If you use OpenGl blending functions, you probably are doing something with the alpha buffer (or not). By default the alpha buffer is disabled on the html / gwt / web config.

So you need to go to the HtmlLauncher and set the alpha boolean to true:

public GwtApplicationConfiguration getConfig() {
	final GwtApplicationConfiguration config = new ...;
	config.alpha = true;
	return config;
}

A side effect by enabling the alpha buffer is the actual background will become pseudo transparent. At the end of the drawing the alpha buffer will be handled as the alpha channel of the whole canvas. So if there is no need for some transparency, at the end of drawing the whole alpha buffer should be filled with 1s. 

done_

So as you write a simple a html file with one or two resources, lets say one css and one js file, and you then deploy it (= copy paste) to a sever, and then you make some changes (= fix a bug), and then you redeploy (= copy paste, overwrite popup, press yes), and then nothing changes.

The browser, like always, remembers the old 'main.js' from before and then you pres Ctrl+F5. But your tester in the other side, has no clue what a Ctrl is. So you have to do something.

The first thing is to add a simple '?1' at the end of 'main.js' and every other resource, the browser thinks it may be a different file and deletes the cached version.

So now lets make a script to automate the replacement of the '?1' with '?2':

sed 's/"\(.*\)?.*"/"\1?2"||/' -i index.html

But we may want the browser to actually keep some cached files, the files that have not changed. Only if, instead of '?2', we could generate a number that only changes if the actual file changes and also does not repeat it self.

Hash functions? Checksums? Yes.

Lets use 'md5sum' to freak out the people who don't know. A single sed will not make it, lets write a sed to generate multiple seds and pipe it into a sh.

First we find checksums:

find -regex '.*\(js\|css\)$' -exec md5sum {} \+

Then we pipe that to our first sed:

sed 's/\(.*\)  \(.*\)/ ... \2 ... \1 ... /'

where in the place '...' we reconstruct version of our original sed (gets very unreadable). And finally we pipe it to a sh to actually do the substitution.

The whole thing if placed in Makefile would look like this:

index.html: *.css *.js
    find *.css *.js -exec md5sum {} \+ | \
        sed 's/\(.*\)  \(.*\)/sed \"s|\\"\2?[^\\"]*|\\"\2?\1|\" -i index.html/' | sh

_done

 So we have the requestAnimationFrame, you pass a function and it called after a very specific while (irrelevant to the following).

Now lets see the basic structure:

function loop() {
    update()
    requestAnimationFrame(loop)
}
loop()

Ok now lets wrap the function and call it without calling it by name:

(function loop() {
    update()
    requestAnimationFrame(loop)
})()

Is there any way to remove the name of function and still pass it? There is a magical object called arguments which appears out of nothing every time a function is executed. And the member that we need is arguments.callee which is self reference to the function being executed. So we get rid of the name:

(function () {
    update()
    requestAnimationFrame(arguments.callee)
})()

And of course to maximize the coolness we put in a single line:

(function() { update(); requestAnimationFrame(arguments.callee) })()

Ok, this very cool, but is it worth it? Let's analyze what this code succeeds to do:

1. Confuses the next reader of the code.
2. Confuses also the 2nd reader.
3. Confuses also the 3rd reader.
...
N. Confuses also the N-th reader.

So you have to choose what is cooler: confusing no people or confusing up to infinite people? Comment below, like and subscribe.

done_

 Usually when things/files are packaged from simple files to single monstrosity, you no longer have the ability to ls/dir to lookup what things/files exist.

An example is a Java jar, where to list for example all the packaged files you either cannot or you need to open a zip stream and figure out yourself.

Also in Java and other languages with limited introspection you cannot for example list all the classes that implement the interface X.

So:

Create a script than generates all the information you want.

Put that script in the build/compile process.

Include the file in the project.

Write some code to parse the file.

Example of listing all the inheritance properties by finding all the extends keyword:

grep -hr extends | sed -E 's/.*class (\w+) extends (\w+) .*/\2 -> \1/'

Parent -> Child1
Parent -> Child2
...

