[1_3_3] Why subtract 1 from the length of the infoLog vector? about learn-opengl-rs

[benridley]

For those who also may be wondering why this occurs, the gist is this:

When we create the vector with a capacity of 1024, we have reserved the memory for 1024 bytes but not populated it yet. We then hand a pointer to the vector to OpenGL, which modifies the underlying data, however Rust has no awareness of this happening yet so it still thinks there is no data in the vector. To tell Rust that there's data, we use set_len (remember that with a vector, capacity and length are two different concepts, where length is the actual quantity of data 'used' in the vector). Now, Rust thinks the vector is full and allows us to use it.

This is of course not the ideal way to do this, it was pointed out to me that we can use the 'log_length' variable to then inform Rust of how long the data in the vec is. So basically defer calling set_len until we have the log_length variable back.