[英]Problem when trying to rotate a 2D shape in a 3D space
i'm working on a batch renderer and i'm having trouble implementing a rotation feature for 2D shapes like a rectangle or a triangle.我正在开发批处理渲染器,但在为矩形或三角形等 2D 形状实现旋转功能时遇到了麻烦。 I'm using a Vertex* (struct Vertex code below) to store the position and color values, which works pretty well, until i got to rotations.
我正在使用 Vertex*(下面的结构 Vertex 代码)来存储位置和颜色值,效果很好,直到我开始旋转。
struct Vertex
{
glm::vec3 position;
glm::vec4 color;
};
I tried to make a mat4 and use the corresponding rotation function accordingly, which worked well when i set the model view projection in the shader, but converting the data to a Vertex wasn't working and very laggy.我尝试制作一个 mat4 并相应地使用相应的旋转功能,当我在着色器中设置模型视图投影时效果很好,但是将数据转换为顶点不起作用并且非常滞后。 Therefore i thought i use some math that i found online, but my squares that i drew were streched to rectangles sometimes and the positions were off.
因此,我想我使用了一些我在网上找到的数学方法,但是我绘制的正方形有时会被拉伸成矩形并且位置不正确。 I put in alot of hours now and tried different stuff, but nothing worked.
我现在投入了很多时间并尝试了不同的东西,但没有任何效果。 That's why i hope someone can maybe find an obvious bug in my code or direct me to a good source where i can read about this topic (the stuff i found was either irrelevant for my purposes or hard to understand).
这就是为什么我希望有人能在我的代码中找到一个明显的错误,或者将我引导到一个很好的来源,我可以在那里阅读这个主题(我发现的东西要么与我的目的无关,要么难以理解)。
Here is my summarized code, i tried to keep it as short as possible:这是我总结的代码,我尽量保持简短:
void rotateX(float angle)
{
yr = yr * cos(angle) - zr * sin(angle);
zr = zr * cos(angle) + yr * sin(angle);
}
void rotateY(float angle)
{
xr = xr * cos(angle) - zr * sin(angle);
zr = zr * cos(angle) + xr * sin(angle);
}
void rotateZ(float angle)
{
xr = xr * cos(angle) - yr * sin(angle);
yr = yr * cos(angle) + xr * sin(angle);
}
std::array<Vertex, 4> createQuad(glm::vec3 pos, glm::vec3 rotation, glm::vec4 rgba)
{
float xr = 1.0f;
float yr = 1.0f;
float zr = 1.0f;
rotateX(rotation.x);
rotateY(rotation.y);
rotateZ(rotation.z);
Vertex v0;
v0.position = glm::vec3(pos.x, pos.y + yr, pos.z);
v0.color = rgba;
Vertex v1;
v1.position = glm::vec3(pos.x + xr, pos.y + yr, pos.z);
v1.color = rgba;
Vertex v2;
v2.position = glm::vec3(pos.x + xr, pos.y, pos.z + zr);
v2.color = rgba;
Vertex v3;
v3.position = glm::vec3(pos.x, pos.y, pos.z + zr);
v3.color = rgba;
return { v0, v1, v2, v3 };
}
Other notes:其他注意事项:
I'm going to bed for now, it's really late and i have a headache... hopefully my question wasn't too nooby or stupid, in that case i'm sorry for bothering you.我现在要睡觉了,真的很晚了,我头疼...希望我的问题不是太笨拙或愚蠢,在这种情况下,我很抱歉打扰你。 Thanks in advance for any help!
在此先感谢您的帮助!
First, change your rotate
functions to accept a vector as an argument, rather than apply the rotations to globals (or whatever those are).首先,更改您的
rotate
函数以接受向量作为参数,而不是将旋转应用于全局变量(或任何其他变量)。
Then instead of one vector:然后代替一个向量:
r = {1, 1, 1}
use two:使用两个:
r = {1, 0, 0}
s = {0, 1, 0}
Rotate them both (using the same angle arguments), then construct the square.旋转它们(使用相同的角度参数),然后构造正方形。 (I don't know the syntax of a
glm::vec3
, but this is simple vector addition): (我不知道
glm::vec3
的语法,但这是简单的向量加法):
Vertex v0 = pos;
Vertex v1 = pos + r;
Vertex v2 = pos + r + s;
Vertex v3 = pos + s;
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