I'm trying to make a game with the XNA library. I want a sprite to throw a fireball to hit falling asteroids. But I have a problem with pressing the concrete key: I want to throw fireballs, for example, with one second between throws.
I want to measure the time difference between creating instances. How can I do that?
UYou can use the ElapsedGameTime property of the gameTime variable passed to the Update method like this:
const float shootTimer = 1.0f;
float elapsedTime = 0f;
protected override void Update(GameTime gameTime)
{
// Allows the game to exit
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
this.Exit();
elapsedTime += gameTime.ElapsedGameTime.TotalSeconds;
if(elapsedTime >= shootTimer && /* Your logic to see if you should shoot a fireball */ )
{
// Shoot the fireball!
elapsedTime = 0f;
}
base.Update(gameTime);
}
Basically, what you are doing in the above code is setting a minimum value (seconds) that need to pass between each shot.
Then you create a variable that will store the amount of time that has passed between each shot.
In the Update method, you add the time between each Update call and then check if it is bigger than the timer, and if it is, then you shoot and reset the elapsed time.
Note: I wrote that piece of code out of the top of my mind so it may have some minor issue.
Each call to Update of your main Game class or any GameComponent receives an instance of GameTime as an argument. Its property ElapsedGameTime can be used to accumulate the passage of time.
Related
I can't make the jump work in my game made in game maker studio 2
this project uses gravity and the game maker's language.
this is now just random words so stack overflow lets me post this question so Minecraft is a cool game :).
here is the code:
/// #description this is the create event
// You can write your code in this editor
sprite_index=Sprite1;
image_speed = 1;
image_index = 0;
step event:
/// #description Insert description here
// You can write your code in this editor
#region //gravedad
if place_free(x,y+1){
gravity =1;
}else{
gravity=0;
}
if vspeed >=20{vspeed=20}
#endregion
#region //movimiento
if keyboard_check(ord("D")){
direction=0
speed = brr;
}
else{
speed=0;
}
if keyboard_check(ord("A")){
direction=180
speed = brr;
}
if keyboard_check_pressed(vk_space) && !place_free(x,y+1){
vspeed = -broo;
}
#endregion
I think the !place_free(x,y+1) is the problem here
if keyboard_check_pressed(vk_space) && !place_free(x,y+1){
vspeed = -broo;
}
Assuming place_free checks if there's no collision, it may either be a case of setting the origin point of the player object to the bottom center, or not having a solid instance or collision mask. (as seen in the manual)
I personally prefer using place_meeting to check on collisions with a specific object, and ignore the requirements needed for place_free to work, maybe that could work better for you.
I'm quite new to Processing.
I'm trying to make Processing randomly play a video after I clear the screen by mouseclick, so I create an array that contain 3 videos and play one at a time.
Holding 'Spacebar' will play a video and release it will stop the video. Mouseclick will clear the screen to an image. The question is how can it randomize to another video if I press spacebar again after clear the screen.
I've been searching all over the internet but couldn't find any solution for my coding or if my logic is wrong, please help me.
Here's my code.
int value = 0;
PImage photo;
import processing.video.*;
int n = 3; //number of videos
float vidN = random(0, n+1);
int x = int (vidN);
Movie[] video = new Movie[3];
//int rand = 0;
int index = 0;
void setup() {
size(800, 500);
frameRate(30);
video = new Movie[3];
video[0] = new Movie (this, "01.mp4");
video[1] = new Movie (this, "02.mp4");
video[2] = new Movie (this, "03.mp4");
photo = loadImage("1.jpg");
}
void draw() {
}
void movieEvent(Movie video) {
video.read();
}
void keyPressed() {
if (key == ' ') {
image(video[x], 0, 0);
video[x].play();
}
}
void mouseClicked() {
if (value == 0) {
video[x].jump(0);
video[x].stop();
background(0);
image(photo, 0, 0);
}
}
You have this bit of logic in your code which picks a random integer:
float vidN = random(0, n+1);
int x = int (vidN);
In theory, if you want to randomise to another video when the spacebar is pressed again you can re-use this bit of logic:
void keyPressed() {
if (key == ' ') {
x = int(random(n+1));
image(video[x], 0, 0);
video[x].play();
}
}
(Above I've used shorthand of the two lines declaring vidN and x, but the logic is the same. If the logic is harder to follow since two operations on the same line (picking a random float between 0,n+1 and rounding down to an integer value), feel free to expand back to two lines: readability is more important).
As side notes, these bit of logic look a bit off:
the if (value == 0) condition will always be true since value never changes, making both value and the condition redundant. (Perhaps you plan to use for something else later ? If so, you could save separate sketches, but start with the simplest version and exclude anything you don't need, otherwise, in general, remove any bit of code you don't need. It will be easier to read, follow and change.)
Currently your logic says that whenever you click current video resets to the start and stops playing and when you hit the spacebar. Once you add the logic to randomise the video that the most recent frame of the current video (just randomised) will display (image(video[x], 0, 0);), then that video will play. Unless you click to stop the current video, previously started videos (via play()) will play in the background (e.g. if they have audio you'll hear them in the background even if you only see one static frame from the last time space was pressed).
Maybe this is the behaviour you want ? You've explained a localised section of what you want to achieve, but not overall what the whole of the program you posted should do. That would help others provide suggestions regarding logic.
In general, try to break the problem down to simple steps that you can test in isolation. Once you've found a solid solution for each part, you can add each part into a main sketch one at a time, testing each time you add something. (This way if something goes wrong it's easy to isolate/fix).
Kevin Workman's How To Program is a great article on this.
