build.rs

  1#![cfg_attr(not(target_os = "macos"), allow(unused))]
  2
  3use std::{
  4    env,
  5    path::{Path, PathBuf},
  6};
  7
  8use cbindgen::Config;
  9
 10fn main() {
 11    #[cfg(target_os = "macos")]
 12    generate_dispatch_bindings();
 13    #[cfg(target_os = "macos")]
 14    let header_path = generate_shader_bindings();
 15    #[cfg(target_os = "macos")]
 16    #[cfg(feature = "runtime_shaders")]
 17    emit_stitched_shaders(&header_path);
 18    #[cfg(target_os = "macos")]
 19    #[cfg(not(feature = "runtime_shaders"))]
 20    compile_metal_shaders(&header_path);
 21}
 22
 23fn generate_dispatch_bindings() {
 24    println!("cargo:rustc-link-lib=framework=System");
 25    println!("cargo:rerun-if-changed=src/platform/mac/dispatch.h");
 26
 27    let bindings = bindgen::Builder::default()
 28        .header("src/platform/mac/dispatch.h")
 29        .allowlist_var("_dispatch_main_q")
 30        .allowlist_var("DISPATCH_QUEUE_PRIORITY_DEFAULT")
 31        .allowlist_var("DISPATCH_QUEUE_PRIORITY_HIGH")
 32        .allowlist_var("DISPATCH_TIME_NOW")
 33        .allowlist_function("dispatch_get_global_queue")
 34        .allowlist_function("dispatch_async_f")
 35        .allowlist_function("dispatch_after_f")
 36        .allowlist_function("dispatch_time")
 37        .parse_callbacks(Box::new(bindgen::CargoCallbacks))
 38        .layout_tests(false)
 39        .generate()
 40        .expect("unable to generate bindings");
 41
 42    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap());
 43    bindings
 44        .write_to_file(out_path.join("dispatch_sys.rs"))
 45        .expect("couldn't write dispatch bindings");
 46}
 47
 48fn generate_shader_bindings() -> PathBuf {
 49    let output_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("scene.h");
 50    let crate_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
 51    let mut config = Config::default();
 52    config.include_guard = Some("SCENE_H".into());
 53    config.language = cbindgen::Language::C;
 54    config.export.include.extend([
 55        "Bounds".into(),
 56        "Corners".into(),
 57        "Edges".into(),
 58        "Size".into(),
 59        "Pixels".into(),
 60        "PointF".into(),
 61        "Hsla".into(),
 62        "ContentMask".into(),
 63        "Uniforms".into(),
 64        "AtlasTile".into(),
 65        "PathRasterizationInputIndex".into(),
 66        "PathVertex_ScaledPixels".into(),
 67        "ShadowInputIndex".into(),
 68        "Shadow".into(),
 69        "QuadInputIndex".into(),
 70        "Underline".into(),
 71        "UnderlineInputIndex".into(),
 72        "Quad".into(),
 73        "SpriteInputIndex".into(),
 74        "MonochromeSprite".into(),
 75        "PolychromeSprite".into(),
 76        "PathSprite".into(),
 77        "SurfaceInputIndex".into(),
 78        "SurfaceBounds".into(),
 79    ]);
 80    config.no_includes = true;
 81    config.enumeration.prefix_with_name = true;
 82
 83    let mut builder = cbindgen::Builder::new();
 84
 85    let src_paths = [
 86        crate_dir.join("src/scene.rs"),
 87        crate_dir.join("src/geometry.rs"),
 88        crate_dir.join("src/color.rs"),
 89        crate_dir.join("src/window.rs"),
 90        crate_dir.join("src/platform.rs"),
 91        crate_dir.join("src/platform/mac/metal_renderer.rs"),
 92    ];
 93    for src_path in src_paths {
 94        println!("cargo:rerun-if-changed={}", src_path.display());
 95        builder = builder.with_src(src_path);
 96    }
 97
 98    builder
 99        .with_config(config)
100        .generate()
101        .expect("Unable to generate bindings")
102        .write_to_file(&output_path);
103
104    output_path
105}
106
107/// To enable runtime compilation, we need to "stitch" the shaders file with the generated header
108/// so that it is self-contained.
109#[cfg(feature = "runtime_shaders")]
110fn emit_stitched_shaders(header_path: &Path) {
111    use std::str::FromStr;
112    fn stitch_header(header: &Path, shader_path: &Path) -> std::io::Result<PathBuf> {
113        let header_contents = std::fs::read_to_string(header)?;
114        let shader_contents = std::fs::read_to_string(shader_path)?;
115        let stitched_contents = format!("{header_contents}\n{shader_contents}");
116        let out_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("stitched_shaders.metal");
117        let _ = std::fs::write(&out_path, stitched_contents)?;
118        Ok(out_path)
119    }
120    let shader_source_path = "./src/platform/mac/shaders.metal";
121    let shader_path = PathBuf::from_str(shader_source_path).unwrap();
122    stitch_header(header_path, &shader_path).unwrap();
123    println!("cargo:rerun-if-changed={}", &shader_source_path);
124}
125#[cfg(not(feature = "runtime_shaders"))]
126fn compile_metal_shaders(header_path: &Path) {
127    use std::process::{self, Command};
128    let shader_path = "./src/platform/mac/shaders.metal";
129    let air_output_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("shaders.air");
130    let metallib_output_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("shaders.metallib");
131    println!("cargo:rerun-if-changed={}", shader_path);
132
133    let output = Command::new("xcrun")
134        .args([
135            "-sdk",
136            "macosx",
137            "metal",
138            "-gline-tables-only",
139            "-mmacosx-version-min=10.15.7",
140            "-MO",
141            "-c",
142            shader_path,
143            "-include",
144            &header_path.to_str().unwrap(),
145            "-o",
146        ])
147        .arg(&air_output_path)
148        .output()
149        .unwrap();
150
151    if !output.status.success() {
152        eprintln!(
153            "metal shader compilation failed:\n{}",
154            String::from_utf8_lossy(&output.stderr)
155        );
156        process::exit(1);
157    }
158
159    let output = Command::new("xcrun")
160        .args(["-sdk", "macosx", "metallib"])
161        .arg(air_output_path)
162        .arg("-o")
163        .arg(metallib_output_path)
164        .output()
165        .unwrap();
166
167    if !output.status.success() {
168        eprintln!(
169            "metallib compilation failed:\n{}",
170            String::from_utf8_lossy(&output.stderr)
171        );
172        process::exit(1);
173    }
174}