Add integration example

It showcases how to integrate iced in an existing graphical application.

examples/integration/src/scene.rs

@@ -0,0 +1,119 @@
+use iced_wgpu::wgpu;
+use iced_winit::Color;
+
+pub struct Scene {
+    pub background_color: Color,
+    pipeline: wgpu::RenderPipeline,
+    bind_group: wgpu::BindGroup,
+}
+
+impl Scene {
+    pub fn new(device: &wgpu::Device) -> Scene {
+        let (pipeline, bind_group) = build_pipeline(device);
+
+        Scene {
+            background_color: Color::BLACK,
+            pipeline,
+            bind_group,
+        }
+    }
+
+    pub fn draw(
+        &self,
+        encoder: &mut wgpu::CommandEncoder,
+        target: &wgpu::TextureView,
+    ) {
+        let mut rpass =
+            encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+                color_attachments: &[
+                    wgpu::RenderPassColorAttachmentDescriptor {
+                        attachment: target,
+                        resolve_target: None,
+                        load_op: wgpu::LoadOp::Clear,
+                        store_op: wgpu::StoreOp::Store,
+                        clear_color: {
+                            let [r, g, b, a] =
+                                self.background_color.into_linear();
+
+                            wgpu::Color {
+                                r: r as f64,
+                                g: g as f64,
+                                b: b as f64,
+                                a: a as f64,
+                            }
+                        },
+                    },
+                ],
+                depth_stencil_attachment: None,
+            });
+
+        rpass.set_pipeline(&self.pipeline);
+        rpass.set_bind_group(0, &self.bind_group, &[]);
+        rpass.draw(0..3, 0..1);
+    }
+}
+
+fn build_pipeline(
+    device: &wgpu::Device,
+) -> (wgpu::RenderPipeline, wgpu::BindGroup) {
+    let vs = include_bytes!("shader/vert.spv");
+    let fs = include_bytes!("shader/frag.spv");
+
+    let vs_module = device.create_shader_module(
+        &wgpu::read_spirv(std::io::Cursor::new(&vs[..])).unwrap(),
+    );
+
+    let fs_module = device.create_shader_module(
+        &wgpu::read_spirv(std::io::Cursor::new(&fs[..])).unwrap(),
+    );
+
+    let bind_group_layout =
+        device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+            bindings: &[],
+        });
+
+    let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
+        layout: &bind_group_layout,
+        bindings: &[],
+    });
+
+    let pipeline_layout =
+        device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
+            bind_group_layouts: &[&bind_group_layout],
+        });
+
+    let pipeline =
+        device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+            layout: &pipeline_layout,
+            vertex_stage: wgpu::ProgrammableStageDescriptor {
+                module: &vs_module,
+                entry_point: "main",
+            },
+            fragment_stage: Some(wgpu::ProgrammableStageDescriptor {
+                module: &fs_module,
+                entry_point: "main",
+            }),
+            rasterization_state: Some(wgpu::RasterizationStateDescriptor {
+                front_face: wgpu::FrontFace::Ccw,
+                cull_mode: wgpu::CullMode::None,
+                depth_bias: 0,
+                depth_bias_slope_scale: 0.0,
+                depth_bias_clamp: 0.0,
+            }),
+            primitive_topology: wgpu::PrimitiveTopology::TriangleList,
+            color_states: &[wgpu::ColorStateDescriptor {
+                format: wgpu::TextureFormat::Bgra8UnormSrgb,
+                color_blend: wgpu::BlendDescriptor::REPLACE,
+                alpha_blend: wgpu::BlendDescriptor::REPLACE,
+                write_mask: wgpu::ColorWrite::ALL,
+            }],
+            depth_stencil_state: None,
+            index_format: wgpu::IndexFormat::Uint16,
+            vertex_buffers: &[],
+            sample_count: 1,
+            sample_mask: !0,
+            alpha_to_coverage_enabled: false,
+        });
+
+    (pipeline, bind_group)
+}