As a mental excercise it will help to read through the code line by line and imagine what it might do. Then run it and see if the code behaves as you predicted/intended. Slowly and surely this will get better and better. Have fun learning!
I'm a new in Unity and making my first 2D game. I seen several topics on this forum in this issue, but I didn't found the solution.
So I have a lovely shooting animation and the bullet generation. My problem, I have to generate the bullet somewhere at the middle of the animation, but the character shoots the bullet and the animation at the same time, which killing the UX :)
I attached an image, about the issue, this is the moment, when the bullet should be initialized, but as you can see it's already on it's way.
Please find my code:
The GameManager update method calls the attackEnemy function:
public void Awake(){
animator = GetComponent ();
animator.SetTrigger ("enemyIdle");
}
//if the enemy pass this point, they stop shooting, and just go off the scren
private float shootingStopLimit = -6f;
public override void attackPlayer(){
//animator.SetTrigger ("enemyIdle");
if (!isAttacking && gameObject.transform.position.y > shootingStopLimit) {
isAttacking = true;
animator.SetTrigger("enemyShoot");
StartCoroutine(doWait());
gameObject.GetComponentInChildren ().fireBullet ();
StartCoroutine (Reload ());
}
}
private IEnumerator doWait(){
yield return new WaitForSeconds(5);
}
private IEnumerator Reload(){
animator.SetTrigger ("enemyIdle");
int reloadTime = Random.Range (4,7);
yield return new WaitForSeconds(reloadTime);
isAttacking = false;
}......
My questions:
- How can I sync the animation and the bullet generation ?
Why not the doWait() works ? :)
Is it okay to call the attackPlayer method from the GameManager update ?
The enemies are flynig from the right side of the screen to the left, when they reach the most right side of the screen, they became visible to the user. I don't know why, but they to a shooting animation (no bullet generation happen )first, only after it they do the idle. Any idea why ?
Thanks,
K
I would suggest checking out animation events. Using animation events, you can call a method to instantiate your bullet.
To use Mecanim Animation Events you need to write the name of the function you want to call at the selected frame in the "Function" area of the "Edit Animation Event" window.
The other boxes are for any variables that you want to pass to that function to trigger whatever you have in mind.
Triggering/blending between different animations can be done in many different ways. The event area is more for other things that you want to trigger that are not related to animation (e.g. audio, particle fx, etc).
How do I use implemented Animation in LibGDX? I know, that the documentation can be found here, but when I want to get a frame out of the Animation, I need to use stateTime, which isn't explained anywhere in the documentation. So the question is, what is stateTime in terms of LibGDX's Animation?
There is some more doc on the getKeyFrame method documentation:
Returns a TextureRegion based on the so called state time. This is the amount of seconds an object has spent in the state this Animation instance represents, e.g. running, jumping and so on.
(This documentation doesn't really make any sense to me either.)
But, the Animation.java source is readable. It looks like it boils down to
getKeyFrameIndex
which divides the stateTime by frameDuration (which is a parameter of the constructor -- how long each frame lasts) to compute an array index. getKeyFrameIndex does different things for looping or non-looping sequences, but basically it takes the array index to look up the right key frame in the sequence to display.
So the "stateTime" is the input to pick a key frame from your Animation. The documentation is assuming you have one Animation instance for "running" and another for "jumping" (these are the "states" its referring to). To find the right key frame within an Animation, you tell it how long you've been in this "state". So, if you've been in the "running" Animation instance for 1.2 seconds, it does some math to figure out which key frame to show (say you've initialized the instance with 30 frames that show for 0.0333 seconds and loop -- it picks the 6th frame).
The wiki https://github.com/libgdx/libgdx/wiki/2D-Animation has some more details and an example, but doesn't address this directly, either.
animationFrames = walkSheetArray[moveDirection];
animation = new Animation(1f / 5f, animationFrames);
myAnimatedActor = new AnimatedActor(animation);
stage.addActor(myAnimatedActor);
public class AnimatedActor extends Image {
private float stateTime = 0;
Animation animation;
public AnimatedActor(Animation animation) {
super(animation.getKeyFrame(0));
this.animation = animation;
}
#Override
public void act(float delta) {
((TextureRegionDrawable) getDrawable()).setRegion(animation.getKeyFrame(stateTime += delta, true));
super.act(delta);
}
}
I know that jQuery, for example, can do animation of sorts. I also know that at the very core of the animation, there must me some sort of loop doing the animation. What is an example of such a loop?
A complete answer should ideally answer the following questions:
What is a basic syntax for an effective animation recursion that can animate a single property of a particular object at a time? The function should be able to vary its target object and property of the object.
What arguments/parameters should it take?
What is a good range of reiterating the loop? In milliseconds? (Should this be a parameter/argument to the function?)
REMEMBER:
The answer is NOT necessarily language specific, but if you are writing in a specific language, please specify which one.
Error handling is a plus. {Nothing is more irritating (for our purposes) than an animation that does something strange, like stopping halfway through.}
Thanks!
typically (for jQuery at least) this is not done in a loop, but rather in a series of callbacks.
pseudojavascript:
function startAnimation(element, endPosition, duration) {
var startPosition = element.position;
var startTime = getCurrentTime();
function animate() {
var timeElapsed = getCurrentTime() - startTime;
if (timeElapsed > duration) {
element.position = endPosition;
stopTimer();
} else {
// interpolate based on time
element.position = startPosition +
(endPosition - startPosition) * timeElapsed / duration;
}
}
startRepeatingTimerWithCallbackAndInterval(animate, 1.0 / 30.0);
}
It's also possible to use objects to store starting data instead of closures.
This doesn't completely answer all the points in the question, but it's a starting point.