Add DirectX support behind feature flag

imgui-examples/Cargo.toml

@@ -9,6 +9,11 @@ repository = "https://github.com/Gekkio/imgui-rs"
 license = "MIT/Apache-2.0"
 publish = false
 
+[features]
+opengl = ["imgui-gfx-renderer/opengl"]
+directx = ["imgui-gfx-renderer/directx"]
+default = ["opengl"]
+
 [dev-dependencies]
 gfx = "0.17"
 gfx_window_glutin = "0.28"

imgui-examples/README.md

@@ -0,0 +1,4 @@
+# `imgui-examples`
+
+- Run with OpenGL backend: `cargo run --example hello_gfx`
+- Run with DirectX backend: `cargo run --example hello_gfx --features directx --no-default-features`

imgui-examples/examples/hello_gfx.rs

@@ -5,11 +5,17 @@ mod support_gfx;
 const CLEAR_COLOR: [f32; 4] = [1.0, 1.0, 1.0, 1.0];
 
 fn main() {
-    support_gfx::run_dx11("hello_gfx.rs".to_owned(), CLEAR_COLOR, hello_world);
+    support_gfx::run("hello_gfx.rs".to_owned(), CLEAR_COLOR, hello_world);
 }
 
 fn hello_world<'a>(ui: &Ui<'a>) -> bool {
-    ui.window(im_str!("Hello world"))
+    #[cfg(feature = "opengl")]
+    let window_title = im_str!("Hello world (OpenGL)");
+
+    #[cfg(feature = "directx")]
+    let window_title = im_str!("Hello world (DirectX)");
+
+    ui.window(window_title)
         .size((300.0, 100.0), ImGuiCond::FirstUseEver)
         .build(|| {
             ui.text(im_str!("Hello world!"));

imgui-examples/examples/support_gfx/mod.rs

@@ -3,6 +3,7 @@ use imgui_gfx_renderer::{Renderer, Shaders};
 use imgui_winit_support;
 use std::time::Instant;
 
+#[cfg(feature = "opengl")]
 pub fn run<F: FnMut(&Ui) -> bool>(title: String, clear_color: [f32; 4], mut run_ui: F) {
     use gfx::{self, Device};
     use gfx_window_glutin;
@@ -146,8 +147,8 @@ pub fn run<F: FnMut(&Ui) -> bool>(title: String, clear_color: [f32; 4], mut run_
     }
 }
 
-// #[cfg(windows)]
-pub fn run_dx11<F: FnMut(&Ui) -> bool>(title: String, clear_color: [f32; 4], mut run_ui: F) {
+#[cfg(feature = "directx")]
+pub fn run<F: FnMut(&Ui) -> bool>(title: String, clear_color: [f32; 4], mut run_ui: F) {
     use gfx::{self, Device};
     use gfx_window_dxgi;
     use glutin;

imgui-gfx-renderer/Cargo.toml

@@ -9,6 +9,11 @@ repository = "https://github.com/Gekkio/imgui-rs"
 license = "MIT/Apache-2.0"
 categories = ["gui", "rendering"]
 
+[features]
+opengl = []
+directx = []
+default = ["opengl"]
+
 [badges]
 travis-ci = { repository = "Gekkio/imgui-rs" }
 

imgui-gfx-renderer/build.rs

@@ -21,6 +21,8 @@ mod hlsl_build {
             .join("shader")
             .join("sm_40.hlsl");
 
+        println!("cargo:rerun-if-changed={}", source_path.display());
+
         let src_data = fs::read_to_string(&source_path).unwrap();
 
         let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());

imgui-gfx-renderer/src/lib.rs

@@ -76,7 +76,21 @@ macro_rules! extended_defines {
     }
 }
 
-#[cfg(not(windows))]
+#[cfg(feature = "directx")]
+mod constants {
+    use gfx::gfx_constant_struct_meta;
+    use gfx::gfx_impl_struct_meta;
+
+    gfx::gfx_constant_struct! {
+        Constants {
+            // `matrix` is a reserved keyword in HLSL
+            matrix: [[f32; 4]; 4] = "matrix_",
+        }
+    }
+}
+
+// This version of `pipe` uses a single uniform for `matrix`, used in GLSL shaders
+#[cfg(not(feature = "directx"))]
 extended_defines! {
     pipeline pipe {
         vertex_buffer: gfx::VertexBuffer<ImDrawVert> = (),
@@ -91,12 +105,12 @@ extended_defines! {
     }
 }
 
