• 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
oddant

[SDL] WarpMouse kinda buggy

2 posts in this topic

[b]Hello[/b] y'all,

first of all, I'd like to say I'm glad third places like gamedev stand on the web, i'm new on here then I hope I'll make a good impression and won't be so dreadful with this trouble...

here's the situation:

I try to emalute physical attraction, I'm moving the mouse in the screen and as I goes closer from a specific element (e.g. planet or atom) the cursor comes faster until it touches it.

I'm not here to find the function or some equations (I got them) but because I can't figure out how to manage the cursor moving.

I can't simply use SDL_warpMouse( x, y ) because actually this method generates events and cause the program being crazy!

I just need some leading into the documentation because I don't know how I can handle this problem.

to simplify the problem,
let say I want to move the cursor 1px to the right every 0.2s, let see the code :

[CODE]Uint32 mousex, mousey;

int running = 1;
while (running) {

SDL_PollEvent(&Event);

switch (event.type) {

case SDL_MOUSEMOTION:
{
mousex = event.motion.x;
mousey = event.motion.y;
}
break;

}

// drawings

mousex += 1;
SDL_warpMouse( mousex, mousey ); // <-- this function seems so inappropriate
SDL_Delay( 200 );
}[/CODE]


thanks for your help my friends
0

Share this post


Link to post
Share on other sites
You could simply separate the mouse position from the "cursor" you display, if you hide the cursor and grab input (SDL_ShowCursor(0); and SDL_WM_GrabInput(SDL_GRAB_ON);) then you will recieve relative motion events even if the cursor is at the edge of the screen, then you use those relative events rather than the absolute cursor position to move your cursor (Which you can then also apply things like gravity to)

So something like

[code]
int running = 1;
unsigned int currentTime,oldTime;
oldTime = SDL_GetTicks;
currentTime = oldTime;
while (running) {

while (SDL_PollEvent(&event)) { //While loop to process all pending events to prevent the event queue from filling up
switch (event.type) {

case SDL_MOUSEMOTION:
cursor.addVelocity(event.motion.xrel,event,motion.yrel);
break;
}
}
currentTime = SDL_GetTicks();
if (currentTime-oldTime>10) { //10ms have passed, time to update (updating once every 200ms will be choppy really)
//pseudo code incoming (This will not compile)
for each object:obj that can attract the cursor do {
Vector2f dir = GetDistanceVector(obj,cursor);
float distancesq = dir.length()*dir.length();
Vector2f normDir = dir.normalize();

cursor.addVelocity(normDir.x*obj.gravity/distancesq , normDir.y*obj.gravity/distancesq);
}
cursor.x+=cursor.xvel*0.01f; //positions have to be stored as floats so that we can move partial pixels aswell, we can round them off to even pixels when rendering
cursor.y+=cursor.yvel*0.01f;
//end of pseudo code
}
//Draw everything here.
}
[/code]
0

Share this post


Link to post
Share on other sites
Thanks for your answer,
Well I wasn't looping the queue, that is why I got some unexpected results.
Thanks for the comment at the top of the main loop, it seems to work like a charm now. [img]http://public.gamedev.net//public/style_emoticons/default/smile.png[/img]
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