Merge pull request #44 from Gekkio/feature/gfx-renderer

gfx 0.16 support and renderer implementation

.travis.yml

@@ -5,7 +5,7 @@ rust:
   - stable
   - beta
   - nightly
-  - 1.15.1
+  - 1.16.0
 os:
   - linux
   - osx
@@ -18,8 +18,5 @@ before_install:
   - git submodule update --init --recursive
 
 script:
-  # 1.15 doesn't yet support cargo build --all
-  - cd imgui-sys && cargo build --verbose && cd ..
-  - cd imgui-glium-renderer && cargo build --verbose && cd ..
-  - cargo build --verbose
+  - cargo build --all --verbose
   - cargo test --all --verbose

CHANGELOG.markdown

@@ -5,6 +5,8 @@
 ### Added
 
 - ImString owned type for strings
+- Experimental support for gfx-rs in imgui-sys
+- Experimental renderer for gfx-rs
 
 ### Changed
 
@@ -32,6 +34,8 @@
 - Support for 2-4 -element float sliders
 - `ImVec4::zero()`
 - `Into` array and tuple conversions for ImVec2 and ImVec4
+- gfx 0.15 support in imgui-sys
+- gfx 0.15 renderer implementation
 
 ### Changed
 

Cargo.toml

@@ -16,4 +16,4 @@ travis-ci = { repository = "gekkio/imgui-rs" }
 imgui-sys = { version = "0.0.14-pre", path = "imgui-sys" }
 
 [workspace]
-members = ["imgui-examples", "imgui-sys", "imgui-glium-renderer"]
+members = ["imgui-examples", "imgui-sys", "imgui-gfx-renderer", "imgui-glium-renderer"]

README.markdown

@@ -2,7 +2,7 @@
 
 **Still fairly experimental!**
 
-Minimum Rust version: 1.15
+Minimum Rust version: 1.16
 
 [![Build Status](https://travis-ci.org/Gekkio/imgui-rs.svg?branch=master)](https://travis-ci.org/Gekkio/imgui-rs)
 [![Latest release on crates.io](https://meritbadge.herokuapp.com/imgui)](https://crates.io/crates/imgui)

imgui-examples/Cargo.toml

@@ -9,7 +9,11 @@ license = "MIT/Apache-2.0"
 publish = false
 
 [dev-dependencies]
+gfx = "0.16"
+gfx_window_glutin = "0.16"
 glium = { version = "0.16", default-features = true }
+glutin = "0.8"
 imgui = { version = "0.0.14-pre", path = "../" }
+imgui-gfx-renderer = { version = "0.0.14-pre", path = "../imgui-gfx-renderer" }
 imgui-glium-renderer = { version = "0.0.14-pre", path = "../imgui-glium-renderer" }
-imgui-sys = { version = "0.0.14-pre", path = "../imgui-sys", features = ["glium"] }
+imgui-sys = { version = "0.0.14-pre", path = "../imgui-sys", features = ["gfx", "glium"] }

imgui-examples/examples/hello_gfx.rs

@@ -0,0 +1,28 @@
+extern crate gfx;
+extern crate gfx_window_glutin;
+extern crate glutin;
+#[macro_use]
+extern crate imgui;
+extern crate imgui_gfx_renderer;
+
+use imgui::*;
+
+mod support_gfx;
+
+const CLEAR_COLOR: [f32; 4] = [1.0, 1.0, 1.0, 1.0];
+
+fn main() {
+    support_gfx::run("hello_gfx.rs".to_owned(), CLEAR_COLOR, hello_world);
+}
+
+fn hello_world<'a>(ui: &Ui<'a>) {
+    ui.window(im_str!("Hello world"))
+        .size((300.0, 100.0), ImGuiSetCond_FirstUseEver)
+        .build(|| {
+            ui.text(im_str!("Hello world!"));
+            ui.text(im_str!("This...is...imgui-rs!"));
+            ui.separator();
+            let mouse_pos = ui.imgui().mouse_pos();
+            ui.text(im_str!("Mouse Position: ({:.1},{:.1})", mouse_pos.0, mouse_pos.1));
+        })
+}

