我正在尝试为SpriteAnimation类实现一个自动旋转方法（尝试移植SpriteAnimation）。
一切正常，精灵正确绘制（它使用正确的动画）它根本不能正确旋转，通常只有在目标与其位置匹配时才会指向原点（0,0）我希望它的旋转在移动时更新，我尝试了两个度数和弧度，两者都不起作用。它应该旋转以匹配当前的方向。我已经在这个问题上苦苦挣扎了大约一个星期，但仍然没有得到预期的结果。
相关代码：
来自SpriteAnimation
// The x position of the sprite's upper left corner pixel.
public int getX() { return (int)position.x; }
public void setX(int value)
{
prevPosition.x = position.x;
position.x = value;
updateRotation();
}
// The y position of the sprite's upper left corner pixel.
public int getY() { return (int)position.y; }
public void setY(int value)
{
prevPosition.y = position.y;
position.y = value;
updateRotation();
}
void updateRotation()
{
if (rotateByPosition)
{
Vector2 rotationVector = new Vector2(position.x - prevPosition.x, position.y - prevPosition.y);
rotationRad = rotationVector.angle();
rotationDeg = rotationRad * MathUtils.radiansToDegrees;
}
}
public void MoveBy(int x, int y)
{
prevPosition = new Vector2(position);
position.x += x;
position.y += y;
updateRotation();
}
public void Update(float deltaTime)
{
// Don't do anything if the sprite is not animating
if (animating)
{
// If there is not a currently active animation
if (getCurrentFrameAnimation() == null)
{
// Make sure we have an animation associated with this sprite
if (animations.size() > 0)
{
// Set the active animation to the first animation
// associated with this sprite
String[] sKeys = new String[animations.size()];
int index = 0;
for (Entry<String, FrameAnimation> mapEntry : animations.entrySet()) {
sKeys[index] = mapEntry.getKey();
index++;
}
setCurrentAnimation(sKeys[0]);
}
else
{
return;
}
}
// Run the Animation's update method
getCurrentFrameAnimation().Update(deltaTime);
// Check to see if there is a "follow-up" animation named for this animation
if (getCurrentFrameAnimation().getNextAnimation() != null && !getCurrentFrameAnimation().getNextAnimation().isEmpty())
{
// If there is, see if the currently playing animation has
// completed a full animation loop
if (getCurrentFrameAnimation().getPlayCount() > 0)
{
// If it has, set up the next animation
setCurrentAnimation(getCurrentFrameAnimation().getNextAnimation());
}
}
}
}
public void Draw(SpriteBatch spriteBatch, int xOffset, int yOffset)
{
updateRotation(); // Calling this while testing to make sure that it is being called
spriteBatch.draw(getCurrentTextureRegion(), getPosition().x + xOffset - center.x, getPosition().y + yOffset - center.y, center.x, center.y, getCurrentFrameAnimation().getFrameWidth(), getCurrentFrameAnimation().getFrameHeight(), 1.0f, 1.0f, rotationRad);
}
TestScreen类
package com.darkstudio.darkisle.screens;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Screen;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.OrthographicCamera;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.math.Vector2;
import com.badlogic.gdx.math.Vector3;
import com.darkstudio.darkisle.DarkIsle;
import com.delib.engine.sprite.MobileSprite;
/**
* Created by DarkEnder on 2017/06/27.
