Come up with a better way to pass strings into the bindings.

[floooh]

This doesn't look very nice:

 let window_title = b"mrt\0".as_ptr() as _;

If that's the only way to define a C string in Rust then maybe it would make sense to create 2 structs in the bindings, one internal struct with C compatible types, and a separate public struct with 'Rust-y' types. The wrapper function would then create a temporary C-compatible struct, copy the values from the public struct over and do any type conversion.

[floooh]

...look at imgui-rs for inspiration:

https://github.com/imgui-rs/imgui-rs/blob/main/imgui/src/string.rs

...sokol-rust can probably be easier it can temp-allocate before the C function is called, and free right after, because the sokol headers copy the data internally if needed.

[EriKWDev]

Yes. I partially did this for functions that took a string as a parameter.

These functions will have a &str as signature and than inside the function temporarily allocate a CString and pass it to the ffi functions.

The reason I didn't do this for the structs (such as where the window title is needed^) was that it would become a bit more complicated since we would have to do this in all functions that take a struct that holds a string. This is of course possible but was a bit more bookkeeping than I was willing to think about for the initial bindings xP

[waywardmonkeys]

In #25, Floh commented:

Thanks!

Btw, I noticed that Rust 1.77 has proper C string literals now via c"Hello World", but simply plugging those in doesn't work, because those literals resolve to &CStr, while the current sokol-rust bindings currently use a c_char pointer (*const core::ffi::c_char).

Since you have more Rust experience than me, do you know if allowing something like this would be an 'easy fix'?

    sapp::run(&sapp::Desc {
        // ...
        window_title: c"Hello World",
        // ...
        ..Default::default()
    });

...instead of the currently very awkward:

    sapp::run(&sapp::Desc {
        // ...
        window_title: b"clear\0".as_ptr() as _;
        // ...
        ..Default::default()
    });

I've been using this syntax in other crates and it is very nice.

Trying this out in this repo, this compiles and runs on macOS:

--- a/examples/cube/shader.rs
+++ b/examples/cube/shader.rs
@@ -342,42 +342,42 @@ pub fn cube_shader_desc(backend: sg::Backend) -> sg::ShaderDesc {
     let mut desc = sg::ShaderDesc::new();
     match backend {
         sg::Backend::Glcore33 => {
-            desc.attrs[0].name = b"position\0".as_ptr() as *const _;
-            desc.attrs[1].name = b"color0\0".as_ptr() as *const _;
+            desc.attrs[0].name = c"position".as_ptr();
+            desc.attrs[1].name = c"color0".as_ptr();
             desc.vs.source = &VS_SOURCE_GLSL330 as *const _ as *const _;
-            desc.vs.entry = b"main\0".as_ptr() as *const _;
+            desc.vs.entry = c"main".as_ptr();
             desc.vs.uniform_blocks[0].size = 64;
             desc.vs.uniform_blocks[0].layout = sg::UniformLayout::Std140;
-            desc.vs.uniform_blocks[0].uniforms[0].name = b"vs_params\0".as_ptr() as *const _;
+            desc.vs.uniform_blocks[0].uniforms[0].name = c"vs_params".as_ptr();
             desc.vs.uniform_blocks[0].uniforms[0]._type = sg::UniformType::Float4;
             desc.vs.uniform_blocks[0].uniforms[0].array_count = 4;
             desc.fs.source = &FS_SOURCE_GLSL330 as *const _ as *const _;
-            desc.fs.entry = b"main\0".as_ptr() as *const _;
-            desc.label = b"cube_shader\0".as_ptr() as *const _;
+            desc.fs.entry = c"main".as_ptr();
+            desc.label = c"cube_shader".as_ptr();
         },
         sg::Backend::D3d11 => {
-            desc.attrs[0].sem_name = b"TEXCOORD\0".as_ptr() as *const _;
+            desc.attrs[0].sem_name = c"TEXCOORD".as_ptr();
             desc.attrs[0].sem_index = 0;
-            desc.attrs[1].sem_name = b"TEXCOORD\0".as_ptr() as *const _;
+            desc.attrs[1].sem_name = c"TEXCOORD".as_ptr();
             desc.attrs[1].sem_index = 1;
             desc.vs.source = &VS_SOURCE_HLSL4 as *const _ as *const _;
-            desc.vs.d3d11_target = b"vs_4_0\0".as_ptr() as *const _;
-            desc.vs.entry = b"main\0".as_ptr() as *const _;
+            desc.vs.d3d11_target = c"vs_4_0".as_ptr();
+            desc.vs.entry = c"main".as_ptr();
             desc.vs.uniform_blocks[0].size = 64;
             desc.vs.uniform_blocks[0].layout = sg::UniformLayout::Std140;
             desc.fs.source = &FS_SOURCE_HLSL4 as *const _ as *const _;
-            desc.fs.d3d11_target = b"ps_4_0\0".as_ptr() as *const _;
-            desc.fs.entry = b"main\0".as_ptr() as *const _;
-            desc.label = b"cube_shader\0".as_ptr() as *const _;
+            desc.fs.d3d11_target = c"ps_4_0".as_ptr();
+            desc.fs.entry = c"main".as_ptr();
+            desc.label = c"cube_shader".as_ptr();
         },
         sg::Backend::MetalMacos => {
             desc.vs.source = &VS_SOURCE_METAL_MACOS as *const _ as *const _;
-            desc.vs.entry = b"main0\0".as_ptr() as *const _;
+            desc.vs.entry = c"main0".as_ptr();
             desc.vs.uniform_blocks[0].size = 64;
             desc.vs.uniform_blocks[0].layout = sg::UniformLayout::Std140;
             desc.fs.source = &FS_SOURCE_METAL_MACOS as *const _ as *const _;
-            desc.fs.entry = b"main0\0".as_ptr() as *const _;
-            desc.label = b"cube_shader\0".as_ptr() as *const _;
+            desc.fs.entry = c"main0".as_ptr();
+            desc.label = c"cube_shader".as_ptr();
         },
         _ => {},
     }

[waywardmonkeys]

So if you want, I can do this across the repo and submit a PR.

[floooh]

Ah I see, so the new form would be c"bla".as_ptr();, yeah, looks good! (PS: for later I wonder if we can also get rid of the .as_ptr()... hmm)

If you want to provide a PR to fix the examples, please don't bother with the shader.rs files since those are code-generated via sokol-shdc anyway. But a fix for the actual example sources would be much appreciated :)

I'm currently working on sokol-shdc in a branch anyway and will integrate the change there as a 'drive-by fix', and then convert the shader.rs files in the sokol-rust repo once that PR is merged (might take a little while, since the actual reason for the PR is storage-buffer support).

[waywardmonkeys]

Already did the shader files ... just 2 search / replace functions. :)

I'll finish up and submit the PR tomorrow though as it is late here (and should also update docs to say that the samples require Rust 1.77).