imgui-examples/examples/support_gfx/mod.rs

@@ -0,0 +1,161 @@
+use gfx;
+use gfx::Device;
+use gfx_window_glutin;
+use glutin;
+use glutin::{ElementState, MouseButton, MouseScrollDelta, VirtualKeyCode, TouchPhase, WindowEvent};
+use imgui::{ImGui, Ui, ImGuiKey};
+use imgui_gfx_renderer::Renderer;
+use std::time::Instant;
+
+type ColorFormat = gfx::format::Rgba8;
+type DepthFormat = gfx::format::DepthStencil;
+
+#[derive(Copy, Clone, PartialEq, Debug, Default)]
+struct MouseState {
+    pos: (i32, i32),
+    pressed: (bool, bool, bool),
+    wheel: f32
+}
+
+pub fn run<F: FnMut(&Ui)>(title: String, clear_color: [f32; 4], mut run_ui: F) {
+    let mut imgui = ImGui::init();
+
+    let events_loop = glutin::EventsLoop::new();
+    let builder = glutin::WindowBuilder::new()
+        .with_title(title)
+        .with_dimensions(1024, 768)
+        .with_vsync();
+    let (window, mut device, mut factory, mut main_color, mut main_depth) =
+        gfx_window_glutin::init::<ColorFormat, DepthFormat>(builder, &events_loop);
+    let mut encoder: gfx::Encoder<_, _> = factory.create_command_buffer().into();
+    let mut renderer = Renderer::init(&mut imgui, &mut factory, main_color.clone())
+        .expect("Failed to initialize renderer");
+
+    configure_keys(&mut imgui);
+
+    let mut last_frame = Instant::now();
+    let mut mouse_state = MouseState::default();
+    let mut quit = false;
+
+    loop {
+        events_loop.poll_events(|glutin::Event::WindowEvent{event, ..}| {
+            match event {
+                WindowEvent::Resized(_, _) => {
+                    gfx_window_glutin::update_views(&window, &mut main_color, &mut main_depth);
+                    renderer.update_render_target(main_color.clone());
+                }
+                WindowEvent::Closed => quit = true,
+                WindowEvent::KeyboardInput(state, _, code, _) => {
+                    let pressed = state == ElementState::Pressed;
+                    match code {
+                        Some(VirtualKeyCode::Tab) => imgui.set_key(0, pressed),
+                        Some(VirtualKeyCode::Left) => imgui.set_key(1, pressed),
+                        Some(VirtualKeyCode::Right) => imgui.set_key(2, pressed),
+                        Some(VirtualKeyCode::Up) => imgui.set_key(3, pressed),
+                        Some(VirtualKeyCode::Down) => imgui.set_key(4, pressed),
+                        Some(VirtualKeyCode::PageUp) => imgui.set_key(5, pressed),
+                        Some(VirtualKeyCode::PageDown) => imgui.set_key(6, pressed),
+                        Some(VirtualKeyCode::Home) => imgui.set_key(7, pressed),
+                        Some(VirtualKeyCode::End) => imgui.set_key(8, pressed),
+                        Some(VirtualKeyCode::Delete) => imgui.set_key(9, pressed),
+                        Some(VirtualKeyCode::Back) => imgui.set_key(10, pressed),
+                        Some(VirtualKeyCode::Return) => imgui.set_key(11, pressed),
+                        Some(VirtualKeyCode::Escape) => quit = true,
+                        Some(VirtualKeyCode::A) => imgui.set_key(13, pressed),
+                        Some(VirtualKeyCode::C) => imgui.set_key(14, pressed),
+                        Some(VirtualKeyCode::V) => imgui.set_key(15, pressed),
+                        Some(VirtualKeyCode::X) => imgui.set_key(16, pressed),
+                        Some(VirtualKeyCode::Y) => imgui.set_key(17, pressed),
+                        Some(VirtualKeyCode::Z) => imgui.set_key(18, pressed),
+                        Some(VirtualKeyCode::LControl) |
+                        Some(VirtualKeyCode::RControl) => imgui.set_key_ctrl(pressed),
+                        Some(VirtualKeyCode::LShift) |
