Convert `const unsigned char` to `[]byte`, not `string`

[makew0rld]

Looking at the raylib cheatsheet, you can see that in many places const char is used for strings, while const unsigned char is used for bytes. But this package converts both of those to Go's string type. This is a problem, because if I load some bytes from a file or memory (maybe to load an image), I need to convert those bytes first with string(bytes). This copies all of the bytes before giving them to the library, because strings are immutable. Copying the bytes is an expensive and useless operation here.

There are ways around the copying, but could you just change the binding, so it converts const unsigned char to []byte? Thanks!

Example function that does this:

Image LoadImageFromMemory(const char *fileType, const unsigned char *fileData, int dataSize);

[chunqian]

OK Let me see how to change I need to review the code in c-for-go project

[chunqian]

@makeworld-the-better-one The slice memory model in go is not the same as the array in c Slice cannot be passed directly into c You can look at func unpackSByte() in cgo_helpers.go

[chunqian]

I have tested Basically, there is no difference in performance with raylib c version But the memory model is different, so there will be inevitably some memory conversions with cgo

[makew0rld]

Ah ok, that's too bad.

There definitely is a performance drop though, because string(bytes) copies all the bytes. For now I will use the function I linked to prevent that copying:

func ByteSlice2String(bs []byte) string {
    return *(*string)(unsafe.Pointer(&bs))
}

[chunqian]

@makeworld-the-better-one raylib-go just not dealing with the memory model So I started a new project The focus is to solve this memory model conversion problem

texture := rl.LoadTexture("../models/resources/cubicmap_atlas.png")
model.Materialser(0).Mapser(rl.MAP_DIFFUSE).Texture = texture

Here the Materialsser Mapser is the manager

[makew0rld]

Ok, thanks.

Another way to solve this might be to create your own type like type RlBytes string, and then provide the function above as a way to convert to that type. And then turn all const unsigned char C code into the RlBytes type. But anyway, I can work around this.

[chunqian]

@makeworld-the-better-one Slice in plain type converts to c without problems Only Slice in struct type converts to c will have go pointer problem I have updated go-raylib

[makew0rld]

Oh great! I can confirm 9be3f7a95814 works with passing []bytes. Thanks for adding this!