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Rusty GL

Note: This is a work in progress.

Crate: https://crates.io/crates/rgl

Build Status

Summary

Very thin wrapper over gl-rs, aiming to make code more "rust-like" and safer, while still allowing the control you have with classic OpenGL code.

Current features

  • Vertex buffer objects
  • Vertex array objects
  • Shaders
  • Texture 2D
  • Single-tuple struct such as VAO(GLuint) to enforce correct OpenGL object type is passed in functions

Tuple Struct

Current tuple structs:

  • pub struct VBO(GLuint); for vertex buffer objects
  • pub struct VAO(GLuint); for vertex array objects
  • pub struct GLTexture(GLuint); for texture objects
  • pub struct GLShader(GLuint); for programs/ shader object

These structs have no implemention (assosiated function), they are just there to enforce that the correct OpenGL functions are passed into functions. For example:

let mut vao = gl_gen_vertex_array();
gl_bind_buffer(GLTarget::ArrayBuffer, vao);

would not work, as gl_bind_buffer expects type struct VBO(GLuint), but vao is of type VAO(GLuint).

Roadmap

  • Framebuffer objects
  • More OpenGL functions (Right now there is basically only the minimum!)

Usage

[dependancies]
rgl = "0.2.0"
gl = "0.6.0"

The gl-rs create (gl) is still needed for certain things such as window proc address and types (eg GLuint, GLfloat etc)

Examples

As mentioned above, this crate aims to be a more rust-like alternative to gl-rs.

For example, code from gl-rs such as:

let mut vao = 0;
let mut vbo = 0;

unsafe {
    // Create Vertex Array Object
    gl::GenVertexArrays(1, &mut vao);
    gl::BindVertexArray(vao);

    // Create a Vertex Buffer Object and copy the vertex data to it
    gl::GenBuffers(1, &mut vbo);
    gl::BindBuffer(gl::ARRAY_BUFFER, vbo);
    gl::BufferData(
        gl::ARRAY_BUFFER,
        (VERTEX_DATA.len() * mem::size_of::<GLfloat>()) as GLsizeiptr,
        mem::transmute(&VERTEX_DATA[0]),
        gl::STATIC_DRAW,
    );
    gl::EnableVertexAttribArray(0);
    gl::VertexAttribPointer(
        0,
        2,
        gl::FLOAT,
        gl::FALSE as GLboolean,
        0,
        ptr::null(),
    );
}

Is instead written like

    //Create a vertex array object and a vertex buffer object
    let mut vao = rgl::gen_vertex_array();
    let mut vbo = rgl::gen_buffer();

    //Generate and bind the VAO
    rgl::gl_bind_vertex_array(vao);

    //Generate and bind the VBO
    rgl::gl_bind_buffer(rgl::Target::ArrayBuffer, vbo);

    //Buffer the vertex data and tell OpenGL the structure
    rgl::buffer_data(rgl::Target::ArrayBuffer, &VERTEX_DATA, rgl::Usage::StaticDraw);
    rgl::enable_vertex_attrib_array(0);
    rgl::vertex_attrib_pointer(0, 2, rgl::Type::Float, false, 0);

Changes include:

  • snake_case over PascalCase for function names
  • rgl crate
  • No need for the unsafe {...} blocks
  • Strongly typed enums over the error-prone GLenum (Where you can easily pass the incorrect enum)
  • No need to cast types to std::os::raw::c_void, rusty-gl will do this for you
  • No need to cast string to std::ffi::CString, rusty-gl will do this for you

More examples

Examples on using this crate can be found in the examples folder: https://github.com/Hopson97/rusty-gl/tree/master/Examples

Run the examples with cargo run.