+                        Some(VirtualKeyCode::RShift) => imgui.set_key_shift(pressed),
+                        Some(VirtualKeyCode::LAlt) |
+                        Some(VirtualKeyCode::RAlt) => imgui.set_key_alt(pressed),
+                        Some(VirtualKeyCode::LWin) |
+                        Some(VirtualKeyCode::RWin) => imgui.set_key_super(pressed),
+                        _ => {}
+                    }
+                }
+                WindowEvent::MouseMoved(x, y) => mouse_state.pos = (x, y),
+                WindowEvent::MouseInput(state, MouseButton::Left) => {
+                    mouse_state.pressed.0 = state == ElementState::Pressed
+                }
+                WindowEvent::MouseInput(state, MouseButton::Right) => {
+                    mouse_state.pressed.1 = state == ElementState::Pressed
+                }
+                WindowEvent::MouseInput(state, MouseButton::Middle) => {
+                    mouse_state.pressed.2 = state == ElementState::Pressed
+                }
+                WindowEvent::MouseWheel(MouseScrollDelta::LineDelta(_, y), TouchPhase::Moved) => {
+                    mouse_state.wheel = y
+                }
+                WindowEvent::MouseWheel(MouseScrollDelta::PixelDelta(_, y), TouchPhase::Moved) => {
+                    mouse_state.wheel = y
+                }
+                WindowEvent::ReceivedCharacter(c) => imgui.add_input_character(c),
+                _ => ()
+            }
+        });
+
+        let now = Instant::now();
+        let delta = now - last_frame;
+        let delta_s = delta.as_secs() as f32 + delta.subsec_nanos() as f32 / 1_000_000_000.0;
+        last_frame = now;
+
+        update_mouse(&mut imgui, &mut mouse_state);
+
+        let size_points = window.get_inner_size_points().unwrap();
+        let size_pixels = window.get_inner_size_pixels().unwrap();
+
+        let ui = imgui.frame(size_points, size_pixels, delta_s);
+
+        run_ui(&ui);
+
+        encoder.clear(&mut main_color, clear_color);
+
+        renderer.render(ui, &mut factory, &mut encoder)
+            .expect("Rendering failed");
+        encoder.flush(&mut device);
+        window.swap_buffers().unwrap();
+        device.cleanup();
+
+        if quit { break }
+    };
+}
+
+fn configure_keys(imgui: &mut ImGui) {
+    imgui.set_imgui_key(ImGuiKey::Tab, 0);
+    imgui.set_imgui_key(ImGuiKey::LeftArrow, 1);
+    imgui.set_imgui_key(ImGuiKey::RightArrow, 2);
+    imgui.set_imgui_key(ImGuiKey::UpArrow, 3);
+    imgui.set_imgui_key(ImGuiKey::DownArrow, 4);
+    imgui.set_imgui_key(ImGuiKey::PageUp, 5);
+    imgui.set_imgui_key(ImGuiKey::PageDown, 6);
+    imgui.set_imgui_key(ImGuiKey::Home, 7);
+    imgui.set_imgui_key(ImGuiKey::End, 8);
+    imgui.set_imgui_key(ImGuiKey::Delete, 9);
+    imgui.set_imgui_key(ImGuiKey::Backspace, 10);
+    imgui.set_imgui_key(ImGuiKey::Enter, 11);
+    imgui.set_imgui_key(ImGuiKey::Escape, 12);
+    imgui.set_imgui_key(ImGuiKey::A, 13);
+    imgui.set_imgui_key(ImGuiKey::C, 14);
+    imgui.set_imgui_key(ImGuiKey::V, 15);
+    imgui.set_imgui_key(ImGuiKey::X, 16);
+    imgui.set_imgui_key(ImGuiKey::Y, 17);
+    imgui.set_imgui_key(ImGuiKey::Z, 18);
+}
+
+fn update_mouse(imgui: &mut ImGui, mouse_state: &mut MouseState) {
+    let scale = imgui.display_framebuffer_scale();
+    imgui.set_mouse_pos(mouse_state.pos.0 as f32 / scale.0,
+                        mouse_state.pos.1 as f32 / scale.1);
+    imgui.set_mouse_down(&[mouse_state.pressed.0,
+                              mouse_state.pressed.1,
+                              mouse_state.pressed.2,
+                              false,
+                              false]);
+    imgui.set_mouse_wheel(mouse_state.wheel / scale.1);
+    mouse_state.wheel = 0.0;
+}