No need to say again and again "This is not supported, I cannot do it", supported yourself, you are a damn programmer! 

done_ 

public boolean validPlace(BuildingType type, Location location) {

    for (int ix = 0; ix < type.w; ix++) {
        for (int iy = 0; iy < type.h; iy++) {
            
            if (/* check if overlapping */) {
                return false;
            } else if (/* check if road missing */) {
                return false;
            }
        }
    }
    return true;
}

public enum PlacementValidity {
    Ok,
    Overlapping,
    RoadMissing;

    public boolean ok() {
        return this == Ok;
    }
}

public PlacementValidity validPlace(BuildingType type, Location location) {

    for (int ix = 0; ix < type.w; ix++) {
        for (int iy = 0; iy < type.h; iy++) {
                
            if (/* check if overlapping */) {
                return PlacementValidity.Overlapping;
            } else if (/* check if road missing */) {
                return PlacementValidity.RoadMissing;
            }
        }
    }
    return PlacementValidity.Ok;
}

if (validPlace(/* ... */).ok()) {

int send(cost char* text) {

grep '^\w.* {$' | sed 's/ {/;/'

%.h: %.c
    cat $< | grep '^\w.* {$$' | sed 's/ {/;/' > $@

public class Time implements Serializable {

    private long duration;
    private long start;

    // crazy things

}

    private void writeObject(java.io.ObjectOutputStream out) throws ... {
        Map map = new HashMap<>();

        map.put("duration", duration);
        map.put("start", start);
        out.writeObject(map);
    }

    private void readObject(java.io.ObjectInputStream in) throws ... {
        Map map = (java.util.Map) in.readObject();

        duration = (long) map.get("duration");
        start = (long) map.get("start");
    }

    public static final long serialVersionUID = 1L;

    private TimeUnit unit;  // v.2

    private void writeObject(java.io.ObjectOutputStream out) throws ... {
        Map map = new HashMap<>();

        map.put("duration", duration);
        map.put("start", start);
        map.put("unit", unit);
        out.writeObject(map);
    }

    private void readObject(java.io.ObjectInputStream in) throws ... {
        Map map = (Map) in.readObject();

        duration = (long) map.get("duration");
        start = (long) map.get("start");
        if (map.containsKey("unit")) {
            unit = (TimeUnit) map.get("unit");
        } else {
            // TODO unit
        }
    }

    unit = TimeUnit.Milliseconds

public class Player {
    public final String name;
    private Team team;
    ....
    public boolean friendly(Player other) {
        return team.has(other);
    }
}

    private Optional<Team> team;

    return team.isPresent() && team.get().has(other)

    return team.map(i -> i.has(other)).orElse(false);

    return team.filter(i -> i.has(other)).isPresent();

    return team.orElse(Team.EMPTY).has(other);

    return team != null && team.has(other);

.... <span data-value="simple"></span> ....

<script>

var data = {
    simple: gen_simple(),
    ....
}

for (var i of document.querySelectorAll('[data-value]')) {
    i.innerHTML = data[i.getAttribute('data-value')];
}

<script>

.... <script>document.write(gen_simple())</script> ....

....
<script>
for (var i of document.querySelectorAll('script')) i.parentNode.removeChild(i);
</script>

public class SuperIterator<T> implements Iterator<T>, Iterable<T> {

@Override
public Iterator<Character> iterator() {
    return this;
}

 public void setVisible(boolean value) { ...

 public enum Visibility { Visible, Gone }

 public void setVisible(Visibility value) { ...

 setVisible(Visibility.Visible)

 setVisible(value ? Visibility.Visible : Visibility.Gone)

 public void setVisible(boolean value) {
     setVisible(value ? Visibility.Visible : Visibility.Gone)
 }

 public void setVisible(Visibility value) { ...

 public void show() {
     setVisible(Visibility.Visible)
 }

 show()
 setVisible(true)
 setVisible(Visibility.Visible)

 float dx = x1 - x2;
 float dy = y1 - y2;
 return std::hypot(dx, dy);

 float dx = x1 - x2;
 float dy = y1 - y2;
 return std::sqrt(dx*dx + dy*dy);

 float dx = x1 - x2;
 float dy = y1 - y2;
 return dx*dx + dy*dy;

 return (x1 - x2)*(x1 - x2) + (y1 - y2)*(y1 - y2);

Site *maanoo = new (std::nothrow) Site("maanoo.com");

• Text example
• Image example