Inspired by Andre michelle, I`m building a tone matrix in AS3.
I managed to create the matrix and generate the different sounds. They don´t sound that good, but I´m getting there
One big problem I have is when more than one dot is set to play, it sounds just horrible. I googled a lot and found the additive synthesis method but don´t have a clue how to apply it to as3.
anybody out there knows how to play multiple sounds together? any hint?
my demo is at www.inklink.co.at/tonematrix
Oh common the sound was horrible...
Checked wiki? It is not that hard to understand... Even if you don't know that much of mathematics... Which you should - PROGRAMMING music is not easy.
So:
Let's first define something:
var harmonics:Array = new Array();
harmonics is the array in which we will store individual harmonics. Each child will be another array, containing ["amplitude"] (technically the volume), ["frequency"] and ["wavelength"] (period). We also need a function that can give us the phase of the wave given the amplitude, wavelength and offset (from the beginning of the wave). For square wave something like:
function getSquarePhase(amp:Number, wl:Number, off:Number):Number {
while (off > wl){off -= wl;}
return (off > wl / 2 ? -amp : amp); // Return amp in first half, -amp in 2.
}
You might add other types, or even custom vector waves if you want.
Now for the harder part.
var samplingFrequency; // set this to your SF
function getAddSyn(harmonics:Array, time:Number):Number {
if (harmonics.length == 1){ // We do not need to perform AS here
return getSquarePhase(harmonics[0]["amplitude"], harmonics[0]["wavelength"], time);
} else {
var hs:Number = 0;
hs += 0.5 * (harmonics[0]["amplitude"] * Math.cos(getSquarePhase(harmonics[0]["amplitude"], harmonics[0]["wavelength"], time)));
// ^ You can try to remove the line above if it does not sound right.
for (var i:int = 1; i < harmonics.length; i++){
hs += (harmonics[0]["amplitude"] * Math.cos(getSquarePhase(harmonics[0]["amplitude"], harmonics[0]["wavelength"], time)) * Math.cos((Math.PI * 2 * harmonics[0]["frequency"] / samplingFrequency) * time);
hs -= Math.sin(getSquarePhase(harmonics[0]["amplitude"], harmonics[0]["wavelength"], time)) * Math.sin((Math.PI * 2 * harmonics[0]["frequency"] / samplingFrequency) * time);
}
return hs;
}
}
This is all just converted (weakly :D) from the Wikipedia, I may have done a mistake somewhere in there... But I think you should get the idea... And if not, try to convert the AS from Wikipedia yourself, as I said, it is not so hard.
I also somehow ignored the Nyquist frequency...
I have tried your demo and thought it sounded pretty good actually. What do you mean it doesn't sound that good? What's missing? My main area of interest is music and I haven't found anything wrong , only it's a little frustrating , because after creating a sequence, I feel the need to add new sounds! Had I been able to record what I was playing with, I would have sent it to you.
Going into additive synthesis doesn't look like a light undertaking though. How far do you want to push it, would you want to create some form of synthesizer?
Related
I am currently trying to simulate ballistics on an object, that is otherwise not affected by physics. To be precise, I have a rocket-like projectile, that is following an parabolic arc from origin to target with a Lerp. To make it more realistic, I want it not to move at constant speed, but to slow down towards the climax and speed up on its way back down.
I have used the Mathf.Smoothstep function to do the exact opposite of what i need on other objects, i.e. easing in and out of the motion.
So my question is: How do I get an inverted Smoothstep?
I found out that what i would need is actually the inverted formula to smoothstep [ x * x*(3 - 2*x) ], but being not exactly a math genius, I have no idea how to do that. All I got from online calculators was some pretty massive new function, which I'm afraid would not be very efficient.
So maybe there is a function that comes close to an inverted smoothstep, but isn't as complex to compute.
Any help on this would be much appreciated
Thanks in advance,
Tux
Correct formula is available here:
https://www.shadertoy.com/view/MsSBRh
Solution by Inigo Quilez and TinyTexel
Flt SmoothCubeInv(Flt y)
{
if(y<=0)return 0;
if(y>=1)return 1;
return 0.5f-Sin(asinf(1-2*y)/3);
}
I had a similar problem. For me, mirroring the curve in y = x worked:
So an implementation example would be:
float Smooth(float x) {
return x + (x - (x * x * (3.0f - 2.0f * x)));
}
This function has no clamping, so that may have to be added if x can go outside the 0 to 1 interval.
Wolfram Alpha example
If you're moving transforms, it is often a good idea to user iTween or similar animation libraries instead of controlling animation yourself. They have a an easy API and you can set up easing mode too.
