Posts tagged programming

Python, flatten a list

Oct 8th

Surprisingly python doesn’t have a shortcut for flatten a list (more generally a list of lists of lists of…).

I made a simple implementation that doesn’t use recursion and tries to be written clearly.

I get a element from a “bad” list (a list that can have another lists). If the element is not a list we store in our flat list. If the element is still a list we deal with him later. The flat list always have elements that are not a list.
To preserve the original order we reverse the elements at the end.

flatten, lists, programming, Python

OpenPixels: simple sprite sheet with Processing

Aug 22nd

Posted by Silveira in english

No comments

/**
 * Openpixels example in Processing.
 * This simple example of how to get a sprite
 * from a sprite sheet.
 */
 
PImage bg;
PImage sprite_sheet;
PImage player;
 
void setup() {
  // load images
  bg = loadImage("kitchen.png");
  sprite_sheet = loadImage("guy.png");
 
  /* The sprite size is 32x49.
     Look guy.png, the "stand position" is at (36,102). */
 
  player = createImage(32, 49, ARGB);
  player.copy(sprite_sheet, 36, 102, 32, 49, 0, 0, 32, 49);
 
  // set screen size and background
  size(bg.width, bg.height);
  background(bg);
 
  frameRate(30);
}
 
void draw() {
  background(bg);
  image(player, 100, 50);
}

See more at OpenPixels.

Openpixels, Pixelart, Processing, programming

Atiaia early releases

Jul 23rd

Posted by Silveira in english

1 comment

This was a project that me and Marco Diego created during our graduation for the Computer Graphics course. It is a ray tracing engine build from scratch in C. It was great exercise of experimentation on how implement object-oriented design patterns in ANSI C. Later Marco continued it in his master’s degree thesis implementing more features.

Parts of the sources were lost during a disk failure in the forge we hosted the project. I found some early releases and packed them here for future use. It can be useful for someone studying C or how to implement a ray tracer.

Download: atiaia_sources_by_2006.zip

Enjoy it.

ps: with this project we won the 1st place project of class and maximum grade. ;)

Atiaia, C, Marco Diego, programming, Ray Tracying

Android screen height and width

Mar 12th

Posted by Silveira in english

1 comment

Context ctx = getContext();
Display display = ((WindowManager)ctx.getSystemService(ctx.WINDOW_SERVICE)).getDefaultDisplay();
int width = display.getWidth();
int height = display.getHeight();

Yes, there are easier ways to retrieve the screen width on Android but there are cases that this long code is the only solution. You may already have the Context. WindowManager or the Display and so it would be smaller, but this code is more general.

Android, Java, mobile, programming, screensize

PHP: array, all elements but first

Mar 9th

Posted by Silveira in english

No comments

$bric = array("Brazil", "Russia", "India", "China");
$ric = $bric; // array copy
$br = array_shift($ric); // left shift at $ric. $br stores "Brazil" 
print_r($bric); // $bric remains the same
print_r($ric); // $ric lost "Brazil"

Output:

Array
(
    [0] => Brazil
    [1] => Russia
    [2] => India
    [3] => China
)
Array
(
    [0] => Russia
    [1] => India
    [2] => China
)

Reference: PHP array_shift at php.net.

array, array_shift, PHP, programming

Java: invoking a method by name

Apr 29th

Posted by Silveira in english

2 comments

import java.lang.reflect.*;
 
public class Foo {
	public void bar(int param){
		System.out.println(param);
	}
 
	public static void main(String args[]){
		Object f = new Foo();
		try {
			Method m = f.getClass().getMethod("bar", int.class);
			m.invoke(f, 42);
		} catch (Exception e){
			System.err.println(e);
		}
	}
 
}