Question

我有轮换问题。

我设置了摄像机，使向上矢量为Z，-X为正向，右为Y.我有模型导出到另一个坐标系，其中Y为向上，-Z为向前，X为向右。

我的挑战/问题在于轮换。在这种情况下如何正确旋转而不更改我导入的对象的坐标系。规模和变换正在按预期工作。

到目前为止，我已经尝试在旋转矩阵手册中交换Y轴和Z轴，分别进行旋转矩阵，在读取控制文件时进行旋转，翻转Z和Y旋转轴，将矩阵更改为

| 1 0 0 |

| 0 0 1 |

| 0 1 0 |

等。

PS。我不想更改我现在导入的目标文件的坐标系，当我在控制文件中写入rotateY时，它将在Y轴上旋转对象而不是对象Y轴。

这是我尝试转换的代码的一部分

// control file is where i store transform, rotate and scale in a text file and objects that i want to read. 
for(int i = 0; i< controls.size(); i++) {
        meshStruct tempMesh;

        int isMeshLoaded = loadObjFile((char*)controls[i].path, &tempMesh.objectInfo_, &tempMesh.numObjects_);
        if(isMeshLoaded)
        {
            cout<< "Mesh " << controls[i].path << " loaded sucesfully." << endl;
        } else {
            cout<< "Mesh " << controls[i].path << " loaded failed." << endl;
        }

        tempModelMatrix = mat4(1.0f, 0.0f, 0.0f, 0.0f,
                                0.0f, 1.0f, 0.0f, 0.0f,
                                0.0f, 0.0f, 1.0f, 0.0f,
                                0.0f, 0.0f, 0.0f, 1.0f);

        //mat4 tempModelMatrixFlip = mat4(1.0f, 0.0f, 0.0f, 0.0f,
        //                              0.0f, 0.0f, 1.0f, 0.0f,
        //                              0.0f, 1.0f, 0.0f, 0.0f,
        //                              0.0f, 0.0f, 0.0f, 1.0f);
        //tempModelMatrix *= tempModelMatrixFlip;

        tempModelMatrix = glm::translate(tempModelMatrix, controls[i].translate);

        tempModelMatrix = glm::rotate(tempModelMatrix, radians(controls[i].rotation.x), vec3(1.0, 0.0, 0.0));
        // I dont want to flip here Y and Z because some objects are in the correct coordinate system
        tempModelMatrix = glm::rotate(tempModelMatrix, radians(controls[i].rotation.y), vec3(0.0, 1.0, 0.0));
        tempModelMatrix = glm::rotate(tempModelMatrix, radians(controls[i].rotation.z), vec3(0.0, 0.0, 1.0)); 
        /*
        mat4 r  = mat4(1.0f);
        mat4 rx = mat4(1.0f); 
        mat4 ry = mat4(1.0f);
        mat4 rz = mat4(1.0f);
        rx = rotate(radians(controls[i].rotation.x), vec3(1.0, 0.0, 0.0));
        ry = rotate(radians(controls[i].rotation.y), vec3(0.0, 1.0, 0.0));
        rz = rotate(radians(controls[i].rotation.z), vec3(0.0, 0.0, 1.0));
        r = rx * ry * rz;       

        vec4 temp;

        temp = column(r, 1);
        cout << to_string(temp) << endl;
        r = column(r,1, column(r, 2));
        r = column(r,2, temp);

        temp = row(r,1);
        r = row(r, 1,row(r,2));
        r = row(r, 2, temp);
        //cout << to_string(column(tempModelMatrix, 1)) << endl;