imgui-gfx-renderer/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "imgui-gfx-renderer"
+version = "0.0.14-pre"
+authors = ["Joonas Javanainen <joonas.javanainen@gmail.com>", "imgui-rs contributors"]
+description = "gfx renderer for the imgui crate"
+homepage = "https://github.com/gekkio/imgui-rs"
+repository = "https://github.com/gekkio/imgui-rs"
+license = "MIT/Apache-2.0"
+categories = ["gui", "rendering"]
+
+[dependencies]
+gfx = "0.16"
+imgui = { version = "0.0.14-pre", path = "../" }
+imgui-sys = { version = "0.0.14-pre", path = "../imgui-sys", features = ["gfx"] }

imgui-gfx-renderer/src/lib.rs

@@ -0,0 +1,173 @@
+#[macro_use]
+extern crate gfx;
+extern crate imgui;
+
+use gfx::{Bind, Bundle, CommandBuffer, Encoder, Factory, IntoIndexBuffer, Rect, Resources, Slice};
+use gfx::handle::{Buffer, RenderTargetView};
+use gfx::traits::FactoryExt;
+use imgui::{DrawList, ImDrawIdx, ImDrawVert, ImGui, Ui};
+
+pub type RendererResult<T> = Result<T, RendererError>;
+
+#[derive(Clone, Debug)]
+pub enum RendererError {
+    Update(gfx::UpdateError<usize>),
+    Buffer(gfx::buffer::CreationError),
+    Pipeline(gfx::PipelineStateError<String>),
+    Combined(gfx::CombinedError)
+}
+
+impl From<gfx::UpdateError<usize>> for RendererError {
+    fn from(e: gfx::UpdateError<usize>) -> RendererError { RendererError::Update(e) }
+}
+
+impl From<gfx::buffer::CreationError> for RendererError {
+    fn from(e: gfx::buffer::CreationError) -> RendererError { RendererError::Buffer(e) }
+}
+
+impl From<gfx::PipelineStateError<String>> for RendererError {
+    fn from(e: gfx::PipelineStateError<String>) -> RendererError { RendererError::Pipeline(e) }
+}
+
+impl From<gfx::CombinedError> for RendererError {
+    fn from(e: gfx::CombinedError) -> RendererError { RendererError::Combined(e) }
+}
+
+gfx_defines!{
+    pipeline pipe {
+        vertex_buffer: gfx::VertexBuffer<ImDrawVert> = (),
+        matrix: gfx::Global<[[f32; 4]; 4]> = "matrix",
+        tex: gfx::TextureSampler<[f32; 4]> = "tex",
+        out: gfx::BlendTarget<gfx::format::Rgba8> = ("Target0", gfx::state::MASK_ALL, gfx::preset::blend::ALPHA),
+        scissor: gfx::Scissor = (),
+    }
+}
+
+pub struct Renderer<R: Resources> {
+    bundle: Bundle<R, pipe::Data<R>>,
+    index_buffer: Buffer<R, u16>,
+}
+
+impl<R: Resources> Renderer<R> {
+    pub fn init<F: Factory<R>>(imgui: &mut ImGui,
+                               factory: &mut F,
+                               out: RenderTargetView<R, gfx::format::Rgba8>)
+                               -> RendererResult<Renderer<R>> {
+        let pso = factory.create_pipeline_simple(include_bytes!("shader/vert_110.glsl"),
+                                    include_bytes!("shader/frag_110.glsl"),
+                                    pipe::new())?;
+        let vertex_buffer = factory.create_buffer::<ImDrawVert>(256,
+                                         gfx::buffer::Role::Vertex,
+                                         gfx::memory::Usage::Dynamic,
+                                         Bind::empty())?;
+        let index_buffer = factory.create_buffer::<ImDrawIdx>(256,
+                                        gfx::buffer::Role::Index,
+                                        gfx::memory::Usage::Dynamic,
+                                        Bind::empty())?;
+        let (_, texture) = imgui.prepare_texture(|handle| {
+            factory.create_texture_immutable_u8::<gfx::format::Rgba8>(gfx::texture::Kind::D2(handle.width as u16, handle.height as u16, gfx::texture::AaMode::Single), &[handle.pixels])
+        })?;
+        // TODO: set texture id in imgui
+        let sampler = factory.create_sampler_linear();
+        let data = pipe::Data {
+            vertex_buffer: vertex_buffer,
+            matrix: [[0.0, 0.0, 0.0, 0.0],
+                     [0.0, 0.0, 0.0, 0.0],
+                     [0.0, 0.0, -1.0, 0.0],
+                     [-1.0, 1.0, 0.0, 1.0]],
+            tex: (texture, sampler),
+            out: out,
+            scissor: Rect {
+                x: 0,
+                y: 0,
+                w: 0,
+                h: 0,
+            },
+        };
+        let slice = Slice {
+            start: 0,
+            end: 0,
+            base_vertex: 0,
+            instances: None,
+            buffer: index_buffer.clone().into_index_buffer(factory),
+        };
+        Ok(Renderer {
+            bundle: Bundle::new(slice, pso, data),
