游戏引擎矩阵乘法

Question

我一直在关注 TheChernoProject 关于如何制作游戏引擎的教程，但到目前为止我一直收到一个错误，我似乎无法弄清楚如何解决它。 Here is the link to the episode where I am currently at, my problem starts at 28:40. 我一直收到错误 "Control reaches end of non-void function." 我正在使用 Xcode.

这是mat4.cpp

#include "mat4.h"

namespace engine { namespace maths {

mat4::mat4() {
    for(int i=0;i<4*4;i++) {
        elements[i] = 0.0f;

    }

}

mat4::mat4(float diagonal) {
    for(int i=0;i<4*4;i++) {
        elements[i] = 0.0f;

        elements[0 + 0 * 4] = diagonal;
        elements[1 + 1 * 4] = diagonal;
        elements[2 + 2 * 4] = diagonal;
        elements[3 + 3 * 4] = diagonal;


    }

}

mat4 mat4::identity() {
    return mat4(1.0f);

}

mat4& mat4::multiply(const mat4& other) {
    for(int y=0;y<4;y++) {
        for(int x=0;x<4;x++) {
            float sum = 0.0f;
            for(int e=0;e<4;e++) {
                sum += elements[x + e * 4] * other.elements[e + y * 4];

            }
            elements[x + y * 4] = sum;

        }

    }

}

} }

这是头文件mat4.h

#pragma once

#include "maths.h"

namespace engine { namespace maths {

struct mat4 {
    float elements[4 * 4];

    mat4();
    mat4(float diagonal);

    static mat4 identity();

    mat4& multiply(const mat4& other);
    friend mat4 operator*(mat4 left, const mat4& right);
    mat4& operator*=(const mat4& other);

    static mat4 orthographic(float left, float right, float bottom, float top, float near, float far);
    static mat4 perspective(float fov, float aspectRatio, float near, float far);

    static mat4 translation(const vec3& translation);
    static mat4 rotation(float angle, const vec3& axis);
    static mat4 scale(const vec3& scale);
};

} }

Answer 1

    mat4& mat4::multiply(const mat4& other) {
    for(int y=0;y<4;y++) {
        for(int x=0;x<4;x++) {
            float sum = 0.0f;
            for(int e=0;e<4;e++) {
                sum += elements[x + e * 4] * other.elements[e + y * 4];

            }
            elements[x + y * 4] = sum;

        }

    }

}

return 除了声明为 return mat4&

什么都没有