I cant find `Glutin` tutorials

tutorials
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I can not seem to find good tutorials for the rust glutin crate, (which is made form opengl) their aren't any docs at there that strike me, the official docs are pretty bad as well.

https://github.com/rust-windowing/glutin

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unfortunately, there's indeed lack good documentation to get start with glutin. personally I feel the documents are written with the assumption that the users are familiar with how to use OpenGL with EGL. the current glutin API is basically modeled after the OpenGL ES + Egl.

in fact, it helps to understand the concepts if you know a little bit of newer APIs like vulkan. in short:

  • first of all, you create a Display, which serves as the connection between your application and the platform, anology is VkInstance with WSI (aka VK_HKR_Surface) extension enabled.

    NOTE: useful methods are defined in the GlDisplay extension trait, which is re-exported from the glutin::prelude namespace, it is recommended to use glutin::prelude::*;, similar extension traits are used for Context, Surface, etc

  • from a Display, you enumerate and select a compatible Config, by supply a ConfigTemplate. you may use Default::default() if you don't have specific requirements, or configure your to suit your needs (e.g. multisampling) using a ConfigTemplateBuilder`, vulkan anology is selecting physical devices by enumerate their properties.

  • create a Surface using the config you selected for each of your windows to be rendered into. it's similar to vulkan VkSurfaceKHR

    alternatively, you can create a surface for offline rendering, e.g. rendering into a pixel map

  • create your Context, anology to VkDevice

  • before rendering, don't forget to set one surface as the current surface; there's no vulkan anology here, as vulkan doesn't have a implicit "current" thingy, you must pass the swapchain image (or other offline image) explictly as render target.

    Tip: if you only have one window surface, you can make it current after create the context and forget about "setting surface as current".

  • render like a pro. you can use any OpenGL loader, such as glium, glow, gl_generator, etc. glutin itself doesn't provide bindings for OpenGL functions, but you might need to use get_proc_address to load the the funciton pointers, e,g, for the glow crate

  • after rendering is done, present the back buffer like old school OpenGL does, but explictly for a specific surface.

hope this helps you get started.

also note, since OpenGL platform integration must be done in a platform specific way by its nature, although glutin provided somewhat abastraction, you still need to consider platform specifc requirements, for instance, on Windows, you must have a RawWindowHandle to create the Display, otherwise, the create_context probably will fail, also the get_proc_address will be useless (it would return NULL for most of the OpenGL function pointers).

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It may be worth considering an alternative API, like the higher-level wgpu crate. Which abstracts over not only OpenGL, but also Vulkan, Metal, and DirectX. It also has quite good learning resources such as Learn Wgpu.

And because it's a higher-level abstraction, you don't have to worry about managing GPU memory and barriers like you do in Vulkan. Even though its API is heavily inspired by Vulkan.

Bevy uses wgpu for rendering, FWIW.

1 Like
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I have thought of using that

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