But if you need this as a math function, you can use something like this:
y = 0.5 + (x > 0.5 ? 1 : -1) * Mathf.Pow(Mathf.Abs(2x - 1),p)/2
Where p is the measure of steepness that you want. Here's how it looks:
You seem to want a regular parabola. See the graph of this function:
http://www.wolframalpha.com/input/?i=-%28x%2A2-1%29%5E2%2B1
Which is the graph that seems to do what you want: -(x*2-1)^2+1
It goes from y=0 to y=1 and then back again between x=0 and x=1, staying a bit at the top around x=0.5 . It's what you want, if I understood it correctly.
Other ways to write this function, according to wolfram alpha, would be -(4*(x-1)*x) and (4-4*x)*x
Hope it helps.
I'm trying to code something where there are creatures running back and forth, up and down across the stage, and I the player, have to try to go up to them, and pick them up. There are also boundaries on stage-
The map constraints- a big rectangle box is easy enough to accomplish. I've done this.
The boundaries within the map, which are also rectangles, but instead of bouncing the player back INSIDE the rectangle, I'm trying to do the opposite- keep the player out of it.
My code for it looks like this as of now:
//Conditions that check if player/monsters are hittesting the boxes (rocks
//and stuff), then if correct, bounce them away. Following code excludes
//the monsters for simplicity.
if((mcPlayer.x - aBounceBox[b].x) < 0 && mcPlayer.y <= (aBounceBox[b].y + aBounceBox[b].height/2) && mcPlayer.y >= (aBounceBox[b].y - aBounceBox[b].height/2))
{
mcPlayer.x = aBounceBox[b].x - aBounceBox[b].width/2 - mcPlayer.width/2;
}
//Duplicate above code for right side of box here
if((mcPlayer.y - (aBounceBox[b].y + aBounceBox[b].height/2)) < 0 && (mcPlayer.x + mcPlayer.width/2) > (aBounceBox[b].x - aBounceBox[b].width/2) && (mcPlayer.x - mcPlayer.width/2) < (aBounceBox[b].x + aBounceBox[b].width/2))
{
mcPlayer.y = aBounceBox[b].y + aBounceBox[b].height/2;
}
//Duplicate above code for Upper boundary of box here
The above doesn't work very well because the code to bounce for the left and right sides of the box conflicts with the upper and lower parts of the box I'm hit-testing for. Any ideas how to do that smoothly?
Also, another problem I am having is the pathing for the monsters in the game. I'm trying to get them to do the following:
Move around "organically", or a little randomly- move a little, stop. If they encounter a boundary, they'd stop and move, elsewhere. Not concerned where to, as long as they stop moving into rocks and trees, things like that.
Not overlap as much as possible as the move around on stage.
To push each other apart if they are overlapping, although I'd like to allow them to overlap very slightly.
I'm building that code slowly, but I thought I'd just ask if anyone has any ideas on how to do that.
To answer your first question, you may try to implement a new class/object which indicates the xy-offset between two display objects. In order to illustrate the idea more clearly, you can have a function similar to this:
public function getOffset(source:DisplayObject, target:DisplayObject):Object {
var dx:Number = target.x - source.x;
var dy:Number = target.y - source.y;
return { x:dx, y:dy };
}
Check if the hero character is colliding with another object first by hitTestObject(displayObj) of DisplayObject class. Proceed if the result is true.
Suppose you pass in your hero character as the source object, and another obstacle as the target object,
var offset:Object = getOffset(my_hero.mc, some_obstacle.mc);
After getting the resulting offset values, compare the magnitude (absolute value) of offset.x and offset.y. The outcome can be summarized as follows:
Let absDx be Math.abs(offset.x), absDy be Math.abs(offset.y),
absDx < absDy
offset.y < 0, target is above source
offset.y > 0, target is below source
absDx > absDy
offset.x < 0, target is to the left of source
offset.x > 0, target is to the right of source
absDx == absDy
refer to one of the above cases, doesn't really matter
Then you can update the position of your hero character according to different situations.
For your second question concerning implementing a very simple AI algorithm for your creatures, you can make use of the strategy above for your creatures to verify if they collide with any other stuff or not. If they do collide, assign them other directions of movement, or even simpler, just flip the signs(+/-) of their velocities and they will travel in opposite directions.
It is easier to implement simple algorithms first. Once it is working, you can apply whatever enhancements you like afterwards. For example, change directions when reaching junctions or per 3 seconds etc.
As i am working on top view racing game in which am trying to add slow motion effect when a car hits objects. I have tried with decreasing Stage.frameRate but the game appears lagging. and i have also tried with online tutorial called touch my pixel ( ref : http://blog.touchmypixel.com/2009/12/box2d-contactpoint-filtering/ ). But i didn't understand.
Is there any solution for showing such kind of slow motion effect. can anybody help me in this regard
Thanks and regards,
Chandrasekhar
Easiest way would be to have a global modifier property somewhere which can be used to multiply the movement of everything in the game.
