In my program, running your mouse over the screen will leave a trail of black, semi-transparent circles. I want to be able to change that by pressing the 'i' key, at which point it should draw a trailing blue line. Currently, upon pressing the 'i' key, it does draw a trailing blue line, but that line is surrounded by black, semi-transparent circles. If I try to call background, it solves the circle problem, but makes the line's trail disappear shortly after being drawn.
if (mouseY < 417) { //canvas is 500x500
noStroke();
fill(0,100);
ellipse(mouseX,mouseY,20,20);
}
if (keyIsPressed && key == 'i') {
if (mouseY < 417) {
stroke(0,0,255);
line(mouseX,mouseY,pmouseX,pmouseY);
}
}
Please help!
If you want one thing OR another thing to happen, but not both, you need to use an if statement and an else statement.
if (condition) {
// this stuff happens if condition is true...
} else {
// ...otherwise this other stuff happens
}
Related
I have a function where I can control my character.
I also have a movieclip on the stage called assassin_table.
I want to make it so that the character can't move in the table, a.k.a make the table work like a wall.
I have this code:
if(!this.hitTestObject(_root.assassin_table))
{
if(upKeyDown)
{
gotoAndStop(4);
y-=Math.cos(rotation/-180*Math.PI)*(mainSpeed +7);
x-=Math.sin(rotation/-180*Math.PI)*(mainSpeed +7);
}
if(!upKeyDown)
{
gotoAndStop(3);
}
}
However, if I touch the table, then I can't move at all.
I know it's because if(!this.hitTestObject(_root.assassin_table)), but I don't understand the logic behind NOT moving through objects. I'd much rather have a near pixel-perfect collision detection system, but since it's so hard to find any good info online which isn't confusing, I'll stick with hitTestObject for now :)
EDIT: Tried something, didn't really work that well.
if(!_root.assassinDead && !teleporting && this.currentFrame != 5)
{
if(this.hitbox.hitTestObject(_root.assassin_table))
{
_root.assassin_table.gotoAndStop(2);
if(this.x > _root.assassin_table.x)
{
trace("Can't move right");
canMoveRight = false;
}
if(this.x <_root.assassin_table.x)
{
trace("Can't move left");
canMoveLeft = false;
}
if(this.y > _root.assassin_table.y)
{
trace("Can't move up");
canMoveUp = false;
}
if(this.y < _root.assassin_table.y)
{
trace("Can't move down");
canMoveDown = false;
}
}
else
{
canMoveRight = true;
canMoveLeft = true;
canMoveUp = true;
canMoveDown = true;
}
}
This causes me to sometimes be able to walk through the table. I figure it's because my character can move in essentially every possible angle (since he's always facing the mouse and there are no tiles/grids).
How would I make it so that it would work with the advanced movement I have?
Moving up runs this:
y-=Math.cos(rotation/-180*Math.PI)*(mainSpeed +7);
x-=Math.sin(rotation/-180*Math.PI)*(mainSpeed +7);
And the rotation is decided by this:
this.rotation = Math.atan2((stage.mouseY - this.y), (stage.mouseX - this.x)) * 180/ Math.PI + 90;
You should seperate your hittest functions for four different moving directions.
I mean, you shouldn't use this "hitTestObject" stuff, that only returns a boolean value "true" or "false", and that's not going to work for you.
You need a function like "testPoint(player.x, player.y);" and returns the object at the given position, so you can implement it for your game like that
if (upKeyDown && testPoint(player.x, player.y - mainSpeed +7) == null) y-=Math.cos(rotation/-180*Math.PI)*(mainSpeed +7);
player.y - mainSpeed +7 // that checks for plus mainSpeed+7 because of trying to stop your player before it get stack inside object
Basically your logic flow should be like this:
Sample input (key press)
Move character
Check for collisions
If collision then move character to it's "outside" the object that it's touching
In your particular case, if your character is on the left of the table, and you're moving right, then first things first, you move your character. At your new position, check for any collisions. If you have a collection, then because you were moving from the left, we want to be on the left of the object that we colliding with, in this case the table, so we position our character to the left of the table.
The first part of that (checking if the character has hit the table) is called collision detection. Moving the character so that it's outside the bounds of the table is called collision response. Collision detection is a pretty big field and really depends on the type of game you're making; you can do grid-based, hit-test based (if you don't have a ton of objects), physics-based, math-based etc. Collision response can be anything and everything, depending on how you want to react to a collision - you can destroy the object (balloon on a spike), change its speed (character running through mud), bounce off it (ball off wall), or stop any further movement (character against wall).
