glium 0.32.0

Elegant and safe OpenGL wrapper. Glium is an intermediate layer between OpenGL and your application. You still need to manually handle the graphics pipeline, but without having to use OpenGL's old and error-prone API. Its objectives: - Be safe to use. Many aspects of OpenGL that can trigger a crash if misused are automatically handled by glium. - Provide an API that enforces good pratices such as RAII or stateless function calls. - Be compatible with all OpenGL versions that support shaders, providing unified API when things diverge. - Avoid all OpenGL errors beforehand. - Produce optimized OpenGL function calls, and allow the user to easily use modern OpenGL techniques.
Documentation
#![cfg(not(feature = "test_headless"))]

#[macro_use]
extern crate glium;

use glium::{Surface};
use glium::index::PrimitiveType;
use glium::program::{ ShaderStage, is_subroutine_supported };
use glium::backend::Facade;
use glium::DrawError;

mod support;

#[derive(Copy, Clone)]
struct Vertex {
    position: [f32; 2],
}

implement_vertex!(Vertex, position);

#[test]
fn subroutine_bindings_simple() {
    let display = support::build_display();
    if !is_subroutine_supported(display.get_context()) {
        println!("Backend does not support subroutines");
        return
    };

    let program = program!(&display,
        150 => {
            vertex: "
                #version 150

                in vec2 position;

                void main() {
                    gl_Position = vec4(position, 0.0, 1.0);
                }
            ",

            fragment: "
                #version 150
                #extension GL_ARB_shader_subroutine : require

                out vec4 fragColor;
                subroutine vec4 color_t();

                subroutine uniform color_t Color;

                subroutine(color_t)
                vec4 ColorRed()
                {
                  return vec4(1, 0, 0, 1);
                }

                subroutine(color_t)
                vec4 ColorBlue()
                {
                  return vec4(0, 0, 1, 1);
                }

                void main()
                {
                    fragColor = Color();
                }
            "
        },
    ).unwrap();
    let vb = glium::VertexBuffer::new(&display, &[
        Vertex { position: [-1.0,  1.0] }, Vertex { position: [1.0,  1.0] },
        Vertex { position: [-1.0, -1.0] }, Vertex { position: [1.0, -1.0] },
    ]).unwrap();

    let indices = glium::IndexBuffer::new(&display, PrimitiveType::TrianglesList,
                                          &[0u16, 1, 2, 2, 1, 3]).unwrap();

    let texture = support::build_renderable_texture(&display);

    let uniforms = uniform!(
        Color: ("ColorBlue", ShaderStage::Fragment),
    );
    texture.as_surface().clear_color(0.0, 0.0, 0.0, 0.0);
    texture.as_surface().draw(&vb, &indices, &program, &uniforms,
                              &Default::default()).unwrap();

    let data: Vec<Vec<(u8, u8, u8, u8)>> = texture.read();

    assert_eq!(data[0][0], (0, 0, 255, 255));
    assert_eq!(data.last().unwrap().last().unwrap(), &(0, 0, 255, 255));

    display.assert_no_error(None);

    let uniforms = uniform!(
        Color: ("ColorRed", ShaderStage::Fragment),
    );
    texture.as_surface().clear_color(0.0, 0.0, 0.0, 0.0);
    texture.as_surface().draw(&vb, &indices, &program, &uniforms,
                              &Default::default()).unwrap();

    let data: Vec<Vec<(u8, u8, u8, u8)>> = texture.read();

    assert_eq!(data[0][0], (255, 0, 0, 255));
    assert_eq!(data.last().unwrap().last().unwrap(), &(255, 0, 0, 255));

    display.assert_no_error(None);
}

#[test]
fn subroutine_bindings_explicit_location() {
    let display = support::build_display();
    if !is_subroutine_supported(display.get_context()) {
        println!("Backend does not support subroutines");
        return
    };

    let program = program!(&display,
        150 => {
            vertex: "
                #version 150

                in vec2 position;

                void main() {
                    gl_Position = vec4(position, 0.0, 1.0);
                }
            ",