+            index_buffer: index_buffer,
+        })
+    }
+    pub fn update_render_target(&mut self, out: RenderTargetView<R, gfx::format::Rgba8>) {
+        self.bundle.data.out = out;
+    }
+    pub fn render<'a, F: Factory<R>, C: CommandBuffer<R>>(&mut self,
+                                                          ui: Ui<'a>,
+                                                          factory: &mut F,
+                                                          encoder: &mut Encoder<R, C>)
+                                                          -> RendererResult<()> {
+        let (width, height) = ui.imgui().display_size();
+
+        if width == 0.0 || height == 0.0 {
+            return Ok(());
+        }
+        self.bundle.data.matrix = [[2.0 / width as f32, 0.0, 0.0, 0.0],
+                                   [0.0, -2.0 / height as f32, 0.0, 0.0],
+                                   [0.0, 0.0, -1.0, 0.0],
+                                   [-1.0, 1.0, 0.0, 1.0]];
+
+        ui.render(|ui, draw_list| self.render_draw_list(ui, factory, encoder, draw_list))
+    }
+    fn render_draw_list<'a, F: Factory<R>, C: CommandBuffer<R>>(&mut self,
+                                                                ui: &'a Ui<'a>,
+                                                                factory: &mut F,
+                                                                encoder: &mut Encoder<R, C>,
+                                                                draw_list: DrawList<'a>)
+                                                                -> RendererResult<()> {
+        let (scale_width, scale_height) = ui.imgui().display_framebuffer_scale();
+
+        self.bundle.slice.start = 0;
+        for cmd in draw_list.cmd_buffer {
+            // TODO: check cmd.texture_id
+
+            self.upload_vertex_buffer(factory, encoder, draw_list.vtx_buffer)?;
+            self.upload_index_buffer(factory, encoder, draw_list.idx_buffer)?;
+
+            self.bundle.slice.end = self.bundle.slice.start + cmd.elem_count;
+            self.bundle.data.scissor = Rect {
+                x: (cmd.clip_rect.x * scale_width) as u16,
+                y: (cmd.clip_rect.y * scale_height) as u16,
+                w: ((cmd.clip_rect.z - cmd.clip_rect.x).abs() * scale_width) as u16,
+                h: ((cmd.clip_rect.w - cmd.clip_rect.y).abs() * scale_height) as u16,
+            };
+            self.bundle.encode(encoder);
+            self.bundle.slice.start = self.bundle.slice.end;
+        }
+        Ok(())
+    }
+    fn upload_vertex_buffer<F: Factory<R>, C: CommandBuffer<R>>(&mut self,
+                                                                factory: &mut F,
+                                                                encoder: &mut Encoder<R, C>,
+                                                                vtx_buffer: &[ImDrawVert])
+                                                                -> RendererResult<()> {
+        if self.bundle.data.vertex_buffer.len() < vtx_buffer.len() {
+            self.bundle.data.vertex_buffer = factory.create_buffer::<ImDrawVert>(vtx_buffer.len(),
+                                             gfx::buffer::Role::Vertex,
+                                             gfx::memory::Usage::Dynamic,
+                                             Bind::empty())?;
+        }
+        Ok(encoder.update_buffer(&self.bundle.data.vertex_buffer, vtx_buffer, 0)?)
+    }
+    fn upload_index_buffer<F: Factory<R>, C: CommandBuffer<R>>(&mut self,
+                                                               factory: &mut F,
+                                                               encoder: &mut Encoder<R, C>,
+                                                               idx_buffer: &[ImDrawIdx])
+                                                               -> RendererResult<()> {
+        if self.index_buffer.len() < idx_buffer.len() {
+            self.index_buffer = factory.create_buffer::<ImDrawIdx>(idx_buffer.len(),
+                                            gfx::buffer::Role::Index,
+                                            gfx::memory::Usage::Dynamic,
+                                            Bind::empty())?;
+            self.bundle.slice.buffer = self.index_buffer.clone().into_index_buffer(factory);
+        }
+        Ok(encoder.update_buffer(&self.index_buffer, idx_buffer, 0)?)
+    }
+}