To make things a bit easier:
Separate your systems - your input shouldn't be dependant on your collision for example. If the up key is down, just register that fact - what you do with it later (make your character move) is up to you
Separate your objects position in memory from its position on screen - this will let you move it around, react to collisions etc, and only when everything is good, update the graphics (stops things like graphics entering a wall only to jump out the next frame)
Solve for one axis at a time - e.g. collide on the x axis first, then the y
Pixel perfect collision is rarely needed :) Non-rotated boxes and circles will work a lot more than you'd think
Somewhat related - the shape of your object doesn't have to be the shape that you're colliding with - e.g. your table collision shape could just be a box; your character collision shape could just be a circle
Update
This causes me to sometimes be able to walk through the table
Assuming that we're going to collide our character and table as boxes, you need to take into account their sizes - i.e. we don't just compare the x values, but the right side of our character box against the left side of the table box etc. Something like:
// assumes objects have their anchor point in the top left - if its
// not the case, adjust as you see fit
if( char.x + char.width > table.x ) // right side of the char is overlapping the left side of the table
canMoveRight = false;
else if( char.x < table.x + table.width ) // left side of char vs right side of table
canMoveLeft = false;
// etc
When working with collisions, it's always nice to see the actual boxes, for debugging. Something like this:
var debug:Shape = new Shape;
debug.addEventListener( Event.ENTER_FRAME, function():void
{
debug.graphics.clear();
debug.graphics.lineStyle( 2.0, 0xff0000 );
// char (again assuming anchor point is top left)
debug.graphics.drawRect( char.x, char.y, char.width, char.height );
// table
debug.graphics.drawRect( table.x, table.y, table.width, table.height );
});
// add our debug. NOTE: make sure it's above everything
stage.addChild( debug );
I created a script that allows your character to move around with wall collision for every direction. How do I add gravity to it on the y-axis and still have it work the same way (like a platform game)?
I tried something like char.y-- when it hits the platform if it were just the floor, but all that does is slowly bring char up no matter where it is in the object, and once it reaches the top, it shakes like crazy.
A preview of the stage: http://puu.sh/63Y1g.png
//WALL COLLISION
if(walls.hitTestPoint(char.x-(char.width/2),char.y,true) && Key.isDown(Key.A)){
char.x+=5
}
if(walls.hitTestPoint(char.x+(char.width/2),char.y,true) && Key.isDown(Key.D)){
char.x-=5
}
if(walls.hitTestPoint(char.x,char.y-(char.height/2),true) && Key.isDown(Key.W)){
char.y+=5
}
if(walls.hitTestPoint(char.x,char.y+(char.height/2),true) && Key.isDown(Key.S)){
char.y-=5
}
//CHARACTER CONTROLS
char.x+=0;
if(Key.isDown(Key.A)){
char.x+=-5;
speed=-5;
}
if(Key.isDown(Key.D)){
char.x+=5;
speed=5;
}
if(Key.isDown(Key.W)){
char.y+=-5;
speed=5;
}
if(Key.isDown(Key.S)){
char.y+=5;
speed=5;
}
To do this really simply, something like this would suffice:
// Check if there is a floor below the char
if (!floor.hitTestPoint(char.x, char.y + (char.height/2) + 2 , true))
{
// If not, apply Gravity
char.y += 5
}
This will only apply gravity if there is no floor 2 pixels directly below the char (this will stop the jittering, feel free to try with different pixel offsets that might work better in your case), I wasn't sure how you were differentiating between the walls and floor, so replace 'floor' with how you are doing it.
===============
If you would like to add realistic accelerating gravity, you will need to add a variable to track the current vertical speed of the char, then add to that each step
eg. Each step do this instead of just adding to y
// Apply gravity
vSpeed += 5
char.y += vSpeed
But if you are going to do that you might as well start getting into vectors and more complex things, there's a lot of materials on the net for this.
I have to move some pictures in my flash. So I have got a background image in my main MovieClip(which I get by Loader class). Inside the image I have rectangles. I'm going to put small image in this rectangle and move it. I need the small image slowly disappear while crossing the rectangle boundaries.
I tried to put another movieclip in rectangles and moved image in this movieclip. But while crossing the rectangle the image didnt disappear. The image just continued its motion without disappearing.
How can I make dissapearing of image while crossing rectangle boundaries?
Sorry for my English.
Get TweenLite. It's an animation "tweening" library that makes animation a breeze. There are others, but this is the one I use.
It depends on the methodology you employ to move and detect your overlaps of image & rectangles.
Let's imagine you have two squares (red square, and blue square) and you want red square to fade-out whenever it overlaps blue square. Is this controlled with the mouse, keyboard, or a pre-calculated move that performs a guaranteed eclipse? Is the fade a factor of the percentage of overlap, or a straight-up 0-to-100 timed transition the moment it comes in contact with blue square? It's not clear from the description you gave as to what exactly you expect your code to do. Please review SO's "Asking" section, to help improve the quality of your question so that you get the right answer you're looking for.
