Start on metal rendering infrastructure

gpui/src/platform/mac/renderer.rs

@@ -0,0 +1,63 @@
+use anyhow::{anyhow, Result};
+
+use crate::Scene;
+
+use super::window::RenderContext;
+
+const SHADERS_METALLIB: &'static [u8] =
+    include_bytes!(concat!(env!("OUT_DIR"), "/shaders.metallib"));
+
+pub struct Renderer {
+    quad_pipeline_state: metal::RenderPipelineState,
+}
+
+impl Renderer {
+    pub fn new(device: &metal::DeviceRef, pixel_format: metal::MTLPixelFormat) -> Result<Self> {
+        let library = device
+            .new_library_with_data(SHADERS_METALLIB)
+            .map_err(|message| anyhow!("error building metal library: {}", message))?;
+
+        Ok(Self {
+            quad_pipeline_state: build_pipeline_state(
+                device,
+                &library,
+                "quad",
+                "quad_vertex",
+                "quad_fragment",
+                pixel_format,
+            )?,
+        })
+    }
+
+    pub fn render(&mut self, scene: &Scene, ctx: RenderContext) {}
+}
+
+fn build_pipeline_state(
+    device: &metal::DeviceRef,
+    library: &metal::LibraryRef,
+    label: &str,
+    vertex_fn_name: &str,
+    fragment_fn_name: &str,
+    pixel_format: metal::MTLPixelFormat,
+) -> Result<metal::RenderPipelineState> {
+    let vertex_fn = library
+        .get_function(vertex_fn_name, None)
+        .map_err(|message| anyhow!("error locating vertex function: {}", message))?;
+    let fragment_fn = library
+        .get_function(fragment_fn_name, None)
+        .map_err(|message| anyhow!("error locating fragment function: {}", message))?;
+
+    let mut descriptor = metal::RenderPipelineDescriptor::new();
+    descriptor.set_label(label);
+    descriptor.set_vertex_function(Some(vertex_fn.as_ref()));
+    descriptor.set_fragment_function(Some(fragment_fn.as_ref()));
+    descriptor
+        .color_attachments()
+        .object_at(0)
+        .unwrap()
+        .set_pixel_format(pixel_format);
+
+    device
+        .new_render_pipeline_state(&descriptor)
+        .map_err(|message| anyhow!("could not create render pipeline state: {}", message))
+}