Libgdx之間的兩點計算

這裏我是計算演員和接觸點之間的度數，並將這個度數傳遞給演員作爲旋轉角度。我希望演員應該指向手指接觸或手指拖動方向（考慮我拉車在路上通過手指觸摸並拖動）Libgdx之間的兩點計算

float degrees = (float) ((Math.atan2(touchPoint.x - crocodile.position.x, -(touchPoint.y - crocodile.position.y)) * 180.0d/Math.PI));

其計算程度正確。只是有時在它之間有一點不同的程度。所以當結果與預期完全不同時，我的演員會波動。

結果，我印刷是：

塊引用

degree is :: 141.93233 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 158.61426 
    degree is :: 90.0 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 90.0 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93057 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93306 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93257 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93134 
    degree is :: 141.93257 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93134 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93306 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93257 
    degree is :: 180.0 
    degree is :: 141.93134 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93257 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93257 
    degree is :: 180.0 
    degree is :: 141.93134 
    degree is :: 180.0 
    degree is :: 141.93257 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93008 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93306 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93257 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 141.93134 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 180.0 
    degree is :: 180.0

現在，180和141爲什麼它與那些值波動。考慮到我期望不斷地或者不斷地180我需要改變上面的公式。

來源

2013-08-20 Chavan Parmeshwar

它不能，只要你輸入沒有變化而變化（假設你有一個確定性的CPU，應該是這種情況...）。所以你的接觸點改變了，或者你的鱷魚的位置。此外：類似於'touchPoint.sub（crocodile.position）.angle（）'的東西可能更容易理解？ – noone

@noone，我認爲通過使用 '代碼' touchPoint.sub（crocodile.position）.angle（）我可以找到角度正確嗎？但crocodile.position是Vector2值，並且子未採用Vector2值，並且如果我正在使用 'code' touchPoint.sub（crocodile.position.x，crocodile.position.y，0）.angle（）; 然後它也不符合任何API文檔功能。意味着角度（）不解決那裏.... 在上面的答案「你說你的鱷魚的位置改變」是「我想告訴你，是的，我正在更新鱷魚的位置到接觸點。那麼我該怎麼辦，如果我想在那裏移動.. 謝謝。 –

'Vector3'沒有角度（），但是'Vector2'。所以嘗試一下'flot angle =（new Vector2（touchPoint.x，touchPoint.y））。sub（crocodile.position）.angle（）'。 – noone

第一個參數必須是y，第二個參數是x。

double atan2(double y, double x)

ATAN2實際上是因爲，通常第一參數指定的Y/X

的反正切函數被取收率

此外，當您交換x和y時，您可以獲得適當的程度，因爲在某些邊框（如x < 0和y < 0）中，交換與否都無關緊要。

Look here for more explanation

來源

2015-03-26 18:48:13

請[格式]（http://stackoverflow.com/help/formatting）提供您的答案，以提高其可讀性。 – ryanyuyu

結合的問題和答案幫助我儘快解決我的問題。只是爲了澄清溶液一點：

double degrees = Math.atan2(
    towards.getY() - pointer.getY(), 
    towards.getX() - pointer.getX() 
) * 180.0d/Math.PI; 
pointer.setRotation((float) degrees);

還要注意的是，爲了圍在中間旋轉，你需要做的：

pointer.setOrigin(Align.center);

來源

2015-09-25 04:48:50 DHa

Libgdx之間的兩點計算

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