There are several tutorials which use the J3DI.js and J3DIMath.js libraries, for example: Tutorial - WebGL Public Wiki

There are problems I found (with some help) with this library. I’m not sure where I should be posting these bugs so I’ll put them here:

In J3DIMath.js in J3DIMatrix4.prototype.lookat() the following code:

```
matrix.$matrix.m11 = xx;
matrix.$matrix.m12 = xy;
matrix.$matrix.m13 = xz;
matrix.$matrix.m14 = 0;
matrix.$matrix.m21 = yx;
matrix.$matrix.m22 = yy;
matrix.$matrix.m23 = yz;
matrix.$matrix.m24 = 0;
matrix.$matrix.m31 = zx;
matrix.$matrix.m32 = zy;
matrix.$matrix.m33 = zz;
matrix.$matrix.m34 = 0;
```

must be changed to:

```
matrix.$matrix.m11 = xx;
matrix.$matrix.m12 = yx;
matrix.$matrix.m13 = zx;
matrix.$matrix.m14 = 0;
matrix.$matrix.m21 = xy;
matrix.$matrix.m22 = yy;
matrix.$matrix.m23 = zy;
matrix.$matrix.m24 = 0;
matrix.$matrix.m31 = xz;
matrix.$matrix.m32 = yz;
matrix.$matrix.m33 = zz;
matrix.$matrix.m34 = 0;
```

In J3DIVector3.prototype.cross(), J3DIVector3.prototype.combine() and probably others, variables are used after they are changed when temporary values should be used to store the original values.

I’m posting this here because it has wasted a lot of my time trying to find the problem. If anyone knows where these should go, let me know. Hope it helps someone.