Initial gfx support in imgui-sys

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 = "0.14", 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;