Improving Click and Drag with C++
- by Josh
I'm currently using SFML 2.0 to develop a game in C++. I have a game sprite class that has a click and drag method. The method works, but there is a slight problem. If the mouse moves too fast, the object the user selected can't keep up and is left behind in the spot where the mouse left its bounds. I will share the class definition and the given function implementation.
Definition:
class codePeg
{
protected:
FloatRect bounds;
CircleShape circle;
int xPos, yPos, xDiff, yDiff, once;
int xBase, yBase;
Vector2i mousePos;
Vector2f circlePos;
public:
void init(RenderWindow& Window);
void draw(RenderWindow& Window);
void drag(RenderWindow& Window);
void setPegPosition(int x, int y);
void setPegColor(Color pegColor);
void mouseOver(RenderWindow& Window);
friend int isPegSelected(void);
};
Implementation of the "drag" function:
void codePeg::drag(RenderWindow& Window)
{
mousePos = Mouse::getPosition(Window);
circlePos = circle.getPosition();
if(Mouse::isButtonPressed(Mouse::Left))
{
if(mousePos.x > xPos && mousePos.y > yPos
&& mousePos.x - bounds.width < xPos && mousePos.y - bounds.height < yPos)
{
if(once)
{
xDiff = mousePos.x - circlePos.x;
yDiff = mousePos.y - circlePos.y;
once = 0;
}
xPos = mousePos.x - xDiff;
yPos = mousePos.y - yDiff;
circle.setPosition(xPos, yPos);
}
}
else
{
once = 1;
xPos = xBase;
yPos = yBase;
xDiff = 0;
yDiff = 0;
circle.setPosition(xBase, yBase);
}
Window.draw(circle);
}
Like I said, the function works, but to me, the code is very ugly and I think it could be improved and could be more efficient. The only thing I can think of as to why the object cannot keep up with the mouse is that there are too many function calls and/or checks. The user does not really have to mouse the mouse "fast" for it to happen, I would say at an average pace the object is left behind. How can I improve the code so that the object remains with the mouse when it is selected?
Any help improving this code or giving advice is greatly appreciated.
