getAbsolutePosition());
 
// move towards the enemy
playerSceneNode->setPosition(getIn(playerSceneNode) * movement speed * elapsedtime);
 

however, you may want to slowly turn the player before you start moving, in which case I will need more space for the answer

[danielmccarthy]

I create a timer by storing the current time from one movement and then checking it before the next movement. The lower the time difference you check for. The faster the model moves.

In your main loop you then do something like
PlayerHandler::process();

Then in the player handler you loop through all the current players ect. Check to see if bools in the Player class are set these bools would state weather a movement update is required. You can then use if statements to check to see if it has reached the position and you would then move the scene node depending on where it needs to move to. So it would move like 1 position each time the timer delay has been reached.

Thats how I do it in my game anyway