For example, you could have the property speedModifier default to 1.
public var speedModifier:Number = 1;
And whenever you apply velocities, just multiply by the modifier:
body.SetLinearVelocity( new b2Vec2(x * speedModifier, y * speedModifier) );
This way all you need to do to half the speed of the game is to half the modifier:
speedModifier = 0.5;
To keep your code tidier and make managing this component of your game easier, there is probably a straightforward way to iterate over all of the bodies within the Box2D world and modify their velocities at the top of each update step. Something along the lines of:
for each(var i:b2Body in world.GetBodyList())
{
var currentVel:b2Vec2 = i.GetLinearVelocity();
var newVel:b2Vec2 = new b2Vec2(
currentVel.x * speedModifier,
currentVel.y * speedModifier
);
i.SetLinearVelocity( newVel );
}
I'm trying to create a guessing game that has the user clicking on different colored boxes to see which one is correct. I have a public var that dictates which color(later image) to use. The code is this in my update:
if (FlxG.mouse.justPressed())
{
block2.distributionp = Math.random() * 2;
block2.colorArray = block2.distributionp;
block2.colorUnit = block2.colorArray;
}
(colorUnit and colorArray both equal distributionp, which is a ranom of 2 in the class file)
When I run this code, the change does occur, but it only seems to switch out once. The other times it's ignored. How can I get this to continuously switch out a random number that I can use later?
Thanks in advance!
Math.random() * 2 Returns a Number ranging from 0.000000000000 to 2.00000000, this includes numbers like 0.123456789 and 1.99999999 (Not sure exactly what decimal place it goes to but just saying it doesn't only return integers 0, 1 and 2). I'm not sure but I think you're problem lies in the range, so if you want a better range use this code.
MIN_VALUE * Math.random() + (MAX_VALUE - MIN_VALUE);
If you would like to only get integers you can use either Math.ceil() or Math.floor() like so :
Math.ceil(MIN_VALUE * Math.random() + (MAX_VALUE - MIN_VALUE));
I'm sorry if this does not help you but let me know if it doesn't and I will continue to try and help.
The value I'm getting is whole integers between 0 and 2. What I'm trying to do, is change the vaue for each time I click. I'm not sure what occurs. Perhaps I shouldn't have asked now. I'll ask later when I have more info. Sorry.
The program will show the student a line graph. The student will have to recreate that line graph by moving a character away from or toward a motion detector using the arrow keys, creating a distance-time plot. I can capture the data points that the program generates when drawing its graph. I can also capture the data points gnerated by the student. How can I compare the two graphs while allowing for some tolerance on the student's part? Should I try to detect incorrect graphs as they are being drawn or after all data points are recorded? While some of the graphs will be linear and easy to compare others will be piecewise functions with positive, negative, and zero slopes at random intervals.
Thanks!
Does the order in which the graph lines are drawn matter ?
You could record the points with a certain threshold into an Array/Vector and compare.
A quick'n'dirty way would be using 2 binary(monochrome, just black and white) images:
One image will be a 'print screen'(BitmapData.draw()) of the graph(e.g. black on white)
The other image will be a white(blank) BitmapData that you'll use to write black pixels
where the user/student draws(has the mouse while it's pressed).
e.g.
userBitmapData.setPixel(mouseX,mouseY,0x000000);
When the drawing is complete(either the mouse is released or whatever rule you set),
you run a function that checks how much black pixels from the source(original graph) image
are matched in the destination(user graph) image.
Either you create a BitmapData containing the other two bitmaps blended on Difference mode, so anything that isn't black is not a match, or just loop through all the pixels once and manually check if the pixels match. Note that this relies on the fact that dimensions(width,height) of the two images are the same.
Here's a bit of code to illustrate this:
function compare(source:BitmapData,destination:BitmapData,threshold:Number):Boolean{
var commonPixels:Number = 0, totalPixels:Number = 0;
for(var j:int = 0 ; j < source.height ; j++){
for(var i:int = 0 ; i < source.width; i++){
pixels++;
if(source.getPixel(i,j) == destination.getPixel(i,j)) commonPixels++;
}
}
trace('matching: ' + (commonPixels/pixels * 100) + ' % ');//delete this line,just testing
if(commonPixels/pixels >= threshold) return true;
else return false;
}
//usage:
trace('is the graph correct ?: ' + compare(graphBitmapData,userBitmapData,0.7));
The Vector/Array version would be similar, but there would be no visual cues. Depending on your setup, you might want to test which would work best for you: BitmapData takes more memory than Arrays, but you can easily create a Bitmap, add it to the display list and check if looks right, etc.
If speed is an issue:
using Vector. instead of Array might be faster
looping in reverse(highest number to 0, decrementing) also should speed up things a bit
you probably get away with one loop instead of two
e.g.
var pixels:int = source.width * source.height;
for(pixels; pixels >=0; pixels--)
HTH