[glium-examples] Add custom_textures example

imgui-glium-examples/examples/custom_textures.rs

@@ -0,0 +1,83 @@
+extern crate glium;
+extern crate imgui;
+extern crate imgui_glium_renderer;
+extern crate imgui_glutin_support;
+
+use std::borrow::Cow;
+
+use glium::{
+    backend::Facade,
+    texture::{ClientFormat, RawImage2d},
+    Texture2d,
+};
+use imgui::*;
+
+mod support;
+use support::Textures;
+
+const CLEAR_COLOR: [f32; 4] = [1.0, 1.0, 1.0, 1.0];
+
+#[derive(Default)]
+struct CustomTexturesApp {
+    my_texture_id: Option<ImTexture>,
+}
+
+impl CustomTexturesApp {
+    fn register_textures<F>(&mut self, gl_ctx: &F, textures: &mut Textures)
+    where
+        F: Facade,
+    {
+        const WIDTH: usize = 100;
+        const HEIGHT: usize = 100;
+
+        if self.my_texture_id.is_none() {
+            // Generate dummy texture
+            let mut data = Vec::with_capacity(WIDTH * HEIGHT);
+            for i in 0..WIDTH {
+                for j in 0..HEIGHT {
+                    // Insert RGB values
+                    data.push(i as u8);
+                    data.push(j as u8);
+                    data.push((i + j) as u8);
+                }
+            }
+
+            let raw = RawImage2d {
+                data: Cow::Borrowed(&data),
+                width: WIDTH as u32,
+                height: HEIGHT as u32,
+                format: ClientFormat::U8U8U8,
+            };
+            let gl_texture = Texture2d::new(gl_ctx, raw).expect("Create texture");
+            let texture_id = textures.insert(gl_texture);
+
+            self.my_texture_id = Some(texture_id);
+        }
+    }
+
+    fn show_textures(&self, ui: &Ui) {
+        ui.window(im_str!("Hello textures"))
+            .size((300.0, 400.0), ImGuiCond::FirstUseEver)
+            .build(|| {
+                ui.text(im_str!("Hello textures!"));
+                if let Some(my_texture_id) = self.my_texture_id {
+                    ui.image(my_texture_id, (100.0, 100.0)).build();
+                }
+            });
+    }
+}
+
+fn main() {
+    let mut my_app = CustomTexturesApp::default();
+
+    support::run(
+        "custom_textures.rs".to_owned(),
+        CLEAR_COLOR,
+        |ui, gl_ctx, textures| {
+            my_app.register_textures(gl_ctx, textures);
+            my_app.show_textures(ui);
+
+            true
+        },
+    );
+}