            fragment: "
                #version 150
                #extension GL_ARB_shader_subroutine : require
                #extension GL_ARB_explicit_uniform_location : require
                #extension GL_ARB_explicit_attrib_location : require

                out vec4 fragColor;
                subroutine vec4 color_t();

                layout(location = 5) subroutine uniform color_t Color;

                subroutine(color_t)
                vec4 ColorRed()
                {
                  return vec4(1, 0, 0, 1);
                }

                subroutine(color_t)
                vec4 ColorBlue()
                {
                  return vec4(0, 0, 1, 1);
                }

                void main()
                {
                    fragColor = Color();
                }
            "
        },
    ).unwrap();
    let vb = glium::VertexBuffer::new(&display, &[
        Vertex { position: [-1.0,  1.0] }, Vertex { position: [1.0,  1.0] },
        Vertex { position: [-1.0, -1.0] }, Vertex { position: [1.0, -1.0] },
    ]).unwrap();

    let indices = glium::IndexBuffer::new(&display, PrimitiveType::TrianglesList,
                                          &[0u16, 1, 2, 2, 1, 3]).unwrap();

    let texture = support::build_renderable_texture(&display);

    let uniforms = uniform!(
        Color: ("ColorBlue", ShaderStage::Fragment),
    );
    texture.as_surface().clear_color(0.0, 0.0, 0.0, 0.0);
    texture.as_surface().draw(&vb, &indices, &program, &uniforms,
                              &Default::default()).unwrap();

    let data: Vec<Vec<(u8, u8, u8, u8)>> = texture.read();

    assert_eq!(data[0][0], (0, 0, 255, 255));
    assert_eq!(data.last().unwrap().last().unwrap(), &(0, 0, 255, 255));

    display.assert_no_error(None);

    let uniforms = uniform!(
        Color: ("ColorRed", ShaderStage::Fragment),
    );
    texture.as_surface().clear_color(0.0, 0.0, 0.0, 0.0);
    texture.as_surface().draw(&vb, &indices, &program, &uniforms,
                              &Default::default()).unwrap();

    let data: Vec<Vec<(u8, u8, u8, u8)>> = texture.read();

    assert_eq!(data[0][0], (255, 0, 0, 255));
    assert_eq!(data.last().unwrap().last().unwrap(), &(255, 0, 0, 255));

    display.assert_no_error(None);
}

// Start of more complex tests with multiple uniforms and such.

fn build_program_complex(display: &glium::Display) -> glium::Program {
    let program = program!(display,
        150 => {
            vertex: "
                #version 150

                in vec2 position;

                void main() {
                    gl_Position = vec4(position, 0.0, 1.0);
                }
            ",

            fragment: "
                #version 150
                #extension GL_ARB_shader_subroutine : require

                out vec4 fragColor;
                subroutine vec4 color_t();
                subroutine vec4 modify_t(vec4 color);

                subroutine uniform color_t Color;
                subroutine uniform modify_t Modify;

                subroutine(color_t)
                vec4 ColorRed()
                {
                  return vec4(1, 0, 0, 1);
                }

                subroutine(color_t)
                vec4 ColorBlue()
                {
                  return vec4(0, 0, 1, 1);
                }

                subroutine(modify_t)
                vec4 SwapRB(vec4 color)
                {
                  return vec4(color.b, color.g, color.r, color.a);
                }

                subroutine(modify_t)
                vec4 DeleteR(vec4 color)
                {
                  return vec4(0, color.g, color.b, color.a);
                }

                void main()
                {
                    vec4 color = Color();
                    fragColor = Modify(color);
                }
            "
        },
    ).unwrap();
    program
}

