• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
ankhd

How do I use my scroll bar to increment a std::vector

3 posts in this topic

Hello all.

 

Ok I have my list box its a std::vector.

My scroll bar moves within the ranges of -104 to - 230

 

my question is how do I use the scroll ranges to move my list elements

my list elements start at 0 to max entrys.

 

I think its more complicated because the number of entrys you can see at a time is 4 so I can scroll the bar down 4 slots before it needs to move

any elements into view.

What would you all do.This is my first ever scroll bar I normally go for the arrow keys.

0

Share this post


Link to post
Share on other sites

You need to convert your scrollbar position into an index into the vector so you know the first item to draw. Then its easy, you draw the next three items after that one.

 

So -104 to 230, that's a total range of 334. So your scrollbar range is between 0 and 334 if you normalize it into positive coordinates. Now say you have ten items in your list. You display 4 at a time, so your scrollbar needs to be able to have the first index as 0 - 6 (10 - 4) so that in its bottom position, it is showing the last 4 items.

 

So 334 / 6 = 55.667. So divide your scrollbar position by 55.667 and truncate it to int to get a number between 0 and 6. That is the index of the vector that is the first one that should be drawn.

 

Sort of. It depends if you want smooth scrolling or not but that's the idea.

1

Share this post


Link to post
Share on other sites

Thanks All. It works well

init code

//we need to calculate the delta range this range is maped to the total amount in the list box
	ScrollDelta = fabs(ScrollRangeMin - ScrollRangeMax);

	//the ScrollIncrement is the amount we can move for each slot of the list box
	//its the number of list Items devided by the ScrollDelta
	//this maps the range of the slider to the number of items in the list box
	ScrollIncrement = ScrollDelta / (NumberDlgs - MaxDisplayListItems);
	

	//set the default range and check to see if the number of dlg boxes is less then max display items
	VectorEndRange = MaxDisplayListItems;
	if(NumberDlgs < MaxDisplayListItems)
		VectorEndRange = NumberDlgs;


OnMouse move code

//calculate the display start range
					StartListDisplayElement = fabs(fabs(ScrollRangeMin - v.y) / ScrollIncrement);
					if(StartListDisplayElement < 0)
							StartListDisplayElement = 0;

					if(StartListDisplayElement > ListDialogBox.size() - MaxDisplayListItems)
							StartListDisplayElement = ListDialogBox.size() - MaxDisplayListItems;


					//set the rendering of the list box vector here
					VectorEndRange = StartListDisplayElement + MaxDisplayListItems;

					if(VectorEndRange > ListDialogBox.size())
						VectorEndRange = ListDialogBox.size() - MaxDisplayListItems;

					if(VectorEndRange < 0)
						VectorEndRange = 0;



Render code
for(UINT ctr = StartListDisplayElement; ctr < VectorEndRange; ctr++)
{
    render items
}

Here it is

DlgScroll.jpg?psid=1

0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0