• 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
munchor

Moving diagonally

3 posts in this topic

I'm having an issue with moving diagonally. Firstly, I don't want my player to move faster when moving diagonally. Secondly, I want to mimic the movement of most modern video games (think about first person shooters, that is the kind of movement I want, although my game is 2D).

This is my main game loop:

[code]

while (running) {
SDL_PollEvent(&event);
if (event.type == SDL_QUIT) {
SDL_Quit();
return 0;
}

if (event.type == SDL_KEYDOWN) {
switch (event.key.keysym.sym) {
case SDLK_LEFT:
player.vx = -1;
break;
case SDLK_RIGHT:
player.vx = 1;
break;
case SDLK_DOWN:
player.vy = 1;
break;
case SDLK_UP:
player.vy = -1;
break;
case SDLK_ESCAPE:
SDL_Quit();
return 0;
break;
}
}

player.draw(screen);

SDL_Flip(screen);
clear_screen(screen);
}
[/code]

I have that, but I also tried to add a (if event.type == SDL_KEYUP), and then for cases UP and DOWN, set vy = 0, RIGHT and LEFT, set vx = 0. However, that didn't work so well either. I also tried using both SDL_PollEvent(&event); and while (SDL_PollEvent(&event)) {}.

I tried combinations of those too, and I'm updating "player.x += player.vx", and "player.y += player.vy;", but I just can't get proper diagonal movement.

Any idea of what I can try? Thank you in advance!
0

Share this post


Link to post
Share on other sites
You have to add the events together.

//On SDLK_LEFT key [u]press[/u]
[i]player.vx [color=#ff0000]+=[/color] -1;[/i]

You also need to capture the 'key release', and do the opposite (subtracting instead of adding).

//On SDLK_LEFT key [u]release[/u]
[i]player.vx [color=#FF0000]-=[/color] -1;[/i]

You'll more slightly faster going diagonally than normal. You can fix it quite easily... but it will require changing how you're handling several parts of your other code, and right now, you might not want to bother with it at this point in time (it might disrupt your game development more than benefit it, for such a small issue).
If interested (after having gotten the regular diagonal movement working), respond with your main loop code and we'll walk you through the changes you need to make.
1

Share this post


Link to post
Share on other sites
If you want to move at the same speed diagonally, you need to move by sin(45) instead of 1 (thats about 0.707 i think) and that requires you to use floats or something. OR, you could make the player move more slowly diagonally but that would only look not-terrible if your player jumps 1 meter leaps anyways. OR, you could make the scale bigger and instead of 1, move 100, and when moving diagonally move 71 (or 10 and 7 might be ok)
1

Share this post


Link to post
Share on other sites
How about:

[code]
bool keys[256];
for (int i=0;i<256;i++) {
keys[i]=false;
}

//event stuff, should be in a loop with pollevent since you want to process more than one event per frame if there is more than one in the queue
if (event.type == SDL_KEYDOWN) {
keys[event.key.keysym.sym]=true;
} else if (event.type == SDL_KEYUP) {
keys[event.key.keysym.sym]=false;
}

//update stuff here:
player.vx=0.0f;
player.vy=0.0f;
if (keys[SDLK_UP] {
player.vy-=1.0f;
}
if (keys[SDLK_DOWN] {
player.vy+=1.0f;
}
if (keys[SDLK_LEFT] {
player.vx-=1.0f;
}
if (keys[SDLK_RIGHT] {
player.vx+=1.0f;
}
//normalize direction:
float length = sqrt(player.vx*player.vx + player.vy*player.vy);
if (length>0.0f) {
player.vx/=length;
player.vy/=length;
}
[/code]
1

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