libgdx为什么相机不跟随角色呢？

Question

I'm new with libgdx and I have read a Tutorial (the Tutorial Code is my base). I have a character that I can move, but the camera won't follow the character :(

Here's my WorldRenderer.java:

package com.evolutio.tee.view;

import com.evolutio.tee.model.Block;
import com.evolutio.tee.model.Tee;
import com.evolutio.tee.model.World;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
import com.badlogic.gdx.math.Rectangle;

public class WorldRenderer {

    private static final float CAMERA_WIDTH = 10f;
    private static final float CAMERA_HEIGHT = 7f;

    private World world;
    private OrthographicCamera cam;

    /** for debug rendering **/
    ShapeRenderer debugRenderer = new ShapeRenderer();

    /** Textures **/
    private Texture teeTexture;
    private Texture blockTexture;

    private SpriteBatch spriteBatch;
    private boolean debug = false;
    private int width;
    private int height;
    private float ppuX; // pixels per unit on the X axis
    private float ppuY; // pixels per unit on the Y axis

    public void setSize (int w, int h) {
        this.width = w;
        this.height = h;
        ppuX = (float)width / CAMERA_WIDTH;
        ppuY = (float)height / CAMERA_HEIGHT;
    }

    public WorldRenderer(World world, boolean debug) {
        Tee tee = world.getTee();
        this.world = world;
        cam = new OrthographicCamera(CAMERA_WIDTH, CAMERA_HEIGHT);
        cam.position.set(CAMERA_WIDTH / 2f, CAMERA_HEIGHT / 2f, 0);
        cam.update();
        this.debug = debug;
        spriteBatch = new SpriteBatch();
        loadTextures();
    }

    private void loadTextures() {
        teeTexture = new  Texture(Gdx.files.internal("tee/tee.png"));
        blockTexture = new Texture(Gdx.files.internal("world/dreck.png"));
    }

    public void render() {
        spriteBatch.begin();
            drawBlocks();
            drawTee();
        spriteBatch.end();
        //if (debug) drawDebug();
    }


    private void drawBlocks() {
        for (Block block : world.getBlocks()) {
            spriteBatch.draw(blockTexture, block.getPosition().x * ppuX, block.getPosition().y * ppuY, Block.SIZE * ppuX, Block.SIZE * ppuY);
        }
    }

    private void drawTee() {
        Tee tee = world.getTee();
        spriteBatch.draw(teeTexture, tee.getPosition().x * ppuX, tee.getPosition().y * ppuY, Tee.SIZE * ppuX, Tee.SIZE * ppuY);
        cam.position.set(tee.getPosition().x, tee.getPosition().y, 0);
    }

    private void drawDebug() {
        // render blocks
        debugRenderer.setProjectionMatrix(cam.combined);
        debugRenderer.begin(ShapeType.Rectangle);
        for (Block block : world.getBlocks()) {
            Rectangle rect = block.getBounds();
            float x1 = block.getPosition().x + rect.x;
            float y1 = block.getPosition().y + rect.y;
            debugRenderer.setColor(new Color(1, 0, 0, 1));
            debugRenderer.rect(x1, y1, rect.width, rect.height);
        }
        // render Tee
        Tee tee = world.getTee();
        Rectangle rect = tee.getBounds();
        float x1 = tee.getPosition().x + rect.x;
        float y1 = tee.getPosition().y + rect.y;
        debugRenderer.setColor(new Color(0, 1, 0, 1));
        debugRenderer.rect(x1, y1, rect.width, rect.height);
        debugRenderer.end();
    }
}

at drawTee() I try to make the camera following the Tee.

cam.position.set(tee.getPosition().x, tee.getPosition().y, 0);

Answer 1

Try this

public class WorldRenderer {

private static final float CAMERA_WIDTH = 10f;
private static final float CAMERA_HEIGHT = 7f;

private World world;
private OrthographicCamera cam;

/** for debug rendering **/
ShapeRenderer debugRenderer = new ShapeRenderer();

/** Textures **/
private Texture teeTexture;
private Texture blockTexture;

private SpriteBatch spriteBatch;
private boolean debug = false;
private int width;
private int height;
private float ppuX; // pixels per unit on the X axis
private float ppuY; // pixels per unit on the Y axis

public void setSize (int w, int h) {
    this.width = w;
    this.height = h;
    ppuX = (float)width / CAMERA_WIDTH;
    ppuY = (float)height / CAMERA_HEIGHT;
}

public WorldRenderer(World world, boolean debug) {
    Tee tee = world.getTee();
    this.world = world;
    this.cam = new OrthographicCamera(CAMERA_WIDTH, CAMERA_HEIGHT);
    this.cam.setToOrtho(false,CAMERA_WIDTH,CAMERA_HEIGHT);
    this.cam.position.set(CAMERA_WIDTH / 2f, CAMERA_HEIGHT / 2f, 0);
    this.cam.update();
    this.debug = debug;
    spriteBatch = new SpriteBatch();
    loadTextures();
}

private void loadTextures() {
    teeTexture = new  Texture(Gdx.files.internal("tee/tee.png"));
    blockTexture = new Texture(Gdx.files.internal("world/dreck.png"));
}

public void render() {
    moveCamera(tee.getPosition().x, CAMERA_HEIGHT / 2);
    spriteBatch.setProjectionMatrix(cam.combined);
    spriteBatch.begin();
        drawBlocks();
        drawTee();
    spriteBatch.end();
    //if (debug) drawDebug();
}

public void moveCamera(float x,float y){
    if ((tee.getPosition().x > CAMERA_WIDTH / 2)) {
        cam.position.set(x, y, 0);
        cam.update();
    }

}


private void drawBlocks() {
    for (Block block : world.getBlocks()) {
        spriteBatch.draw(blockTexture, block.getPosition().x, block.getPosition().y, Block.SIZE, Block.SIZE);
    }
}

private void drawTee() {
    Tee tee = world.getTee();
    spriteBatch.draw(teeTexture, tee.getPosition().x, tee.getPosition().y, Tee.SIZE, Tee.SIZE);
}

Using the sprite.setProjectionMatrix(cam.combined) before the spriteBatch.begin() is needed because if you don't the spriteBatch uses it's own camera, therefore your updates do nothing for what appears on screen. You have to take out the ppuX, ppuY stuff. I know that's to resize the screen for different devices, but it screws up the camera, therefore if you keep it in and call the setProjectionMatrix, it will be way way zoomed in (actually the size of all images will be huge.)