imgui-gfx-renderer/src/shader/frag_110.glsl

@@ -0,0 +1,10 @@
+#version 110
+
+uniform sampler2D tex;
+
+varying vec2 f_uv;
+varying vec4 f_color;
+
+void main() {
+  gl_FragColor = f_color * texture2D(tex, f_uv.st);
+}

imgui-gfx-renderer/src/shader/frag_140.glsl

@@ -0,0 +1,12 @@
+#version 140
+
+uniform sampler2D tex;
+
+in vec2 f_uv;
+in vec4 f_color;
+
+out vec4 Target0;
+
+void main() {
+  Target0 = f_color * texture(tex, f_uv.st);
+}

imgui-gfx-renderer/src/shader/vert_110.glsl

@@ -0,0 +1,16 @@
+#version 110
+
+uniform mat4 matrix;
+
+attribute vec2 pos;
+attribute vec2 uv;
+attribute vec4 col;
+
+varying vec2 f_uv;
+varying vec4 f_color;
+
+void main() {
+  f_uv = uv;
+  f_color = col;
+  gl_Position = matrix * vec4(pos.xy, 0, 1);
+}

imgui-gfx-renderer/src/shader/vert_140.glsl

@@ -0,0 +1,16 @@
+#version 140
+
+uniform mat4 matrix;
+
+in vec2 pos;
+in vec2 uv;
+in vec4 col;
+
+out vec2 f_uv;
+out vec4 f_color;
+
+void main() {
+  f_uv = uv;
+  f_color = col;
+  gl_Position = matrix * vec4(pos.xy, 0, 1);
+}

imgui-sys/Cargo.toml

@@ -12,6 +12,7 @@ build = "build.rs"
 [dependencies]
 bitflags = "0.8"
 glium = { version = "0.16", default-features = false, optional = true }
+gfx = { version = "0.16", optional = true }
 
 [build-dependencies]
 gcc = "0.3"

imgui-sys/src/gfx_support.rs

@@ -0,0 +1,58 @@
+use gfx::format::{Format, Formatted, U8Norm};
+use gfx::pso::buffer::{Element, ElemOffset, Structure};
+use gfx::traits::Pod;
+use std::mem;
+
+use super::{ImDrawVert, ImVec2};
+
+unsafe impl Pod for ImDrawVert {}
+
+impl Structure<Format> for ImDrawVert {
+    fn query(name: &str) -> Option<Element<Format>> {
+        // array query hack from gfx_impl_struct_meta macro
+        let (sub_name, big_offset) = {
+            let mut split = name.split(|c| c == '[' || c == ']');
+            let _ = split.next().unwrap();
+            match split.next() {
+                Some(s) => {
+                    let array_id: ElemOffset = s.parse().unwrap();
+                    let sub_name = match split.next() {
+                        Some(s) if s.starts_with('.') => &s[1..],
+                        _ => name,
+                    };
+                    (sub_name, array_id * (mem::size_of::<ImDrawVert>() as ElemOffset))
+                }
+                None => (name, 0),
+            }
+        };
+        let dummy: &ImDrawVert = unsafe { mem::transmute(0usize) };
+        match sub_name {
+            "pos" => {
+                Some(Element {
+                    format: <ImVec2 as Formatted>::get_format(),
+                    offset: unsafe { mem::transmute::<_, usize>(&dummy.pos) } as ElemOffset +
+                            big_offset,
+                })
+            }
+            "uv" => {
+                Some(Element {
+                    format: <ImVec2 as Formatted>::get_format(),
+                    offset: unsafe { mem::transmute::<_, usize>(&dummy.uv) } as ElemOffset +
+                            big_offset,
+                })
+            }
+            "col" => {
+                Some(Element {
+                    format: <[U8Norm; 4] as Formatted>::get_format(),
+                    offset: unsafe { mem::transmute::<_, usize>(&dummy.col) } as ElemOffset +
+                            big_offset,
+                })
+            }
+            _ => None,
+        }
+    }
+}
+
+gfx_format! {
+    ImVec2: R32_G32 = Vec2<Float>
+}

imgui-sys/src/glium_support.rs

@@ -1,7 +1,7 @@
 use glium::vertex::{Attribute, AttributeType, Vertex, VertexFormat};
 use std::borrow::Cow;
 use std::mem;
-use std::os::raw::{c_float};
+use std::os::raw::c_float;
 
 use super::{ImDrawVert, ImVec2, ImVec4};
 

imgui-sys/src/lib.rs

@@ -3,6 +3,10 @@
 #[macro_use]
 extern crate bitflags;
 
+#[cfg(feature = "gfx")]
+#[macro_use]
+extern crate gfx;
+
 #[cfg(feature = "glium")]
 extern crate glium;
 
@@ -11,6 +15,9 @@ use std::mem;
 use std::os::raw::{c_char, c_float, c_int, c_short, c_uchar, c_uint, c_ushort, c_void};
 use std::slice;
 
+#[cfg(feature = "gfx")]
+mod gfx_support;
+
 #[cfg(feature = "glium")]
 mod glium_support;