如何在C ++中乘以4x4浮点矩阵?

时间:2017-12-02 22:48:13

标签: c++ math matrix-multiplication

我有一个简单的结构" mat4",由 float [4] [4] 和一个 * = 函数组成,用于乘以4x4矩阵。它需要一个const mat4& "的 RHS "如下:

this->m[0][0] = this->m[0][0] * rhs[0][0] + this->m[0][1] * rhs[1][0] + this->m[0][2] * rhs[2][0] + this->m[0][3] * rhs[3][0];
this->m[0][1] = this->m[0][0] * rhs[0][1] + this->m[0][1] * rhs[1][1] + this->m[0][2] * rhs[2][1] + this->m[0][3] * rhs[3][1];
this->m[0][2] = this->m[0][0] * rhs[0][2] + this->m[0][1] * rhs[1][2] + this->m[0][2] * rhs[2][2] + this->m[0][3] * rhs[3][2];
this->m[0][3] = this->m[0][0] * rhs[0][3] + this->m[0][1] * rhs[1][3] + this->m[0][2] * rhs[2][3] + this->m[0][3] * rhs[3][3];

this->m[1][0] = this->m[1][0] * rhs[0][0] + this->m[1][1] * rhs[1][0] + this->m[1][2] * rhs[2][0] + this->m[1][3] * rhs[3][0];
this->m[1][1] = this->m[1][0] * rhs[0][1] + this->m[1][1] * rhs[1][1] + this->m[1][2] * rhs[2][1] + this->m[1][3] * rhs[3][1];
this->m[1][2] = this->m[1][0] * rhs[0][2] + this->m[1][1] * rhs[1][2] + this->m[1][2] * rhs[2][2] + this->m[1][3] * rhs[3][2];
this->m[1][3] = this->m[1][0] * rhs[0][3] + this->m[1][1] * rhs[1][3] + this->m[1][2] * rhs[2][3] + this->m[1][3] * rhs[3][3];

this->m[2][0] = this->m[2][0] * rhs[0][0] + this->m[2][1] * rhs[1][0] + this->m[2][2] * rhs[2][0] + this->m[2][3] * rhs[3][0];
this->m[2][1] = this->m[2][0] * rhs[0][1] + this->m[2][1] * rhs[1][1] + this->m[2][2] * rhs[2][1] + this->m[2][3] * rhs[3][1];
this->m[2][2] = this->m[2][0] * rhs[0][2] + this->m[2][1] * rhs[1][2] + this->m[2][2] * rhs[2][2] + this->m[2][3] * rhs[3][2];
this->m[2][3] = this->m[2][0] * rhs[0][3] + this->m[2][1] * rhs[1][3] + this->m[2][2] * rhs[2][3] + this->m[2][3] * rhs[3][3];

this->m[3][0] = this->m[3][0] * rhs[0][0] + this->m[3][1] * rhs[1][0] + this->m[3][2] * rhs[2][0] + this->m[3][3] * rhs[3][0];
this->m[3][1] = this->m[3][0] * rhs[0][1] + this->m[3][1] * rhs[1][1] + this->m[3][2] * rhs[2][1] + this->m[3][3] * rhs[3][1];
this->m[3][2] = this->m[3][0] * rhs[0][2] + this->m[3][1] * rhs[1][2] + this->m[3][2] * rhs[2][2] + this->m[3][3] * rhs[3][2];
this->m[3][3] = this->m[3][0] * rhs[0][3] + this->m[3][1] * rhs[1][3] + this->m[3][2] * rhs[2][3] + this->m[3][3] * rhs[3][3];

我只想确认它是否正确 - 当我在C ++ (投影*视图矩阵)中将两个矩阵相乘并将结果矩阵提供给着色器时,我什么也得不到屏幕显示。

但如果我给出着色器投影&单独查看矩阵,并将它们乘以GLSL 中的 - 然后一切正常,结果如预期。

那么矩阵乘法函数一定有问题吗?

1 个答案:

答案 0 :(得分:0)

应该不是

this->m[0][1] = this->m[0][0] * rhs[0][1] + this->m[0][1] * rhs[1][1] + this->m[0][2] * rhs[2][1] + this->m[0][3] * rhs[3][1];

乘以rhs [1] [0] .. rhs [1] [3]?当你逐步浏览这些行时,你并没有单步执行rhs列。