Moving along odd angles

[69_Jeremy_69]

Ok currently I have a game piece object at position 1,1 and I move it to position 5,4.  Its just a simple repaint from there to here.

But in my move() call I want to animate the piece sliding on the board.  I already do simple move calls to float text or move a card in straight lines.  But its always only on one axis, either x or y.

And the moving of a game piece can be at any odd angle. So what type of equation should I be looking to use to figure out my where to redraw the gamepiece as it slides along the board.

I current brain storm was something like this.

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void setDestination(int destX, int destY) {       this.destX = destX;       this.destY = destY;              if(currentX < destX){             moveX = 1;       }else{             moveX = -1;       }              if(currentY < destY){             moveY = 1;       }else{             moveY = -1;       }              moving = true; } void move() {             if(moving == false) return;              if(currentX != destX)             currentX += moveX;              if(currentY != destY)             currentY += moveY;              if(currentX == destX && currentY == destY)             moving = false; }

Is there a better way to do this?

[69_Jeremy_69]

Actually thats pretty ugly.  It moves at an angle depending on the x and y.  Then it may move in a straight line to get to the bigger point.


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So it works but is crap.  So whats the proper way to do this?

[woogley]

I'm pretty new to trig so I apologize if I'm totally wrong (I didn't test)

first you need to find the angle between the two points. use this method:

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protected double calcAngle(Point p1,Point p2) {       return Math.atan2(p2.y-p1.y,p2.x-p1.x)*180.0/Math.PI; }

note: it's a better idea to use atan2 because atan cannot handle a full circle...

Then to move along at that angle, use:

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piece.x+=Math.cos(angle)*velocity; piece.y+=Math.sin(angle)*velocity;

where velocity is how fast you want it to move

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[69_Jeremy_69]

Looks good, I'll plug it in when I get home and try it out.