I'm trying to make this thing:
When user press a key once, the sprite smoothly moves on some pixels. But it just "teleporting" to the position. Here is the code:
int co = 0; Vector2 ppos=new Vector2(x,y); if (Gdx.input.isKeyJustPressed(Keys.A)){ while (co < 33) { batch.begin(); ppos.y += Gdx.graphics.getDeltaTime()*5; Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); batch.draw(Splayer, ppos.x, ppos.y); //Splayer is a sprite batch.end(); co++; out(co+""); } } What am I doing wrong?
I will deconstuct your code:
while (co < 33) { So this will loop 33 times since you have co = 0 and increment co each loop.
ppos.y += Gdx.graphics.getDeltaTime()*5; You increment the y position by your framerate * 5. so something like 5 * 0.02 * 33 is happening which makes 3.3. Nothing wrong with that but it is kinda unconventional to use a loop for that. Since doing y = 5 * framerate * 33 would be the same, easier and faster.
It depends on what you want to end up with but basically "we" do something like this.
//Have position variable private Vector2 position; //Have a speed variable private float speed; //direction variable private Vector2 direction; //have a velocity variable (direction * speed) private Vector2 velocity; velocity should be direction * speed and the velocity can then be added each frame to the position. let's say we want to move up. The direction would be (0,1) (the direction should never exceed the length of 1, if it does then normalize the vector direction.nor(). This will make sure it is 1 long so multiplying this will results in the same speed in any direction.
direction = new Vector2(0,1); //an easy way to make it go 45 degree up/right would be direction = new Vector2(1,1); direction.nor(); //normalized to 1 long. //now we can make the velocity velocity = direction.cpy().scl(speed); //we copy the vector first so we are not changing the direction vector. //If you want to have this framerate independent velocity = direction.cpy().scl(speed * Gdx.graphics.getDeltatime); Now we just add velocity to position. Basic math (1, 1) + (0, 1) = (1 ,2). Yes that is how simple Vectors are. original pos (0, 0)plus direction multiplied by speed+ (0 * 10, 1 * 10) = (0, 10)`. So to add velocity to position in code:
position.add(velocity); batch.draw(textures, position.x, position.y); This would be my way of doing it, I find this very easy.
What you are doing wrong is generating a new Vector each game loop when you press "A". You should think twice about having the new keyword in your loop. It is better the change you vector or reset it since it the old one will be lost in memory and needs to be collected. One Vector will not get you into trouble but 1 Texture that needs manual disposing will, learn it the right way.
Other then that, why have a variable named ppos? Why not just position or patientPosition or palaeoanthropologyPosition or whatever the "p" stands for. You are only required to type it once in most IDE because intellisense will pick it up. So make your and others life easier by clearly defining variables.
you should use Scene2D for smooth movement.
