Question regarding image arrays.

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elterado

Question regarding image arrays.

in General Discussion • Other • 5 months ago

Hi there!

I'm 10 weeks into my programming subject for games design and I've ran into a bit of an issue for one of the assignments- we've been told we can recreate the classic game 'snake', and given my teacher is convinced that my talents lie more in the art side of things, he's requested me to use PImages to represent the snake head and body- which, I don't mind given I like making things pretty- but I've never been good with arrays to begin with, and now the idea of making a image array is scaring me horrendously. I've tried emailing the lecturer for help, but he continues to go over my head with his explanations.

The main idea is to get an image loaded as a head of the snake, and then another image that will act as the snakes body as it continues to eat fruit, gradually increasing. (Which is another part I haven't been able to wrap my head around, the idea of spawning fruit from an image)

I was hoping that would be kind enough to point me in the right direction?

I've loaded images into processing before, but never had to actually use them as an active part of the code. If need be, I can email the code to you- I just haven't uploaded it on here as 1. it's a little embarrassing, and 2. I've got quite a few tabs going at this rate.

Replies(9)

tfguy44

Re: Question regarding image arrays.

5 months ago

I can take a crack at it, but no promises*.

tfguy44 (at) gmail (dot) com

Be sure to send me the images you're trying to use too.

Also:

1) No one cares. You type with punctuation, so your code can't be that bad.

2) Tabs are just for your benefit. You could dump all the code in one tab and it'd work just fine.

*This is a lie. I can totally promise you a working snake game. Certain restrictions may apply.

elterado

Re: Re: Question regarding image arrays.

5 months ago

Sorry, I only just saw this reply! I just sent off the email then and attached the processing file as a zip.

And hm- I think that may be debatable, haha! I don't mean to make excuses- but I focus more on the art side of the games degree, programming just seems to go over my head sadly.

Thank you so much! I really appreciate this.

benj.n.su..

Re: Question regarding image arrays.

5 months ago

There are plenty of implementations at openprocessing.org:

http://www.openprocessing.org/search/?q=snake

I thought the following one was a pretty simple example.

http://www.openprocessing.org/sketch/90963

I'm having a difficult time thinking of an implementation without using classes.

Using an PImage array is no different than using an int[] or in the case of the one above a snake[]. I just think of them as an egg carton that you can dynamically change the size of. To get better with arrays, I would start first by creating a very simple program that adds and subtracts elements from an array using keys from the keyboard. When you type any key, it adds it to the array, when you press the delete key, it subtracts it. Once you've got that down, try creating an PImage array where you have to display something, I'm thinking kind of like a volume meter. You press the right arrow and the meter adds images, the left, it subtracts. Once you're feeling more comfortable, then take a look at the example I linked to and see how they've implemented their own Snake array.

elterado

Re: Re: Question regarding image arrays.

5 months ago

I've tried lurking through the numerous examples at openprocessing- I just can't seem to wrap my head around getting individual aspects of codes to work with what I've got. They're definitely a big help though.

Technically after the ten weeks of the class (one day a week), we're meant to have the 'knowledge' to do this- I'm just horrible at piecing what I know together, especially when we're not meant to use classes yet and I've used those in past assignments.

I'll try give that a go- I've got the 'learning processing' book by Daniel Shiffman which I've been trying to follow in regards to arrays. I just think it's one of those things that takes practice like you've suggested. I've been able to turn the snake head into image[] type's, but it's going from there and doing the whole (I'm borrowing from the snake that you just linked)
" array [i].slither( array [i-1].x, array [i-1].y, i-1);" part that just never makes sense to me. Half the time I'm getting errors about [i], haha!

Thank you for your reply!

benj.n.su..

Re: Question regarding image arrays.

5 months ago

PS: I happened to do a search for "snake" on the processing forum because I wanted to check back in and I couldn't find the discussion. Turns out there is a surprising number of people who have asked questions about it. Who knew? Anyway, searching for "snake" in the forums might yield some good advice, too.

benj.n.su..

Re: Question regarding image arrays.

5 months ago

sorry. i didn't realize you had responded which is why i didn't reply in response to your response. i'm having a terribly difficult time conceiving of this without using classes.

getting a snake made of an array to move and grow in length is fairly simple. the part i'm having trouble wrapping my mind around is how you would get that array to move in the way the game works: how when it changes direction, the individual elements don't change direction until they hit the mark where the change in direction occurred.

you could try creating a snake made up of four arrays. an array that only moves up, one that only moves right, one that only moves left, and one that only moves down. when the entire snake is moving to the right, the moveRight array has all of the elements and all of the other arrays have no elements in them. when you press the up arrow, each element is moved one at a time into the moveUP array. it's sort of difficult to explain in words and unfortunately I don't have enough skills to whip it out to show you.

as far as this goes:

" array[i].slither(array[i-1].x, array[i-1].y, i-1);" part that just never makes sense to me. Half the time I'm getting errors about [i], haha!

I'm not sure why you're getting errors about i without seeing how you are using it in context however I can explain a bit about what it's saying. in the program you are referring to, there is a class of objects called Snake. Each Snake object has an x position and a y position. There is also an array of snake objects called "array" (not a great name choice, better would be snakeArray). If you find class Snake, you'll see that each object of class snake has a method called slither and that method takes three int parameters, an X position (prevX), a Y position (prevY) and previous position (prev). that line is in a for loop where i is constantly being increased. suppose i is 5. what that line says is:

array[i]

"take the fifth snake object in the array"

.slither(

"and do all of the stuff found in the slither method using the following parameters"

array[i-1].x,

"use the x position of the forth Snake object in the array as prevX"

array[i-1].y,

"use the y position of the fourth Snake object in the array as prevY"

i-1);

"and use number 4 as prev."

GoToLoop

Re: Question regarding image arrays.

5 months ago

To unclass a class , you just need to make an Array or ArrayList for each field variable from that class.

Let's say we have fields -> x, y, w, h, c. Which correspond to location pair, dimension pair and color.

Then we need 5 Arrays:

import java.util.List;

// Snake's Body Arrays:
final static List<Short> bodyX = new ArrayList();
final static List<Short> bodyY = new ArrayList();

final static List<Short> bodyW = new ArrayList();
final static List<Short> bodyH = new ArrayList();

final static List<Integer> bodyC = new ArrayList();

void setup() {
  exit();
}

GoToLoop

Re: Question regarding image arrays.

5 months ago

Of course, if all dimensions (width & height) for the snake's body parts are the same.

And all of them have the same colors.

Then, we can turn bodyW, bodyY and bodyC into regular primitive variables or constants:

import java.util.List;

// Snake's Body:
final static List<Short> bodyX = new ArrayList();
final static List<Short> bodyY = new ArrayList();

final static short BODY_W = 16, BODY_H = 16;

final static color BODY_C = #00FF00;  // #green

void setup() {
  exit();
}

GoToLoop

Re: Question regarding image arrays.

5 months ago

Also, you have to decide if you're gonna use a grid of fixed pixels, like 16x16 or 32x32.

Or freely move pixel by pixel.

In a grid game, movement is anything but smooth, since it moves a # of pixels = grid at once!

But it's very easy to detect whether the snake ate an apple, bitten its tail or reached the screen's limit!

In a freely movement game, collision detection is a lot harder; but results are professional!

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