#[test]
fn subroutine_bindings_multi() {
    let display = support::build_display();
    if !is_subroutine_supported(display.get_context()) {
        println!("Backend does not support subroutines");
        return
    };

    let program = build_program_complex(&display);
    let vb = glium::VertexBuffer::new(&display, &[
        Vertex { position: [-1.0,  1.0] }, Vertex { position: [1.0,  1.0] },
        Vertex { position: [-1.0, -1.0] }, Vertex { position: [1.0, -1.0] },
    ]).unwrap();

    let indices = glium::IndexBuffer::new(&display, PrimitiveType::TrianglesList,
                                          &[0u16, 1, 2, 2, 1, 3]).unwrap();

    let texture = support::build_renderable_texture(&display);

    let uniforms = uniform!(
        Color: ("ColorBlue", ShaderStage::Fragment),
        Modify: ("DeleteR", ShaderStage::Fragment),
    );
    texture.as_surface().clear_color(0.0, 0.0, 0.0, 0.0);
    texture.as_surface().draw(&vb, &indices, &program, &uniforms,
                              &Default::default()).unwrap();

    let data: Vec<Vec<(u8, u8, u8, u8)>> = texture.read();

    assert_eq!(data[0][0], (0, 0, 255, 255));
    assert_eq!(data.last().unwrap().last().unwrap(), &(0, 0, 255, 255));

    display.assert_no_error(None);

    let uniforms = uniform!(
        Color: ("ColorRed", ShaderStage::Fragment),
        Modify: ("SwapRB", ShaderStage::Fragment),
    );
    texture.as_surface().clear_color(0.0, 0.0, 0.0, 0.0);
    texture.as_surface().draw(&vb, &indices, &program, &uniforms,
                              &Default::default()).unwrap();

    let data: Vec<Vec<(u8, u8, u8, u8)>> = texture.read();

    assert_eq!(data[0][0], (0, 0, 255, 255));
    assert_eq!(data.last().unwrap().last().unwrap(), &(0, 0, 255, 255));

    display.assert_no_error(None);
}

#[test]
fn not_all_subroutine_uniforms_set() {
    let display = support::build_display();
    if !is_subroutine_supported(display.get_context()) {
        println!("Backend does not support subroutines");
        return
    };

    let program = build_program_complex(&display);
    let vb = glium::VertexBuffer::new(&display, &[
        Vertex { position: [-1.0,  1.0] }, Vertex { position: [1.0,  1.0] },
        Vertex { position: [-1.0, -1.0] }, Vertex { position: [1.0, -1.0] },
    ]).unwrap();

    let indices = glium::IndexBuffer::new(&display, PrimitiveType::TrianglesList,
                                          &[0u16, 1, 2, 2, 1, 3]).unwrap();

    let texture = support::build_renderable_texture(&display);

    let uniforms = uniform!(
        Color: ("ColorBlue", ShaderStage::Fragment),
        // Not setting Modify on purpose
    );
    texture.as_surface().clear_color(0.0, 0.0, 0.0, 0.0);
    match texture.as_surface().draw(&vb, &indices, &program, &uniforms,
                              &Default::default()) {
                                  Err(DrawError::SubroutineUniformMissing{ .. }) => (),
                                  _ => panic!("Drawing should have errored")
                              }

    display.assert_no_error(None);
}

#[test]
fn mismatched_subroutines() {
    let display = support::build_display();
    if !is_subroutine_supported(display.get_context()) {
        println!("Backend does not support subroutines");
        return
    };

    let program = build_program_complex(&display);
    let vb = glium::VertexBuffer::new(&display, &[
        Vertex { position: [-1.0,  1.0] }, Vertex { position: [1.0,  1.0] },
        Vertex { position: [-1.0, -1.0] }, Vertex { position: [1.0, -1.0] },
    ]).unwrap();

    let indices = glium::IndexBuffer::new(&display, PrimitiveType::TrianglesList,
                                          &[0u16, 1, 2, 2, 1, 3]).unwrap();

    let texture = support::build_renderable_texture(&display);

    let uniforms = uniform!(
        Color: ("ColorBlue", ShaderStage::Fragment),
        Modify: ("ColorBlue", ShaderStage::Fragment)
    );
    texture.as_surface().clear_color(0.0, 0.0, 0.0, 0.0);
    match texture.as_surface().draw(&vb, &indices, &program, &uniforms,
                              &Default::default()) {
                                  Err(DrawError::SubroutineNotFound{ .. }) => (),
                                  _ => panic!("Drawing should have errored")
                              }

    display.assert_no_error(None);
}