That said, here's one way you could resolve the issue:
import com.greensock.*;
// Create some sample red & blue squares
var red:Sprite = new Sprite();
red.graphics.beginFill(0xFF0000, 1);
red.graphics.drawRect(0, 0, 100, 100);
red.graphics.endFill();
addChild(red);
stage.addEventListener(MouseEvent.MOUSE_MOVE, updateRed);
var blue:Sprite = new Sprite();
blue.graphics.beginFill(0x0000FF, 1);
blue.graphics.drawRect(0, 0, 100, 100);
blue.graphics.endFill();
addChild(blue);
blue.x = 200;
blue.y = 100;
var overlap:Boolean = false; // global state tracker
function updateRed(e:MouseEvent):void {
// Position the red square every time the mouse moves
red.x = stage.mouseX - red.width/2; // center relative to red square's dimensions
red.y = stage.mouseY - red.height/2;
if (red.hitTestObject(blue) && overlap != true) {
// Make sure we only animate on the initial overlap
overlap = true;
TweenLite.to(red, 1, {alpha:0});
} else if (red.hitTestObject(blue) == false && overlap) {
// And converserly, on the initial exit
overlap = false;
TweenLite.to(red, 1, {alpha:1});
}
}
I am programing a little game in flash,
and I am programing the animations of the character,
the character body is made of different objects, for example, I have an movie clip that is the head, Torso, Arms, Hands, Legs, etc,.
and I am making the animations with AS3, for example:
(only programed 1 leg movement)
public function walk(){
if(_etapa==5){
_etapa=1;
}
var etapa=_etapa;
switch(etapa){
case 1:
Animar(musloDer,22,RetomarAnimacion);
break;
case 2:
Animar(musloDer,0,RetomarAnimacion);
break;
case 3:
Animar(musloDer,-22,RetomarAnimacion);
break;
case 4:
Animar(musloDer,0,RetomarAnimacion);
break;
}
}
the walk animation haves 4 stages,
then I have the Animar function:
private function Animar(parte, valor, callback){
trace(direccion);
if(direccion=="SE" || direccion=="NO"){
valor=valor+45
valor=Math.abs(valor);
if(valor>180){
valor=360-valor;
}
if(valor<0){
}
_scaleY = (1-(valor)/90);
trace(_scaleY);
_rotation = 0;
}
else if(direccion=="N" || direccion=="S"){
_scaleY = .5;
_rotation = -valor;
}
_etapa++;
TweenLite.to(parte, 2.5, {rotation:_rotation, scaleY:_scaleY,ease:Linear.easeNone, onComplete:caminar});
}
that function moves the body part to the degrees that I want, It also decides what to do, the character can walk in 8 directions, front back, left right, and diagonals, and the character is showed from isometric view,. So the animation function decides what to do depending on the direction that the character is.
for example, if the character is walking right, viewed from lateral view, in that case rotating one leg 22 degrees is very simple, just LeftLeg.rotation = 22; great, but when the character is facing the camera, the leg rotation is not a rotation, is a change in scaleY property, for example, since the body is in isometric view, the scaleY of 1 leg in normal position is .5 (or 50%) when the leg is at 45º the scaleY is 1, and so on.
But I have a problem, because, for example if the LEG initial position is 0º (scaleY = 0.5) and I want to move it to 90º, 90º would be also scaleY = 0.5, so my function does nothing, it tweens from .5 to .5 (nothing), it should go from .5 to 0 and then to .5 again.
I hope someone understands my problem.
best,
Alvaro
Not sure if this is of any use...
http://dragonbones.github.com/index.html#.ULZvXqUq54F
I move a Sprite across the screen using the keyboard, at a rate of 10 pixels/ENTER_FRAME event fire. The issue is that, when it moves, you can see it being "redrawn" every 10 pixels, which makes it hard to look at. I haven't seen this in other Flash games.
If you look closely, you can also see this here (although at a much lower scale): http://kirill-poletaev.blogspot.com/2010/07/smooth-character-movement-using-as3.html
I want to get rid of that effect, any ideas?
If the player is at a distance of ... from the screen edge, it stops moving (by moving in the opposite direction), and the BG starts scrolling (the same visual effect can be seen).
