Creating WebGL buffers using three_d::Context methods

[BladeTransformerLLC]

Hi there! I need to create a WebGL buffer without using eg. three_d::core::buffer::VertexBuffer.

let gl: Context = window.gl();

let program = Program::from_source(
    &gl,
    include_str!("triangle.vert"),
    include_str!("triangle.frag"),
)
.unwrap();

let index_buffer = gl.create_buffer().unwrap();
let a_index = gl.get_attrib_location(program, "index").unwrap();

But gl.get_attrib_location() returns an error: expected WebProgramKey, found Program. What should I do?

Thanks.

[asny]

Sorry for the late reply. What exactly are you trying to achieve? 🤔 Why do you want to use a three-d Program together with a GL vertex buffer? Right now that's not possible, however, it would be simple to add a method to Program similar to use_raw_texture but it requires a good reason.

[BladeTransformerLLC]

Nevermind. I now use context::Program instead of core::Program so that I can create buffers more flexibly for my 3D Gaussian Splatting renderer.
https://github.com/BladeTransformerLLC/gauzilla

[asny]

I'm kind of curious, what flexibility did you need related to vertex buffers?
What are you using three-d for then, couldn't you just use glow?

[BladeTransformerLLC]

I wanted to use three-d mainly because it integrates egui nicely even for WASM + WebGL (which is my primary target platform).

Re vertex buffers, I needed more granular control:

let triangle_vertices = &mut [ // quad
    -1_f32, -1.0,
    1.0, -1.0,
    1.0, 1.0,
    -1.0, 1.0,
];
triangle_vertices.iter_mut().for_each(|v| *v *= 2.0);
vertex_buffer = Some(gl.create_buffer().unwrap());
log!("main(): vertex_buffer={:?}", vertex_buffer);
gl.bind_buffer(context::ARRAY_BUFFER, vertex_buffer);
gl.buffer_data_u8_slice(context::ARRAY_BUFFER, transmute_slice::<_, u8>(triangle_vertices), context::STATIC_DRAW);
a_position = gl.get_attrib_location(id, "position").unwrap();
log!("main(): a_position={:?}", a_position);
gl.enable_vertex_attrib_array(a_position);
gl.bind_buffer(context::ARRAY_BUFFER, vertex_buffer);
gl.vertex_attrib_pointer_f32(a_position, 2, context::FLOAT, false, 0, 0);

https://github.com/BladeTransformerLLC/gauzilla/blob/main/src/renderer.rs#L165

[asny]

Thanks for the reply. Using three-d for the egui integration makes sense 👍 I don't see that that code is any different from what three-d is doing (which is nice, then I don't have to do any new feature 😆 ), but of course, it's completely up to you if you want to do that yourself 🙂