如何设置固定shaperenderer旋转libgdx？ [英] How can i set fixed shaperenderer rotation in libgdx?

问题描述

我有这样一个三角形;

I have a triangle like this;

shapeRenderer.begin(ShapeType.Line);
shapeRenderer.setColor(1, 1, 0, 1);
shapeRenderer.polygon(new float[] { -10, 0, 10, 0, 0, 200 });
shapeRenderer.rotate(0, 0, 1, 1);
shapeRenderer.end();

和我在旋转，每个渲染1度。但我想修复旋转（例如45），以一个角度。我怎样才能做到这一点？
谢谢你。

and I rotate 1 degree in each render. But I want to fix rotation (e.g. 45) to an angle. How can I do this? Thanks.

推荐答案

要你有甲肝旋转 ShapeRenderer 只有一次固定的旋转。
有2种可能的方式我能想到的：

To have a fixed rotation you hav to rotate the ShapeRenderer only once. There are 2 possible ways i can think about:

1. 通话 shapeRenderer.rotate（0，0，1，45）; 在构造函数或创建（） / 显示（）方法
   这个调用转动你的 ShapeRenderer 45°（最后一个参数）约于 Z轴（第三个参数）


2. 通话 shapeRenderer.rotate（0，0，1，45）; 在rendermethod，只要你还没有旋转。所以，你必须保持一个布尔旋转且仅当它是假你叫旋转（ ）键，将其设置为真正。

1. call shapeRenderer.rotate(0, 0, 1, 45); in the constructor or in create() / show() method This call rotates your ShapeRenderer by 45° (last parameter) arround the Z-Axis (The 3rd parameter)
2. call shapeRenderer.rotate(0, 0, 1, 45); in the rendermethod, only if you did not rotate yet. So you have to keep a boolean rotated and only if it is false you call rotate() and set it to true.

要回答您的评论的问题：你不能直接设置旋转，你只能旋转（相对于当前旋转）。所以我建议来存储浮动旋转，并且每次你旋转你的 ShapeRenderer 设置的新值。要设置旋转度，你必须像旋转：

To answer the question in your comment: You cannot directly set the rotation, you can only rotate (relative to the current rotation). So i would suggest to store a float rotation, and everytime you rotate your ShapeRenderer you set the new value. To set a rotation in degrees you have to rotate like:

shapeRenderer.rotate(0, 0, 1, newRotation - rotation);
rotation = newRotation;

这只能如果你总是旋转约于同一轴线上，你的情况 Z轴。否则你将不得不储存3个旋转（X，Y，Z）。如果您旋转角落找寻一个自定义的轴，通过例如（0.1，0.3，0.6）定义的，你需要计算旋转所有轴。但我真的不知道该怎么做。我想有些Vectormath会做到这一点。但我不认为你需要的。

This works only if you always rotate arround the same axis, in your case the Z-axis. Else you would have to store 3 rotations (x,y,z). If you rotate arround a custom axis, defined by for example (0.1, 0.3, 0.6) you would need to calculate the rotation for all axes. But i don't really know how to do that. I think some Vectormath would do that. But i don't think you need that.

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