[英]How to make sprite bounce of the sides of the screen
我在Java Android Studio中使用libgdx。 我才剛開始。 我正在使用Android手機。 我沒有使用任何相機。 我想要的只是屏幕所有四個側面的精靈反彈而無需點擊。 我嘗試了很多我認為會起作用的代碼,但沒有。 我希望你們能幫助我。 我希望盡快得到答案。 謝謝
這就是我所擁有的:
SpriteBatch batch;
Texture background;
Sprite backgroundsprite;
Sprite ballsprite;
Texture line;
Texture ballimg;
BitmapFont credits;
BitmapFont input;
BitmapFont play;
float dt;
String string = "";
float ballx;
float bally;
float speedx;
float speedy;
Rectangle screenrect;
Rectangle ballrect;
float screenLeft ;
float screenBottom ;
float screenTop ;
float screenRight ;
@Override
public void create() {
batch = new SpriteBatch();
speedx = 5f * dt;
speedy = 5f * dt;
createsprite();
createbackground();
createtext();
ballx = ballsprite.getX();
bally = ballsprite.getY();
}
@Override
public void render() {
Gdx.gl.glClearColor(1, 1, 1, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
dt = Gdx.graphics.getDeltaTime();
ballsprite.setPosition(ballx + speedx,ballsprite.getY());
ballsprite.translateX(speedx);
float left = ballrect.getX();
float bottom = ballrect.getY();
float top = bottom + ballrect.getHeight();
float right = left + ballrect.getWidth();
if(left < screenLeft) {
string = "left";
speedx = 5f*dt;
}
if(right > screenRight)
{
string = "right";
speedx = -5f*dt;
}
if(bottom < screenBottom)
{
string = "bottom";
}
if(top > screenTop)
{
string = "top";
}
batch.begin();
backgroundsprite.draw(batch);
ballsprite.draw(batch);
rendertext();
batch.end();
}
public void createbackground() {
background = new Texture("images/BackgroundGodwin.jpg");
backgroundsprite = new Sprite(background);
backgroundsprite.setSize(Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
screenrect = new Rectangle(0,0,Gdx.graphics.getWidth(),Gdx.graphics.getHeight());
screenLeft = screenrect.getX();
screenBottom = screenrect.getY();
screenTop = screenBottom + screenrect.getHeight();
screenRight = screenLeft + screenrect.getWidth();
}
public void createsprite() {
ballimg = new Texture("images/SpriteGodwin.png");
ballsprite = new Sprite(ballimg);
ballsprite.setScale(0.65f);
ballsprite.setPosition(Gdx.graphics.getWidth()/3,Gdx.graphics.getHeight()/2);
ballrect = new Rectangle(ballsprite.getBoundingRectangle());
}
@Override
public void dispose() {
batch.dispose();
ballimg.dispose();
background.dispose();
credits.dispose();
play.dispose();
input.dispose();
line.dispose();
}
public void createtext(){
play = new BitmapFont(Gdx.files.internal("fonts/realfont.fnt"));
play.setColor(com.badlogic.gdx.graphics.Color.GOLD);
credits = new BitmapFont(Gdx.files.internal("fonts/realfont.fnt"));
credits.setColor(com.badlogic.gdx.graphics.Color.GOLD);
input = new BitmapFont(Gdx.files.internal("fonts/realfont.fnt"));
input.setColor(com.badlogic.gdx.graphics.Color.OLIVE);
}
public void rendertext() {
credits.draw(batch, "Maded", Gdx.graphics.getWidth() / 7 - 50, Gdx.graphics.getHeight() / 9);
play.draw(batch, "Touch the Screen to play!!", Gdx.graphics.getWidth() / 2 - 175, Gdx.graphics.getHeight() - 80);
input.draw(batch, string, Gdx.graphics.getWidth() / 2 - 160, Gdx.graphics.getHeight() - 120);
}
}
我對您想要的內容做了一個非常簡單的版本:
public class BouncyGame extends ApplicationAdapter {
SpriteBatch batch;
Texture ball;
float speedX = 3f;
float speedY = 3f;
int x;
int y;
@Override
public void create () {
batch = new SpriteBatch();
ball = new Texture("ball.png");
x = Gdx.graphics.getWidth()/2;
y = Gdx.graphics.getHeight()/2;
}
@Override
public void render () {
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
//When the ball's x position is on either side of the screen.
//The width of the sprite is taken into account.
if (x > Gdx.graphics.getWidth() - ball.getWidth()/2 || x < 0 + ball.getWidth()/2) {
//Here we flip the speed, so it bonces the other way.
speedX = -speedX;
}
//Same as above, but with on the y-axis.
if (y > Gdx.graphics.getHeight() - ball.getHeight()/2 || y < 0 + ball.getHeight()/2) {
speedY = -speedY;
}
//Move the ball according to the speed.
x += speedX;
y += speedY;
batch.begin();
//Draw the ball so the center is at x and y. Normally it would be drawn from the lower left corner.
batch.draw(ball, x - ball.getWidth()/2, y - ball.getHeight()/2);
batch.end();
}
}
結果如下:
http://gfycat.com/TatteredCarefreeHapuku
有很多方法可以改進此代碼,例如可以使用向量,但我不建議在最終產品中使用它,但是它可以幫助您弄清楚如何為自己的項目做類似的事情。
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