-// TODO need constant buffer support
-#[cfg(windows)]
+// This version of `pipe` uses a constant buffer containing `matrix`, used in the HLSL shader
+#[cfg(feature = "directx")]
 extended_defines! {
     pipeline pipe {
         vertex_buffer: gfx::VertexBuffer<ImDrawVert> = (),
-        matrix: gfx::Global<[[f32; 4]; 4]> = "transform",
+        constants: gfx::ConstantBuffer<constants::Constants> = "Constants",
         tex: gfx::TextureSampler<[f32; 4]> = "tex",
         out: gfx::BlendTarget<gfx::format::Rgba8> = (
             "Target0",
@@ -109,13 +123,20 @@ extended_defines! {
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum Shaders {
-    GlSl400,   // OpenGL 4.0+
-    GlSl150,   // OpenGL 3.2+
-    GlSl130,   // OpenGL 3.0+
-    GlSl110,   // OpenGL 2.0+
-    GlSlEs300, // OpenGL ES 3.0+
-    GlSlEs100, // OpenGL ES 2.0+
-    HlslSm40,  // HLSL Shader Model 4.0+
+    /// OpenGL 4.0+
+    GlSl400,
+    /// OpenGL 3.2+
+    GlSl150,
+    /// OpenGL 3.0+
+    GlSl130,
+    /// OpenGL 2.0+
+    GlSl110,
+    /// OpenGL ES 3.0+
+    GlSlEs300,
+    /// OpenGL ES 2.0+
+    GlSlEs100,
+    /// HLSL Shader Model 4.0+
+    HlslSm40,
 }
 
 impl Shaders {
@@ -147,13 +168,13 @@ impl Shaders {
                 include_bytes!("shader/glsles_100.frag"),
             ),
             HlslSm40 => {
-                #[cfg(not(windows))]
+                #[cfg(not(feature = "directx"))]
                 {
                     // panic instead?
                     (&[0], &[0])
                 }
 
-                #[cfg(windows)]
+                #[cfg(feature = "directx")]
                 {
                     (
                         include_bytes!(concat!(env!("OUT_DIR"), "/hlsl_vertex_shader_bytecode")),
@@ -174,6 +195,8 @@ pub struct Renderer<R: Resources> {
     bundle: Bundle<R, pipe::Data<R>>,
     index_buffer: Buffer<R, u16>,
     textures: Textures<Texture<R>>,
+    #[cfg(feature = "directx")]
+    constants: Buffer<R, constants::Constants>,
 }
 
 impl<R: Resources> Renderer<R> {
@@ -230,6 +253,8 @@ impl<R: Resources> Renderer<R> {
             },
             index_buffer,
             textures,
+            #[cfg(feature = "directx")]
+            constants: factory.create_constant_buffer(1),
         })
     }
 
@@ -309,9 +334,19 @@ impl<R: Resources> Renderer<R> {
                     .min(fb_height)
                     .round() as u16,
             };
+
+            #[cfg(feature = "directx")]
+            {
+                let constants = constants::Constants { matrix: *matrix };
+                encoder.update_constant_buffer(&self.constants, &constants);
+            }
+
             let data = pipe::BorrowedData {
                 vertex_buffer: &self.bundle.vertex_buffer,
+                #[cfg(not(feature = "directx"))]
                 matrix,
+                #[cfg(feature = "directx")]
+                constants: &self.constants,
                 tex,
                 out: &self.bundle.out,
                 scissor: &scissor,

imgui-gfx-renderer/src/shader/sm_40.hlsl

@@ -1,16 +1,9 @@
 cbuffer Constants : register(b0) {
-  float4x4 transform;
+  float4x4 matrix_;
 }
 
 Texture2D tex;
-
-// Should be trilinear clamp
-SamplerState linear_clamp_sampler
-{
-    Filter = MIN_MAG_MIP_LINEAR;
-    AddressU = Clamp;
-    AddressV = Clamp;
-};
+SamplerState tex_;
 
 struct VIn {
   float2 position : pos;
@@ -28,7 +21,7 @@ struct VOut
 VOut VertexMain(VIn vertex)
 {
     VOut output;
-    output.position = mul(transform, float4(vertex.position, 0.0, 1.0));
+    output.position = mul(matrix_, float4(vertex.position, 0.0, 1.0));
     output.uv = vertex.uv;
     output.color = vertex.color;
 
@@ -37,5 +30,5 @@ VOut VertexMain(VIn vertex)
 
 float4 PixelMain(VOut vout) : SV_TARGET
 {
-  return vout.color * tex.Sample(linear_clamp_sampler, vout.uv);
+  return vout.color * tex.Sample(tex_, vout.uv);
 }