Android Studio，LibGDX在一定时间后自动增加速度

Question

我正在做一个项目，我正在学习 LibGDX，但到目前为止，该项目进展顺利，但是，教程没有说明如何在经过一定时间后提高速度，例如（10秒过去了，我希望我的敌人将速度提高到 0.1f，这意味着 10%，再过 10 秒后，自动将速度提高到 0.2f，依此类推。）这是我代码的唯一部分需要改变以使他们的敌人提高他们的速度public static final Vector2 ENEMY_LINEAR_VELOCITY = new Vector2(-10f, 0);教程在这里（'http://williammora.com/a-running-game-with-libgdx-part-1/'）我该怎么做？有人可以帮我吗？我将不胜感激！

常量类：

package com.avoidcrashjump;

import com.badlogic.gdx.math.Vector2;


/**
 * Created by Felipe on 2/29/2016.
 */
public class Constants {
    public static final int APP_WIDTH = 1024;
    public static final int APP_HEIGHT = 640;

    public static final Vector2 WORLD_GRAVITY = new Vector2(0, -10);

    public static final float GROUND_X = 0;
    public static final float GROUND_Y = 0;
    public static final float GROUND_WIDTH = 50f;
    public static final float GROUND_HEIGHT = 2f;
    public static final float GROUND_DENSITY = 0f;
    public static final float PLAYER_X = 2;
    public static final float PLAYER_Y = GROUND_Y + GROUND_HEIGHT;
    public static final float PLAYER_WIDTH = 1f;
    public static final float PLAYER_HEIGHT = 1f;
    public static final float PLAYER_GRAVITY_SCALE = 2.5f;
    public static float PLAYER_DENSITY = 0.5f;
    public static final float PLAYER_DODGE_X = 2f;
    public static final float PLAYER_DODGE_Y = 1.5f;
    public static final Vector2 PLAYER_JUMPING_LINEAR_IMPULSE = new Vector2(0,13f);
    public static final float PLAYER_HIT_ANGULAR_IMPULSE = 10f;
    public static final float ENEMY_X = 25f;
    public static final float ENEMY_DENSITY = PLAYER_DENSITY;
    public static final float RUNNING_SHORT_ENEMY_Y = 1.5f;
    public static final float RUNNING_LONG_ENEMY_Y = 2f;
    public static final float FLYING_ENEMY_Y = 3f;
    public static final Vector2 ENEMY_LINEAR_VELOCITY = new Vector2(-10f, 0);


}

Answer 1

您的班级名为Constants，您的速度使用final 声明。类的名称告诉我们我们不应该尝试更改这些，final 不允许我们这样做。

但是，如果您更改变量声明（将其移动到某处并删除 final 关键字）。要使其增加，您可以使用Gdx.graphics.getDeltaTime()。

创建一个变量来计算经过的时间：

float timer = 0;

然后在你的 render() 方法中

timer += Gdx.graphics.getDeltaTime(); //returns time between two frames
if(timer > 10) { //after 10 seconds
    speed = speed * 1.1F;
    timer = 0; //reset timer
}