*/
public class TestScreen implements Screen {
final DarkIsle game;
OrthographicCamera camera;
Texture tankTexture;
MobileSprite mouseTank;
public TestScreen(final DarkIsle game)
{
this.game = game;
camera = new OrthographicCamera();
configureCamera();
tankTexture = new Texture(Gdx.files.internal("MulticolorTanks.png"));
mouseTank = new MobileSprite(tankTexture, 32, 32);
mouseTank.getSprite().AddAnimation("red", 0, 32, 32, 32, 8, 0.1f);
mouseTank.getSprite().AddAnimation("purple", 0, 128, 32, 32, 8, 0.1f, "red");
mouseTank.getSprite().AddAnimation("yellow", 0, 64, 32, 32, 8, 0.1f);
mouseTank.getSprite().setAutoRotate(true);
mouseTank.setPosition(new Vector2(100, 100));
mouseTank.setTarget(new Vector2(mouseTank.getPosition()));
mouseTank.setIsPathing(true);
mouseTank.setEndPathAnimation("yellow");
mouseTank.setLoopPath(false);
mouseTank.setSpeed(2);
}
@Override
public void show() {
}
@Override
public void render(float delta) {
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT);
update();
game.batch.begin();
mouseTank.draw(game.batch);
game.batch.end();
}
@Override
public void resize(int width, int height) {
}
@Override
public void pause() {
}
@Override
public void resume() {
}
@Override
public void hide() {
}
@Override
public void dispose() {
}
private void configureCamera()
{
Vector3 camPos = new Vector3(camera.position);
float size = 800;
float cameraWidth = 0;
float cameraHeight = 0;
if (Gdx.graphics.getHeight() < Gdx.graphics.getWidth())
{
cameraWidth = size;
cameraHeight = size * Gdx.graphics.getHeight() / Gdx.graphics.getWidth();
}
else
{
cameraWidth = size * Gdx.graphics.getWidth() / Gdx.graphics.getHeight();
cameraHeight = size;
}
camera.setToOrtho(true, cameraWidth, cameraHeight);
camera.position.set(camPos.x + camera.viewportWidth / 2f, camPos.y + camera.viewportHeight / 2f, 0);
}
private void update() {
int xTouch = Gdx.input.getX(0);
int yTouch = Gdx.input.getY(0);
mouseTank.setTarget(xTouch, yTouch);
mouseTank.update(Gdx.graphics.getDeltaTime());
}
}
编辑：现在说我已经尝试在MathUtils中使用atan2并且它给出了相同的结果。
MobileSprite更新方法
public void update(float deltaTime)
{
if (active && movingTowardsTarget)
{
if ((target != null))
{
// Get a vector pointing from the current location of the sprite
// to the destination.
Vector2 Delta = new Vector2(target.x - sprite.getX(), target.y - sprite.getY());
if (Delta.len() > getSpeed())
{
Delta.nor();
Delta.scl(getSpeed());
getPosition().add(Delta);
}
else
{
if (target == sprite.getPosition())
{
if (pathing)
{
if (queuePath.size() > 0)
{
target = queuePath.remove();
if (loopPath)
{
queuePath.remove(target);
}
}
else
{
if (!(endPathAnimation == null))
{
if (!(getSprite().getCurrentAnimation() == endPathAnimation))
{
getSprite().setCurrentAnimation(endPathAnimation);
}
}
if (deactivateAtEndOfPath)
{
setIsActive(false);
}
if (hideAtEndOfPath)
{
setIsVisible(false);
}
}
}
}
else
{
sprite.setPosition(target);
}
}
}
}
if (active)
sprite.Update(deltaTime);
}
答案 0 :(得分：0)
获得弧度角：
void updateRotation()
{
if (rotateByPosition)
{
Vector2 rotationVector = new Vector2(position.x - prevPosition.x, position.y - prevPosition.y);
rotationRad = rotationVector.angleRad();
rotationDeg = rotationRad * MathUtils.radiansToDegrees;
}
}
并且draw方法需要一个角度：
spriteBatch.draw(
getCurrentTextureRegion(),
getPosition().x + xOffset - center.x,
getPosition().y + yOffset - center.y,
center.x, center.y,
getCurrentFrameAnimation().getFrameWidth(), getCurrentFrameAnimation().getFrameHeight(),
1.0f, 1.0f,
rotationDeg
);
屏幕鼠标位置来自渲染器左下角的左上角：
int xTouch = Gdx.input.getX(0);
int yTouch = Gdx.graphics.getHeight() - Gdx.input.getY(0);