Music in playing in the background, a minimap is updated with the player's position.
private function updater(e:Event):void
{
if(up && GlobalVars.vars.upPossible)
{
cont.y-=unit;
setu(); // Player graphics state
}
else if(down && GlobalVars.vars.downPossible)
{
cont.y+=unit;
setd(); // Player graphics state
}
else if(left && GlobalVars.vars.leftPossible)
{
cont.x-=unit;
setl(); // Player graphics state
}
else if(right && GlobalVars.vars.rightPossible)
{
cont.x+=unit;
setr(); // Player graphics state
}
else
{
ups.visible=false; downs.visible=false; rights.visible=false;
lefts.visible=false; normals.visible=true; // Player graphics state
GlobalVars.vars.scXr=0; GlobalVars.vars.scYu=0; GlobalVars.vars.scXl=0;
GlobalVars.vars.scYd=0; cont.x=int(cont.x); cont.y=int(cont.y); //Someone from the Kongregate.com forums suggested this, no visible effect
}
if((cont.x=GlobalVars.vars.maxX))
{
if(cont.x=GlobalVars.vars.maxX && right && GlobalVars.vars.canScrollR) GlobalVars.vars.scXr=1, cont.x-=unit, setr();
}
else GlobalVars.vars.scXl=0, GlobalVars.vars.scXr=0; //BG Scrolling
if((cont.y=stage.stageHeight*7.3/10))
{
if(cont.y=stage.stageHeight*7.3/10 && down && GlobalVars.vars.canScrollD) GlobalVars.vars.scYd=1, cont.y-=unit, setd();
}
else GlobalVars.vars.scYu=0, GlobalVars.vars.scYd=0; //BG Scrolling
if(cont.y>=stage.stageHeight*7.3/10 && cont.x>=GlobalVars.vars.maxX) GlobalVars.vars.minimapTr=1;
else GlobalVars.vars.minimapTr=0;
if(cont.y-unitGlobalVars.vars.sH-cont.height-3.1) GlobalVars.vars.downPossible=false;
else GlobalVars.vars.downPossible=true;
if(cont.x-unitGlobalVars.vars.sW-cont.width-3.5) GlobalVars.vars.rightPossible=false;
else GlobalVars.vars.rightPossible=true;
GlobalVars.vars.plX=cont.x; //for minimap
GlobalVars.vars.plY=cont.y;
Also, key listener functions:
stage.addEventListener(KeyboardEvent.KEY_DOWN, keyD, false, 0, true);
stage.addEventListener(KeyboardEvent.KEY_UP, keyU, false, 0, true);
private function keyD(e:KeyboardEvent):void
{
if(e.keyCode==37 || e.keyCode==65) left=true;
if(e.keyCode==38 || e.keyCode==87) up=true;
if(e.keyCode==39 || e.keyCode==68) right=true;
if(e.keyCode==40 || e.keyCode==83) down=true;
}
private function keyU(e:KeyboardEvent):void
{
if(e.keyCode==37 || e.keyCode==65) left=false;
if(e.keyCode==38 || e.keyCode==87) up=false;
if(e.keyCode==39 || e.keyCode==68) right=false;
if(e.keyCode==40 || e.keyCode==83) down=false;
}
I've encountered some improvement by increasing the FPS to 120, and decreasing the step to 4, but it's still there. I'm fairly sure it's not a performance issue, but, rather, a movement method fault.
A couple of suggestions:
Increase the frame rate
Use a tween library (e.g. GTween) with some easing effect.
Basically, if you want the object to jump 10px to the right, don't just move it right away, let it animate to its new position with some easing effect. Additionally, if the object is still moving and the key is pressed again, you probably want to accelerate the movement a bit (but only up to a point!).
I think you're asking how to make it more smooth. Well:
If you change the movement 2px per frame, then you'll have a much smoother experience. However, the movement will see very slow. To combat this, you just increase the frame rate of your swf. I believe the maximum is 120 frames, but that should be more than enough.
I love Tweenlite, it's great for pre-defined effects. It isn't for the core of your game though so I'd use Tweenlite for UI effects but barely for ingame movements responding to user controls.
I think around 24-30 fps for games is great, that's how I set all my games. I think abit you're picky, but perhaps what you're missing is a bit of edge: a smooth start and end for the movement. In most platformers I have a similar mechanic:
You want the start of the movement to start slow, reach the normal (max) speed you define and when the player lets go of a button, it slows down back to 0. This means you need to check the speed on enter frame regardless of the button triggers (they increment the speed but aren't the only condition to change speed and move the object)
enterframe loop:
//check for each direction:
if up, y_speed++
else if down, y_speed--
else if right, x_speed++
else if left, x_speed--
else // perform a decrease:
y_speed *= .8
x_speed *= .8
// make sure we aren't past the max speed
if x_speed>max_x_speed
x_speed = max_x_speed
etc. else other direction and y_speed
// now apply the movement
object.x += x_speed
object.y += y_speed
// remove the enterframe for better performance
if math.abs(x_speed)<.1 && math.abs(y_speed)<.1
// remove enterframe for movement here, add it again next time we know we have movement (button downs related to the movement, etc.)
I would implement this in your code but your code is too crowded. Anyway otherwise, most games with these simple controls are working just like your application does.