        //tempModelMatrix *= r;
        float tempModelMatrix2[16];// = mat4(1.0f);

        tempModelMatrix2[0] =  controls[i].scale.x * column(r, 0).x;//controls[i].scale.x * controls[i].rotation.x;
        tempModelMatrix2[1] =  controls[i].scale.x * column(r, 0).y;//controls[i].scale.x * controls[i].rotation.x;
        tempModelMatrix2[2] =  controls[i].scale.x * column(r, 0).z;//controls[i].scale.x * controls[i].rotation.x;
        tempModelMatrix2[3] =  0.0f;
        tempModelMatrix2[4] =  controls[i].scale.y * column(r, 2).x;//controls[i].scale.y * controls[i].rotation.y;
        tempModelMatrix2[5] =  controls[i].scale.y * column(r, 2).y;//controls[i].scale.y * controls[i].rotation.y;
        tempModelMatrix2[6] =  controls[i].scale.y * column(r, 2).z;//controls[i].scale.y * controls[i].rotation.y;
        tempModelMatrix2[7] =  0.0f;
        tempModelMatrix2[8] =  controls[i].scale.z * column(r, 1).x;//controls[i].scale.z * controls[i].rotation.z;
        tempModelMatrix2[9] =  controls[i].scale.z * column(r, 1).y;//controls[i].scale.z * controls[i].rotation.z;
        tempModelMatrix2[10] = controls[i].scale.z * column(r, 1).z;//controls[i].scale.z * controls[i].rotation.z;
        tempModelMatrix2[11] = 0.0f;
        tempModelMatrix2[12] = controls[i].translate.x;
        tempModelMatrix2[13] = controls[i].translate.y;
        tempModelMatrix2[14] = controls[i].translate.z;
        tempModelMatrix2[15] = 1.0f;*/

        tempModelMatrix = glm::scale(tempModelMatrix, controls[i].scale);
        //cout << controls[i].path << " controls[i].translate " << to_string(controls[i].translate) << endl;
        //cout << controls[i].path << " controls[i].rotation.X " <<  controls[i].rotation.x << endl;
        //cout << controls[i].path << " controls[i].rotation.y " <<  controls[i].rotation.y << endl;
        //cout << controls[i].path << " controls[i].rotation.Z " <<  controls[i].rotation.z << endl;
        //cout << controls[i].path << " controls[i].scale " << to_string(controls[i].scale) << endl;

        string basedir = dirname(controls[i].path);
        for(int j = 0; j < tempMesh.numObjects_; j++){
            //tempMesh.objectInfo_[j].modelMatrix = controls[i].modelMatrix;
            tempMesh.objectInfo_[j].modelMatrix = tempModelMatrix;
            //tempMesh.objectInfo_[j].modelMatrix = make_mat4(tempModelMatrix2);

Answer 1

由于我无法确定您如何存储来自对象的顶点数据，因此我将定义一些简单的内容：

struct Vertex {
    glm::vec3 position;
};

struct Mesh {
    std::vector<Vertex> vertices;
};

现在遍历所有顶点位置并将它们转换为世界坐标：

Mesh originalMesh = loadObjectFromFile("object.file");
Mesh convertedMesh = Mesh();

for (Vertex v : originalMesh.vertices) {
    convertedMesh.push_back(glm::vec3(v.y, v.z, v.x));
}

这里要注意的关键是我们正在进行以下映射：

x = v.y
y = v.z
z = v.x

如果你有其他顶点数据（例如法线，texcoords），请确保它们也被转换。

Answer 2

通过与教授的一些电子邮件修复了问题，并在计算旋转矩阵时出现了一个小错误。我是以相反的方式做的

tempModelMatrix = glm::rotate(tempModelMatrix, radians(controls[i].rotation.x), vec3(1.0, 0.0, 0.0));
tempModelMatrix = glm::rotate(tempModelMatrix, radians(controls[i].rotation.y), vec3(0.0, 1.0, 0.0));
tempModelMatrix = glm::rotate(tempModelMatrix, radians(controls[i].rotation.z), vec3(0.0, 0.0, 1.0));

而不是

tempModelMatrix = glm::rotate(tempModelMatrix, radians(controls[i].rotation.z), vec3(0.0, 0.0, 1.0));
tempModelMatrix = glm::rotate(tempModelMatrix, radians(controls[i].rotation.y), vec3(0.0, 1.0, 0.0));
tempModelMatrix = glm::rotate(tempModelMatrix, radians(controls[i].rotation.x), vec3(1.0, 0.0, 0.0));

感谢@Exide的建议

将矢量从Y向Z翻转时的旋转

2 个答案: